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American Societ o Plumbing Engineers
Plumbing Engineering
Design Handbook A Plumbing Engineer’s Guide to Sstem Design and Specications
All rights reserved, including rights o reproduction and use in an orm or b an means, including the making o copiesb an photographic process, or b an electronic or mechanical device, printed or written or oral, or recording orsound or visual reproduction, or or use in an knowledge or retrieval sstem or device, unless permission in writing isobtained rom the publisher.
The ASPE Plumbing Engineering Design Handbook is designed to provide accurate and authoritative inormation or the design and
specication o plumbing systems. The publisher makes no guarantees or warranties, expressed or implied, regarding the data and inor-
mation contained in this publication. All data and inormation are provided with the understanding that the publisher is not engaged in
rendering legal, consulting, engineering, or other proessional services. I legal, consulting, or engineering advice or other expert assistance
is required, the services o a competent proessional should be engaged.
American Society of Plumbing Engineers6400 Shafer Court, Suite 350
Rosemont, IL 60018(847) 296-0002 • Fax: (847) 269-2963
Chapter 10: Water TreatmentDavid E. DeBord, CPD, LEED AP, ARCSA AP
Carol L. Johnson, CPD, LEED AP
E.W. Boulware, PE
Chapter 11: Thermal Epansion Jodie L. Sherven, PE, CPDKarl E. Yrjanainen, PE, CPD
Chapter 12: Potable Water Coolers andCentral Water Sstems
Frank Sanchez, CPDKarl E. Yrjanainen, PE, CPD
Chapter 13: Bioremediation Pretreatment
SstemsMax Weiss
Chapter 14: Green Plumbing David E. DeBord, CPD, LEED AP, ARCSA AP
Larisa Miro, CPD
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About ASPE
The American Society o Plumbing Engineers (ASPE) is the international organization or proessionals skilled inthe design and specication o plumbing systems. ASPE is dedicated to the advancement o the science o plumbing
engineering, to the proessional growth and advancement o its members, and to the health, welare, and saety o
the public.
The Society disseminates technical data and inormation, sponsors activities that acilitate interaction with
ellow proessionals, and, through research and education programs, expands the base o knowledge o the plumbing engineering industry. ASPE members are leaders in innovative plumbing design, eective materials and energy use,
and the application o advanced techniques rom around the world.
W orldWide MeMbership — ASPE was ounded in 1964 and currently has 6,000 members. Spanning the globe,
members are located in the United States, Canada, Asia, Mexico, South America, the South Pacic, Australia, andEurope. They represent an extensive network o experienced engineers, designers, contractors, educators, code
ocials, and manuacturers interested in urthering their careers, their proession, and the industry. ASPE is at the
oreront o technology. In addition, ASPE represents members and promotes the proession among all segments o the
construction industry.
Aspe MeMbership CoMMuniCAtion — All members belong to ASPE worldwide and have the opportunity to
belong to and participate in one o the 61 state, provincial, or local chapters throughout the U.S. and Canada. ASPE
chapters provide the major communication links and the rst line o services and programs or the individual member.
Communication with the membership is enhanced through the Society’s ocial publication, Plumbing Engineer,
and the e-newsletter ASPE Pipeline.
teChniCAl publiCAtions — The Society maintains a comprehensive publishing program, spearheaded by the
proession’s basic reerence text, the Plumbing Engineering Design Handbook. The Plumbing Engineering Design
Handbook, encompassing 51 chapters in our volumes, provides comprehensive details o the accepted practices and
design criteria used in the eld o plumbing engineering. In 2011, the Illustrated Plumbing Codes Design Handbook
joined ASPE’s published library o proessional technical manuals and handbooks.
Convention And teChniCAl s yMposiuM—The Society hosts a biennial Convention & Exposition in even-numbered
years and a Technical Symposium in odd-numbered years to allow proessional plumbing engineers and designers to
improve their skills, learn original concepts, and make important networking contacts to help them stay abreast o
current trends and technologies. The ASPE Exposition is the largest gathering o plumbing engineering and designproducts, equipment, and services. Everything rom pipes to pumps to xtures, rom compressors to computers to
consulting services is on display, giving engineers and speciers the opportunity to view the newest and most innovative
materials and equipment available to them.Certified in pluMbing design— ASPE sponsors a national certication program or engineers and designers o plumbing systems, which carries the designation “Certied in Plumbing Design” or CPD. The certication program
provides the proession, the plumbing industry, and the general public with a single, comprehensive qualication o
proessional competence or engineers and designers o plumbing systems. The CPD, designed exclusively by and or
plumbing engineers, tests hundreds o engineers and designers at centers throughout the United States. Created to
provide a single, uniorm national credential in the eld o engineered plumbing systems, the CPD program is notin any way connected to state-regulated Proessional Engineer (PE) registration.
Aspe reseArCh foundAtion— The ASPE Research Foundation, established in 1976, is the only independent,
impartial organization involved in plumbing engineering and design research. The science o plumbing engineering
aects everything, rom the quality o our drinking water to the conservation o our water resources to the building codes or plumbing systems. Our lives are impacted daily by the advances made in plumbing engineering technology
through the Foundation’s research and development.
Volume 1 Fundamentals o Plumbing Engineering (Revised 2009)
Chapter 1 Formulas, Smbols, and Terminolog
2 Standards or Plumbing Materials and Equipment
3 Specications
4 Plumbing Cost Estimation
5 Job Preparation, Drawings, and Field Reports
6 Plumbing or People with Disabilities
7 Energ and Resource Conservation in Plumbing Sstems
8 Corrosion
9 Seismic Protection o Plumbing Equipment
10 Acoustics in Plumbing Sstems
11 Basics o Value Engineering
12 Ensuring High-Qualit Plumbing Installations
13 Eisting Building Job Preparation and Condition Surve
Volume 2 Plumbing Sstems (Revised 2010)
Chapter 1 Sanitar Drainage Sstems
2 On-Site Wastewater Ruse and Storm Water Harvesting
3 Vents and Venting
4 Storm Drainage Sstems
5 Cold Water Sstems
6 Domestic Water Heating Sstems
7 Fuel Gas Piping Sstems
8 Private On-Site Wastewater Treatment Sstems
9 Private Water Wells
10 Vacuum Sstems11 Water Treatment, Conditioning, and Purication
12 Special Waste Drainage Sstems
Volume 3 Special Plumbing Sstems (Revised 2011)
Chapter 1 Fire Protection Sstems
2 Plumbing Design or Healthcare Facilities
3 Treatment o Industrial Waste
4 Irrigation Sstems
5 Refecting Pools and Fountains
6 Public Swimming Pools
7 Gasoline and Diesel Oil Sstems
8 Steam and Condensate Piping
9 Compressed Air Sstems10 Solar Energ
11 Site Utilit Sstems
12 Laborator Gases
(The chapters and subjects listed or these volume are subject to modication, adjustment and change.The contents shown or each volume are proposed and ma not represent the nal contents o the volume.
A nal listing o included chapters or each volume will appear in the actual publication.)
xii ASPE Plumbing Engineering Design Handbook — Volume 4
Figures
Figure 1-1 Blowout (A) and Siphon-Jet (B) Water Closets ................................................................... 3
Figure 1-2 (A) Close-Coupled, (B) One-Piece, and (C) Flushometer Water Closets ............................ 3
Figure 1-3 Floor-Mounted, Back-Outlet Water Closet .......................................................................... 4
Figure 1-4 Wall-Hung Water Closet ....................................................................................................... 4Figure 1-5 Standard Rough-In Dimension or Water Closet Outlet to the Back Wall ........................ 4
Figure 1-6 Water Closet Compartment Spacing Requirements ........................................................... 6
Figure 1-7 Minimum Chase Sizes or Carriers ...................................................................................... 7
Figure 1-8 (A) Gravity Tank and (B) Flushometer Tank ..................................................................... 8
Figure 4-1 Portion o a Close-Coupled Centriugal Pump With an End-Suction Design ................. 92
Figure 4-2 Inline Centriugal Pump with a Vertical Shat ................................................................. 92Figure 4-3 Enclosed Impeller ............................................................................................................... 93
Figure 4-4 Centriugal Pump with a Double-Suction Inlet Design .................................................... 93
Figure 4-5 Net Fluid Movement From an Impeller Represented by Vector Y .................................. 95
Figure 4-6 Typical Pump Curve Crossing a System Curve ................................................................ 95
Figure 4-7 Typical Pump Curves and Power Requirements .............................................................. 96
Figure 4-8 Blade Shape and Quantity Versus Perormance Curve .................................................... 96
Figure 4-9 Multistage or Vertical Lineshat Turbine Pump ............................................................... 97
Figure 4-10 Cross-Section o a Grinder Pump with Cutting Blades at the Inlet ................................ 99
Figure 5-1 Insulating Around a Split Ring Hanger .......................................................................... 104Figure 5-2 Insulating Around a Clevis Hanger ................................................................................. 105
Figure 5-3 Temperature Drop o Flowing Water in a Pipeline ......................................................... 112
Figure 6-1 Types o Hangers and Supports ....................................................................................... 120
Figure 6-2 Types o Hanger and Support Anchors ........................................................................... 124
Figure 6-3 Hanger and Support Anchors or Particular Applications ............................................. 127
Figure 7-1 Transmissibility vs. Frequency Ratio .............................................................................. 139
Figure 7-2 Calculator or Vibration Isolation .................................................................................... 140
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xiv ASPE Plumbing Engineering Design Handbook — Volume 4
Figure 7-2(M) Calculator or Vibration Isolation ................................................................................ 141
Figure 7-3 Typical Elastomer and Elastomer-Cork Mountings ....................................................... 142
Figure 7-4 Typical Steel Spring Mounting ....................................................................................... 142
Figure 8-1 Rising and Settling Rates in Still Water .......................................................................... 146
Figure 8-2 Cross-Section o a Grease Interceptor Chamber ............................................................. 147
Figure 10-13 Ion Exchange Vessel—Internal Arrangement ................................................................. 183
Figure 10-14 Hydrogen-Sodium Ion Exchange Plant ........................................................................... 184
Figure 10-15 Sodium Cycle Sotener Plus Acid Addition ..................................................................... 184
Figure 10-16 Lime Deposited rom Water o 10 Grains Hardness as a Function o Water Use andTemperature ........................................................................................................................................ 185
Figure 10-17 Water Sotener Survey Data ............................................................................................. 189
Figure 10-18 Water Sotener Sizing Procedure ..................................................................................... 190
Figure 10-19 Water Sotener with Salt Recycling System .................................................................... 191
Figure 11-2 Closed Hot Water System Showing the Eects as Water and Pressure Increase .............. 210
Figure 11-3 Eects o an Expansion Tank in a Closed System as Pressure and TemperatureIncrease ........................................................................................................................................... 210
Figure 11-4 Sizing the Expansion Tank .............................................................................................. 212
Figure 12-1 Early Drinking Faucet ...................................................................................................... 215
Figure 12-2 Bottled Water Cooler ........................................................................................................ 216
Figure 12-3 Wheelchair-Accessible Pressure-Type Water Cooler....................................................... 216
Figure 12-4 Pressure-Type Pedestal Water Cooler.............................................................................. 216
Figure 12-5 Wheelchair-Accessible Unit .............................................................................................. 217
Figure 12-13 Water Cooler Accessories .................................................................................................. 219Figure 12-14 Upeed Central System ..................................................................................................... 220
Figure 12-15 Downeed Central System ................................................................................................ 221
Table 2-1 Dimensions o Hubs, Spigots, and Barrels or Extra-Heavy Cast Iron Soil Pipe andFittings ............................................................................................................................... 27
Table 2-1(M) Dimensions o Hubs, Spigots, and Barrels or Extra-Heavy Cast Iron Soil Pipe andFittings ............................................................................................................................... 27
Table 2-2 Dimensions of Hubs, Spigots, and Barrels for Service Cast Iron Soil Pipe and Fittings ...28
Table 2-2(M) Dimensions of Hubs, Spigots, and Barrels for Service Cast Iron Soil Pipe and Fittings ........ 28
Table 2-3 Dimensions o Spigots and Barrels or Hubless Pipe and Fittings ................................. 29
Table 2-4 Standard Minimum Pressure Classes o Ductile Iron Single-Thickness Cement-LinedPipe ..................................................................................................................................... 30
Table 2-5 Dimensions and Approximate Weights o Circular Concrete Pipe ................................. 30
Table 2-6 Commercially Available Lengths o Copper Plumbing Tube .......................................... 32
Table 2-7 Dimensional and Capacity Data—Type K Copper Tube ................................................. 33
Table 2-7(M) Dimensional and Capacity Data—Type K Copper Tube ................................................. 34
Table 2-8 Dimensional and Capacity Data—Type L Copper Tube.................................................. 35
Table 2-8(M) Dimensional and Capacity Data—Type L Copper Tube ................................................. 36
Table 2-9 Dimensional and Capacity Data—Type M Copper Tube................................................. 37
Table 2-9(M) Dimensional and Capacity Data—Type M Copper Tube ................................................ 38
Table 7-1 The Relative Eectiveness o Steel Springs, Rubber, and Cork in the Various SpeedRanges .............................................................................................................................. 139
Table 8-1 Droplet Rise Time ............................................................................................................ 149
Table 9-1 Plumbing System Hazards .............................................................................................. 161
Table 9-2 Application o Cross-Connection Control Devices ......................................................... 163
Table 9-3 Types o Back-Pressure Backfow Preventer ................................................................. 164Table 9-4 Types o Vacuum Breakers .............................................................................................. 164
Table 10-1 Chemical Names, Common Names, and Formulas ........................................................ 173
Table 10-2 Water Treatment—Impurities and Constituents, Possible Eects and SuggestedTreatments ....................................................................................................................... 174
Table 10-3 Water Consumption Guide .............................................................................................. 187
Table 10-4 Comparison o Laboratory-Grade Water Quality Produced by Centralized Systems .. 197
Table 10-5 Applications o Puried Water ........................................................................................ 199
Table 11-1 Linear Coecients o Thermal Expansion or Contraction ........................................... 207
Table 11-2 Developed Length o Pipe to Accommodate 1½-inch Movement .................................. 207
Table 11-3 Approximate Sine Wave Conguration With Displacement ......................................... 208
Table 11-4 Thermodynamic Properties o Water at a Saturated Liquid ......................................... 209
Table 11-5 Nominal Volume o Piping .............................................................................................. 211
Table 12-1 Standard Rating Conditions ........................................................................................... 216
Table 12-2 Drinking Water Requirements ........................................................................................ 223
Table 14-4 Storage Tank Options ...................................................................................................... 238
Table 14-5 Comparison o Graywater and Black Water ................................................................... 239
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Plumbing Fitures1It has been said that without plumbing xtures,there would be no indoor plumbing. Each xture isdesigned or a specic unction to maintain publichealth and sanitation, such as discharging potablewater or carrying away waste. Some o the numer-ous plumbing xtures used in plumbing systems
are water closets and urinals, showerheads, aucets,drinking ountains, bidets, foor drains, and emer-gency eyewashes.
Fixtures are connected to the plumbing systempiping by dierent types o ttings that also helpregulate fow or perorm some other unction toensure that the xture and the entire system workproperly.
FIxTURE MATERIALSThe surace o a plumbing xture must be smooth,impervious, and easily cleanable to maintain a highlevel o sanitation. Common plumbing xture materi-als include the ollowing.
Vitreous ChinaThis is a unique material that is specially suited toplumbing xtures. Unlike other ceramic materials,vitreous china does not absorb water because it is notporous. Vitreous china plumbing xture suraces areglazed, which provides an appealing nish that is eas-ily cleaned. Vitreous china is also an extremely strong material. Because vitreous china is nonporous, it hasa very high shrinkage rate when red in a kiln, whichaccounts or the slight dierences among otherwiseidentical plumbing xtures.
Nonvitreous ChinaNonvitreous china is a porous ceramic that requiresglazing to prevent water absorption. The advantageo nonvitreous china is its low shrinkage rate, whichallows the xture to be more ornately designed.
Enameled Cast IronThe base o enameled cast iron xtures is a high-gradecast iron. The exposed suraces have an enameledcoating, which is used to the cast iron, resulting in
a hard, glossy, opaque, and acid-resistant surace.Enameled cast iron plumbing xtures are heavy,strong, ductile, and long-lasting.
Porcelain Enameled SteelPorcelain enamel is a substantially vitreous or glossy
inorganic coating that is bonded to sheet steel by u-sion to create this material.
Stainless Steel A variety o stainless steels is used to produce plumb-ing xtures, including 316, 304, 302, 301, 202, 201,and 430. One o the key ingredients in stainless steelis nickel, and a higher nickel content tends to producea superior nish in the stainless steel. Types 302and 304 have 8 percent nickel, and Type 316 has 10percent nickel.
PlasticPlastic is a generic category or a variety o synthetic
materials used in plumbing xtures. The variousplastic materials used to produce plumbing xturesinclude acrylonitrile butadiene styrene (ABS), poly-vinyl chloride (PVC), gel-coated berglass-reinorcedplastic, acrylic, cultured marble, cast-lled berglass,polyester, cast-lled acrylic, gel-coated plastic, cul-tured marble acrylic, and acrylic polymer. Plasticsused in plumbing xtures are subject to numeroustests to determine their quality, including ignition(torch) test, cigarette burn test, stain-resistance test,and chemical-resistance test.
Glass
Tempered glass xtures can be ornately designed andare ound in numerous designs and colors.
SoapstoneThis material is used predominantly in the manu-acture o laundry trays and service sinks. Soapstoneis steatite, which is extremely heavy and very du-rable.
TerrazzoThis composite material consists o marble, quartz,granite, glass, or other suitable chips sprinkled or
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poured with a cementitious chemical or combinationbinder. It is cured, ground, and polished to a smoothnish to produce a uniormly textured surace.
ACCESSIBILITy Several ederal and plumbing industry codes andstandards require certain plumbing xtures to beaccessible to people with disabilities. The ederalguidelines are the Americans with Disabilities Act
(ADA) Standards or Accessible Design. Accessibilitystandards also are ound in American National Stan-dards Institute (ANSI)/International Code Council(ICC) A117.1: Accessible and Usable Buildings and Facilities. More inormation about accessibility re-quirements can be ound in Plumbing Engineering Design Handbook, Volume 1, Chapter 6.
APPLICABLE STANDARDSPlumbing xtures are regulated by nationally devel-oped consensus standards, which speciy materials,
ixture designs, and testing requirements. Whilestandards or plumbing xtures are considered vol-untary, the requirements become mandatory whenthey are reerenced in plumbing codes. Most xturemanuacturers enlist a third-party testing laboratory to certiy their products as being inconormance with the applicable standard.
Table 1-1 identiies the most commonconsensus standards regulating plumbing xtures. A complete list o standards canbe ound in Plumbing Engineering Design
Handbook, Volume 1, Chapter 2.
LEED AND PLUMBINGFIxTURESThe LEED (Leadership in Energy and Envi-ronmental Design) program is put orth bythe U.S. Green Building Council (USGBC)to provide a benchmark or the design o en-ergy- and water-ecient buildings. Ecientplumbing systems can earn a building pointsin several categories, including irrigation,wastewater treatment, and water use reduc-tion, by including water-ecient xtures.For instance, at least one LEED point can beobtained simply by speciying dual-fush water
closets (not recommended or public spaces),high-eciency toilets (1.28 gallons per fush[gp] or less), high-eciency urinals (0.5 gp or less), and low-fow aucets (0.5 gallon perminute [gpm] or public spaces and 0.38 gpmor non-public spaces). For current inorma-tion on the LEED program, visit the USGBCwebsite at usgbc.org or turn to Chapter 14 o this volume or more inormation on greenbuilding in general.
WATER CLOSETSPassage o the Energy Policy Act o 1992 by the U.S.government changed the way water closets (WCs)were designed. The act imposed a maximum fush-ing rate o 1.6 gp, which was a signicant decreasein the amount o water used to fush a toilet. Prior tothe rst enactment o water conservation in the late
1970s, water closets typically fushed between 5 and7 gallons o water. Now, ultra-low-fow WCs, whichfush as little as 0.4 gp, and dual-fush models areavailable. Dual-fush WCs give the user the option tofush the ull 1.6 gallons or solid waste or one-thirdless or liquid waste.
With the modication in water fush volume, thestyle o each manuacturer’s water closets changed,and the ormer terminology or identiying waterclosets no longer t. Water closets previously werecategorized as blowout, siphon jet, washout, reversetrap, and washdown. O these styles, the only twocommonly in use now are siphon jet and blowout
(see Figure 1-1). In the siphon jet, a jet o water isdirected through the trapway to quickly ll the bowland start the siphonic action immediately upon fush-
Table 1-1 Plumbing Fixture Standards
Plumbing Fixture Applicable Standard Fixture MaterialWater closet ANSI/ASME A112.19.2 Vitreous china
ing. The blowout operates via a high-velocity direct jet action.
Water closets are urther categorized as the ol-lowing:
• Closecoupled:Atwo-piecexturecomprisedofaseparate tank and bowl (see Figure 1-2A)
• Onepiece:Thetankandthebowlaremoldedasone piece (see Figure 1-2B)
• Flushometer:Abowlwithaspudconnectionthatreceives the connection rom a fushometer valve(see Figure 1-2C).Flushometer water closets alsoare reerred to as “top spud” or “back spud” bowlsdepending on the location o the connection orthe fushometer valve.
Water closets are fushed via one o the ollowing methods:
• Inagravityush,usedwithtank-typewaterclos-ets, the water is not under pressure and fushesby gravity.
• Withaushometertank,thewaterisstoredinapressurized vessel and fushed under a pressureranging between 25 and 35 pounds per squareinch (psi).
• Aushometervalveusesthewatersupply linepressure to fush the water closet. Because o thedemand or a ast, large-volume fush, the watersupply pipe must be larger in diameter than thator gravity or fushometer tank fushes. Flushom-eter water closets require 35–80-psi static pres-sure and 25 gpm to operate properly.
Another distinction used to identiy a water closetis the manner o mounting and connection. The com-
mon methods are as ollows:
• Aoor-mountedwaterclosetsitsontheoorandconnects directly to the piping through the foor.
• Floor-mounted,back-outletwaterclosets sit onthe foor yet connect to the piping through thewall (see Figure 1-3). The advantage o this modelis that foor penetrations are reduced.
• Awall-hungwaterclosetissupportedbyawallhanger and never comes in contact with the foor
(see Figure 1-4). This model is advantageous roma maintenance standpoint because it doesn’t in-terere with foor cleaning.
Water Closet Bowl Shape and Size A water closet bowl is classied as either round orelongated. The ront opening o an elongated bowlextends 2 inches arther than a round bowl. Mostplumbing codes require elongated bowls or public
and employee use. The additional 2 inches providesa larger opening, oten called a “target area.” Withthe larger opening, the ability to maintain a cleanerwater closet or each user is increased.
For loor-mounted water closets, the outlet isidentied based on the rough-in dimension, or thedistance rom the back wall to the center o theoutlet when the water closet is installed. A standardrough-in bowl outlet is 12 inches (see Figure 1-5).
Figure 1-1 Blowout (A) and Siphon-Jet (B) Water Closets
(A) (B)
Figure 1-2 (A) Close-Coupled, (B)One-Piece, and (C) Flushometer Water
Closets
(A)
(B)
(C)
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Most manuacturers also make water closets with a 10-inch or 14-inch rough-in.
The size o the bowl also is based on the height o the bowl’s rim rom the foor, as ollows:
• Therimheightofastandardwaterclosetis14to15 inches. This is the most common water closetinstalled.
• A child’s water closet has a rim height of 10inches. Many plumbing codes require these waterclosets in daycare centers and kindergarten toiletrooms or use by small children.
• Awaterclosetforthephysicallychallengedhasa rim height o 17 inches. With the addition o the water closet seat, the xture is designed toconorm to the accessibility requirement o 17 to19 inches.
Bariatric Water Closets
Bariatric WCs are made to accommodate overweightand obese people and support weights o 500 to 1,000pounds. They are available in vitreous china as wellas stainless steel. Wall-hung bariatric xtures requirespecial, larger carriers designed or the increasedloads, which also requires a deeper chase. Thus,most bariatric WCs are loor mounted. Bariatric WCs should be mounted at the accessibility-requiredheight.
Water Closet Seat A water closet seat must be designed or the shapeo the bowl to which it connects. Two styles o wa-
ter closet seat are available: solid and open ront.Plumbing codes typically require an open ront seator public and employee use. The open ront seat isdesigned to acilitate easy wiping by emales and toprevent contact between the seat and the penis withmales. This helps maintain a high level o hygiene inpublic acilities.
Many public water closets include a plastic wraparound the seat that can be changed ater each use.The seat is intended to replace the open rim seat inpublic and employee locations.
Water Closet Flushing Perormance
The fushing perormance requirements or a watercloset are ound in ANSI/American Society o Me-chanical Engineers (ASME) A112.19.6: Hydraulic Perormance Requirements or Water Closets and Uri-
nals. The testing requirements also can be ound in ANSI/ASME A112.19.2/CSA B45.1: Ceramic Plumb-
ing Fixtures, which is a consolidation and revision o several ASME and Canadian Standards Association(CSA) standards developed in response to industryrequests or uniorm standards that would be accept-able in both the United States and Canada. These
Figure 1-3 Floor-Mounted, Back-Outlet Water Closet
Figure 1-4 Wall-Hung Water Closet
Figure 1-5 Standard Rough-In Dimension or WaterCloset Outlet to the Back Wall
standards identiy the ollowing tests that must beperormed to certiy a water closet.
• The ball removal test utilizes 100 polypropyl-ene balls that are ¾ inch in diameter. The watercloset must fush at least an average o 75 ballson the initial fush o three dierent fushes. Thepolypropylene balls are intended to replicate the
density o human eces.• The granule test utilizes approximately 2,500
disc-shaped granules o polyethylene. The initialfush o three dierent fushes must result in nomore than 125 granules on average remaining inthe bowl. The granule test is intended to simulatea fush o watery eces (diarrhea).
• The ink test isperformedon the insidewallofthe water closet bowl. A elt-tip marker is used todraw a line around the inside o the bowl. Aterfushing, no individual segment o line can exceed½ inch. The total length o the remaining ink linemust not exceed 2 inches. This test determines
that the water fushes all interior suraces o thebowl.
• Thedyetestusesacoloreddyeaddedtothewatercloset’s trap seal. The concentration o the dyeis determined both beore and ater fushing thewater closet. A dilution ratio o 100:1 must beobtained or each fush. This test determines theevacuation o urine in the trap seal.
• Thewaterconsumptiontestdeterminesthatthewater closet meets the ederal mandate o 1.6gp.
• Thetrapsealrestorationtestdeterminesthatthe
water closet rells the trap o the bowl ater eachfush. The remaining trap seal must be a mini-mum o 2 inches in depth.
• Thewaterrisetestevaluatestheriseofwaterinthe bowl when the water closet is fushed. Thewater cannot rise above a point 3 inches belowthe top o the bowl.
• Theback-pressuretestisusedtodeterminethatthe water seal remains in place when exposed toa back pressure (rom the outlet side o the bowl)o 2½ inches o water column (wc). This test de-termines i sewer gas will escape through the x-ture when high pressure occurs in the drainagesystem piping.
• Therim topand seatfouling testdeterminesifthe water splashes onto the top o the rim or seato the water closet. This test ensures that theuser does not encounter a wet seat.
• Thedrainline carrytestdeterminestheperfor-mance o the water closet’s fush. The water clos-et is connected to a 4-inch drain 60 eet in lengthpitched ¼ inch per oot. The same 100 polypro-pylene balls used in the fush test are used in the
drainline carry test. The average carry distance o the polypropylene balls must be 40 eet. This testdetermines the ability o the water closet to fushthe contents in such a manner that they properlyfow down the drainage piping.
Water Closet Installation RequirementsThe water closet must be properly connected to the
drainage piping system. For foor-mounted waterclosets, a water closet fange is attached to the piping and permanently secured to the building. For wood-rame buildings, the fange is screwed to the foor. Forconcrete foors, the fange sits on the foor.
Noncorrosive closet bolts connect the water closetto the foor fange. The seal between the foor fangeand the water closet is made with either a wax ring oran elastomeric seal. The connection ormed betweenthe water closet and the foor must be sealed withcaulking or tile grout.
For wall-hung water closets, the xture must con-nect to a wall carrier. The carrier must transer the
loading o the water closet to the foor. A wall-hung water closet must be capable o supporting a loado 500 pounds at the end o the water closet. Whenthe water closet is connected to the carrier, none o this load can be transerred to the piping system. Water closet carriers must conorm to ANSI/ASME A112.6.1M: Supports or O-the-Floor Plumbing
Fixtures or Public Use. For bariatric WCs, the loadslisted by the manuacturers vary rom 650 to 1,000pounds. These carriers must conorm to ANSI/ASME A112.6.1 as well.
The minimum spacing required or a water closetis 15 inches rom the centerline o the bowl to theside wall and 21 inches rom the ront o the watercloset to any obstruction in ront o the water closet(see Figure 1-6). The standard dimension or a watercloset compartment is 30 inches wide by 60 incheslong. The water closet must be installed in the centero the standard compartment. The minimum distancerequired between water closets is 30 inches.
While a 3-inch double sanitary tee or a 3-inchdouble xture tting could be used to connect back-to-back 3.5-gp water closets, current plumbing codesprohibit the installation o a double sanitary tee ordouble xture tting or back-to-back 1.6-gp water
closets due to their superior fushing. The only accept-able tting is the double combination wye and eighthbend. Also, since the minimum spacing required touse a double sanitary tee tting is 30 inches rom thecenterline o the water closet outlet to the entrance o the tting, this rules out a back-to-back water closetconnection.
One o the problems associated with short patternttings is the siphon action created in the initial fusho the water closet. This siphon action can draw thewater out o the trap o the water closet connected
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to the other side o the tting. Another potentialproblem is the interruption o fow when fushing a water closet. The fow rom one water closet canpropel water across the tting, interering with theother water closet.
Proper clearances within chases or wall-hung carriers should be maintained. Figure 1-7 shows the
minimum chase sizes or carriers (as published bythe Plumbing and Drainage Institute [PDI]). Car-rier sizes vary by manuacturer, so always check themanuacturer’s specications beore committing tochase size. Also, wall-hung bariatric carriers requiremore space than indicated by PDI. Bariatric chasesshould be coordinated with the speciied carriermanuacturer.
Water Closet Flushing Sstems
Gravity Flush
The most common means o fushing a water closet isa gravity fush (see Figure 1-8A), used with tank-type
water closets. The tank stores a quantity o nonpres-surized water to establish the initial fush o the bowl. A trip lever raises either a fapper or a ball, allowing the fush to achieve the maximum siphon in the bowl. Ater the fush, the fapper or ball reseals, closing o the tank rom the bowl. To achieve the lowest fowin the dual-fush WC, the trip lever raises the fapperor ball a bit less, which results in a reduced-volumefush.
The ballcock, located inside the tank, controlsthe fow o water into the tank. A foat mechanismopens and closes the ballcock. The ballcock directs themajority o the water into the tank and a smaller por-tion o water into the bowl to rell the trap seal. Theballcock must be an antisiphon ballcock conorming to ANSI/American Society o Sanitary Engineering
(ASSE) 1002: Siphon Fill Valves or Water ClosetTanks. This prevents the contents o the tank rombeing siphoned back into the potable water supply.
Flushometer Tank
A fushometer tank (see Figure 1-8B) has the sameoutside appearance as a gravity tank. However, insidethe tank is a pressure vessel that stores the water orfushing. The water in the pressure vessel must be a minimum o 25 psi to operate properly. Thus, the linepressure on the connection to the fushometer tankmust be a minimum o 25 psi. A pressure regulatorprevents the pressure in the vessel rom rising above
35 psi (typical o most manuacturers).The higher pressure rom the fushometer tankresults in a fush similar to a fushometer valve. Oneo the dierences between the fushometer tank andthe fushometer valve is the sizing o the water dis-tribution system. The water piping to a fushometertank is sized the same as the water piping to a gravityfush tank. Typically, the individual water connectionis ½ inch in diameter. A fushometer valve requiresa high fow rate demand, resulting in a larger piping connection, typically 1 inch in diameter.
Figure 1-6 Water Closet Compartment Spacing Requirements
The fushometer tank WC tends to be noisier thanthe gravity tank WC. Their advantage over grav-ity tanks is that the increased velocity o the wastestream provides as much as a 50 percent increase indrainline carry. In long horizontal run situations, thismeans ewer drainline and sewer blockages.
Flushometer Valve
A fushometer valve, also reerred to as a fush valve,is available in two designs. A diaphragm valve is de-signed with upper and lower chambers separated bya diaphragm. A piston valve is designed with upperand lower chambers separated by a piston. The waterpressure in the upper chamber keeps the valve inthe closed position. When the trip lever is activated,the water in the upper chamber escapes to the lower
chamber, starting the fush. The fush o 1.6 gallonsor less passes through the fush valve. The valve isclosed by line pressure as water reenters the upperchamber.
For 1.6-gp water closets, fushometer valves areset to fow 25 gpm at peak to fush the water closet.The fushing cycle is very short, lasting 4 to 5 seconds.The water distribution system must be properly de-signed to allow the peak fow during heavy use o theplumbing system.
Flushometer valves have either a manual or an au-tomatic means o fushing. The most popular manualmeans o fushing is a handle mounted on the sideo the fush valve. The wave-activated fushometerprovides manual activation without touching the
Figure 1-7 Minimum Chase Sizes or CarriersCourtesy o Plumbing and Drainage Institute
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valve, promoting maximum sanitation. Automatic,electronic sensor fushometer valves are available ina variety o styles. The sensor-operated valves canbe battery operated, directly connected to the powersupply o the building, or powered by a 30-year hybridenergy system or other ecoriendly power generation
system.
URINALSThe urinal was developed to expedite use o a toiletroom. It is designed or the removal o urine and thequick exchange o users. The Energy Policy Act o 1992restricted urinals to a maximum water use o 1 gp,but most urinals now use 0.5 gp or less. Ultra-low-fow (0.125 gp) and waterless urinals are becoming more common in LEED-certied buildings.
Urinal StlesUrinals are identied as blowout, siphon jet, wash-
out, stall, washdown, and waterless. A stall urinal isa type o washdown urinal. Blowout, siphon-jet, andwashout urinals all have integral traps. Stall andwashdown urinals have an outlet to which an exter-nal trap is connected. Many plumbing codes prohibitthe use o stall and washdown urinals in public andemployee toilet rooms because o concerns about theability to maintain a high level o sanitation atereach fush. Waterless urinals are gaining acceptanceby code enorcement bodies, but are not allowed inall jurisdictions.
The style identies the type o fushing actionin the urinal. Blowout and siphon-jet types rely on
complete evacuation o the trap. Blowout urinalsorce the water and waste rom the trap to the drain.Siphon-jet urinals create a siphon action to evacuatethe trap. Washout urinals rely on a water exchange tofush, with no siphon action or complete evacuationo the trapway. Stall and washdown urinals have anexternal trap. The fushing action is a water exchange;however, it is a less ecient water exchange than thato a washout urinal.
Urinals with an integral trapmust be capable o passing a ¾-inch-diameter ball. The outlet connection istypically 2 inches in diameter. Stall andwashdown urinals can have a 1½-inchoutlet with an external 1½-inch trap.
Waterless urinals are used in many jurisdictions to reduce water consump-tion. Some waterless urinals utilizea cartridge lled with a biodegrad-able liquid sealant. A more sanitaryoption utilizes a trap to contain thebiodegradable liquid sealant, elimi-nating the biohazard o disposing o old cartridges. Urine is heavier than
the sealant, so it fows through the cartridge or trapwhile leaving the sealant. According to manuacturerliterature, a typical cartridge lasts or 7,000 uses. Thecartridge-less system lasts equally long, and the trapmust be fushed when the sealant is reinstalled. Wa-
terless urinals are inexpensive to install. The wasteand vent piping are the same as or conventional uri-nals, but no water piping is required. The inside wallso the urinal must be washed with a special solutionon a periodic basis or proper sanitation.
Urinal Flushing PerormanceThe fushing perormance or a urinal is regulatedby ANSI/ASME A112.19.2/CSA B45.1. The threetests or urinals are the ink test, dye test, and waterconsumption test.
In the ink test, a elt-tip marker is utilized to drawa line on the inside wall o the urinal. The urinal isfushed, and the remaining ink line is measured. Thetotal length o the ink line cannot exceed 1 inch, andno segment can exceed ½ inch in length.
The dye test uses a colored dye to evaluate thewater exchange rate in the trap. Ater one fush, thetrap must have a dilution ratio o 100:1. The dye testis perormed only on urinals with an integral trap.This includes blowout, siphon-jet, and washout uri-nals. It is not possible to dye test stall and washdownurinals since they have external traps. This is one o the concerns that has resulted in the restricted useo these xtures.
The water consumption test determines i the
urinal fushes with 1 gallon o water or less.Urinal Flushing Requirements With the ederal requirements or water consumption,urinals must be fushed with a fushometer valve.The valve can be either manually or automaticallyactivated.
A urinal fushometer valve has a lower fush vol-ume and fow rate than a water closet fushometervalve. The total volume is 1 gp or less, and the peakfow rate is 15 gpm. The water distribution system
Figure 1-8 (A) Gravity Tank and (B) Flushometer Tank
must be properly sized or the peak fow rate or theurinal.
Urinal fushometer valves operate the same aswater closet fushometer valves. For additional in-ormation, reer back to the “Water Closet Flushing Systems” section.
Urinal Installation Requirements
The minimum spacing required between urinals is30 inches center to center. The minimum spacing between a urinal and the sidewall is 15 inches. Thisspacing provides access to the urinal without the usercoming in contact with the user o the adjacent xture(see Figure 1-9). The minimum spacing required inront o the urinal is 21 inches.
For urinals with an integral trap, the outlet is lo-cated 21 inches above the foor or a standard-heightinstallation. Stall urinals are mounted on the foor. Wall-hung urinals must be mounted on carriers thattranser the weight o the urinal to the foor. Thecarrier also connects the urinal to the waste piping system. Sucient room should be provided in thechase or the carrier. Figure 1-10 shows the minimumchase sizes recommended by PDI.
Many plumbing codes require urinals or publicand employee use to have a visible trap seal. Thisreers to blowout, siphon-jet, and washout urinals.
LAVATORIES A lavatory is a washbasin used or personal hygiene.In public locations, a lavatory is intended to be used
or washing one’s hands and ace. Residential lavato-ries are intended or hand and ace washing, shaving,applying makeup, cleaning contact lenses, and similarhygienic activities.
Lavatory aucet fow rates are regulated as parto the Energy Policy Act o 1992. The original fowrate established by the government was 2.5 gpm at 80psi or private-use lavatories and 0.5 gpm, or a cycle
discharging 0.25 gallon, or public-use lavatories. Nowthe regulations require 2.2 gpm at 60 psi or private(and residential) lavatories and 0.5 gpm at 60 psi, or a cycle discharging 0.25 gallon, or public lavatories.
Lavatory aucets are available with electronicvalves. These aucets can reduce water usage by sup-plying water only when hands are inside the bowl.
Lavator Size and ShapeManuacturers produce lavatories in every conceivablesize and shape: square, round, oblong, rectangular,
Figure 1-9 Required Urinal Spacing
Figure 1-10 Minimum Chase Sizes or UrinalsCourtesy o Plumbing and Drainage Institute
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shaped or corners, with or without ledges, decorativebowls, and molded into countertops.
The standard outlet or a lavatory is 1¼ inches indiameter. The standard lavatory has three holes onthe ledge or the aucet. With a typical aucet, the twooutside holes are 4 inches apart. The aucets installedin these lavatories are called 4-inch centersets. Whenspread aucets are to be installed, the spacing betweenthe two outer holes is 8 inches.
For many years, xture standards required lava-tories to have an overfow based on the concept thatthe basin was lled prior to cleaning. I the user let
the room while the lavatory was being lled, thewater would not overfow onto the foor. However,studies have shown that lavatories are rarely used inthis capacity. It is more common to not ll the basinwith water during use. As a result, overfows noware typically an optional item or lavatories, yet someplumbing codes still require them. The minimumcross-sectional area o an overfow is 1⅛ inches.
Another style o lavatory is the circular or semi-circular group washup. The plumbing codes considerevery 20 inches o space along a group washup to beequivalent to one lavatory.
Lavator InstallationThe standard height o a lavatory is 31 inches abovethe nished foor. A spacing o 21 inches is requiredin ront o the lavatory to access the xture (seeFigure 1-11).
Lavatories can be counter mounted, under-countermounted, or wall hung. When lavatories are wall hung in public and employee acilities, they must be con-nected to a carrier that transers the weight o thexture to the foor. Proper clearances within chasesor wall-hung lavatories should be maintained. Figure
1-12 shows the minimum chase sizes recommendedby PDI.
KITCHEN SINKS A kitchen sink is used or culinary purposes. Thetwo distinct classications o kitchen sink are resi-dential and commercial. Residential kitchen sinks
Figure 1-11 Recommended InstallationDimensions or a Lavatory
Figure 1-12 Minimum Chase Sizes or LavatoriesCourtesy o Plumbing and Drainage Institute
can be installed in commercial buildings, typicallyin kitchens used by employees. Commercial kitchensinks are designed or restaurant and ood-handling establishments.
The Energy Policy Act o 1992 required the fowrate o aucets or residential kitchen sinks to be 2.5gpm at 80 psi. Fixture standards have since modiedthe fow rate to 2.2 gpm at 60 psi.
Residential Kitchen SinksCommon residential kitchen sinks are single- ordouble-compartment (or bowl) sinks. No standarddimension or the size o the sink exists; however,most kitchen sinks are 22 inches measured rom theront edge to the rear edge. For single-compartmentsinks, the most common width o the sink is 25 inches.For double-compartment kitchen sinks, the mostcommon width is 33 inches. The common depth o the compartments is 9 to 10 inches. Accessible sinksare 5.5 to 6.5 inches deep.
Most plumbing codes require the outlet o a
residential kitchen sink to be 3½ inches in diameter.This is to accommodate the installation o a oodwaste grinder.
Some specialty residential kitchen sinks havethree compartments. Typically, the third compart-ment is smaller and does not extend the ull deptho the other compartments.
Kitchen sinks have one, three, or our holes or theinstallation o the aucet. Some single-lever aucetsrequire only one hole or installation. The three-holearrangement is or a standard two-handle valve in-stallation. The our-hole arrangement is designed toallow the installation o a side spray or other kitchenappurtenance such as a soap dispenser.
The standard installation height or a residentialkitchen sink is 36 inches above the nished foor (seeFigure 1-13). Most architects tend to ollow the 6-oottriangle rule when locating a kitchen sink. The sinkis placed no more than 6 eet rom the range and 6eet rom the rerigerator.
Residential kitchen sinks mount either above orbelow the counter. Counter-mounted kitchen sinksare available with a sel-rimming ledge or a sink
rame.Commercial Kitchen SinksCommercial kitchen sinks are typically larger insize and have a deeper bowl than residential kitchen
sinks. The depth o the bowl typically ranges rom16 to 20 inches. Commercial kitchen sinks areoten reestanding sinks with legs or support.Because o health authority requirements, mostcommercial kitchen sinks are stainless steel.
In commercial kitchens, three types o sinkstypically are provided: hand sinks, prep sinks, andtriple-basin sinks. Prep sinks usually are a singlebasin used in conjunction with ood preparation.Triple-basin sinks are used or washing pots,pans, and utensils.
Health authorities require either a two- orthree-compartment sink in every commercialkitchen. The requirement or a three-compart-ment sink dates back to the use o the irstcompartment or dishwashing, the second com-partment or rinsing the dishes, and the thirdcompartment or sanitizing the dishes. Withthe increased use o dishwashers in commercialkitchens, some health codes have modied therequirements or a three-compartment sink.
Commercial kitchen sinks used or ood prepa-ration are required to connect to the drainagesystem through an indirect waste. This preventsthe possibility o contaminating ood in the evento a drainline backup resulting rom a stoppagein the line.
Commercial kitchen sinks that could dischargegrease-laden waste must connect to either a grease interceptor or a grease trap (see Figure1-14). Plumbing codes used to permit the greasetrap to serve as the trap or the sink i it was
Figure 1-13 Standard Dimensions or a Residential KitchenSink
Figure 1-14 Commercial Kitchen Sink Discharging to a GreaseInterceptor
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located within 60 inches o the sink. Most plumbing codes have since modied this requirement by man-dating a separate trap or each kitchen sink to providebetter protection against the escape o sewer gas. Analternative to this is to spill the sink into an indirectwaste drain that fows to a grease trap.
SERVICE SINKS A service sink is a general-purpose sink intended to beused in the cleaning or decorating o a building, suchas to ll mop buckets and dispose o their waste oror cleaning paint brushes, rollers, and paper-hanging equipment.
There is no standard size, shape, or style o a service sink. They are available both wall mountedand foor mounted. Mop basins, installed on the foor,qualiy as service sinks in the plumbing codes.
A service sink typically is located in a janitor’sstorage closet or a separate room or use by custodialemployees. The plumbing codes do not speciy the
location or a standard height or installing a servicesink. Furthermore, the fow rate rom the service sinkaucet has no limitations.
Service sinks are selected based on the anticipateduse o the xture and the type o building in whichit is installed. The plumbing codes require either a 1½-inch or 2-inch trap or the service sink. Servicesinks also may be tted with a 2-inch or 3-inch trapstandard.
SINKS A general classication or xtures that are neitherkitchen sinks nor service sinks is simply “sinks.” This
category contains those xtures typically not requiredbut installed or the convenience o the building users.Some installations include doctors’ oces, hospitals,laboratories, photo-processing acilities, quick marts,and oce buildings.
Sinks come in a variety o sizes and shapes. Thereare no height or spacing requirements, and the fowrate rom the aucet is not regulated. Most plumbing codes require a 1½-inch drain connection.
LAUNDRy TRAyS A laundry tray, or laundry sink, is located in thelaundry room and is used in conjunction with washing
clothes. The sink has either one or two compart-ments. The depth o the bowl is typically 14 inches.There are no standard dimensions or the size o laundry trays; however, most single-compartmentlaundry trays measure 22 inches by 24 inches, andmost double-compartment laundry trays measure 22inches by 45 inches.
Plumbing codes permit a domestic clothes washerto discharge into a laundry tray. The minimum size o a trap and outlet or a laundry tray is 1½ inches.
At one time, laundry trays were made predomi-nantly o soapstone. Today, the majority o laundrytrays are plastic. However, stainless steel, enameledcast iron, and porcelain enameled steel laundry traysalso are available.
FAUCETS All sinks and lavatories need a aucet to direct andcontrol the fow o water into the xture. A aucetperorms the simple operations o opening, closing,and mixing hot and cold water. While the process isrelatively simple, xture manuacturers have devel-oped extensive lines o aucets.
Faucet CategoriesFaucets are categorized by application, such as lava-tory aucets, residential kitchen sink aucets, laundryaucets, sink aucets, and commercial aucets. Theclassication “commercial aucets” includes commer-cial kitchen aucets and commercial sink aucets. Itdoes not include lavatory aucets. All lavatories are
classied the same, whether they are installed in resi-dential or commercial buildings. It should be noted,however, that some lavatory aucet styles are usedstrictly in commercial applications. These includesel-metering lavatory aucets that discharge a speci-ed quantity o water and electronic lavatory aucetsthat operate via sensors. The sensor-operated lavatoryaucets can be battery operated, directly connectedto the power supply o the building, or powered bya 30-year hybrid energy system or other ecoriendlypower generation system.
Faucet Flow Rates
The fow rates are regulated or lavatories and non-commercial kitchen sinks. Table 1-2 identies thefow rate limitations o aucets.
Table 1-2 Faucet Flow Rate Restrictions
Type o Faucet Maximum Flow Rate
Kitchen aucet 2.2 gpm @ 60 psi
Lavatory aucet 2.2 gpm @ 60 psi
Lavatory aucet (public use) 0.5 gpm @ 60 psi
Lavatory aucet (public use,metering)
0.25 gal per cycle
Backfow Protection or FaucetsIn addition to controlling the fow o water, a aucetmust protect the potable water supply against back-fow. This is oten a orgotten requirement, sincemost aucets rely on an air gap to provide protectionagainst backfow. When an air gap is provided betweenthe outlet o the aucet and the food-level rim o thexture (by manuacturer design), no additional pro-tection is necessary.
Backfow protection becomes a concern whenevera aucet has a hose thread outlet, a fexible hose con-nection, or a pull-out spray connection. For thesestyles, additional backfow protection is necessary.The hose or hose connection potentially eliminatesthe air gap by submerging the spout or outlet in a nonpotable water source.
The most common orm o backfow protection oraucets not having an air gap is the use o a vacuumbreaker. Many manuacturers include an atmosphericvacuum breaker in the design o aucets that requireadditional backfow protection. Atmospheric vacuumbreakers must conorm to ANSI/ASSE 1001: Peror-
mance Requirements or Atmospheric-type Vacuum Breakers.
Faucets with pull-out sprays or gooseneck spoutscan be protected by a vacuum breaker or a backfowsystem that conorms to ANSI/ASME A112.18.3: Perormance Requirements or Backow Protection Devices and Systems in Plumbing Fixture Fittings.
This standard species the testing requirements ora aucet to be certied as protecting the water sup-ply against backfow. Many o the new pull-out spraykitchen aucets are listed in ANSI/ASME A112.18.3.These aucets have a spout attached to a fexible hosewhereby the spout can detach rom the aucet bodyand be used similarly to a side spray.
Side-spray kitchen aucets must have a diverterthat ensures that the aucet switches to an air gapwhenever the pressure in the supply line decreases. Air gaps are regulated by ANSI/ASME A112.1.2: Air
Gaps in Plumbing Systems.The most important installation requirement is
the proper location o the backfow preventer (orthe maintenance o the air gap). When atmosphericvacuum breakers are installed, they must be locateda minimum distance above the food-level rim o thexture, as specied by the manuacturer.
DRINKING FOUNTAINS A drinking ountain is designed to provide drinking water to users. The two classications o drinking ountains are water coolers and drinking ountains. A water cooler has a rerigeration component that chillsthe water. A drinking ountain is a nonrerigeratedwater dispenser.
Drinking ountains and water coolers come inmany styles. The height o a drinking ountain is notregulated, except or accessible drinking ountainsconorming to ANSI/ICC A117.1. For grade school in-stallations, drinking ountains typically are installed30 inches above the nished foor to the rim o theountain. In other locations, the drinking ountain istypically 36 to 44 inches above the nished foor (seeFigure 1-15).
Space must be provided in ront o the drinking ountain to allow proper access to the xture. Plumb-ing codes prohibit drinking ountains rom being installed in toilets or bathrooms.
The water supply to a drinking ountain is ⅜ inchor ½ inch in diameter. The drainage connection is1¼ inches.
Many plumbing codes permit bottled water or theservice o water in a restaurant to be substituted orthe installation o a drinking ountain. However, theauthority having jurisdiction must be consulted todetermine i such a substitution is permitted.
SHOWERS A shower is designed to allow ull-body cleansing.The size and conguration o a shower must permitan individual to bend at the waist to clean lower-bodyextremities. Plumbing codes require a minimumsize shower enclosure o 30 inches by 30 inches. Thecodes urther stipulate that a shower must have a
30-inch-diameter circle within the shower to allowree movement by the bather.The water fow rate or showers is regulated by the
Energy Policy Act o 1992. The maximum permittedfow rate rom a shower valve is 2.5 gpm at 80 psi.
Three dierent types o shower are available:preabricated shower enclosure, preabricated showerbase, and built-in-place shower. Preabricated showerenclosures are available rom plumbing ixturemanuacturers in a variety o sizes and shapes. A preabricated shower base is the foor o a showerdesigned so that the walls can be either preabri-cated assemblies or built-in-place ceramic tile walls.
Built-in-place showers are typically ceramic tile instal-lations or both the foor and walls.
Figure 1-15 Typical Drinking Fountain Height
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Preabricated shower enclosures and preabricatedshower bases have a drainage outlet designed or a connection to a 2-inch drain. Certain plumbing codeshave decreased the shower drain size to 1½ inches.The connection to a 1½-inch drain also can be madewith preabricated showers.
A built-in-place shower allows the installation o a shower o any shape and size. The important instal-lation requirement or a built-in-place shower is theshower pan (see Figure 1-16). The pan is placed onthe foor prior to the installation o the ceramic base.The pan must turn up at the sides o the shower a minimum o 2 inches above the nished threshold o the shower (except the threshold entrance). The ma-terials commonly used to make a shower pan includesheet lead, sheet copper, PVC sheet, and chlorinatedpolyethylene sheet. The sheet goods are commonlyreerred to as a waterproo membrane.
At the drainage connection, weep holes are re-quired to be installed at the base o the shower pan.
The weep holes and shower pan are intended to serveas a backup drain in the event that the ceramic foorleaks or cracks.
Shower ValvesShower valves must be thermostatic mixing, pressurebalancing, or a combination o thermostatic mixing and pressure balancing and conorm to ANSI/ASSE1016/ASME A112.1016/CSA B125.16: Perormance
Requirements or Automatic Compensating Valves or Individual Showers and Tub/Shower Combinations. Shower valves control the fow and temperature o the water as well as any variation in the water tem-perature. These valves provide protection againstscalding and sudden changes in water temperature,which can cause slips and alls.
A pressure-balancing valve maintains a constanttemperature o the shower water by constantly adjust-ing the pressure o the hot and cold water supply. I the pressure on the cold water supply changes, the hotwater supply balances to the equivalent pressure set-ting. When tested, a pressure-balancing valve cannothave a fuctuation in temperature that exceeds 3°F.I the cold water shuts o completely, the hot watershuts o as well.
Thermostatic mixing valves adjust the tem-
perature o the water by maintaining a constanttemperature once the water temperature is set. Thisis accomplished by thermally sensing controls thatmodiy the quantity o hot and cold water to keep theset temperature.
The maximum fow rate permitted or each showeris 2.5 gpm at 80 psi. I body sprays are added to theshower, the total water fow rate is still 2.5 gpm at80 psi. A handheld shower spray is considered a showerhead.
The shower valve typically is located 48 to 50inches above the foor. The installation height or a showerhead ranges rom 65 to 84 inches above thefoor o the shower. The standard height is 78 inchesor showers used by adult males.
BATHTUBSThe bathtub was the original xture used to bathe orcleanse one’s body. Eventually, the shower was addedto the bathtub to expedite the bathing process. The
standard installation is a combination tub/shower,but some installations come with a separate whirlpoolbathtub and shower.
Bathtubs tend to be installed within residentialunits only. The standard bathtub size is 5 eet long by 30 inches wide, with a depth o 14 to 16 inches(see Figure 1-17). However, many dierent sizes andshapes o bathtubs and whirlpool bathtubs are avail-able. The drain can be either a let-hand (drain holeon the let side as you ace the bathtub) or right-handoutlet. When whirlpool bathtubs are installed, thecontrols or the whirlpool must be accessible.
All bathtubs must have an overfow drain. This isnecessary since the bathtub oten is lled while thebather is not present. Porcelain enameled steel andenameled cast-iron bathtubs are required to have a slip-resistant base to prevent slips and alls. Plasticbathtubs are not required to have the slip-resistantsurace since the plastic is considered to have an in-herent slip resistance. However, slip resistance canbe specied or plastic bathtub suraces.
Bathtub Fill ValvesThe two types o bathtub ll valve are the tub llerand the combination tub and shower valve. Tub andshower valves must be pressure-balancing, thermo-static mixing, or combination pressure-balancing andthermostatic mixing valves conorming to ANSI/ASSE1016/ASME A112.1016/CSA B125.16. The tub ller
is not required to meet these requirements, althoughpressure-balancing and thermostatic mixing tub llervalves are available.
The spout o the tub ller must be properly in-stalled to maintain a 2-inch air gap between the outletand the food-level rim o the bathtub. I this air gapis not maintained, the outlet must be protected rombackfow by some other means. Certain decorativetub llers have an atmospheric vacuum breaker in-stalled to protect the opening that is located belowthe food-level rim.
The standard location o the bathtub ll valve is14 inches above the top rim o the bathtub. The spout
typically is located 4 inches above the top rim o thebathtub to the centerline o the pipe connection.
BIDETThe bidet is a ixture designed or cleaning theperineal area. The bidet oten is mistaken to be a xture designed or use by the emale populationonly. However, the xture is meant or both male andemale cleaning. The bidet has a aucet that comeswith or without a water spray connection. When a water spray is provided, the outlet must be protectedagainst backfow since the opening is located belowthe food-level rim o the bidet. Manuacturers pro-
vide a decorative atmospheric vacuum breaker thatis located on the deck o the bidet.
Bidets are vitreous china xtures that are mountedon the foor. The xture, being similar to a lavatory,has a 1¼-inch drainage connection. Access must beprovided around the bidet to allow a bather to straddlethe xture and sit down on the rim. Most bidets havea fushing rim to cleanse the xture ater each use.
The bidet is used only or external cleansing. It isnot designed or internal body cleansing. This oten ismisunderstood since the body spray may be reerredto as a douche (the French word or shower).
FLOOR DRAINS A foor drain (see Figure 1-18) is a plumbing xturethat is the exception to the denition o a plumb-ing xture because it has no supply o cold and/orhot water. Floor drains typically are provided as anemergency xture in the event o a leak or overfowo water. They also are used to assist in the cleaning o a toilet or bathroom.
Floor drains are available in a variety o shapes
and sizes. The minimum size drainage outlet requiredby the plumbing codes is 2 inches. Most plumbing codes do not require foor drains; it is consideredan optional xture that the plumbing engineer mayconsider installing. Most public toilet rooms have atleast one foor drain. They also are used on the lowerlevels o commercial buildings and in storage areas,commercial kitchens, and areas subject to potentialleaks. Floor drains may serve as indirect waste recep-tors or condensate lines, overfow lines, and similarindirect waste lines.
A trench drain is considered a type o foor drain(see Figure 1-19). Trench drains are continuous
drains that can extend or a number o eet in length.Trench drains are popular in indoor parking struc-tures and actory and industrial areas. Each sectiono a trench drain must have a separate trap.
When foor drains are installed or emergencypurposes, the lack o use can result in the evapora-tion o the trap seal and the escape o sewer gases.Floor drain traps subject to such evaporation arerequired to be protected with trap seal primer valvesor devices. These valves or devices ensure that thetrap seal remains intact and prevents the escape o sewer gases.
EMERGENCy FIxTURESThe two types o emergency xture are the emergencyshower (see Figure 1-20) and the eyewash station.Combination emergency shower and eyewash sta-tions also are available. These xtures are designedto wash a victim with large volumes o water in theevent o a chemical spill or burn or another hazard-ous material spill.
Emergency xtures typically are required by Oc-cupational Saety and Health Administration (OSHA)
Figure 1-17 Standard Bathtub
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regulations. In industrial buildings and chemicallaboratories, emergency xtures are sometimes addedat the owner’s request in addition to the minimumnumber required by OSHA.
An emergency shower is also called a drench show-er because o the large volume o water discharged. An emergency shower should discharge 20 gpm at30 psi to comply with ANSI/ISEA Z358.1: Emergency Eyewash and Shower Equipment. The minimum sizewater connection is 1 inch or showers and 1¼ inchesor combination units. The showerhead typically isinstalled 7 eet above the nished foor.
Eyewash stations are used to fush the eyes andace, and the water fow rate is gentle so the eyes canremain open during the washing process. The fowrates or an eyewash station range rom 0.4 gpm oran eyewash to 3 gpm or an eye/acewash.
Most plumbing codes do not require a drain oremergency showers and eyewash stations to allowgreater fexibility in the location o the xtures andthe spot cleanup o any chemicals that may be washedo the victim.
ANSI/ISEA Z358.1 requires the water supply toemergency xtures to be tepid, which is assumed tobe in the range o 85°F to 95°F. A medical proessionalshould be consulted to determine the optimal watertemperature. When controlling the water tempera-ture, the thermostatic control valve must permit theull fow o cold water in the event o a ailure o thehot water supply. This can be accomplished withthe use o a ail-sae thermostatic mixing valve ora bypass valve or the thermostatic mixing valve.Since showers and eyewash stations are or extremeemergencies, a supply o water to the xtures must
always be available.
MINIMUM FIxTUREREQUIREMENTS FOR BUILDINGSThe minimum number o required plumbing xturesor buildings is specied in the plumbing codes (seeTable 1-3 and Table 1-4). Both the InternationalPlumbing Code and the Uniorm Plumbing Code basethe minimum number o plumbing xtures on the oc-cupant load o the building. It should be recognizedthat the occupant load and occupancy o the building
Figure 1-18 Floor Drain
Figure 1-19 Trench DrainSource: Courtesy o Jay R. Smith Company
Figure 1-20 Emergency ShowerSource: Courtesy o Haws Corporation
are sometimes signicantly dierent. For example,in an oce building, the occupancy is typically 25percent o the occupant load. The xture tables havetaken this into account in determining the minimumnumber o xtures required. Most model plumbing codes do not provide occupancy criteria. The occupantload rules can be ound in the building codes.
Single-Occupant Toilet RoomsThe International Plumbing Code has added a re-quirement or a single-occupant toilet room or useby both sexes. This toilet room is also called a unisextoilet room. The single-occupant toilet room must bedesigned to meet the accessible xture requirementso ANSI/ICC A117.1. The purpose o the single-occupant toilet room is to allow a husband to help a wie or vice versa. It also allows a ather to oversee a daughter or a mother to oversee a son. These rooms
are especially important or those temporarily inca-pacitated and the severely incapacitated.
The International Plumbing Code requires a single-occupant toilet room in mercantile and assem-bly buildings when the total number o water closetsrequired (both men and women) is six or more. Wheninstalled in airports, the acilities must be located toallow use beore an individual passes through thesecurity checkpoint.
Another eature typically added to single-occupanttoilet rooms is a diaper-changing station. This allowseither the mother or the ather to change a baby’sdiaper in privacy. To allow all possible uses o thesingle-occupant toilet room, it oten is identied as a amily toilet room to clearly indicate that the room isnot reserved or the physically challenged.
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Table 1-3 Minimum Number o Required Plumbing Fixtures (IPC Table 403.1)a
No. Classication Occupancy Description
Water Closets (UrinalsSee Section 419.2) Lavatories Bathtubs/
Showers
DrinkingFountaine, (SeeSection 410.1) OtherMale Female Male Female
1 Assembly
A-1d
Theaters and otherbuildings or theperorming arts andmotion pictures
1 per 125 1 per 65 1 per 200 — 1 per 500 1 service sink
A-2d
Nightclubs, bars, taverns,
dance halls and buildingsor similar purposes
1 per 40 1 per 40 1 per 75 — 1 per 500 1 service sink
Restaurants, banquet hallsand ood courts
1 per 75 1 per 75 1 per 200 — 1 per 500 1 service sink
R-1 Hotels, motels, boardinghouses (transient) 1 per sleeping unit 1 per sleeping unit
1 per
sleepingunit
— 1 service sink
R-2Dormitories, raternities,sororities and boardinghouses (not transient)
1 per 10 1 per 10 1 per 8 1 per 100 1 service sink
R-2 Apartment house 1 per dwelling unit 1 per dwelling unit1 per
dwellingunit
—
1 kitchen sinkper dwelling
unit; 1 automaticclothes washerconnection per
20 dwelling units
R-3One- and two-amilydwellings
1 per dwel ling unit 1 per dwel ling unit1 per
dwellingunit
—
1 kitchen sinkper dwelling
unit; 1 automaticclothes washerconnection per
dwelling unitR-4
Congregate living acilitiewith 16 or ewer persons
1 per 10 1 per 10 1 per 8 1 per 100 1 service sink
8 Storage
S-1S-2
Structures or the storageo goods, warehouses,storehouse and reightdepots. Low and ModerateHazard
1 per 100 1 per 100See
Section411
1 per 1,000 1 sink
a. The xtures shown are based on one xture being the minimum required or the number o persons indicated or any raction o the number o persons indicated. The number ooccupants shall be determined by the International Building Code.
b. Toilet acilities or employees shall be separate rom acilities or inmates or care recipients.
c. A single-occupant toilet room with one water closet and one lavatory serving not more than two adjacent patient sleeping units shall be permitted where such room is provided withdirect access rom each patient sleeping unit and with provisions or privacy.
d. The occupant load or seasonal outdoor seating and entertainment areas shall be included when determining the minimum number o acilities required.
e. The minimum number o required drinking ountains shall comply with Table 403.1 and Chapter 11 o the International Building Code.
. Drinking ountains are not required or an occupant load o 15 or ewer.
g. For business and mercantile occupancies with an occupant load o 15 or ewer, service sinks shall not be required.
Excerpted rom the 2012 International Plumbing Code, Copyright 2011. Washington, D.C.: International Code Council. Reproduced with permission. All rights reserved. www.iccsae.org
Each building shall be provided with sanitary acilities, including provisions or persons with disabilities as prescribed by the Department Having Jurisdiction. Table 422.1 applies to newbuildings, additions to a building, and changes o occupancy or type in an existing building resulting in increased occupant load.
Over 400, add 1 xture oreach additional 500 malesand 1 xture or each 125emales.
Over 600, add 1xture or eachadditional 300 males.
Over 750, add 1 xture oreach additional 250 malesand 1 xture or eachadditional 200 emales.
Over 750, add 1xture or eachadditional 500persons.
B Business occupancy (oce,proessional, or service-typetransactions) – banks, vet clinics,hospitals, car wash, beautysalons, ambulatory healthcareacilities, laundries and drycleaning, educational institutions(above high school), or trainingacilities not located withinschools, post oces, and printingshops
Over 400, add 1 additionalxture or each additional
500 males and 1 xture oreach additional 150 emales.
Over 400, add 1 xture oreach additional 250 males
and 1 xture or eachadditional 200 emales.
E Educational occupancy –private or public schools
Male1 per 50
Female1 per 30
Male1 per 100
Male1 per 40
Female1 per 40
1 per 150 1 service sink orlaundry tray
F1, F2 Factory or industrialoccupancy – abricating orassembly work
Male1: 1-502: 51-753: 76-100
Female1: 1-502: 51-753: 76-100
Male1: 1-502: 51-753: 76-100
Female1: 1-502: 51-753: 76-100
1 shower oreach 15 personsexposed toexcessiveheat or to skincontaminationwith poinsonous,inectious, orirritating material
1: 1-2502: 251-5003: 501-750
1 service sink orlaundry tray
Over 100, add 1 xture oreach additional 40 persons.
Over 100, add 1 xture oreach additional 40 persons.
Over 750, add 1xture or eachadditional 500persons.
I-1 Institutional occupancy(houses more than 16 personson a 24-hour basis) – substanceabuse centers, assisted living,group homes, or residentialacilities
Over 400, add 1 xture oreach additional 500 malesand 1 xture or eachadditional 150 emales.
Over 750, add 1 xture oreach additional 500 persons.
Over 750, add 1xture or eachadditional 500persons.
Notes:1 The gures shown are based upon one xture being the minimum required or the number o persons indicated or any raction thereo.2 A restaurant is dened as a business that sells ood to be consumed on the premises.a. The number o occupants or a drive-in restaurant shall be considered as equal to the number o parking stalls.b. Hand-washing acilities shall be available in the kitchen or employees.3 The total number o required water closets or emales shall be not less than the total number o required water closets and urinals or males.
Source: 2012 Uniorm Plumbing Code Table 422.1 Reprinted with the permission o the International Association o Plumbing and Mechanical Oicials. This copyrightmaterial and all points or statements in using this material have not been reviewed by IAPMO. The opinions expressed herein are not representations o act romIAPMO.
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Piping Sstems2The selection o piping materials depends on thepressure, velocity, temperature, and corrosiveness o the medium conveyed within, initial cost, installationcosts, operating costs, and good engineering practice.This chapter provides general application inormationand guidance regarding common types o pipe mate-
rials. The local plumbing code and other regulationsregarding specic piping requirements should bereerred to prior to beginning any design.
SPECIFICATIONOnly new materials should be specied. A typical pip-ing specication should include the ollowing items:t ype o system and materials, applicable standards,wall thickness, joining and support methods, type o end connection and ller material, bolting, gasketmaterials, testing, and cleaning.
Piping usually is tested at 1.5 times the working pressure o the system. It should not be buried, con-cealed, or insulated until it has been inspected, tested,and approved. All deective piping shall be replacedand retested.
All domestic water piping and ttings must con-orm to NSF/ANSI Standard 61.
INSTALLATIONPipes should be neatly arranged—straight, parallel,or at right angles to walls—and cut accurately to es-tablished measurements. Pipes should be worked intoplace without springing or orcing. Sucient headroomshould be provided to enable the clearing o lighting
xtures, ductwork, sprinklers, aisles, passageways,windows, doors, and other openings. Pipes should notinterere with access to maintain equipment.
Pipes should be clean (ree o cuttings and oreignmatter inside), and exposed ends o piping should becovered during site storage and installation. Split,bent, fattened, or otherwise damaged pipe or tub-ing should not be used. Sucient clearance should beprovided rom walls, ceilings, and foors to permit thewelding, soldering, or connecting o joints and valves. A minimum o 6 to 10 inches (152.4 to 254 millime-
ters) o clearance should be provided. Installation o pipe above electrical equipment, such as switchgear,panel boards, and elevator machine rooms, shouldbe avoided. Piping systems should not interere withsaety or relie valves.
A means o draining the piping system should be
provided. A ½-inch or ¾-inch (12.7-mm or 19.1-mm)hose bibb (provided with a threaded end and vacu-um breaker) should be placed at the lowest point o the piping system or this purpose. Constant gradesshould be maintained or proper drainage, and pip-ing systems should be ree o pockets due to changesin elevation.
CAST IRON SOIL PIPECast iron soil pipe is primarily used or sanitarydrain, waste, vent, and storm systems. Cast iron soilpipe used in the United States is classied into twomajor types: hub and spigot and hubless (also calledno-hub).
The Cast Iron Soil Pipe Institute (CISPI) utilizesa quality control program to veriy that its memberoundries are manuacturing cast iron soil pipe andttings, which are marked with the Institute’s collec-tive trademark, to the appropriate standards (CISPI301 or no-hub and ASTM A74 or hub and spigot).Engineers are encouraged to add the ollowing lan-guage to their specication or cast iron soil pipe andttings: “All cast iron soil pipe and ttings shall bearthe collective trademark o the Cast Iron Soil PipeInstitute or receive prior approval by the engineer.”
Hub and Spigot Pipe and FittingsHub and spigot pipe and ttings have hubs into whichthe spigot (plain end) o the pipe or tting is inserted.Both single and double hub versions are available.Hub and spigot pipe and ttings are available in twoclasses, or thicknesses: service (SV) and extra heavy(XH). The extra-heavy class oten is used or under-ground applications. Service and extra-heavy classeshave dierent outside diameters and are not readilyinterchangeable (see Tables 2-1 and 2-2). However,
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these two dierent types o pipe and ttings can beconnected with adapters available rom the manu-acturer.
Hub and spigot pipe and ttings are joined us-ing rubber (neoprene) compression gaskets and mol-ten lead and oakum (see Figure 2-1). Sizes include2-inch to 15-inch (50.8-mm to 381-mm) diameters,and the pipe comes in 5-oot or 10-oot (1.5-meter or3.1-meter) lengths (see Figure 2-2).
Hubless Pipe and FittingsHubless cast iron soil pipe and ttings are simply pipeand ttings manuactured without a hub (see Figure2-3). The method o joining these pipes and ttingsutilizes a hubless shielded coupling or a heavy-duty
shielded coupling, which slips over the plain endso the pipe and ttings and is tightened to seal the joint (see Figure 2-1). Many congurations o ttingsranging in size and shape are available. Hubless castiron soil pipe and ttings are made in only one class,or thickness. They are available in 1½-inch to 15-inch (38.1-mm to 254-mm) diameters, and the pipeis manuactured in 5-oot to 10-oot (1.5-m to 3.1-m)lengths (see Table 2-3).
DUCTILE IRON WATER AND SEWER PIPEDuctile iron pipe is primarily used in water andsewer systems or underground and industrial ap-plications. Ductile iron is a strong material and is not
Figure 2-2 Cast Iron Soil Pipe (Extra-Heavy and Service Classes)
Notes : 1. Laying length, all sizes:single hub 5 t; double hub 5 t less Y, 5-t lengths; single hub 10 t; double hub 10 t less Y, or 10 t lengths. 2. I a bead is
provided on the spigot end, M may be any diameter between J and M. 3. Hub ends and spigot ends can be made with or without drat, and spigot endscan be made with or without spigot bead.
Figure 2-1 Cast Iron Soil Pipe Joints
Figure 2-3 Hubless Cast Iron Soil Pipe and Fittings
Note: Laying length, all sizes: single hub 1.5 m; double hub 1.5 m less Y, 1.5 m lengths; single hub 3.1 m; double hub 3.1 m less Y, for 3.1 m lengths.aI a bead is provided on the spigot end, M may be any diameter between J and M.
bHub ends and spigot ends can be made with or without drat, and spigot ends can be made with or without spigot bead.
Table 2-1 Dimensions o Hubs, Spigots, and Barrels or Extra-Heavy Cast Iron Soil Pipe and Fittings
NominalInside
Diameter(in.)
InsideDiameter o
Hub (in.)
OutsideDiameter oSpigot
a(in.)
OutsideDiameter oBarrel (in.)
TelescopingLength (in.) Thickness o Barrel (in.)
A M J Y T (nominal) T (minimum)2 3.06 2.75 2.38 2.50 0.19 0.16
Note: Laying length, all sizes: single hub 5 t; double hub 5 t less Y, 5-t lengths; single hub 10 t; double hub 10 t less Y, or 10 t lengths.aI a bead is provided on the spigot end, M may be any diameter between J and M.
bHub ends and spigot ends can be made with or without drat, and spigot ends can be made with or without spigot bead.
Table 2-2(M) Dimensions of Hubs, Spigots, and Barrels for Service Cast Iron Soil Pipe and Fittings
Note: Laying length, all sizes: single hub 1.5 m; double hub 1.5 m less Y, 1.5 m lengths; single hub 3.1 m; double hub 3.1 m less Y, or 3.1 m lengths.aI a bead is provided on the spigot end, M may be any diameter between J and M.
bHub ends and spigot ends can be made with or without drat, and spigot ends can be made with or without spigot bead.
15 15.11 383.79 15.83 402.08 16.12 409.55 0.31 7.87 0.36 7.62 0.30 2.75 69.85 60 120aLaying lengths as listed are or pipe only.
bLaying lengths may be either 5 t 0 in. or 10 t 0 in. (1.5 or 3.1 m) long.
as brittle as cast iron. Ductile iron pipe is available inseven classes (50–56) and in 3-inch to 64-inch (76-mmto 1,626-mm) diameters. The pipe is manuacturedwith bell ends and in a length o either 18 eet or 20eet (5.49 m or 6.1 m).
Cement-lined piping typically is required or wa-ter distribution systems. The cement lining provides
a protective barrier between the potable water supplyand the ductile iron pipe to prevent impurities andcontaminants rom leaching into the water supply.Thepressure ratings or cement-lined ductile iron pipecan be ound in Table 2-4.
The methods o joining are push-on rubber (neo-prene) compression gasket, mechanical, and fanged.Special joints also are also available, such as re-strained, ball and socket, and grooved and shouldered.(See Figure 2-4.)
CONCRETE PIPEConcrete pipe is used or sanitary sewers, storm sew-
ers, culverts, detention systems, and low-pressure orcemains. Reinorced concrete pipe is the most durableand economical o all piping products. It is recom-mended or installations where low, moderate, or severecover and/or live load conditions exist and structuralailure might endanger lie or property. Reinorcedpipe, even ater ultimate ailure, retains its shape andwill not collapse. Concrete pipe typically is installed bythe site contractor during site preparation rather thanthe plumbing trade.
This pipe is available in 4-inch to 36-inch (100-mmto 900-mm) diameters. Nonreinorced concrete pipe isnot available in all markets. Reinorced concrete pipe
is made by the addition o steel wire or steel bars. Itis used primarily or sewage and storm drainage andis available in 12-inch to 144-inch (300-mm to 3,600-mm) diameters (see Table 2-5). Concrete pipe is avail-able as a bell and spigot or gasketed bell design.
The methods o joining are rubber (elastomeric)gasket and cement plaster (becoming obsolete).
COPPER PIPECopper pipe is used or drain, waste, and vent (DWV),water supply, boiler eed lines, rerigeration, and simi-lar purposes.
Copper Water TubeCopper water tube is a seamless, almost pure coppermaterial manuactured to the requirements o ASTMB88. It has three basic wall thickness dimensions, des-ignated as Types K, L, and M, with Type K being thethickest, Type L being o intermediate thickness, andType M being the thinnest. All three types o tube arecommonly manuactured rom copper alloy C12200,which has a chemical composition o 99.9 percentminimum copper (Cu) and silver (Ag) combined anda maximum allowable range o phosphorous (P) o 0.015–0.040 percent.
Seamless copper water tube is manuactured insizes o ¼-inch to 12-inch (6.35-mm to 304.8-mm)(nominal) diameters. Types K and L are manuac-tured in drawn temper (hard) o ¼-inch to 12-inch(6.35-mm to 304.8-mm) and annealed temper (sot)coils o ¼-inch to 2-inch (6.35-mm to 50.8-mm) (nomi-nal) diameters, while Type M is manuactured only indrawn (hard) temper o ¼-inch to 12-inch (6.35-mmto 304.8-mm) (nominal) diameters. See Table 2-6 orthe commercially available lengths o copper plumb-ing tube. See Tables 2-7, 2-8, and 2-9 or dimensionaland capacity data or Type K, L, and M copper tuberespectively.
Seamless copper water tube o drawn temper is re-quired to be identied with a colored stripe that con-tains the manuacturer’s name or trademark, type o tube, and nation o origin. This stripe is green or TypeK, blue or Type L, and red or Type M. In addition
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to the colored stripe, thetube is incised with the typeo tube and the manuac-turer’s name or trademarkat intervals not in excesso 1½ eet. Annealed (sot)coils or straight lengths arenot required to be identiedwith a colored stripe.
Various types o ttingso the compression, grooved,and mechanical types maybe used (see Figures 2-5 and2-6). O-rings in ttings areto be ethylene propylenediene monomer (EPDM) orhydrogenated nitrile buta-diene rubber (HNBR).
Joints in copper watertube typically are soldered,
fared, or brazed, althoughroll-grooved and mechani-cal joints also are permit-ted. Soldered joints should be installed in accordancewith the requirements and procedures detailed in ASTM B828 , and the fux used should meet the re-quirements o ASTM B813. The mechanical joining o copper tubing is done with specially manuac-tured ttings. One type known as press-connect is
astened with a crimping tool with interchangeable jaws o ½ inch to 4 inches (12.7 mm to 101.6 mm). Another known as push-connect is pushed on thetube to make a connection and is held in place byan internal or integral stainless steel gripper ring. A third method is accomplished by roll-grooving theend o the tube and using a gasketed tting.
Table 2-4 Standard Minimum Pressure Classes o Ductile Iron Single-ThicknessCement-Lined Pipe
Figure 2-4 Joints and Fittings or Ductile Iron Pipe
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Table 2-6 Commercially Available Lengths o Copper Plumbing Tube
Tube type: Type K; Color code: Green ASTM B88a
Commercially Available Lengthsb
Straight Lengths Coils
Pipe Diameter Drawn Annealed Pipe Diameter Drawn Annealed¼ to 8 in. 20 t 20 t ¼ to 1 in. 60 t 100 t
10 in. 18 t 18 t 1¼ and 1½ in. 60 t —
12 in. 12 t 12 t 2 in. 40 t 45 tStandard applicationsc: Domestic water service and distribution, re protection, solar, uel/uel oil, HVAC, snow melting
Tube type: Type L; Color code: Blue ASTM B88
Commercially Available Lengthsb
Straight Lengths Coils
Pipe Diameter Drawn Annealed Pipe Diameter Drawn Annealed¼ to 8 in. 20 t 20 t ¼ to 1 in. 60 t 100 t
12 in. 18 t 18 t 1¼ and 1½ in. 60 t —
— — — 2 in. 40 t 45 t
Standard applicationsc: Domestic water service and distribution, re protection, solar, uel/uel oil, HVAC, snow melting, natural gas,
liqueed petroleum gas
Tube type: Type M; Color code: Red ASTM B88
Commercially Available Lengthsb
Straight Lengths Coils
Pipe Diameter Drawn Annealed Pipe Diameter Drawn Annealed¼ to 12 in. 20 t — — — —
Standard applicationsc: Domestic water service and distribution, re protection, solar, uel/uel oil, HVAC, snow melting
Tube type: DWV; Color code: Yellow ASTM B306
Commercially Available Lengthsb
Straight Lengths Coils
Pipe Diameter Drawn Annealed Pipe Diameter Drawn Annealed¼ to 8 in. 20 t — — — —
Standard applicationsc: Drain, waste, and vent, solar, HVAC
Tube type: ACR; Color code: Blue ASTM B280
Commercially Available Lengthsb
Straight Lengths Coils
Pipe Diameter Drawn Annealed Pipe Diameter Drawn Annealed3 ⁄ 8 to 41 ⁄ 8 in. 20 t d 1 ⁄ 8 and 15 ⁄ 8 in. 50 t —
Standard applicationsc: Air-conditioning, rerigeration, natural gas, liqueed petroleum gas
Tube type: OXY, MED, OXY/MED, OXY/ACR, ACR/MED; Color code: (K) Green, (L) Blue ASTM B819
Commercially Available Lengthsb
Straight Lengths Coils
Pipe Diameter Drawn Annealed Pipe Diameter Drawn Annealed¼ to 8 in. 20 t N/A — — —
Standard applicationsc: Medical gas
Tube type: Type G; Color code: Yellow ASTM B837
Commercially Available Lengthsb
Straight Lengths Coils
Pipe Diameter Drawn Annealed Pipe Diameter Drawn Annealed3 ⁄ 8 to 11 ⁄ 8 in. 12 t 12 t 3 ⁄ 8 to 7 ⁄ 8 in. 60 t 100 t
Standard applicationsc: Natural gas, liqueed petroleum gas
a Tube made to other ASTM standards is also intended or plumbing applications, although ASTM B88 is by ar the most widely used. ASTM B698: Standard Classifcations lists sixplumbing tube standards, including ASTM B88.
b Individual manuacturers may have commercially available lengths in addition to those shown in this table.
c Many other copper and copper alloy tubes and pipes are available or specialized applications. For inormation on these products, contact the Copper Development Association.
Copper Drainage TubeCopper drainage tube or DWV applications is a seam-less copper tube conorming to the requirements o ASTM B306. Copper drainage tube is urnished indrawn (hard) temper only in sizes o 1¼ inch to 8 inches(31.8 mm to 203.2 mm). It is required to be identiedby a yellow stripe giving the manuacturer’s name or
trademark, nation o origin, and the letters “DWV.” Italso is required to be incised with the manuacturer’sname or trademark and the letters “DWV” at intervalsno greater than 1½ eet. See Table 2-10 or dimensionaldata or Type DWV copper tube.
Fittings or use with copper drainage pipe are usu-ally those conorming to either ANSI/ASME B16.23or ANSI/ASME B16.29. They are required to carrythe incised mark “DWV.”
Joints or drainage applications can be soldered orbrazed (see Figure 2-7).
Medical Gas Tube
Medical gas tube is shipped cleaned and capped andis urnished in Type K or L wall thickness in drawn(hard) temper only. It is identied with an incised markcontaining the manuacturer’s name or trademark at
Table 2-7 Dimensional and Capacity Data—Type K Copper Tube
Diameter (in.)
Wallthickness
(in.)
Cross-sectional area (sq. in.) Weight per oot (lb)
intervals not in excess o 1½ eet. It is color-codedgreen or Type K and blue or Type L.
Fittings or medical gas tube may be those con-orming to ANSI/ASME B16.22, ANSI/ ASME B16.18(where wrought copper ttings are not available), or ANSI/ASME B16.50. They also may be ttings meet-ing the requirements o MSS SP-73.
Joints in medical gas systems are o the socket/ lap type and are typically brazed with copper-phos-phorous or copper-phosphorous-silver (BCuP) alloyswhile being purged with oil-ree nitrogen.
Natural and Liqueed PetroleumNatural and liqueed petroleum pipe is urnished inType G wall thickness. It is color-coded yellow per ASTM B837.
The methods o joining are brazing, compressionttings, and specialized mechanical compressioncouplings.
GLASS PIPEGlass is unique or several reasons. First, it is clear,allowing the contents to be visible. Second, it is the
Table 2-7(M) Dimensional and Capacity Data—Type K Copper Tube
piping system that is least susceptible to re. Glass doesnot burn, but with enough heat, it can melt. In build-ings with a return air plenum or heating, ventilation,and air-conditioning (HVAC), glass pipe can be used tomeet building re code requirements.
Glass pipe (see Figure 2-8) is made o low-expan-sion borosilicate glass with a low alkali content. Itmost commonly is used or chemical waste drainlines,vent piping, and puried water piping. Glass also isused or chemical waste DWV systems in high schools,colleges, laboratories, industrial plants, and hospitalswhere hot fuids are disposed down the system con-stantly. (Hot fuids are those at 200°F with no dilu-
tion.) The coecient o glass expansion is 0.2 inch/100eet/100°F (5 mm/30.4 m/37.8°C), and glass is verystable and can operate up to 300°F (148.9°C).
Glass pipe comes in two options: as pressure ½-inchto 8-inch (13-mm to 203-mm) pipe and as drainage1½-inch to 6-inch (38-mm to 153-mm) pipe. It is avail-able in standard 5-oot and 10-oot (1.5-m and 3.1-m)lengths. Nonstandard lengths are available, or thepipe can be eld cut or abricated to special lengths.Glass can be installed aboveground (padded or withcoated hangers) or buried (with Styrooam blocking around the pipe). Glass is ragile, so care must be tak-en to prevent scratches or impact by sharp objects.
Table 2-8 Dimensional and Capacity Data—Type L Copper Tube
Diameter (in.)
Wallthickness
(in.)
Cross-sectional area (sq. in.) Weight per oot (lb)
Glass pipe is joined with either o two types o cou-pling, depending on whether it is a “bead to bead” or“bead to cut glass end” application (see Figures 2-9and 2-10). Joints are made by using compression-typecouplings consisting o 300 series stainless steel outerbands, electrometric compression liners, and seal-ing members o chemically inert tetrafuoroethylene(TFE).
Fittings are made o borosilicate glass and includea ull range o sanitary and plumbing ttings (see Fig-ure 2-11).
STEEL PIPESteel pipe speciied or heating, air-conditioning,plumbing, gas, and air lines conorms to ASTM A53. Steel pipe conorming to ASTM A53 is intended orcoiling, bending, orming, and other special purposes.Steel pipe that meets the requirements o ASTM A106is used or high-temperature service and is suitable or
coiling, bending, and orming.Steel pipe is also available manuactured to stan-
dards o the American Petroleum Institute (API). Forexample, API 5L steel pipe is in all respects the sameas ASTM A53, but manuactured under API standards
Table 2-8(M) Dimensional and Capacity Data—Type L Copper Tube
or use in petroleum reneries and petrochemical acil-ities. It is rarely specied or use in building services.
Steel pipe may be either seamless (extruded) orwelded. The welding o steel piping is accomplishedby two methods: continuous or electric-resistancewelding (ERW). Continuous welded pipe is heatedand ormed. Electric-resistance welding is cold rolledand then welded. Steel pipe also may be black ironor galvanized (zinc coated). Galvanized steel pipe isdipped and zinc coated to produce a galvanized pro-tective coating both inside and out.
Steel pipe is produced in three basic weight clas-sications: standard, extra strong, and double extra strong. Steel pipe in standard weight and variousweights, or schedules—ranging rom Schedule 10,also known as light wall pipe, to Schedule 160—istypically supplied in random lengths o 6 eet to 22
eet (1.8 m to 6.7 m) and is available in ⅛-inch to24-inch (3.2-mm to 660-mm) diameters. Exceptionsto this are butt-welded standard weight and extra strong, which are not available in diameters largerthan 4 inches, and butt-welded double extra-strong steel pipe, which is not made in diameters larger than2½ inches. See Tables 2-11 and 2-12 or dimensionaland capacity data or Schedule 40 and Schedule 80steel pipe respectively.
Steel pipe conorming to ASTM A135 is made insizes through 12 inches by the electric-resistancewelding method only. Grade A is suitable or fanging or binding. Pipe meeting ASTM A135 is used exten-sively or light-wall pipe in re sprinkler systems.
The methods o joining steel pipe are welding,threading, and grooved.
Table 2-9 Dimensional and Capacity Data—Type M Copper Tube
Diameter (in.)
Wallthickness
(in.)
Cross-sectional area (sq. in.) Weight per oot (lb)
PLASTIC PIPEPlastic pipe is available in compositions designed ornumerous applications, including DWV, water supply,gas service and transmission lines, and laboratoryand other chemical drainage and piping systems. Fueldouble-containment systems, high-purity pharmaceuti-cal and electronic grade water, and R-13, R-13A, andR-13D re protection sprinkler systems are additionalapplications.
The two basic types o plastic pipe are thermosetand thermoplastic. A thermoset plastic is permanent-
ly rigid. Epoxy and phenolics are examples o ther-
mosets. A thermoplastic is a material that sotenswhen heated and hardens when cooled. Acrylonitrilebutadiene styrene (ABS), polyvinyl chloride (PVC),polybutylene (PB), polyethylene (PE), polypropylene(PP), polyvinylidene fuoride (PVDF), cross-linkedpolyethylene (PEX), and chlorinated polyvinyl chlo-ride (CPVC) are thermoplastics. With thermoplastics,consideration must be given to the temperature/pres-sure relationship when selecting the support spacing and method o installation.
With all plastics, certain considerations mustbe reviewed beore installation. These include codecompliance, chemical compatibility, correct maxi-mum temperature, and allowance or proper expan-sion and contraction movement. Certain plastics are
installed with solvent cements; others require heat-ing to join piping networks along with mechanical joints. The designer should consult the manuactur-er’s recommendations or the proper connection o all piping systems.
See Figure 2-12 and Tables 2-13 and 2-14 or gen-eral inormation on plastic pipe and ttings.
PolbutlenePolybutylene is a fexible thermoplastic that wasmanuactured to pipe and tubing specications. PBtubing is no longer manuactured, but a plumbing engineer may encounter the material during a retrot
o an existing system.Polybutylene is an inert polyolen material,
meaning that it is chemically resistant, so it cannotbe solvent cemented like other plastic piping sys-tems. PB pipe was one o the most fexible piping materials acceptable or potable water. It is typicallyblue or gray in color.
Its applications included hydronic slab heating systems, re sprinklers systems, hot and cold waterdistribution, and plumbing and water supply.
Joints were made by mechanical, fared, and heatusion methods.
PolethlenePolyethylene also is an inert polyolen (chemicallyresistant) material, so it cannot be solvent cemented.This type o piping typically is supplied in blue orblack or water and cooling water applications. Black
PE pipe incorporates carbon black or colorization andUV radiation (sunlight) protection. Orange-coloredpolyethylene piping is typically used or gas pipeinstallations.
Joints are made with inserts and clamps andby heat usion. PE cannot be threaded or solventwelded.
PE pipe is classied into the ollowing types: lowdensity, high density, and medium density. The termsreer to ASTM designations based on material densi-ties. Sizes range rom ½ inch to 63 inches (12.7 mmto 1,600.2 mm) in diameter in both iron pipe size(IPS) and copper tube size (CTS). Pressures range
rom 50 psi to 250 psi depending on wall thickness(SDR 7 to SDR 32.5).
High-Density Polyethylene
HDPE comprises 90 percent o the polyethylene pip-ing industry. It has a wide variety o belowgroundand aboveground applications, including domesticwater supply, well water systems, lawn sprinklersystems, irrigation systems, skating rinks, buriedchilled water pipe, underground FM Global-approved
re mains, chemical lines, snow-making lines at skislopes, pressurized chilled water piping undergroundbetween buildings and a central heating or cooling plant, methane gas collection piping, leachate collec-tion lines at landlls, relining water and sewer mains,water transmission mains over highway bridges (itabsorbs vibration), brine at skating rinks, and resi-dential swimming pools.
Typically, HDPE is installed with mechanicalbarbed joints or compression ttings through 2inches (50.8 mm), and the pipe comes in coils, whichcan be 100 eet to 5,000 eet (30.5 m to 1,542 m) onspecial reels. It is also available heat socket used
rom ½ inch to 40 inches (12.7 mm to 1,016 mm),butt used rom 2 inches to 63 inches (50.8 mm to1,600.2 mm) in 40-oot (12.2-m) pipe lengths, and
electroused rom 1½ inches to 30 inches (38.1 mmto 762 mm) in diameter.
HDPE is not a xed, rigid, or perectly straightpipe—it bends. When designing systems with HDPE,expansion must be preplanned, and best eorts shouldbe made to determine what direction it will take (e.g.,bury the pipe in an S or snake pattern to let it expandor contract.)
Both pipe and tubing (IPS and CTS) are manuac-tured using a SDR series. The operating tempera-ture limit is 160°F, but as always, the manuacturero the product should be consulted on temperatureversus pressure.
The color is typically black or HDPE, which ac-cording to ASTM means that 2 percent carbon blackhas been blended with the resin to provide the mini-mum 50-year lie span at ull pressure in direct sun-light. Two unique properties o HDPE pipe are thatit swells and does not break i it reezes and it foatsin water since its specic gravity is 0.95. This is why
HDPE pipe can be preassembled, and thousands o eet can be foated to a certain position and thensunk with concrete collars.
Cross-Linked PolethleneCross-linked polyethylene tubing has been used ex-tensively in Europe or many years or hot and coldpotable water distribution systems.
A specially controlled chemical reaction takesplace during the manuacturing o the polyethylenepipe to orm PEX. Cross-linked molecular structur-
ing gives the pipe greater resistance to rupture overa wider range o temperatures and pressures thanother polyolen piping (PB, PE, and PP).
Because o the unique molecular structure andheat resistance o PEX pipe, heat usion is not per-mitted as a joining method. Being a member o thepolyolen plastic amily, PEX is resistant to solventsand cannot be joined by solvent cementing. Mechan-ical connectors and ttings or PEX piping systemsare proprietary in nature and must be used onlywith the pipe or which they have been designed. A number o mechanical astening techniques havebeen developed to join PEX pipe. The pipe manuac-turer’s installation instructions should be consultedto properly identiy the authorized ttings or theintended system use.
PEX pipe is fexible, allowing it to be bent. It isbent by two methods: hot and cold bending. See themanuacturer’s instructions or the exact require-ments or bending. The tubing can be bent to a
minimum radius o six times the outside diameteror cold bending and a minimum o 2½ times theoutside diameter or hot bending.
PEX is available in nominal pipe size (NPS) ¼inch through 2 inches (6.4 mm through 51 mm).
Cross-Linked Polethlene, Aluminum,Cross-Linked PolethlenePEX-AL-PEX is a composite pipe made o an alumi-num tube laminated with interior and exterior layerso cross-linked polyethylene. The layers are bondedwith an adhesive.
The cross-linked molecular structuring describedabove and the addition o the aluminum core makethe pipe resistant to rupture. Thereore, along withother system usages, the pipe is suitable or hot andcold water distribution. The pipe is rated or 125pounds per square inch (psi) at 180°F (862 kPa at82°C). It is available in nominal pipe size ¼ inchthrough 1 inch (6.4 mm through 25 mm).
Mechanical joints are the only methods currentlyavailable to join PEX-AL-PEX pipe. A number o mechanical compression-type connectors have beendeveloped or joining this type o pipe material topermit transition to other types o pipe and ttings.The installation o any tting shall be in accordance
with the manuacturer’s installation instructions. Although it is partially plastic, PEX-AL-PEX pipe
resembles metal tubing in that it can be bent by handor with a suitable bending device while maintaining its shape without ttings or supports. The minimumradius is ve times the outside diameter.
Polethlene/Aluminum/PolethlenePE-AL-PE is identical to the PEX-AL-PEX compositepipe except or the physical properties o the poly-ethylene.
Polyethylene does not display the same resistanceto temperature and pressure as the cross-linkedpolyethylene. Thereore, this type o pipe is limitedto cold water applications or applications with othersuitable fuids up to 110°F at 150 psi (43°C at 1,034kPa).
It is available in nominal pipe size ¼ inch through1 inch (6.4 mm through 25 mm). The method o join-ing is mechanical (barbed joints and compression t-tings).
Polvinl ChloridePolyvinyl chloride is rigid, pressure- or drainage-typepipe that resists chemicals and corrosion. PVC is usedor water distribution, irrigation, storm drainage,sewage, laboratory and hospital wastes, chemicallines, chilled water lines, heat pumps, undergroundFM Global-approved re mains, animal rearing a-cilities, hatcheries, graywater piping, and ultra-purewater. PVC water service piping is a dierent materialthan PVC drainage pipe, although both pipe materials
are white in color. Two types are available: Schedule40 and Schedule 80.
For pressure, SDR 21 (200 psi) or SDR 26 (160psi) is used. The working pressure varies with thetemperature: as the temperature increases, tensilestrength decreases. The maximum working pressureis continuously marked on the pipe along with themanuacturer’s name, ASTM or CSA standard, andthe grade o PVC material. Temperature should belimited to 140° (60°C). The joints are solvent weldedor threaded. Schedule 40 PVC cannot be threaded,and it can be used only with socket ttings. Schedule80 can be threaded through the 4-inch (101.6-mm)size and used with either socket or threaded ttings.However, it also can be installed with mechanicalgrooved couplings or bell and gasket (undergroundonly and thrust blocked).
The pipe classications and dimensional inorma-tion are:
•DWV: 1¼ inches to 24 inches (31.75 mm to 609.6 mm)
• Schedule 40: ⅛ inch to 30 inches (3.2 mm to 762mm)
• Schedule 80:⅛ inch 30 inches (3.2 mm to 762 mm)
• SDR 21: ¾ inch to 24 inches (22 mm to 609.6 mm),
except ½-inch SDR (13.5 mm)
• SDR 26: 1¼ inches to 24 inches (32 mm to 609.6mm)
The maximum temperature rating or PVC is140°F (60°C). The coecient o linear expansion is2.9 × 10
-5inch/inch/°F. The specic gravity o PVC is
1.40 ± 0.02.
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T a b l e 2 - 1 4
P h
y s i c a l P r o p e r t i e s o P l a s t i c P i p i n g M a t e r i a l s
M a t e r i a l
S p e c i f c
G r a v i t y
T e n s i l e
S t r e n g t h
( p s i a t
7 3 ° F )
M o d u l u s o E l a s t i c -
i t y i n T e n s i o n ( p s i
a t 7 3 ° F × 1 0 5 )
C o m p r e s s i v e
S t r e n g t h ( p s i )
S t r e n g t h
F l e x u r a l
( p s i )
R e s i s t a n c e
t o H e a t
( c o n t i n u o u s )
( ° F )
C o e f c i e n t o
E x p a n s i o n ( i n . /
i n . / ° F × 1 0 - 6 )
T h
e r m a l C o n -
d u c t i v i t y ( B t u h
t 2 / ° F / i n . )
B u r n i n g R a t e
H e a t
D i s t o r t i o n
T e m p ( ° F a t
2 6 4 p s i )
W
a t e r
A b s o r p t i o n
a t
( % / 2 4
h r 7 3 ° F )
I z o d I m p a c t
( 7 3 ° F t l b /
i n . n o t c h )
P V C T y p e I
1 . 3 8
7 , 9 4 0
4 . 1 5
9 , 6 0 0
1 4 , 5 0 0
1 4 0
3 . 0
1 . 2
S e l E x t i n g u i s h i n g
1 6 0
. 0 5
. 6 5
T y p e I I a
1 . 3 5
6 , 0 0 0
3 . 5
8 , 8 0 0
1 1 , 5 0 0
1 4 0
5 . 5 5
1 . 3 5
S e l E x t i n g u i s h i n g
1 5 5
. 0 7
2 - 1 5
C P V C T y p e I V
1 . 5 5
8 , 4 0 0
4 . 2
1 5 , 6 0 0
2 1 0
3 . 8
. 9 5
S e l E x t i n g u i s h i n g
2 2 1
. 0 5
—
P o l y e t h y l e n e
T y p e I
. 9 2
1 , 7 5 0
1 . 9 – . 3 5
1 , 7 0 0
1 2 0
1 0 . 0
2 . 3
S l o w
N A
. 0 1
1 6
T y p e I l l
. 9 5
2 , 8 0 0
1 . 5
2 , 0 0 0
1 2 0
7 . 3
3 . 5
S l o w
N A
0 . 0
3 . 0
P o l y p r o p y l e n e
. 9 1
4 , 9 0 0
1 . 5
8 , 5 0 0
1 6 0 – 2 1 2
3 . 8
1 . 3
S l o w
1 5 0
0 . 0 3
2 . 1
A B S T y p e I
1 . 0 3
5 , 3 0 0
3 . 0
7 , 0 0 0
8 , 0 0 0
1 6 0
6 . 0
1 . 9
S l o w
1 9 7
. 2 0
5 - 9
T y p e I I
1 . 0 8
8 , 0 0 0
1 0 , 0 0 0
1 2 , 0 0 0
1 7 0
3 . 8
2 . 5
S l o w
2 2 5
. 2 0
4
P o l y v i n y l i d e n e
F l o r i d e ( P D V F )
1 . 7 6
7 , 0 0 0
1 . 2
1 0 , 0 0 0
2 0 0 – 2 5 0
8 . 5
1 . 0 5
S e l E x t i n g u i s h i n g
1 9 5
. 0 4
3 . 0
P o l y b u t y l e n e
. 9 3
4 , 8 0 0
. 3 8
—
—
—
7 . 1
1 . 5
S l o w
N A
<
. 0 1
n o b r e a k
N o t e s : 1 . A b o v e d a t a c o m p i l e d i n a c c o r d a n c e w
i t h A S T M t e s t r e q u i r e m e n t s .
2 . N A = N o t A p p l i c a b l e .
a T h e u s a g e o P V C I I i s l i m i t e d t o e l e c t r i c a l c o n d u i t .
T a b l e 2 - 1 4 ( M )
P h y s i c a l P r o p e r t i e s o P l a s t i c P i p i n g M
a t e r i a l s
M a t e r i a l
S p e c i f c
G r a v i t y
T e n s i l e
S t r e n g t h
( M P a a t
2 2 . 8 ° C )
M o d u l u s o
E l a s t i c i t y
i n T e n s i o n
( 1 0 5 k P a a t
2 2 . 8 ° C × 1 0 5 )
C o m p r e s s i v e
S t r e n g t h
( M P a )
S
t r e n g t h
F
l e x u r a l
( M P a )
R e s i s t a n c e
t o H e a t
( c o n t i n u o u s )
( ° C )
C o e f c i e n t o
E x p a n s i o n ( 1 0 -
5 m m / m m / ° C )
T h e r m a l
C o n d u c t i v i t y
( W / m
2 ° K )
B u r n i n g R a t e
H e a t
D i s t o r t i o n
T e m p ( ° C a t
1 . 8 2 M P a )
W a t e r
A b s o r p t i o n
a t ( % / 2
4 h a t
2 2 . 8
° C )
I z o d I m p a c t ( J /
m m n o t c h a t
2 2 . 8 ° C )
P V C T y p e I
1 . 3 8
4 8 . 2 6
2 8 . 6 1
6 6 . 1 9
9 9 . 9 8
6 5 . 6
1 2 7 . 0
5 . 9 6
S e l E x t i n g u i s h i n g
7 3 . 9
0 . 0 7
0 . 0 4
T y p e I I a
1 . 2 5
4 1 . 3 7
2 4 . 1 3
6 0 . 6 7
7 9 . 2 9
6 0 . 0
2 5 1 . 7 3
7 . 5 6
S e l E x t i n g u i s h i n g
6 8 . 3
0 . 0 7
0 . 5 3 – 0 . 8 0
C P V C N A
N A
N A
N A
N A
N A
N A
N A
N A
N A
N A
N A
N A
P o l y e t h y l e n e T y p e I
0 . 9 2
1 2 . 0 7
1 3 1 . 0 – 2 . 4 1
—
1 1 . 7 2
4 8 . 9
4 5 3 . 5 7
1 3 . 0 6
S l o w
—
– 0 . 0 1
0 . 8 5
T y p e I l l
0 . 9 5
1 3 . 7 9
1 0 . 3 4
—
1 3 . 7 9
4 8 . 9
3 3 1 . 1 1
1 9 . 8 7
S l o w
—
0
0 . 1 6
P o l y p r o p y l e n e
0 . 9 1
3 3 . 7 9
1 0 . 3 4
5 8 . 6 1
—
7 1 . 1 – 1 0 0
1 7 2 . 3 6
7 . 3 8
S l o w
6 5 . 6
0 . 0 3
0 . 1 1
A B S T y p e I
1 . 0 3
3 6 . 5 4
2 0 . 6 8
4 8 . 2 6
5 5 . 1 6
7 1 . 1
2 7 2 . 1 4
1 0 . 7 9
S l o w
9 1 . 7
0 . 2 0
0 . 2 7 – 0 . 4 8
T y p e I I
1 . 0 8
5 5 . 1 6
—
6 8 . 9 5
8 2 . 7 4
7 6 . 7
1 7 2 . 3 6
1 4 . 2 0
S l o w
1 0 7 . 2
0 . 2 0
0 . 2 1
P o l y v i n y l i d e n e
F l o r i d e ( P D V F )
1 . 7 6
4 8 . 2 6
8 . 2 7
6 8 . 9 5
—
9 3 . 3 – 1 2 1 . 1
3 8 5 . 5 4
5 . 9 6
S e l E x t i n g u i s h i n g
9 0 . 6
0 . 0 4
0 . 1 6
P o l y b u t y l e n e
0 . 9 3
3 3 . 1 0
2 . 6 2
—
—
—
1 8 0 . 3 4
8 . 5 1
S l o w
N A
< . 0 1
n o b r e a k
N o t e s : 1 . A b o v e d a t a c o m p i l e d i n a c c o r d a n c e w
i t h A S T M t e s t r e q u i r e m e n t s .
2 . N A = N o t a p p l i c a b l e .
a T h e u s a g e o P V C I I i s l i m i t e d t o e l e c t r i c a l c o n
Chlorinated Polvinl ChlorideThe higher-temperature version o PVC is CPVC,which is commonly used as an alternative to copperand PEX. CPVC is available in a variety o pressureapplications in CTS or IPS, Schedule 40 or Schedule80. Copper tube size CPVC is rated at 180°F, and theworking pressure varies with the temperature: as the
temperature increases, tensile strength decreases. Be-cause o its size ranges—CTS: ½ inch to 2 inches (12.7mm to 50.8 mm), Schedule 80: ¼ inch to 24 inches (6.3mm to 609.6 mm)—it can be used in a wide variety o hot or cold water systems. CPVC also has been usedextensively in wet re protection systems in hotels,motels, residences, oce buildings, and dormitories(all applications that all under NFPA 13, 13D, and13R). Pipe sizes or re protection systems are ¾ inchto 3 inches (19 mm to 76.2 mm) and are ideally suitedor the retrot market.
CPVC is joined using solvent welding, threads,fanges, compression ttings, O-rings, transition t-
tings, bell rings, and rubber gaskets.In recent years, CPVC corrosive waste drainage
systems have gained acceptance as a viable alterna-tive to the traditional polypropylene systems. Someo these systems are now certied to meet the CSA plenum rating and are working to pass ASTM E84 aswell. Standard pipe sizes available or CPVC chemi-cal waste systems are 1½ inches to 24 inches (48.3mm to 609.6 mm).
Note: PVC and CPVC piping systems are not rec-ommended or compressed air or compressed gaslines. Compensation or both thermal expansion andcontraction must be taken into account.
Acrlonitrile-Butadiene-Strene ABS is manuactured in Schedules 40 and 80 and inspecial dimensions or main sewers and utility conduitsand in SDR or compressed air. It is commonly usedor DWV plumbing (in the color black), main sanitaryand storm sewers, underground electrical conduits,and applications in the chemical and petroleum in-dustries. Schedule 40 is available in 1½, 2, 3, 4, and 6inches (38.1, 50, 63, 90, 110, and 160 mm), with theappropriate ttings, and Schedule 80 is available in1½, 2, 3, 4, and 6 inches (38.1, 50, 63, 90, 110, and160 mm), with the appropriate ttings. The joints are
solvent welded or Schedule 40 and welded or threadedor Schedule 80.
For industrial applications, ABS piping is gray orlow temperatures (-40°F to 176°F [-72°C to 80°C])and pressure up to 230 psi in sizes ½ inch to 8 inches(12.7 mm to 203.2 mm). It is joined only by solventcementing. The coecient o linear expansion is5.6 × 2
–5inch/inch/°F. Fittings are available or pres-
sure only. The outside diameter o the pipe is nomi-nal IPS, and a second product in the industrial area is air line, which is designed to be used in delivering
compressed air or machine tools rom 0.63 inch to 4inches (16 mm to 101 mm).
PolproplenePP is manuactured or a wide variety o systems.The DWV systems are or chemicals, special waste,or acid waste in both buried and aboveground appli-cations. Pipe is available in Schedule 40 or Schedule
80 black (underground) or fame retardant (FR) oraboveground installation. Polypropylene systems oracid waste installed aboveground must utilize FRpipe and ttings. PP also is used or a wide range o industrial liquids, salt water disposal, and corrosivewaste systems.
Double containment o polypropylene systemshas gained popularity in the DWV acid waste mar-ket. Double-containment polypropylene systems aretypically nonfame pipe (NFPP) or underground andfame-retardant pipe (FRPP) or aboveground appli-cations. Double-containment polypropylene can beinstalled with or without leak-detection systems.
Polypropylene acid waste (AW) pipe systems comewith either mechanical joints (1½, 2, 3, 4, and 6 inches[50, 63, 90, 110, and 160 mm]) or with an internalwire heat used (1½, 2, 3, 4, 6, 8, 10, 12, 14, 16, and18 inches [50, 63, 90, 110, 160, 200, 250, 300, 315, and350 mm]), molded (1½ inches to 6 inches [50 mm to160 mm, and abricated (8 inches to 18 inches [200mm to 450 mm]). Pipe is available in 10-oot and 20-oot (3.05-m and 6.1-m) lengths.
Glue cannot be used to join any polypropylene pip-ing system. Joints are made mechanically or by heatusion (electric coil socket usion, butt usion, IR weld-ing, bead, and crevice-ree welding, see Figure 2-13).Fittings are made in both pressure-type and DWV congurations. Small-diameter (½ inch to 2 inches[12.7 mm to 50.8 mm]) polypropylene may be joinedby threading with a greatly reduced pressure rating,
Figure 2-13 Fusion Lock Process in Operation
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or certain manuacturers have molded ttings withstainless steel rings to restrain or help strengthen thethreads or ull pressure ratings.
Polvinlidene FluoridePVDF is manuactured in Schedules 40 and 80, as wellas SDR or the deionized/ultra-pure water market.Polyvinylidene fuoride is a strong, tough, abrasion-
resistant fuoropolymer material. It is used widelyin high-purity electronic or medical-grade water orchemical piping systems that need to remain pure butunction at high temperatures. Other uses include a wide range o industrial liquids, saltwater disposal,and corrosive waste systems, again where high-tem-perature perormance is required. It also is oten usedor corrosive waste applications in return air plenumspaces. Certain PVDF resins oer excellent fame- andsmoke-resistant characteristics. Other benets are itsability to withstand high temperatures or elevated-temperature cleaning, its noncontaminating qualities,and its smooth surace nish.
The coecient o thermal expansion is 7.9 × 2–5
inch/inch/°F. PVDF is available in metric and IPS sizesranging rom 0.37 inch to 12 inches (9.5 mm to 304.8mm). Pipe is available in 10-oot (3.04-m) lengths.
The color is normally natural, and the resin is notaected by ultraviolet (UV) light. However, i the me-dia being transported within the PVDF piping systemis subject to degradation by UV light, a red pigmenta-tion is added to the resin, resulting in a red-coloredpiping system that protects the fow stream.
Fittings are made in both pressure and DWV congurations. It must be noted that a special fameand smoke package is added to the PVDF resin whenused to manuacture DWV pipe and ttings or re-turn and supply plenum acid waste applications.Only these special PVDF pipe and ttings meet therequirements or plenum installations o UL 723/ ASTM E84. The joints cannot be solvent welded. Joints are made mechanically or by heat usion(electric coil or socket usion).
Polproplene-RandomPP-R is the high temperature and pressure version o PP and is manuactured or a wide variety o pressure-type systems, including potable water (hot and coldwater distribution and water service), reclaimed water,
rainwater, chilled water, condenser water, hydronic/ heating water, geothermal systems, swimming poolpiping, RO/DI water, and chemical or special wastesystems, in both buried and aboveground applications.PP-R is one o the most environmentally riendly pip-ing materials rom cradle to cradle in terms o energyconsumption and air, soil, and water pollution, and ithas a low carbon ootprint. PP-R is compatible withthe POE oils used with modern rerigerants, making it suitable or use in HVAC systems.
Pipe is available in SDR 11, SDR 7.3, or SDR 6wall thicknesses. The methods o joining are heatusion using socket usion ttings, butt usion joints,electrousion ttings, and mechanical ttings ortransition to other materials and union joints. PP-Rcannot be solvent welded. PP-R pipe systems withsocket usion joints come in diameters o ½, ¾, 1, 1¼,1½, 2, 2½, 3, 3½, and 4 inches (20, 25, 32, 40, 50, 63,75, 90, 110, and 125 mm) and with butt usion con-nections in diameters o 6, 8, 10, and 12 inches (160,200, 250, and 315 mm). Pipe is available in 13-oot(4-m) lengths. Fittings are made in both pressure-typeand DWV congurations.
PP-R pipe is manuactured to metric outside di-ameters but usually is reerenced to by the nomi-nal diameter. Transition ttings are available inboth metric and NPT thread sizes, groove steel, and ASME and metric fange connections.
Where thermal expansion is a concern, PP-R canbe extruded with an internal berglass layer that re-
duces thermal expansion by 75 percent. When NSF-listed or potable water and ood grade applications,it typically comes in green and may have a darkgreen stripe to indicate the ber layer. For reclaimedand rainwater applications, the pipe is oered in a purple color. The nonpotable water pipe usually hasblue and green stripes.
Tefon (PTFE)Telon, or polytetraluoroethylene (PTFE), hasoutstanding resistance to chemical attack by mostchemicals and solvents. It has a temperature range o -200°F to 500°F (-128.9°C to 260°C). Tefon typically isconsidered tubing; however, it can be joined by thread-ing in pipe sizes 0.13 inch to 4 inches (3.2 mm to 101.6mm). Tefon piping is well suited or low-pressure—not to exceed 15 psi—laboratory or process industryapplications. I higher pressures or hotter tempera-tures are needed, Tefon-lined steel pipe generally isused. Lined steel pipe is 1 inch to 12 inches (25.4 mmto 304.8 mm) and can handle corrosive chemicals aswell as high-pressure applications.
Low-Etractable PVCLow-extractable PVC provides a very economicalsolution compared to stainless steel, PVDF, or PPor the engineering o ultra-pure water loops or
use in healthcare, laboratory, micro-electronics,pharmaceutical, and various other industrial applica-tions. Tests perormed validate that resistivity can bemaintained at levels greater than 18 megaohms, andonline total oxidizable carbon can average less than 5parts per billion on properly designed and maintainedsystems. Pipe and ttings with valves are joined by a special low-extractable one-step solvent cement. Flu-ids being conveyed cannot exceed 140°F (60°C). Thepipe comes in Schedule 80 wall thickness and ½-inch
to 6-inch (20-mm to 160-mm) diameters. The reer-ence standards are ASTM D1785 and ASTM D2467.
Fiberglass and ReinorcedThermosetting ResinFiberglass piping systems are manuactured and joinedusing epoxy, vinylester, or polyester resins. These threeresins oer a very distinct price/perormance choice
varying rom strongest/most expensive to weakest/leastexpensive. They typically are used in a pressure patternmode and have good chemical resistance as well as ex-cellent stability in the upper temperature limit o 275°F(135°C). It is especially helpul in resisting attacks romthe various oils used in the petroleum industry. How-ever, it should be noted that the chemical resistance o such systems is provided exclusively by the resin-richliner on the inside diameter o the pipe. I the liner isworn down, cracked, or compromised in any way, put-ting the process in direct contact with the glass bers,leaks will result. Depending on the manuacturer, thesesystems also can be joined mechanically with bell and
spigot, plain, or butt and wrap methods. The pipe ismanuactured in sizes o 1 inch to 48 inches (25.4 mmto 1,219 mm) and can be custom made in much largerdiameters. The coecient o linear thermal expansionis 1.57 × 2
–5inch/inch/°F.
Dierent products require dierent approvals.Some must meet American Petroleum Institute(API), Underwriters Laboratories (UL), or military(MIL) specications. For potable water, they mustmeet NSF/ANSI Standard 14 per ASTM D2996 orNSF/ANSI Standard 61 or drinking water.
VITRIFIED CLAy PIPE Vitried clay pipe is used in a building sewer starting outside o the building and connecting to the mainsewer. It also is used or industrial waste because o its outstanding corrosion and abrasion resistance.
Vitried clay pipe is extruded rom a suitablegrade o shale or clay and red in kilns at approxi-mately 2,000°F (1,100°C). Vitrication takes placeat this temperature, producing an extremely hardand dense, corrosion-resistant material. Clay pipeis suitable or most gravity-fow systems and is notintended or pressure service. Available sizes include3-inch to 48-inch (75-mm to 1,220-mm) diameters
and lengths up to 10 eet (3.05 m) in standard orextra-strength grades as well as perorated (see Ta-bles 2-15 and 2-16). Pipe and ttings are joined withpreabricated compression seals.
HIGH SILICON IRON PIPEHigh silicon iron pipe is manuactured o a 14.5percent silicon iron makeup that possesses almostuniversal corrosion resistance. For nearly a century,high silicon iron pipe and ttings have provided a durable and reliable means o transporting corrosive
waste saely. Over the last ew decades, however,thermoplastics (such as PVC, PP, and PVDF) havereplaced this product in most laboratory, school, andhospital applications because o their even greaterinertness to many chemicals, light weight, and easeo installation.
The material is available with hub-and-spigot pipeand ttings (see Figure 2-14) in sizes rom 2 inchesto 15 inches, which are installed using traditionalplumbing techniques. Mechanical joint pipe and t-tings are available rom 1½ inches to 4 inches and o-er ease o installation through the use o couplings.
The bell-and-spigot joint is made using conven-tional plumbing tools, virgin lead, and a special acid-resistant caulking yarn. The caulking yarn is packedinto the bell o the joint, and a small amount o leadis poured over the yarn to ll the hub. The caulk-ing yarn, not the lead, seals the joint. Care must betaken to not overheat the lead used in making the joint. The iron material is very brittle, and ttings
are subject to stress cracking and breakage during abrication i the lead is poured while too hot, espe-cially in cold-weather installations.
The mechanical joints are designed or ast andeasy assembly through the use o the two-bolt me-chanical coupling. A calibrated ratchet is necessaryto complete the joint. The nuts are tightened to 10eet per pound 24 hours prior to testing.
Piping systems manuactured o high siliconiron pipe are similar to cast iron hub-and-spigotpipe and ttings. The pipe has a hub into whichthe spigot (plain end) o a pipe or tting is inserted.Hub-and-spigot pipe and tting sizes include 2-inch
to 15-inch diameters and 5-oot or 10-oot (1.5-m or3.1-m) lengths.
Figure 2-14 (A) Duriron Pipe and (B) Duriron JointSource: Courtesy o Duriron
(A)
(B)
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SPECIAL-PURPOSE PIPINGMATERIALSStainless steel and aluminum are the most commonspecial-purpose piping materials used or a wide rangeo applications where perormance requirementsoutweigh costs. Stainless steel and aluminum requirespecialized skills in design and abrication. Many al-
loys are available or specic applications. Aluminum Aluminum is extruded or drawn in a variety o alloys.Its uses include cryogenic systems with tempera-tures as low as -423°F (-252.8°C), process systems,
heat transer, and pressure lines. The joints can bebrazed or welded, but it should be noted that specialtechniques oten are required, depending on the typeo alloy. Aluminum is available in 8-inch to 48-inchdiameters, depending on the type.
Stainless SteelThe designation “stainless steel” applies to a number
o alloys with dierent properties. Common to allstainless steels is the act that they contain at least12 percent chromium. Stainless steel is manuacturedin three basic types: martensitic (hardenable, straightchromium alloy), erritic (straight chromium, or
Table 2-15(M) Dimensions o Class 1 Standard Strength Perorated Clay Pipe
Size(in.)
Laying Length Maximum Dierence
in Length o 2Opposite Sides (mm)
Outside Diameter oBarrel (mm)
Inside Diametero Socket at
12.7 mm AboveBase (mm)
Minimum(m)
Limit o MinusVariation (mm/m) Minimum Maximum
4 0.61 20.8 7.94 123.83 130.18 146.05
6 0.61 20.8 9.53 179.39 188.91 207.96
8 0.61 20.8 11.11 234.95 247.65 266.70
10 0.61 20.8 11.11 292.10 304.80 323.85
12 0.61 20.8 11.11 349.25 363.54 348.18
15 0.94 20.8 12.70 436.56 452.44 473.08
18 0.94 20.8 12.70 523.88 544.51 565.15
21 0.94 20.8 14.29 612.78 635.00 657.23
24 0.94 31.3 14.29 698.50 723.90 746.13
Table 2-15 Dimensions o Class 1 Standard Strength Perorated Clay Pipe
Size(in.)
Laying length Maximumdierence inlength o twoopposite sides
(in.)
Outside diametero barrel (in.)
Insidediametero socketat ½ in.above
base, (in.)Min.
Rows operora-
tions
Perorations per rowDepth o socket
(in.)Thickness o bar-
rel (in.)
Thickness o sock-et at ½ in. romouter end (in.)
Min.
Limit o minusvariation
(in. per t. olength Min. Max. 2 t. 3 t. 4 t. 5 t. Nominal Min. Nominal Min. Nominal Min.
corrosive service where nickel steel is undesirable),and austenitic (18 percent chromium and 8 percentnickel, or general corrosive service). The joints canbe butt welded, socket welded, screwed, or fanged.Pipe and ttings are available in⅛-inch through 48-inch diameters.
Stainless steel is a clean, durable, corrosion-resis-tant, and long-lasting material. Products are chemi-cally descaled (acid pickled) to enhance the naturalcorrosion resistance and to provide a uniorm, aes-thetically pleasing matte-silver nish.
Stainless steel is used where sanitation and prod-uct contamination resistance are critical (dairies,ood processing, etc.). In processing systems, stain-less steel is used to resist corrosion. All stainlesssteels have inherent corrosion resistance, but theaustenitic group o stainless steels has the great-est resistance to many dierent chemical productsand most detergents. Austenitic steels also have anexcellent ability to resist impacts and shocks at all
temperatures. Hard blows to the material may causedents in certain cases, but it is very dicult to actu-ally damage the steel.
Other uses include applications in the ood indus-try, shipbuilding, pharmaceutical industry, brewer-ies and dairies, industrial kitchens, and institutions. When increased acid resistance is required and spotand crevice corrosion may occur, molybdenum-al-loyed chromium-nickel steels may be used. Theseacid-resistant steels resist a number o organic andinorganic acids. However, acid-proo steels are onlypartially resistant to solutions containing chlorides.
Stainless steel cannot burn and consequently is
classied as nonfammable. This means that pipesand drains made o stainless steel may penetratefoor partitions without the need or special re in-sulation. Likewise, no harmul umes or substancesare released rom the steel in the event o re.
Due to their very low heat expansion coecient,drain products in stainless steel are not in any wayinfuenced by temperatures occurring in drain in-stallations. Furthermore, drain products need notbe stored or installed at specic temperatures. Nei-ther heat nor cold aects stainless steel.
Stainless steel piping is manuactured in two di-erent grades: 304, which is suitable or most envi-
ronments, and 316, which is suitable or corrosiveenvironments. Piping is available in single hub andin eight lengths: 0.5, 0.8, 1.6, 3.3, 4.9, 6.6, 9.8, and16.4 eet (150, 250, 500, 1,000, 1,500, 2,000, 3,000,and 5,000 mm) and 2 inches to 6 inches (50.8 mm to152.4 mm).
It is necessary to determine the lengths requiredbetween tting location points and to select the pipelengths that best minimize waste and eliminate eldcuts when possible. A stainless steel piping system
is lightweight and easy to install. A pipe joint can bemade in a ew seconds.
Corrugated Stainless Steel Tubing Corrugated stainless steel tubing (CSST) is a fexiblegas piping system made rom 300 series stainless steel.The tubing is suitable or natural gas and propane. Itcan be used or both aboveground and underground
installations. (See specic manuacturer’s recommen-dations or underground use and installation.) Thetubing is protected with a re-retardant polyethylene jacket. It is manuactured in ⅜-inch to 2-inch (9.52-mm to 50.8-mm) sizes and in coils o up to 1,000 eet(304.8 m) based on pipe sizes.
Mechanical joints are the only methods currentlyavailable to join CSST tubing. A number o mechan-ical compression-type connectors have been devel-oped or joining CSST to permit transition to othertypes o pipe and ttings. The installation o any t-ting shall be in accordance with the manuacturer’sinstallation instructions.
Manuacturers have specic protective devicesand termination ttings or their products. The de-signer should consult with the manuacturer or allrequired accessories.
DOUBLE CONTAINMENTDouble containment (DC) is the practice o putting a second walled enclosure around a single-wall pipe toprotect people and the environment rom harm i thepipe ails. It is used both underground and aboveg-round or a multitude o purposes, such as to preventcorrosive chemicals rom getting into soils or spilling rom a single-wall overhead pipe onto people below. Itis available in both drainage and pressure systems.
Double containment is most commonly avail-able in PVC DWV × PVC DWV, PVC Schedule40/80 × PVC DWV, PVC 40/80 × PVC 40/80, CPVC80 × PVC 80, DWV PP × DWV PP, FRP × FRP, PEx PE, PP x PVDF, and PVDF x PVDF as well as allmetals and a limitless combination o dissimilar ma-terials (both plastics and metals mixed together). Itcan be ordered with or without leak detection, whichcan be a continuous cable (single use or reusable),point o collections, or non-wetted sensors.
DC currently is not governed by plumbing stan-
dards; however, the standards or the single-wallpiping components that make up the DC system doapply.
When planning or DC, the designer should leaveplenty o space. Labor costs are ve to seven timesthose or installing single-wall pipe. Thereore, thedesigner should ask the system manuacturer to pro-vide, i possible, maniolded sections that can saveinstallation time. The designer should also considerthe dierential in rates o expansion that can occurwithin a carrier pipe as opposed to the container
pipe and make the necessary allowances in layoutfexibility. Again, working with a system manuac-turer is highly recommended in such cases.
When testing DC, the designer should ollow themanuacturer’s requirements or the proper proce-dures or the inner and outer pipe. Testing should beperormed on the inner and outer piping segmentsindependently.
A simple DC size variation is 6 inches inner di-ameter and 10 inches outer diameter, so a great di-erence in size exists. A typical 6-inch trap may takeup 15 inches to 18 inches, and a 6-inch by 10-inchtrap may need 48 inches o space. Thus, maintaining pitch requires a very dierent site plan and pitchelevation plan. The designer should ensure that allburied piping drawings clearly show the nishedfoor elevation, slab thickness, and inverts at severalintervals along the piping run. Also note whetherthe inverts are shown or the inner or outer piping.
PIPE JOINING PRACTICESMechanical JointsMechanical joints include transition (fanged), com-pression, and threaded joints. Mechanical joints shallincorporate a positive mechanical system or axialrestraint in addition to any restraint provided byriction. All internal grab rings shall be manuacturedrom corrosion-resistant steel. Polyethylene sealing rings shall be Type 1 (LDPE) compound. Mechanical joints or chemical, special, or acid waste should neverbe installed where not accessible or routine mainte-nance (e.g., behind walls, buried, or above ceilings).
Compression JointsCompression-type gaskets have been used in pres-sure pipe joints or years. The compression joint useshub-and-spigot pipe and ttings (as does the lead andoakum joint). The major dierence is the one-pieceneoprene rubber gasket. When the spigot end o thepipe or tting is pulled or drawn into the gasketedhub, the joint is sealed by displacement and compres-sion o the neoprene gasket. The resulting joint is leakree, and it absorbs vibration and can be defected upto 5 degrees without leaking or ailing.
Gaskets are precision molded o durable neo-prene. Service gaskets must be used with service
weight pipe and ttings. Extra-heavy gaskets mustbe used with extra-heavy pipe and ttings. The stan-dard specication or rubber gaskets or joining castiron soil pipe and ttings is ASTM C564.
Neoprene does not support combustion, and gas-ket materials can be used saely up to 212°F. Maxi-mum defection should not exceed ½ inch per oot o pipe. This allows 5 inches o defection or a 10-ootpiece o pipe and 2½ inches or 5 eet o pipe. Formore than 5 degrees o defection, use ttings.
Lead and Oakum Joints (Caulked Joints)Hub-and-spigot cast iron soil pipe and tting jointscan be made with oakum ber and molten lead, whichprovides a leak-ree, strong, fexible, and root-proo joint. The waterproong characteristics o oakum -ber have long been recognized by the plumbing trades,and when molten lead is poured over the oakum in a
cast iron soil pipe joint, it completely seals and locksthe joint. This is because the hot lead lls a groovein the bell end o the pipe or tting, rmly anchoring the lead in place ater cooling.
To make a caulked joint, the spigot end o a pipeor tting is placed inside the hub o another pipe ortting. Oakum is placed around the spigot in the hubusing a yarning tool, and then the oakum is packedto the proper depth using a packing tool. Moltenlead is then poured into the joint, ensuring that thelead is brought up near the top o the hub. Aterthe lead has cooled suciently, it is caulked with a caulking tool to orm a solid lead insert. The result
is a lock-tight soil pipe joint with excellent fexuralcharacteristics. I horizontal joints are being made, a joint runner must be used to retain the molten lead.Customary saety precautions should be taken whenhandling molten lead.
Shielded Hubless Coupling The shielded hubless coupling system typically usesa one-piece neoprene gasket, or a shield o stain-less steel retaining clamps. The hubless coupling is manuactured in accordance with CISPI 310 and ASTM C1277.
The advantage o the system is that it permits
joints to be made in limited-access areas. 300 seriesstainless steel is always used with hubless couplingsbecause it oers resistance to corrosion, oxidation,warping, and deormation, rigidity under tensionwith substantial tension strength, and sucientfexibility. The shield is corrugated to grip the gasketsleeve and to give maximum compression distributionto the joint.
The stainless steel worm gear clamps com-press the neoprene gasket to seal the joint. The neo-prene gasket absorbs shock and vibration and com-pletely eliminates galvanic action between the castiron and the stainless steel shield. Neoprene does
not support combustion and can be used saely up to212°F. The neoprene sleeve is completely protectedby a nonfammable stainless steel shield, and as a result, a re rating is not required.
Joint defection using a shielded hubless coupling has a maximum limit o up to 5 degrees. Maximumdefection should not exceed ½ inch per oot o pipe.This allows 5 inches o defection or a 10-oot pieceo pipe. For more than 5 degrees o defection, t-tings should be used.
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Mechanicall Formed Tee Fittings orCopper TubeMechanically ormed tee ttings (see Figure 2-15)shall be ormed in a continuous operation consist-ing o drilling a pilot hole and drawing out thetube surace to orm a tee having a height o notless than three times the thickness o the branch
tube wall to comply with the American Welding Society’s lap joint weld. The device shall be ullyadjustable to ensure proper tolerance and com-plete uniormity o the joint.
The branch tube shall be notched to conormto the inner curve o the run tube and have twodimple/depth stops pressed into the branch tube,one ¼ inch (6.4 mm) atop the other to serve asa visual point o inspection. The bottom dimpleensures that the penetration o the branch tubeinto the tee is o sucient depth or brazing andthat the branch tube does not obstruct the fowin the main line tube. Dimple/depth stops shall
be in line with the run o the tube.Mechanically ormed tee ttings shall be
brazed in accordance with the Copper Develop-ment Association’s Copper Tube Handbook us-ing BCuP series ller metal.
Note that soldered joints are not permitted.Mechanically ormed tee ttings shall conormto ASTM F2014 and ANSI/ASME B31.9.
Mechanical Joining o Copper Tube
Press Connect and Push Connect
Press-connect and push-connect copper joining systems provide ast and clean installations or
both aboveground and belowground applica-tions. The systems do not require heat, whichoers aster and saer installation. Joints madeusing these systems are capable o withstanding pressure and temperature ranges common toresidential and commercial plumbing systems.
Roll Groove
Roll groove is another orm o mechanical joining that does not require heat. Many manuacturersprovide pipe and ttings already roll grooved oraster installation.
Brazing
Brazing is a process in which the ller metals (alloys)melt at a temperature greater than 840°F, and thebase metals (tube and ttings) are not melted. Themost commonly used brazing ller metals melt attemperatures rom 1,150°F to 1,550°F.
Soldering
Soldering is a process wherein the ller metal (solder)melts at a temperature o less than 840°F, and the basemetals (tube and ttings) are not melted. The mostcommonly used leak-ree solders melt at tempera-
Figure 2-15 Copper Pipe Mechanical T-jointSource: Courtesy o T-Drill
tures rom 350°F to 600°F. Lead-ree solders mustcontain less than 0.2 percent lead.
Soldered joints should be installed in accordancewith the requirements, steps, and procedures out-lined in ASTM B828 and the Copper Tube Handbook.Fluxes used or the soldering o copper and copperalloys shall meet the requirements o ASTM B813.
Joining Plastic Pipe PEX
PEX connections are made using PEX press stainlesssteel sleeves or PEX crimp rings. The connection mustmeet or exceed the requirement o ASTM F877 or theappropriate tting standard.
Vinyls and ABS
Schedule 80 plastic piping systems can be solventwelded or threaded. Schedule 40 can only be solventwelded.
The use o cleaners is not always a must. Howeveri dirt, grease, oil, or surace impurities are presenton the areas to be jointed, a cleaner must be used.
Cleaners must be allowed to evaporate completelybeore proceeding.Primers are used to prepare (soten) the surac-
es o the pipe and tting so the usion process canoccur. Unlike with the cleaner, the primer must bewet when the cement is applied. Specially ormu-lated one-step cements (no primer required) are alsoavailable. Most primers are pigmented with either a
Figure 2-18 Anchors and Inserts
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purple or an orange color because most model codesrequire visual evidence o their use. Clear primerscontaining an ultraviolet-sensitive ingredient alsoare available; under UV light they reveal their pur-ple color, which allows the visual evidence to be veri-ed while maintaining a clean look to the abricatedresults. The specier should conrm that the clearprimer is approved or use in the jurisdiction. Use o this primer should in no way relieve the contractor’sresponsibility or cleanliness. Spills should be avoid-ed and cleaned just as i the primer were colored.
Cements must be material specic and must beselected based on the application (pressure, non-pressure, chemicals, sizes, temperatures, etc.).
Assembling Flanged JointsThe ace o the lange should be cleaned with a solvent-soaked rag to remove any rust-preventivegrease. Any dirt should be cleaned rom the gas-ket. The pipe and the fanges should be aligned toeliminate any strain on the coupling. The gasket
should be coated with graphite and oil or some otherrecommended lubricant, inserted, and then bolted.Thread lubricant should be applied to the bolts, andthe bolts should be evenly tightened with a wrench.The nuts should be hand tightened. When tighten-ing the bolts, care should be exercised that they arediametrically opposed; adjacent bolts never shouldbe tightened. Special care is needed when assembling plastic fanges because no solvents or lubricants canbe used on the gaskets or bolts. The bolts should bediametrically tightened in 5 oot-pound incrementsand should not exceed the recommended torque rat-ing o the fange.
Making Up Threaded PipeMale and emale threads should be cleaned with a wire brush. Pipe dope should be applied only to themale thread. (I dope is applied to the emale thread,it will enter the system.) The pipe and coupling shouldbe aligned and hand tightened and then nishedby turning with a wrench. A ew imperect threadsshould be let exposed. Sections o the assembled pip-ing should be blown out with compressed air beorebeing placed in the system. Special care is neededwhen assembling plastic-threaded ttings; a properthread make-up can be achieved by rst assembling
the ttings nger-tight, ollowed by one to two turnso an appropriate strap wrench.
The use o an appropriate paste or tape threadsealant is recommended, but they must not be usedtogether. I tape is used, a TFE sealant with a mini-mum thickness o 2.5 mm is advised. Always cover theend o the tting at the start to prevent the threadrom seizing prior to proper joint makeup. Wrap thetape in the direction o the threads (e.g., clockwiseor a right-hand thread). For head adapters, use onlyFigure 2-18 Anchors and Inserts (continued)
two to three wraps o tape and tighten to the speciedtorque. For emale adapter transitions to metal pipe,use only ve wraps o tape.
Thread Cutting The pipe should be cut with a pipe cutter and clampedin a vise, where the pipe stock and die are engagedwith short jerks. The pipe should be protected when
clamped. When the cutter catches, it should be pulledslowly with a steady movement using both hands.Enough cutting oil should be used during the cutting process to keep the die cool and the edges clean. Thedie should be backed o requently to ree the cutters,and the ollower should be watched when reversing the dies to prevent jumping threads, cross-threading,or stripping threads.
Only PVC and CPVC Schedule 80, or heavier wallpipe, are suitable or threading. Either standard handpipe tools or a pipe-threading machine shall be used.Dies must be sharp and clean and should not be used tocut materials other than plastic pipe. A 5- to 10-degree
negative ront rake angle is preerable when cutting threads by hand. Care should be taken to center the dieon the pipe and align the thread to prevent reducing the wall excessively on one side. A tapered plug shouldbe tapped rmly into the end o the pipe to preventdistortion. This also provides additional support. Useonly lubricants compatible with the plastic material tobe threaded. Leaky threaded joints are usually causedby aulty or improper lubricants.
Welding Basic welding processes include electric arc, oxyacety-lene, and gas shielded. Commercial welding ttings
are available with ends designed or butt welding oror socket-joint welding. The type o joint used de-pends on the type o liquid, pressure in the system,pipe size and material, and applicable codes. The butt joint requently is used with a liner (backing ring).(See Figures 2-16 and 2-17.)
Electric Arc Welding
Electric arc welding is used or standard, extra-heavy,and double extra-heavy commercial steel pipe. ASTM A53 grades o low-carbon steel butt-welded pipe arethe most weldable.
Oxyacetylene Welding
In this welding process, the fame develops a tem-perature to 6,300°F (3,482.2°C), completely melting commercial metals to orm a bond. The use o a rodincreases strength and adds extra metal to the seam.This process is used with many metals (iron, steel,stainless steel, cast iron, copper, brass, aluminum,bronze, and other alloys) and can be used to join dis-similar metals. When cut on site, the pipe ends mustbe beveled or welding. This can be accomplished withan oxyacetylene torch.
Gas-Shielded Arcs
This process is good or nonerrous metals since fux isnot required, producing an extremely clean joint. Thetwo types o gas-shielded arc are tungsten inert gas(TIG) and metallic inert gas (MIG). Gas-shielded arcsare used or aluminum, magnesium, low-alloy steel,carbon steel, stainless steel, copper nickel, titanium,
and others.Joining Glass PipeGlass pipe joints are either bead to bead or beadto plain end. The bead-to-bead coupling is used or joining actory-beaded or eld-beaded-end pipe andttings. The bead-to-plain-end coupling is used to join a pipe section or tting that has a beaded end toa pipe section that has been eld cut to length andis not beaded.
Bending Pipe and Tubing Bending pipe or tubing is easier and more economicalthan installing ttings. Bends reduce the number o
joints (which could leak) and also minimize rictionloss through the pipe.
Pipe bending (cold or hot method) typically is donewith a hydraulic pipe bender. The radius o the bendshould be large enough to ree the surace o cracksor buckles (see ANSI/ASME B31.1). Some bends aredesigned specically to be creased or corrugated. Cor-rugated bends are more fexible than conventionaltypes and may have smaller radii. Straight sections o pipe sometimes are corrugated to provide fexibility.
Copper tube typically is bent with a spring tubebender, grooved wheel and bar, bending press, ormachine. Sharp bends are made by lling the pipe
with sand or other material to prevent fattening orcollapsing.
Electrousion Joining Electrousion is a heat-usion joining process whereina heat source is an integral part o the tting. Wherean electric current is applied, heat is produced, whichmelts and joins the components. Fusion occurs whenthe joint cools below the melting temperature o thematerial. When the cycle is completed there is nodelineation between the pipe and the tting. The ap-plicable standard is ASTM F1290.
Socket Fusion Joining Socket usion requires the use o a heater plate ttedwith properly sized heater bushings and spigots. Thepipe end and tting are inserted into the bushingsor a set time as dened by the manuacturer. Bothhandheld and bench machines are available or usein this joining method. Socket usion typically is usedin pure water and DWV systems.
Inrared Butt Fusion Joining This joining method utilizes inrared radiant heatto use the system components. The materials being
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joined never make contact with the heating surace,thus ensuring a clean, uncontaminated joint, typicallyused or pure water systems.
Beadless Butt Fusion Joining This usion process does not produce any seams orbeads on the inner wall o the pipes and/or ttingsbeing joined. It is used in ultra-pure water applica-
tions where any beads or crevices on the interiorpipe wall could lead to the buildup o contaminantswithin the fow stream. It also is used where the enduser requires the ability to completely drain the pip-ing system.
ACCESSORIES AND JOINTS
Anchors Anchors are installed to secure piping systems againstexpansion or contraction and to eliminate pipe varia-tion. During the installation o anchors, damage tobuilding walls or steel must be prevented. Common
anchor materials are strap steel, cast iron, angles, steelplate, channels, and steel clamps (see Figure 2-18).
Dielectric Unions and FlangesDielectric unions and fanges (see Figure 2-19) areinstalled between errous and nonerrous piping toprevent corrosion and to prevent electric currentsrom fowing rom one part o the pipe to another.The spacer should be suitable or the system pressureand temperature.
Epansion Joints and GuidesExpansion joints and guides (see Figure 2-20) are de-signed to permit ree expansion and contraction andto prevent excessive bending at joints, hangers, andconnections to the equipment caused by heat expan-sion or vibration. Expansion guides should be usedwhere the direction o the expansion is critical.
Figure 2-19 Dielectric Fittings Figure 2-20 Expansion Joints and Guides
Ball JointsBall joints are used in hydronic systems, wherepipe fexibility is desired, or positioning pipe, andwhere rotary or reciprocal movement is required.Ball joints are available with threaded, fanged, orwelded ends o stainless steel, carbon steel, bronze,or malleable iron.
Fleible Couplings (Compression or Slip)Flexible couplings (see Figure 2-21) do not requirethe same degree o piping alignment as fanges andthreaded couplings. They provide ¼ inch to ⅜ inch(6 mm to 9.5 mm) o axial movement because o theelasticity in the gaskets. These couplings should notbe used as slip-type expansion joints or as replace-ments or fexible expansion joints.
Gaskets (Flanged Pipe)Gaskets must withstand pressure, temperature, andattack rom the fuid in the pipe. Gaskets typicallyshould be as thin as possible. ANSI/ASME B16.21
designates the dimensions or nonmetallic gaskets.Mechanical CouplingsMechanical couplings (see Figure 2-22) are sel-cen-tering, lock-in-place grooves or shouldered pipe andpipe tting ends. The ttings provide some angularpipe defection, contraction, and expansion. Mechani-cal couplings oten are used instead o unions, weldedfanges, screwed pipe connections, and soldered tub-ing connections. Mechanical couplings are availableor a variety o piping materials, including steel andgalvanized steel, cast iron, copper tubing, and plastics.Bolting methods are standard and vandal resistant.
The gasketing material varies based on the fuid inthe piping system.
Pipe SupportsPipe can be supported using hangers, clamps, orsaddles (see Figure 2-23). Pipe should be securely
supported with an ample saety actor, and the sup-ports should be spaced according to the ollowing guidelines:
• Lessthan¾-inchpipe:On5-foot(1.5-m)centers
• 1-inchand1¼-inchpipe:On6-foot(1.8-m)cen-ters
• 1½-inchto2½-inchpipe:On10-foot(3.1-m)cen-ters
• 3-inch and4-inchpipe:On12-foot (3.7-m) cen-ters
• 6-inch and largerpipe:On 15-foot (4.6-m)centers
Horizontal suspended pipe should be hung using adjustable pipe hangers with bolted, hinged loops orturnbuckles. Chains, perorated strap irons, and fatsteel strap hangers are not acceptable. Pipes 2 inchesin diameter and smaller (supported rom the sidewall) should have an expansion hook plate. Pipes 2½
inches in diameter and larger (supported rom the sidewall) should have brackets and clevis hangers. Roll-ers should be provided wherever necessary. Trapezehangers, holding several pipes, may be preerred overindividual pipeline hangers. For individual hangers o pipes 2 inches in diameter and smaller, clevis hangersshould be used.
Where hangers are attached to concrete slabs, theslabs should have more concrete-reinorcing rods atthe point o support. The risers can be supported verti-cally using approved methods such as resting on thefoor slab with an elbow support, resting on the foorsleeve with a clamp, or anchoring to the wall.
Pipes installed in nished trenches or tunnelsshould rest on a suitable sidewall or foor supports.
Consideration must be given to seismic condi-tions when designing pipe supports. The designershould consult with local, state, and all other gov-erning agencies or specic requirements.
Hangers and Supports or Copper Piping
In addition to the ollowing instructions, the designershould consult the local plumbing, mechanical, orbuilding code or unique hanger spacing require-ments.First, install hangers or horizontal piping with the maximum spacing and minimum rod sizes as
Table 2-17 Maximum and Minimum RodSizes or Copper Piping
Nominal TubeSize, in.
Copper TubeMaximumSpan, t
Minimum RodDiameter, in.
Up to ¾ 5 3 ⁄ 8
1 6 3 ⁄ 8
1¼ 7 3 ⁄ 8
1½ 8 3 ⁄ 8
2 8 3 ⁄ 8
2½ 9 ½
3 10 ½
3½ 11 ½
4 12 ½
5 13 ½
6 14 5 ⁄ 8
8 16 ¾
10 18 ¾
12 19 ¾
Figure 2-24 Pipe Union
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shown in Table 2-17. Then, support vertical coppertube, copper pipe, or brass pipe at each foor. Finally,in areas where excessive moisture is anticipated, eitherthe piping or the support shall be wrapped with an ap-proved tape or otherwise isolated to prevent contactbetween dissimilar metals and to inhibit galvanic cor-rosion o the supporting member.
Pipe Unions (Flanged Connections)Pipe unions (see Figure 2-24) are installed at severallocations to acilitate dismantling. They typically areinstalled near control valves, regulators, water heaters,meters, check valves, pumps, compressors, and boilersso equipment can be readily disconnected or repair orreplacement. See Table 2-18 or dimensions.
Pipe SleevesFor pipes passing through walls, sleeves (see Figure2-25) should extend completely through the construc-tion, fush with each surace. The sleeves should becaulked with graphite packing and a suitable plasticwaterproo caulking compound. Pipe sleeves in ratedwalls are to be installed to suit the specic manuactur-
er’s hourly re rating. Packing and sealing compoundsshall be the required thickness to meet the specichourly ratings assembly.
Sleeves in bearing walls should be o steel, castiron, or terra-cotta pipe. Sleeves in other masonrystructures may be o sheet metal, ber, or other suit-able material. Sleeves or 4-inch pipe and smallershould be at least two pipe sizes larger than the pipepassing through. For larger pipes, sleeves should beat least one pipe size larger than the enclosed pipe.The inside diameter o pipe sleeves should be at least½ inch (12.7 mm) larger than the outside diameter o the pipe or covering.
Service Connections (Water Piping)Hand-drilled, sel-tapping saddle, or cut-in sleevesshould be used or water service connections. Two typeso cut-in sleeves are available: or pressures to 50 psi
(344.7 kPa) and or pressures to 250 psi (1,727.7 kPa).Tapping valves are or working pressures o 175 psi(1,206.6 kPa) or 2-inch to 12-inch (50.8-mm to 304.8-mm) pipe and 150 psi (1,034.2 kPa) or 16-inch pipe.
ExPANSION AND CONTRACTIONPiping subjected to changes in temperature expands(increases in length) and contracts (decreases inlength), and each material has its own expansion andcontraction characteristics. Piping expands as thetemperature increases and contracts as the tempera-ture decreases. The coecient o expansion (CE) o a material is the material’s characteristic unit increasein length per 1°F (0.56°C) temperature increase.CE values or various materials are given in Marks’Standard Handbook or Mechanical Engineers andmanuacturer literature.
I the piping is restrained, it will be subject to com-pressive (as the temperature increases) and tensile (asthe temperature decreases) stresses. The piping usu-
ally withstands the stresses; however, ailures mayoccur at the joints and ttings. Common methods toabsorb piping expansion and contraction are the useo expansion joints, expansion loops, and osets.
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APPENDIx 2-A
PIPE AND FITTINGS REFERENCESTANDARDS
The ollowing list includes the most common standardsencountered regarding plumbing pipe and ttings
materials. As standards are always being developed,revised, and withdrawn, consult the authority having jurisdiction or the applicable standards in the localarea.
Cast Iron Soil Pipe
ASTM A74: Standard Specifcation or Cast Iron Soil
Pipe and Fittings
ASTM A888: Standard Specifcation or Hubless Cast Iron Soil Pipe and Fittings or Sanitary and Storm Drain, Waste, and Vent Piping Applications
ASTM C564: Standard Specifcation or Rubber Gas-
kets or Joining Cast Iron Soil Pipe and Fittings ASTM C1540: Standard Specifcation or Heavy-Duty
Shielded Couplings Joining Hubless Cast Iron Soil
Pipe and Fittings
CISPI 301: Standard Specifcation or Hubless Cast
Iron Soil Pipe and Fittings or Sanitary and Storm Drain, Waste, and Vent Piping Applications
CISPI 310: Specifcation or Coupling or Use in Con-nection with Hubless Cast Iron Soil Pipe and Fit-
tings or Sanitary and Storm Drain, Waste, andVent Piping Applications
Ductile Iron Water and Sewer Pipe ANSI/AWWA C104: Cement-Mortar Lining or Duc-
tile Iron Pipe and Fittings
ANSI/AWWA C105: Polyethylene Encasement or Duc-tile Iron Pipe Systems
ANSI/AWWA C110: Ductile Iron and Gray Iron Fit-tings
ANSI/AWWA C111: Rubber Gasket Joints or Ductile Iron Pressure Pipe and Fittings
ANSI/AWWA C115: Flanged Ductile Iron Pipe with Ductile Iron or Gray Iron Threaded Flanges
ANSI/AWWA C116: Protective Fusion-Bonded EpoxyCoatings or the Interior and Exterior Suraces o
Ductile Iron and Gray Iron Fittings or Water Sup- ply Service
ANSI/AWWA C150: Thickness Design o Ductile Iron Pipe
ANSI/AWWA C151: Ductile Iron Pipe, CentriugallyCast, or Water
ANSI/AWWA C153: Ductile Iron Compact Fittings
ANSI/AWWA C600: Installation o Ductile Iron Water Mains and Their Appurtenances
AWWA C651: Disinecting Water Mains
ASTM A716: Standard Specifcation or Ductile Iron
Culvert Pipe
ASTM A746: Standard Specifcation or Ductile Iron
Gravity Sewer PipeConcrete
ASTM C14: Standard Specifcation or Nonreinorced
Concrete Sewer, Storm Drain, and Culvert Pipe
ASTM C76: Standard Specifcation or Reinorced
Concrete Culvert, Storm Drain, and Sewer Pipe
ASTM C443: Standard Specifcation or Joints or
Concrete Pipe and Manholes, Using Rubber Gas- kets
ASTM C655: Standard Specifcation or ReinorcedConcrete D-Load Culvert, Storm Drain, and Sewer
ASTM C12: Standard Practice or Installing Vitri- fed Clay Pipe Lines
ASTM C301: Standard Test Methods or Vitrifed
Clay Pipe ASTM C425: Standard Specifcation or Compres-
sion Joints or Vitrifed Clay Pipe and Fittings
ASTM C700: Standard Specifcation or Vitrifed
Clay Pipe, Extra Strength, Standard Strength,and Perorated
ASTM C828: Standard Test Method or Low-Pres- sure Air Test o Vitrifed Clay Pipe Lines
ASTM C896: Standard Terminology Relating to
Clay Products
ASTM C1091: Standard Test Method or Hydrostatic
Infltration Testing o Vitrifed Clay Pipe Lines
ASTM C1208: Standard Specifcation or Vitrifed
Clay Pipe and Joints or Use in Microtunneling,Sliplining, Pipe Bursting, and Tunnels
High-Silicon Iron
ASTM A518/A518M: Standard Specifcation or Cor-rosion-Resistant High-Silicon Iron Castings
ASTM A861: Standard Specifcation or High-Sili- con Iron Pipe and Fittings
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Valves3 Valves serve the purpose o controlling the fuids inbuilding service piping. They come in many shapes,sizes, design types, and materials to accommodatedierent fuids, piping, pressure ranges, and typeso service. Proper selection is important to ensurethe most ecient, cost-eective, and long-lasting
systems. No single valve is best or all services. (Note:This chapter is limited to manually operated valvesthat start, stop, regulate, and prevent the reversalo fow.)
The ollowing organizations publish standards andguidelines governing the use o valves:
• ManufacturersStandardizationSociety(MSS)ofthe Valve and Fittings Industry
• UnderwritersLaboratories(UL)
• FMGlobal
• AmericanPetroleumInstitute(API)
TyPES OF VALVES When selecting a valve, the ollowing service conditions should be taken intoconsideration:
• Pressure
• Temperature
• Type of uid: liquid, gas (steam orair), dirty or abrasive (erosive), cor-rosive
• Flow:on-off,throttling,needtopre-vent fow reversal, concern or pres-
sure drop, velocity
• Operating conditions: orientation,requency o operation, accessibility,overall space available, manual orautomated control, need or bubble-tight shuto, concerns about body joint leaks, re-sae design, speed o closure
Multi-turn valves include gate, globe,angle, and end connection. Quarter-turn
types include ball, butterfy, plug, and end connection.Check type valves include swing, list, silent or non-slam, and end connection.
Gate Valve With starting and stopping fow as its prime unction,
the gate valve is intended to operate either ully openor ully closed. The components o a gate valve areshown in Figure 3-1.
The gate valve uses a gate-like disc actuated by a stem screw and hand wheel that moves up and downat right angles to the path o fow and seats againsttwo aces to shut o fow. Since the disc o the gatevalve presents a fat surace to the oncoming fow,this valve should never be used to regulate or throt-tle fow. Flow through a partially open gate valve cre-
Figure 3-1 Gate Valve
HANDWHEEL NUT
HANDWHEEL
STEM
PACKING NUT
PACKING GLAND
PACKING
BONNET
UNION NUT
BODY
WEDGE
TYPICAL GATE VALVE
SOLID WEDGE DESIGN
DOUBLE WEDGE DESIGN
SPLIT WEDGE DESIGN
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ates vibration and chattering and subjectsthe disc and seat to inordinate wear.
Bypass valves should be provided wherethe dierential pressure exceeds 200 poundsper square inch (psi) (1,378 kilopascals[kPa]) on valves sized 4 to 6 inches (101.6 to152.4 mm) and 100 psi (689 kPa) on valves 8inches (203.2 mm) and larger. Bypass valvesshould be ½ inch (12.7 mm) or 4-inch(101.6-mm) valves and ¾ inch (19.1 mm) or5-inch (127-mm) and larger valves.
Disc and Seat Designs
Many dierent seats and discs suit the con-ditions under which the valve operates. Forrelatively low pressures and temperaturesand or ordinary luids, bronze and ironvalves are preerred. Bronze and iron valvesusually have bronze or bronze-aced seating suraces; iron valves may be all iron. Stain-less steel is used or high-pressure steam and
erosive media. Nonmetallic composition discsare available or tight seatings or hard-to-hold fuids, such as air and gasoline.
Gate discs can be classied as solid-wedge discs,double discs, or split-wedge discs. In the solid-wedgedesign, a single tapered disc, thin at the bottom andthicker at the top, is orced into a similarly shapedseat. In the double and split-wedge disc designs, twodiscs are employed back to back, with a spreading device between them. As the valve wheel turns, thegate drops into its seat (as with any other gate valve),but on the nal turns o the wheel, the spreaderorces the discs outward against the seats, eecting tight closure.
Metal-to-metal seating is not the best choice orrequent operation. Bubble-tight seating should notbe expected with the metal-to-metal design.
Another type, resilient wedge, is a rubber-encapsu-lated metal wedge that seals against an epoxy-coatedbody. The resilient wedge design is limited to coldwater applications.
Globe ValveThe globe valve (see Figure 3-2), which is named or theshape o its body, is much more resistant to fow thanthe gate valve, as can be seen by examining the path
o fow through it. Its main advantages over the gatevalve are its use as a throttling valve to regulate fow,positive bubble-tight shuto when equipped with a resilient seating, and its ease o repair. It also is good orrequent operation. On the negative side, the fow pathcauses a signicant pressure drop, and globe valves aretypically more expensive than other valves.
Because all contact between the seat and the discends when fow begins, the eects o wire drawing (seat erosion) are minimized. The valve can operate
just barely open or ully open with little change inwear. Also, because the disc o the globe valve travelsa relatively short distance between ully open andully closed, with ewer turns o the wheel required,an operator can gauge the rate o fow by the num-ber o turns o the wheel.
Disc and Seat Designs
As with the gate valve, many disc and seat ar-rangements are available. These are classied asconventional disc, plug type, and composition disc.
The conventional disc is relatively fat, with bevelededges. On closure, it is pushed down into a beveled,circular seat. Plug-type discs dier only in that theyare ar more tapered, thereby increasing the contactsurace between the disc and the seat. This charac-teristic has the eect o increasing their resistanceto the cutting eects o dirt, scale, and other oreignmatter. The sliding action o the semi-plug disc as-sembly permits the valve to serve as a shuto valve,throttling valve, or check valve.
The composition disc diers rom the others in thatit does not t into the seat opening, but over it—muchas a bottlecap ts over the bottle opening. This seat
adapts the valve to many services, including use withhard-to-hold substances such as compressed air, andmakes it easy to repair.
Resilient (sot) seat discs are preerred over metalto metal, except where temperature, very close throt-tling, or abrasive fow makes all-metal seating a betterchoice. Stainless steel trim is available or medium-to high-pressure steam and abrasive applications.Tetrafuoroethylene (TFE) is the most resilient discmaterial or most services, although rubber’s sotness
provides good perormance in cold water. TFE is goodup to 400°F (204.4°C). Nitrile rubber (Buna-N) is goodup to 200°F (93.3°).
Angle Valve Akin to the globe valve, the angle valve (see Figure3-3) can decrease piping installation time, labor, andmaterials by serving as both a valve and a 90-degreeelbow. It is less resistant to fow than the globe valve,as fow must change direction twice instead o threetimes. It is also available with conventional, plug type,and composition discs.
Ball ValveThe ball valve derives its name rom the drilled ballthat swivels on its vertical axis and is operated by a handle. Its advantages are its straight-through fow,minimum turbulence, low torque, bubble-tight clo-sure, and compactness. Also, a quarter turn o thehandle makes it a quick-closing or quick-opening valve. Reliability, ease o maintenance, and durabil-ity have made the ball valve popular in industrial,chemical, and gas transmission applications. On thedownside, the cavity around the ball traps media
and does not drain entrapped media. Ball valves aresusceptible to reezing, expansion, and increasedpressure due to increased temperature.
Body StylesBall valves are available in one-, two-, and three-piecebody types, as shown in Figure 3-4. The one-piecebody is machined rom a solid bar o stock material
or is a one-piece casing. The ball is inserted in the endor assembly, and the body insert that acts as the seatring is threaded in against the ball. One-piece valveshave no potential body leak path, but they do have a double-reduced port; thus, signicant pressure dropoccurs. Not repairable, they are used primarily bychemical and rening plants.
The two-piece body is the same as the one-piecevalve, except that the body insert is larger and acts asan end bushing.Two-piece end entries are used mostcommonly in building services. They are the bestvalue valves and are available in ull- or standard-portballs. They are recommended or on/o or throttling
service and are not recommended to be repaired.The three-piece body consists o a center body sec-
tion containing the ball that ts between two body endpieces. Two or more bolts hold the assembly together.Three-piece valves are costly but are easy to disas-semble and oer the possibility o inline repair. Theyare available in ull- or standard-port balls.
Port SizeFull-port ball valves provide a pressure drop equalto the equivalent length o the pipe, slightly betterthan gate valves.
Standard-port (conventional) balls are up to one
pipe size smaller than the nominal pipe size but stillhave signicantly better fow characteristics thanglobe valves.
Reduced-port ball valves have greater than onepipe size fow restriction and are not recommended inbuilding service piping, but rather are used or processpiping or hazardous material transer.
Handle ExtensionsInsulated handle extensions or extended handlesshould be used to keep insulated piping systemsintact.
Figure 3-3 Angle Valve
HANDWHEEL NUT
HANDWHEEL
STEM
PACKING NUT
PACKING
BONNET
BODY
SEAT DISC
OUTLET
INLET
TYPICAL ANGLE VALVE
Figure 3-4 Ball Valves
TYPICAL ONE-PIECE TYPE YPICAL TWO-PIECE TYPE
TYPICAL THREE-PIECE TYPE
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Butterf ValveThe butterfy valve (see Figure 3-5) is the valve mostcommonly used in place o a gate valve in cases whereabsolute, bubble-ree shuto is required. It oersquick, 90-degree open and close and is easier to au-tomate than multi-turn valves.
In addition to its tight closing, one o the valve’sadvantages is that it can be placed in a very smallspace between pipe fanges. It is available with sev-eral types o motorized and manual operators anda variety o component material combinations. A broad selection o trim materials is available tomatch dierent fuid conditions. Butterfy valvesare very cost-eective compared to alternative valvechoices, and they oer a long cycle lie.
Butterfy valves cannot be used with steam, andgear operators are needed or 8-inch and larger valvesto aid in operation and to protect against operating too quickly and causing destructive line shock.
Body StylesThe two most common body types are the waerbody and lug body. The waer body is placed betweenpipe fanges, and the fange bolts surround the valvebody. They are easy to install but cannot be used asisolation valves.
Lug-style valves have waer bodies with tappedlugs matching the bolt circles o class 125/150-poundfanges. They are easily installed with cap screwsrom either side. Screwed-lug valves can be providedso that equipment may be removed without draining down the system.
Groove butterfy valves directly connect to pipeusing iron pipe size, grooved couplings. While morecostly than waer valves, grooved valves are easierto install.
Check ValveSwing checks and lit checks (see Figure 3-6) are themost common types o check valve. Both are designedto prevent reversal o fow in a pipe. The swing checkpermits straight-through fow when open and is,thereore, less resistant to fow than the lit check.
When installed in vertical installations and toensure immediate closure upon reversal o fow, thecheck valve should be o the spring-loaded (non-slam-ming) type. I reverse fow is not stopped immediately,
the backfow velocity could increase to a point thatwhen closure occurs, the resulting shock could causeserious damage to the valve and system.
The lit check is primarily used with gases orcompressed air or in fuid systems where pressuredrop is not critical.
Design Details
Swing-type check valves oer the least pressure dropand simple automatic closure. When fuid fow stops,gravity and fow reversal close the valve. Many bronzevalves oer a Y-pattern body with an angle seat orimproved perormance. Resilient Tefon seating is
preerred or tight shuto.Lit checks come in an inline or globe-style body
pattern. Both cause greater pressure drop than theswing type, with the horizontal pattern similar inrestriction to globe valves.
Some styles are spring actuated and center guidedor immediate closure when fow stops. The inline,
Figure 3-6 Check Valves
OUT IN
OUT
OUT
IN
IN
SWING TYPE LIFT TYPESPRING-LOADEDNON-SLAMMING TYPE
spring-actuated lit check is also reerred to as thesilent check because the spring closes the valve beoregravity and fuid reversal can slam the valve closed.Resilient seating is recommended.
Double-disc check valves have twin discs on a spring-loaded center shat. These valves have betterfow characteristics than lit checks and most oten
use a waer body or low cost and easy installation.Resilient seating is recommended.
Plug ValveThe plug valve has a quarter-turn design similar to a ball valve, with the ball replaced by a plug. The plug can be round, diamond, or rectangular (standard).The plug valve typically requires a higher operating torque or closure, meaning specialized wrenchesor expensive automation packages are required.However, it has a mechanism or power operation orremote control o any size and type to operate withair, oil, or water.
Plug valves oer bubble-tight shuto rom a stemseal o reinorced Tefon as well as quick, 90-degreeopen and close. Flow through the valve can bestraight through, unobstructed, bidirectional, threeway, or our way. Plug valves oer a long cycle lieand an adjustable stop or balancing or throttling service.
Plug valves are available in lubricated, non-lubricated, and eccentric types. The lubricated,sealed check valve and combination lubricant screwand button head tting prevent oreign matter rombeing orced into the lubrication system. However,the temperature and pressure ranges are limited
by the type o lubricant sealant and ANSI standardrating. The non-lubricating type eliminates periodiclubrication and ensures that the valve’s lubricationdoes not contaminate the process media or aect anydownstream instrumentation. The eccentric type isbasically a valve with the plug cut in hal. The ec-centric design allows a high achieved seating orcewith minimal riction encountered rom the open toclosed positions.
VALVE MATERIALS A valve may be constructed o several materials. Forexample, it may have a bronze body, monel seat, and
an aluminum wheel. Metallic materials include brass,bronze, cast iron, malleable iron, ductile iron, steel,and stainless steel. Nonmetallic materials are typi-cally thermoplastics. Material specications dependon the operating conditions.
Brass and BronzeBrass usually consists o 85 percent copper, 5 percentlead, 5 percent tin, and 5 percent zinc. Bronze hasa higher copper content, ranging rom 86 percent to90 percent, with the remaining percentage divided
among lead, tin, and zinc. Due to lead-ree legislationin many states and the ederal government, manu-acturers are decreasing or eliminating the amounto lead in their products that are used in systemsconveying water meant or human consumption.
Under certain circumstances, a phenomenonknown as dezincication occurs in valves or pipes
containing zinc. The action is a result o electrolysis;in eect, the zinc is actually drawn out and removedrom the brass or bronze, leaving a porous, brittle,and weakened material. A higher zinc content leadsto greater susceptibility to dezincication. To slowor prevent the process, tin, phosphorus antimony,and other inhibitors are added.
Brass valves should not be used or operating temperatures above 450°F (232.2°C). The maxi-mum operating temperature or bronze is 550°F(287.8°C).
IronIron used in valves usually conorms to ASTM A126-04: Standard Specifcation or Gray Iron Castings or
Valves, Flanges, and Pipe Fittings. Although iron-bodied valves are manuactured in sizes as small as¼-inch (6.4-mm) nominal diameter, they are mostcommonly stocked in sizes o 2 inches (50.8 mm) andabove. In these larger sizes, they are considerably lessexpensive than bronze.
The higher weight o iron valves, as comparedto bronze valves, should be considered when deter-mining hanger spacing and loads. A typical 2-inch(50.8-mm) bronze screwed globe valve rated at125 psi (861.3 kPa) weighs about 13 pounds (5.9
kg). The same valve in iron weighs 15 pounds (6.8kg) and, i specied with a yoke bonnet, about 22pounds (10 kg).
Malleable IronMalleable iron valves are stronger, stier, and tougherthan iron-bodied valves and hold tighter pressures.Its toughness is most valuable or piping subjectedto stresses and shocks.
Stainless SteelFor highly corrosive fuids, stainless steel valvesprovide the maximum corrosion resistance, highstrength, and good wearing properties. Seating sur-
aces, stems, and discs o stainless steel are suitablewhere oreign materials in the fuids handled couldhave adverse eects.
ThermoplasticMany dierent types o thermoplastic materialsare used or valve construction. Plastic valvesgenerally are limited to a maximum temperatureo 250°F (121.1°C) and a maximum pressure o 150psi (1,035 kPa).
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VALVE RATINGSMost valve manuacturers rate their products interms o saturated steam pressure, pressure o non-
shock cold water, oil, or gas (WOG), or both. Theseratings usually appear on the body o the valve. Forinstance, a valve with the markings “125” with “200 WOG” will operate saely at 125 psi (861.3 kPa) o saturated steam or 200 psi (1,378 kPa) o cold water,oil, or gas.
The engineer should be amiliar with the mark-ings on the valves specied and should keep themin mind during construction inspection. A rupturedvalve can do much damage.
VALVE COMPONENTS
StemsStem designs all into our basic categories: rising
stem with outside screw, rising stem with inside screw,nonrising stem with inside screw, and sliding stem(see Figure 3-7).
Rising Stem with Outside Screw
This design is ideal where the valve is used inre-quently and the possibility o sticking constitutes a hazard, such as in a re protection system. In thisarrangement, the screws are not subject to corrosionor elements in the line fuid that might cause damage
because they are outside the valve body. Also, being outside, they can be lubricated easily.
As with any other rising stem valve, sucientclearance must be allowed to enable a ull opening.
Rising Stem with Inside Screw
This design is the simplest and most common stemdesign or gate, globe, and angle valves. The position
o the hand wheel indicates the position o the disc,opened or closed.
Nonrising Stem
These are ideal where headroom is limited, but theygenerally are limited to use with gate valves. In thistype, the screw does not raise the stem, but ratherraises and lowers the disc. As the stem only rotatesand does not rise, wear on packings is lessenedslightly.
Sliding Stem
These are applied where quick opening and closing are required. A lever replaces the hand wheel, and
stem threads are eliminated.BonnetsIn choosing valves, the service characteristics o thebonnet joint should not be overlooked. Bonnets andbonnet joints must provide a leak-proo closure. Manymodications are available, but the three most com-mon types are screwed-in bonnet, screwed union-ring bonnet, and bolted bonnet.
Screwed-in Bonnet
This is the simplest and least expensive construction,requently used on bronze gate, globe, and anglevalves and recommended where requent dismantling
is not needed. When properly designed with running threads and careully assembled, the screwed-inbonnet makes a durable, pressure-tight seal that issuitable or many services.
Screwed Union-Ring Bonnet
This construction is convenient where valves needrequent inspection or cleaning and also or quickrenewal or changeover o the disc in composition discvalves. A separate union ring applies a direct load onthe bonnet to hold the pressure-tight joint with thebody. The turning motion used to tighten the ring issplit between the shoulders o the ring and bonnet.
Hence, the point-o-seal contact between the bonnetand the body is less subject to wear rom requentopening o the joint.
Contact aces are less likely to be damaged in han-dling. The union ring gives the body added strengthand rigidity against internal pressure and distortion.
While ideal on small valves, the screwed union-ring bonnet is impractical on large sizes.
Bolted Bonnet Joint
A practical and commonly used joint or large valvesor or high-pressure applications, the bolted bonnet joint has multiple boltings with small-diameter boltsthat permit equalized sealing pressure without theexcessive torque needed to make large threaded joints.Only small wrenches are needed.
End Connections Valves are available with screwed, welded, brazed,soldered, fared, fanged, hub, and press-tted ends.
Screwed End
The most widely used type o end connection is thescrewed end. It is ound in brass, iron, steel, and alloypiping materials. It is suited or all pressures but usu-ally is conned to small pipe sizes. It is more dicultto make the screwed joint with larger pipe sizes.
Welded End
Welded ends are available only in steel valves andttings and is mainly or high-pressure and high-
temperature services. It is recommended or lines notrequiring requent dismantling. The two welded-endtypes are butt and socket welding. Butt-welding valvesand ttings come in all sizes; socket-welding ends arelimited to small sizes.
Brazed End
Brazed ends are available in brass materials becausethe ends o such materials are specially designed orthe use o brazing alloys to make the joint. When theequipment and brazing material are heated with a welding torch to the temperature required by thealloy, a tight seal is ormed between the pipe and the
valve or tting. While made in a manner similar toa solder joint, a brazed joint can withstand highertemperatures due to the brazing materials used.
Soldered Joint
Soldered joints are used with copper tubing or plumb-ing and heating lines and or many low-pressureindustrial services. The joint is soldered by applying heat. Because o the close clearance between the tub-ing and the socket o the tting or valve, the solderfows into the joint by capillary action. The use o soldered joints under high temperatures is limitedbecause o the low melting point o the solder. Silversolder or sil-os (silver-copper-phosphorus) is used orhigh pressures and temperatures.
Flared End
The fared end is commonly used on valves and ttingsor metal and plastic tubing up to 2 inches (50.8 mm)in diameter. The end o the tubing is skirted or fared,and a ring nut is used to make a union-type joint.
Flanged End
Flanged ends generally are used when screwed orsoldered ends become impractical because o cost, size,
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or the strength o the joint. They typically are used orlarge-diameter lines due to their ease o assembly anddismantling. Flanged acings are available in variousdesigns depending on the service requirements. Oneimportant rule is to match acings. When bolting ironvalves to orged steel fanges, the acing should be o the fat ace design on both suraces.
Hub EndThe hub end generally is limited to valves or water-supply and sewage piping. The joint is assembled onthe socket principle, with the pipe inserted in the hubend o the valve or tting.
Press-Fitted End
The press-tting method involves crimping the endswith a crimping tool around an ethylene propylenediene monomer (EPDM) seal to orm a water-tightconnection.
WATER PRESSURE REGULATORS A pressure regulator is an automatic valve controlledby an inner valve connected to a diaphragm or pistonor both. The diaphragm, held in the extreme travel(open) position by a preloaded spring, is positionedin the downstream portion o the valve and closes thevalve when the desired pressure has been reached.
The eectiveness o the diaphragm and theamount o preloading must be related to allow thediaphragm to move the inner valve to the extremeopposite travel (closed) position immediately aterthe pressure on the diaphragm passes the desiredoperating pressure. To change the operating pres-sure, tension on the diaphragm is increased or de-
creased by turning the adjusting screw. A regulator typically does not go rom closed to
ully open or rom open to ully closed immediately,but moves between these extreme positions in re-sponse to system requirements. The regulator ad- justs to a ully open position instantaneously only i maximum system demand is imposed quickly, whichis not a common occurrence unless the regulator isundersized. The degree o valve opening, thereore,depends entirely on the regulator’s ability to senseand respond to pressure changes.
A reducing pressure change that causes a valveto open is known as a reduced pressure all-o, or
droop, and is an inherent characteristic o all sel-operated or pilot-operated regulators. Technically,all-o is expressed as the deviation in pressure romthe set value that occurs when a regulator strokesrom the minimum fow position to a desired fowposition. The amount o all-o necessary to open a valve to its rated capacity varies with dierent typeso valves.
It is important to realize that the installation o a regulator sets up a closed system; thereore, it is
necessary to install a relie valve and expansion tankto eliminate any excessive pressure caused by ther-mal expansion o the water in the water heater orhot water storage tank.
Every manuacturer makes regulators with anintegral bypass to eliminate relie valve dripping caused by thermal expansion. During normal opera-tion, the bypass is held closed by high initial pres-sure. However, when thermal expansion pressureequals initial pressure, the bypass opens, passing theexpanded water back into the supply line. The eec-tiveness o this eature is limited to systems whereinitial pressure is less than the pressure setting o the relie valve. The integral bypass is not a replace-ment or the relie valve. It is used only to eliminateexcessive drip rom the relie valve.
Regulator Selection and Sizing Selection o the correct type o regulator dependsentirely on the accuracy o regulation required.The valve plug in oversized valves tends to remain
close to the seat, causing rapid wire drawing andexcessive wear. Unortunately, no set standard orrating a pressure-regulating valve or or sizing it to the system capacity exists. The many meth-ods proposed or selecting the proper valve areoten a cause o conusion to the engineer.
The capacity rating o a pressure-regulating valve usually is expressed in terms o some singlevalue. This value, to be useul, must speciy all o theconditions under which the rating was established.Otherwise, it is impossible to adapt it to dierentsystem conditions.
Manuacturers attempt to recognize the inherentcharacteristics o their own design and to stipulatethose actors that, in their opinion, must be consid-ered in sizing the valve to the system. Some stressthe importance o the dierence between initial andreduced pressure—the dierential pressure. Setpressure and allowable reduced pressure all-o arevery important actors in sizing a valve. A all-o o 15 to 17 psi (103.4 to 117.1 kPa) is considered rea-sonable or the average residential installation and,in well-designed valves, produces a good rating.
Another procedure or establishing valve peror-mance is based on fow rate, with a reduced pressure
all-o o 15 to 17 psi (103.4 to 117.1 kPa) below thereduced lockup or no-fow pressure. For general use,this approach provides an adequate means o valveselection. However, it is not specic enough to en-able the selection o the valve best suited to the par-ticular conditions.
Other manuacturers rate their valves based ona stipulated fow rate at a specic pressure dieren-tial, with the valve open to the atmosphere, withoutregard to changes in pressure drop when the systemdemand is zero. This method does not provide ample
inormation or proper judgment o valve behaviorand capability, which could result in the selection o a valve that, under no-demand conditions, permitsa reduction in pressure great enough to damageequipment in the system. The maximum pressurepermitted under no-fow conditions is a very impor-tant actor, or both physical and economic reasons,and should be stipulated in the specication.
The rule o thumb requently employed is a size-to-size selection—that is, using a valve withthe same connection size as the pipeline in whichit will be installed. This is a gamble inasmuch asthe actual capacities o many valves are inadequateto satisy the service load specied or a pipeline o corresponding size. Consequently, the system maybe starved, and the equipment may operate in aninconsistent manner.
The only sound valve selection procedure to ol-low is to capacity size a valve on the basis o knownperormance data related to system requirements.
Common Regulating Valves Direct Acting, Diaphragm Actuated
This valve is simple in construction and operation,requiring minimum attention ater installation. Thedirect-acting, diaphragm-actuated pressure regulatordoes not regulate the delivery pressure with extremeaccuracy.
Pilot Operated
The pilot-controlled valve operates eciently becausethe pilot magnies the control valve travel or a givenchange in control pressure.
The pilot-type regulator consists o a small, di-
rect-acting, spring-loaded valve and a main valve.The pilot valve opens just enough to supply the nec-essary pressure to operate the main valve. Extremeaccuracy is aected as a constant load exists on theadjusting spring, and variations in initial pressurehave little eect.
Direct Acting, Balanced Piston
This valve is a combination piston and diaphragmand requires little attention ater installation. Withthe dependability o the diaphragm and the simplicityo direct action, this valve is only slightly aected byvariations in initial pressure.
Booster Pump ControlThis is a pilot-operated valve designed to eliminatepipeline surges caused by the starting and stopping o a booster pump. The pump starts against a closedvalve, and ater the pump starts a solenoid valve isenergized, slowly opening the valve and allowing theline pressure to gradually increase to ull pumping head. When the pump shuts o, the solenoid is de-energized, and the valve slowly closes as the pump
continues to run. When the valve is ully closed, thepump stops.
Level Control
This non-modulating valve is used to accurately con-trol the liquid level in a tank. The valve opens ullywhen a preset liquid low point is reached and closesdrip tight when the preset high point is reached.
This is a hydraulically operated diaphragm valvewith the pilot control and foat mechanism mountedon the cover.
Common Tpes o Regulator Installations
Single Regulator in Supply Line
This type o installation is most common in domesticservice and is sel-explanatory.
Two Regulators in Series in Supply Line
This type o installation provides extra protectionwhen the main pressure is so excessive that it mustbe reduced to two stages to prevent high-velocitynoise in the system.
Multiple Regulators Used as a Battery inSupply Line
In many instances, a battery installation is preerableto the use o a single valve, as it provides more preciseregulation over a wide demand variation.
This type o installation consists o a group o parallel regulators, all receiving water rom a com-mon maniold. Ater fowing through the battery o valves, water enters a common maniold o sucientsize to service the system at the reduced pressure.The battery installation is advantageous because itallows maintenance work to be perormed without
the necessity o turning o the entire system. It alsoprovides better perormance where demands varyrom one extreme to the other.
For example, at a school with a 3-inch (76.2-mm)service, demand on drinking ountains during class-es may be approximately 6 to 7 gallons per minute(gpm) (22.7 to 26.5 lpm). However, between classes,when all services are in use, the demand may be ata maximum. With a single 3-inch (76.2-mm) regu-lator in the system, when the aucet is turned on,the regulator must open to allow a small draw. Eachtime this is done, it cuts down on the service lie o the large regulator.
In comparison, with a battery installation o twoor three regulators set at a graduated pressure, withthe smallest valve set 2- to 3-psi (13.8- to 20.7-kPa)higher than the larger ones, the system is more e-cient. For a small demand, only the smallest valveopens. As the demand increases, the larger valvesalso open, providing the system with the capacity o all valves in the battery.
VALVE SIZING AND PRESSURELOSSES Valve size and valve pressure losses can be determinedutilizing a fow coecient (C V ), which is the numbero gallons per minute (lpm) that will pass througha valve with a pressure drop o 1 psi (6.9 kPa). C V is determined by physically counting the number o
gallons (liters) that pass through a valve with 1-psi(6.9-kPa) applied pressure to the valve inlet and zeropressure at the outlet. The C V coecient or specicvalves can be obtained rom the valve manuacturer.Since the C V actor varies in relation to valve size,the C V can be used to determine the proper size valveor the amount o fow at a given pressure drop or,conversely, the pressure drop at a given fow. Theormulas or this are:
Equation 3-1a
Q = C V √P/G
Equation 3-1b
C V =Q
√∆P/G
Equation 3-1c
∆P = [Q/C V ]2
G
whereG = Specic gravity o the fuid
∆P = Pressure drop across the valveQ = Flow through the valve
C V = Valve fow coecient
HOT AND COLD DOMESTIC WATERSERVICE VALVE SPECIFICATIONS
Gate Valves 2 Inches and Smaller Valves 2 inches and smaller shall be class 125, rated125-psi SWP and 200-psi nonshock CWP, and have a rising stem. The body, union bonnet, and solid wedgeshall be o ASTM B62 cast bronze with soldered ends.Stems shall be o dezincication-resistant siliconbronze (ASTM B371 ) or low-zinc alloy (ASTM B99 ). Packing glands shall be bronze (ASTM B62), witharamid ber nonasbestos packing and malleable hand
wheel. Valves shall comply with MSS SP-80.
Gate Valves 2½ Inches and Larger Valves 2½ inches and larger shall be class 125, rated100-psi SWP and 150-psi nonshock CWP, and have aniron body and bronze-mounted outside screw and yoke(OS&Y). The body and bolted bonnet shall conormto ASTM A126 class B cast iron, with fanged ends,aramid ber nonasbestos packing, and two-piecepacking gland assembly. Valves shall comply withMSS SP-70.
All domestic water valves 4 inches and largerthat are buried in the ground shall be o iron bodyand bronze tted, with an O-ring stem seal. Theyshall have epoxy coating (AWWA C550) inside andoutside and a resilient-seated gate valve with non-rising stem and mechanical joint or fanged ends asrequired. All valves urnished shall open let. Allinternal parts shall be accessible without removing the valve body rom the line. Valves shall conormto ANSI/AWWA C509.
Ball Valves 2 Inches and Smaller Valves 2 inches and smaller shall be rated 150-psiSWP and 600-psi nonshock CWP and have two-piece,cast brass bodies, replaceable reinorced Tefon seats,¼-inch to 1-inch ull port or 1¼-inch to 2-inch conven-tional port, blowout-proo stems, chrome-plated brassball, and threaded, soldered, or press-t ends. Valvesshall comply with MSS SP-110. Provide extendedstems or valves in insulated piping.
Globe Valves 2 Inches and Smaller Valves 2 inches and smaller shall be class 125 andrated 125-psi SWP and 200-psi nonshock CWP. Thebody and bonnet shall be o ASTM B62 cast bronzecomposition with threaded or soldered ends. Stemsshall be o dezincication-resistant silicon bronze(ASTM B371) or low-zinc alloy (ASTM B99). Pack-ing glands shall be bronze (ASTM B62), with aramidber nonasbestos packing and malleable hand wheel. Valves shall comply with MSS SP-80.
Globe Valves 2½ Inches and Larger Valves 2½ inches and larger shall be class 125 andrated 125-psi SWP and 200-psi nonshock CWP. Theyshall have an iron body, bronze mounted, and OS&Y,with the body and bolted bonnet conorming to ASTM A126 class B cast iron, with fanged ends, aramid bernonasbestos packing, and two-piece packing glandassembly. Valves shall comply with MSS SP-85.
Butterf Valves 2½ Inches and Larger Valves 2½ inches and larger shall be rated 200-psinonshock CWP and have a lug or IPS grooved-typebody with a 2-inch extended neck or insulating. Theyshall be cast or ductile iron (ASTM A536 or ASTM A126) with an aluminum bronze disc, 416 stainlesssteel stem, EPDM O-ring stem seals, and resilient,
EPDM cartridge-lined seat.Sizes 2½ inches to 6 inches shall be lever operated
with a 10-position throttling plate.Sizes 8 inches to 12 inches shall have gear opera-
tors. Sizes 14 inches and larger shall have worm gearoperators only. They are suitable or use as bidirec-tional isolation valves and, as recommended by themanuacturer, on dead-end service at ull pressurewithout the need or downstream fanges.
Valves shall comply with MSS SP-67.
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Note: Butterfy valves in dead-end service requireboth upstream and downstream fanges or propershuto and retention or must be certied by themanuacturer or dead-end service without down-stream fanges.
Check Valves 2 Inches and Smaller Valves 2 inches and smaller shall be class 125 and
rated 125-psi SWP and 200-psi nonshock CWP. Theyshall have threaded or soldered ends, with the bodyand cap conorming to ASTM B62 cast bronze com-position and a Y-pattern swing-type disc. Valves shallcomply with MSS SP-80
Note: Class 150 valves meeting the above speci-cations may be used where system pressure re-quires. For class 125 seat discs, speciy Buna-N or WOG service and TFE or steam service. For class150 seat discs, speciy TFE or steam service.
Check Valves 2½ Inches and Larger Valves 2½ inches and larger shall be class 125 and
rated 125-psi SWP and 200-psi nonshock CWP. Theyshall have an iron body, bronze mounted, with thebody and bolted bonnet conorming to ASTM A126class B cast iron, with fanged ends, swing-type disc,and nonasbestos gasket. Valves shall comply withMSS SP-71.
Alternative check valves (2½ inches and larger)shall be class 125/250 iron body, bronze mounted, wa-er check valves, with ends designed or fanged-typeconnection, aluminum bronze disc, EPDM seats, 316stainless steel torsion spring, and hinge pin.
A spring-actuated check valve is to be used onpump discharge. A swing check with outside lever
and spring (not center guided) is to be used on sew-age ejectors or storm water sump pumps.
COMPRESSED AIR SERVICE VALVESPECIFICATIONS
Ball Valves 2 Inches and SmallerMain line valves 2 inches and smaller shall be rated150-psi SWP and 600-psi nonshock CWP. They shallhave two-piece, cast bronze bodies, with reinorcedTefon seats, a ull port, blowout-proo stems, chrome-plated brass ball, and threaded or soldered ends. Valves shall comply with MSS SP-110.
Branch line valves 2 inches and smaller shall berated 150-psi SWP and 600-psi nonshock CWP andhave two-piece, cast bronze (ASTM B584) bodies withreinorced Tefon seats. Full-port ¼-inch to 1-inchvalves and conventional-port 1¼-inch to 2-inchvalves require blowout-proo stems, a chrome-platedbrass ball with a saety vent hole on the downstreamside, threaded or soldered ends, and lockout/tagouthandles, which must meet the requirements o Occu-pational Saety and Health Administration (OSHA)
Butterf Valves 2½ Inches and Larger Valves 2½ inches and larger shall be rated 200-psinonshock CWP. Valves shall be lug or IPS, grooved-type body and shall be cast or ductile iron (ASTM A536) with a Buna-N seat, ductile iron, aluminum
bronze disc, ASTM A582 Type 416 stainless steelstem, and Buna-N O-ring stem seals.
Sizes 2½ inches to 6 inches shall be lever operatedwith a 10-position throttling plate.
Sizes 8 inches to 12 inches shall have gear opera-tors. Lever-operated valves shall be designed to belocked in the open or closed position. Butterfy valveson dead-end service or valves needing additional bodystrength shall be lug type conorming to ASTM A536ductile iron, drilled and tapped, with other materialsand eatures as specied above.
Valves shall comply with MSS SP-67.Note: Dead-end service requires lug-pattern or
grooved-type bodies. For dead-end service, fangesare required upstream and downstream or propershuto and retention, or valves must be certiedby the manuacturer or dead-end service withoutdownstream fanges. Ductile iron bodies are pre-erred; however, cast iron may be acceptable.
Check Valves 2 Inches and Smaller Valves 2 inches and smaller shall be o class 125 andrated 125-psi SWP and 200-psi nonshock CWP. Theyshall have threaded ends, with the body and capconorming to ASTM B62 cast bronze composition, Y-pattern, swing-type with TFE seat disc, or spring-
loaded lit type with resilient seating. Valves shallcomply with MSS SP-80.
Check Valves 2½ Inches and Larger Valves 2½ inches and larger shall be class 125, rated200-psi nonshock CWP, and have a maximum temper-ature o 200°F. They shall have an ASTM A126 class Bcast iron body, waer-check valve with ends designedor fanged-type connections, Buna-N resilient seatsmolded to the body, bronze disc, 316 stainless steeltorsion spring, and a hinge pin. Valves shall conormto ANSI B16.10.
Note: I the compressor is the reciprocating
type, check valves shall be downstream o the re-ceiver tank.
VACUUM SERVICE VALVESPECIFICATIONS
Ball Valves 2 Inches and Smaller Valves 2 inches and smaller shall be rated 150-psi SWPand 600-psi nonshock CWP. They shall have two-piece,cast brass bodies, reinorced Tefon seats, a ull port,blowout-proo stems, a chrome-plated brass ball, and
threaded or soldered ends. Valves shall comply withMSS SP-110.
Butterf Valves 2½ Inches and Larger
Valves 2½ inches and larger shall be rated 200-psinonshock CWP. Valves shall be lug or IPS grooved-type body with a 2-inch extended neck or insulating and shall be cast or ductile iron (ASTM A536) with
a Buna-N seat, ductile iron, aluminum bronze disc(ASTM A582), type 416 stainless steel stem, andBuna-N O-ring stem seals.
Sizes 2½ inches to 6 inches shall be lever operatedwith a 10-position throttling plate.
Sizes 8 inches to 12 inches shall have gear opera-tors. Lever-operated valves shall be designed to belocked in the open or closed position.
For butterfy valves on dead-end service or re-quiring additional body strength, valves shall be lug type, conorming to ASTM A536 ductile iron, drilledand tapped, with other materials and eatures asspecied above.
Valves shall comply with MSS SP-67.Note: Dead-end service requires lug-pattern or
grooved-type bodies. For dead-end service, fangesare required upstream and downstream or propershuto and retention, or valves must be certiedby the manuacturer or dead-end service withoutdownstream fanges. Ductile iron bodies are pre-erred; however, cast iron may be acceptable.
MEDICAL GAS SERVICE VALVESPECIFICATIONS
Ball Valves 2 Inches and Smaller Valves 2 inches and smaller shall be rated 600-psinonshock CWP and 200 psi or medical gas. Theyshall have three-piece, cast bronze (ASTM B584)bodies, replaceable reinorced TFE seats, a ull port,blowout-proo stems, a chrome-plated brass/bronzeball, and brazed ends. Valves shall be provided by themanuacturer cleaned and bagged or oxygen service. Valves shall comply with MSS SP-110.
Ball Valves 2½ Inches and Larger Valves 2½ inches and larger shall be rated 600-psinonshock CWP and 200 psi or medical gas. Theyshall have three-piece, cast bronze (ASTM B584)bodies, replaceable reinorced TFE seats, a ull port,
blowout-proo stems, a chrome-plated brass/bronzeball, and brazed ends. Valves shall be provided by themanuacturer cleaned and bagged or oxygen service. Valves shall comply with MSS SP-110.
Note: Where piping is insulated, ball valves shallbe equipped with 2-inch extended handles o a non-thermal, conductive material. Also, a protectivesleeve that allows operation o the valve withoutbreaking the vapor seal or disturbing the insulationshould be provided.
LOW-PRESSURE STEAM ANDGENERAL SERVICE VALVESPECIFICATIONSThis includes service up to 125 psi (861.8 kPa) satu-rated steam to 353°F (178°C).
Butterf ValvesButterfy valves are not allowed in steam service un-less stated as acceptable or the application by themanuacturer.
Gate Valves 2 Inches and Smaller Valves 2 inches and smaller shall be class 125, rated125-psi SWP and 200-psi nonshock CWP, and have a rising stem. The body, union bonnet, and solid wedgeshall be o ASTM B62 cast bronze with threaded ends.Stems shall be o dezincication-resistant siliconbronze (ASTM B371) or low-zinc alloy (ASTM B99).Packing glands shall be bronze (ASTM B62), witharamid iber nonasbestos packing and malleablehand wheel.
Class 150 valves meeting the above specicationsmay be used where pressures approach 100 psi.
Valves shall comply with MSS SP-80.
Gate Valves 2½ Inches and Larger Valves 2½ inches and larger shall be class 125 andrated 100-psi SWP and 150-psi nonshock CWP. Theyshall have an iron body, bronze-mounted, and OS&Y,with the body and bolted bonnet conorming to ASTM A126 class B cast iron, with fanged ends, aramidber nonasbestos packing, and two-piece packing gland assembly.
Class 250 valves meeting the above specications
may be used where pressures approach 100 psi. Valves shall comply with MSS SP-70.
Ball Valves 2 Inches and Smaller Valves 2 inches and smaller shall be 150-psi SWP and600-psi nonshock CWP, WOG. They shall have two-piece, cast bronze bodies, reinorced Tefon seats, a ull port, blowout-proo stems, an adjustable packing gland, a stainless steel ball and stem, and threadedends. Valves shall comply with MSS SP-110.
Note: A standard port may be used where pres-sure drop is not a concern. For on/o service, useball valves with stainless steel balls. For throttling,
use globe valves.Globe Valves 2 Inches and Smaller Valves 2 inches and smaller shall be class 125,rated 125-psi SWP and 200-psi nonshock CWP, andhave a body and bonnet o ASTM B62 cast bronzecomposition, with threaded ends. Stems shall be o dezincication-resistant silicon bronze (ASTM B371)or low-zinc alloy (ASTM B99). Packing glands shall beo bronze (ASTM B62), with aramid ber nonasbes-
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tos packing and malleable hand wheel. Valves shallcomply with MSS SP-80.
Globe Valves 2½ Inches and Larger Valves 2½ inches and larger shall be class 125 andrated 125-psi SWP and 200-psi nonshock CWP. Theyshall have an iron body, bronze-mounted, and OS&Y,with the body and bolted bonnet conorming to ASTM
A126 class B cast iron, with fanged ends, aramidber nonasbestos packing, and two-piece packing gland assembly.
Class 250 valves meeting the above specicationsmay be used where pressures approach 100 psi.
Valves shall comply with MSS SP-85.
Check Valves 2 Inches and Smaller Valves 2 inches and smaller shall be class 125 andrated 125-psi SWP and 200-psi nonshock CWP. Theyshall have threaded ends with the body and capconorming to ASTM B62 cast bronze composition, Y-pattern swing type with TFE seat disc, or spring-
loaded lit type with resilient seating. Valves shallcomply with MSS SP-80.Note: Class 150 valves meeting the above speci-
cations may be used where system pressure requiresthem. For class 150 seat discs, TFE or steam serviceshould be specied.
Check Valves 2½ Inches and Larger Valves 2½ inches and larger shall be class 125 andrated 125-psi SWP and 200-psi nonshock CWP. Theyshall have an iron body, bronze mounted, with thebody and bolted bonnet conorming to ASTM A126class B cast iron, with fanged ends, a swing-typedisc, and nonasbestos gasket. Valves shall complywith MSS SP-71.
MEDIUM-PRESSURE STEAMSERVICE VALVE SPECIFICATIONSThis includes up to 200-psi (1,379 kPa) saturatedsteam to 391°F (201°C).
Butterf ValvesButterfy valves are not allowed in steam service un-less stated as acceptable or the application by themanuacturer.
Gate Valves 2 Inches and Smaller
Valves 2 inches and smaller shall be class 200 andrated 200-psi SWP and 400-psi nonshock CWP. Theyshall have a rising stem, and the body and union bon-net shall be o ASTM B61 cast bronze, with threadedends, ASTM B584 solid wedge, silicon bronze ASTMB371 stem, bronze ASTM B62 or ASTM B584 pack-ing gland, aramid ber nonasbestos packing, andmalleable hand wheel. Valves shall comply with MSSSP-80.
Gate Valves 2½ Inches and Larger Valves 2½ inches and larger shall be class 250 andrated 250-psi SWP and 500-psi nonshock CWP. Theyshall have an iron body and bronze-mounted OS&Y,with the body and bolted bonnet conorming to ASTM A126 class B cast iron, with fanged ends, aramid bernonasbestos packing, and two-piece packing gland
assembly. Valves shall comply with MSS SP-70.Globe Valves 2 Inches and Smaller Valves 2 inches and smaller shall be class 200, rated200-psi SWP and 400-psi nonshock CWP. They shallhave a rising stem, body and union bonnet o ASTMB61 cast bronze, threaded ends, ASTM A276 type 420stainless steel plug-type disc and seat ring, siliconbronze ASTM B371 alloy stem, bronze ASTM B62 or ASTM B584 packing gland, aramid ber nonasbestospacking, and malleable iron hand wheel. Valves shallcomply with MSS SP-80.
Globe Valves 2½ Inches and Larger
Valves 2½ inches and larger shall be class 250, rated250-psi SWP and 500-psi nonshock CWP. They shallhave an iron body and bronze-mounted OS&Y, withthe body and bolted bonnet conorming to ASTM A126 class B cast iron, with fanged ends, aramidber nonasbestos packing, and two-piece packing gland assembly.
Where steam pressure approaches 150 psi or 366°F,gray iron or ductile iron shall be used.
Valves shall comply with MSS SP-85.
Check Valves 2 Inches and Smaller Valves 2 inches and smaller shall be class 200, rated
200-psi SWP and 400-psi nonshock CWP. They shallhave threaded ends with the body and cap conorm-ing to ASTM B61 cast bronze composition and a Y-pattern swing-type disc. Valves shall comply withMSS SP-80.
Check Valves 2½ Inches and Larger Valves 2½ inches and larger shall be class 250, rated250-psi SWP and 500-psi nonshock CWP. They shallhave an iron body, bronze mounted, with the bodyand bolted bonnet conorming to ASTM A126 classB cast iron, with fanged ends and a swing-type discassembly.
Where steam pressure approaches 150 psi or 366°F,gray iron or ductile iron shall be used.
Valves shall comply with MSS SP-71.
HIGH-PRESSURE STEAM SERVICEVALVE SPECIFICATIONSThis includes up to 300-psi (2,068.4-kPa) saturatedsteam to 421°F (216°C).
Gate Valves 2 Inches and Smaller Valves 2 inches and smaller shall be class 300 andrated 300-psi SWP. They shall have a rising stem,
and the body and union bonnet shall be o ASTMB61 cast bronze composition, with threaded ends,bronze ASTM B61 disc, bronze ASTM B371 stem,stainless steel ASTM A276 type 410 seat rings, bronzepacking gland, aramid ber nonasbestos packing,and malleable hand wheel. Valves shall comply withMSS SP-80.
Gate Valves 2½ Inches and Larger Valves 2½ inches and larger shall be class 300, rated300-psi SWP, and have a cast carbon steel (ASTM A216) wrought-carbon grade B (WCB) body and boltedbonnet. The disc and stem shall be ASTM A217 gradeCA 15, cast 12–14 percent chromium stainless steel,with stellite-aced seat rings, fanged ends, and two-piece packing gland assembly. Valves shall complywith MSS SP-70.
Globe Valves 2 Inches and Smaller Valves 2 inches and smaller shall be class 300, rated300-psi SWP. They shall have a body and union bon-
net o ASTM B61 cast bronze composition, threadedends, stainless steel ASTM A276 hardened plug-typedisc and seat ring, silicon bronze ASTM B371 stem,bronze ASTM B62 or ASTM B584 packing gland, ar-amid ber nonasbestos packing, and malleable handwheel. Valves shall comply with MSS SP-80.
Globe Valves 2½ Inches and Larger Valves 2½ inches and larger shall be class 300, rated300-psi SWP. They shall have a cast carbon steel ASTM A216 grade WCB body and bolted bonnet. The disc,stem, and seat rings shall be ASTM A217 grade CA 15, cast 12–14 percent chromium stainless steel, withfanged or welded ends and two-piece packing glandassembly. Valves shall comply with MSS SP-85.
Check Valves 2 Inches and Smaller Valves 2 inches and smaller shall be class 300, rated300-psi SWP. They shall have threaded ends with thebody and cap conorming to ASTM B61 cast bronzecomposition and a Y-pattern swing-type disc. Valvesshall comply with MSS SP-80.
Check Valves 2½ Inches and Larger Valves 2½ inches and larger shall be class 300, rated300-psi SWP. They shall have a cast carbon steel, ASTM A216 grade WCB body and bolted bonnet.
The disc and seat ring shall be ASTM A217 gradeCA 15, cast 12–14 percent chromium stainless steel,with fanged or welded ends. Valves shall comply withMSS SP-71.
HIGH-TEMPERATURE HOT WATERSERVICE VALVE SPECIFICATIONSThis includes service to 450°F (232.2°C).
Nonlubricated Plug Valves Valves shall be ANSI class 300, 70 percent port, withnonlubricated wedge plug and bolted bonnet. Thebody, bonnet, and packing gland fange shall be castcarbon steel (ASTM A216) grade WCB.
The plug shall be cast rom high-tensile, heat-treated alloy iron with two Tefon O-rings inserted
into dovetail-shaped grooves machined into the plug ace. The O-rings shall provide double seating andensure vapor-tight shuto on both the upstreamand downstream seats. Valves are to be seated inboth the open and closed positions to protect thebody seats.
The stem shall be high-strength alloy steel con-orming to American Iron and Steel Institute (AISI)4150 and sulphurized, with ace-to-ace dimensionsto meet ANSI B16.10.
Each valve shall be provided with a position indi-cator or visual indication o the 90-degree rotationo the plug. Valves are to be equipped with a provi-
sion or bypass connections.For valves 3 inches and smaller, the operator shall
be a hand wheel or wrench. Valves 4 inches and larg-er shall have an enclosed gear with a hand wheel.
Each valve shall be certied to have passed theollowing minimum test requirements: 1,100-psihydrostatic shell test and 750-psi hydrostatic (bothsides to be tested) and 100-psi air underwater (bothsides to be tested) seat test.
GASOLINE AND LPG SERVICE VALVESPECIFICATIONS
Plug Valves
Valves shall be ANSI class 150, 70 percent port, withnonlubricated tapered plug and bolted bonnet. Valvebody shall be ASTM A216 grade WCB steel with a drainplug suitable or double block and bleed service.
The plug seals shall be two Tefon O-rings insert-ed into dovetail-shaped grooves machined into theplug ace. The plug shall lit clear o the seats beorerotating 90 degrees.
End connections shall be ANSI class 150 raisedace and fanged. Face-to-ace dimensions are tomeet ANSI B16.10.
FIRE PROTECTION SySTEM VALVE
SPECIFICATIONSGate Valves 2 Inches and Smaller Valves 2 inches and smaller shall be o class 175-psiwater working pressure (WWP) or greater, and thebody and bonnet shall conorm to ASTM B62 castbronze composition, with threaded ends, OS&Y, andsolid disc. They shall be listed by UL, be FM approved,and be in compliance with MSS SP-80.
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Gate Valves 2½ Inches and Larger Valves 2½ inches and larger shall be rated 175-psi WWP or greater. They shall have an iron body, bronzemounted or with resilient rubber-encapsulated wedge,and the body and bonnet shall conorm to ASTM A126class B cast iron, with OS&Y and class 125 fangedor grooved ends. I o the resilient-wedge design, the
interior o the valve is to be epoxy coated. Valves shallmeet or exceed AWWA C509. Valves are to be UL listed,FM approved, and in compliance with MSS SP-70.
Valves 4 Inches and Larger orUnderground Bur These shall be rated 200-psi WWP or greater, andthe body and bonnet shall conorm to ASTM A126class B cast iron, bronze mounted, resilient-seatedgate valve with nonrising stem, with O-ring stemseal, epoxy coating (AWWA C550) inside and outside,and fanged or mechanical joint ends as required. Allvalves urnished shall open let. All internal partsshall be accessible without removing the valve bodyrom the line. Valves shall conorm to AWWA C509. Valves shall come with a mounting plate or an in-dicator post and be UL listed, FM approved, and incompliance with MSS SP-70.
When required, a vertical indicator post may beused on underground valves. Posts must provide a means o knowing i the valve is open or closed. Indi-cator posts must be UL listed and FM approved.
HIGH-RISE SERVICE VALVESPECIFICATIONS
Gate Valves 2½ Inches to 12 Inches
Gate valves 2½ inches to 10 inches shall be rated 300-psi WWP or greater. 12 inches shall be rated 250-psi WWP. They shall have an iron body, bronze mounted,with the body and bonnet conorming to ASTM A126class B cast iron, OS&Y, and fanged ends or use withclass 250/300 fanges. They shall be UL listed, FMapproved, and in compliance with MSS SP-70.
Check Valves 2½ Inches to 12 InchesCheck valves 2½ inches to 10 inches shall be rated300-psi WWP or greater. 12 inches shall be rated250-psi WWP. They shall have an iron body, bronzemounted, with a horizontal swing check design, and
the body and bonnet shall conorm to ASTM A126class B cast iron, with fanged ends or use with class250/300 fanges. They shall be UL listed, FM ap-proved, and in compliance with MSS SP-71.
Note: In New York City, valves are to be approvedby the New York City Materials and Equipment Ac-ceptance Division (MEA) in addition to the abovespecications.
Ball Valves 2 Inches and Smaller Valves 2 inches and smaller shall be constructed o commercial bronze (ASTM B584) and rated 175-psi WWP or higher, with reinorced TFE seats. Valvesshall have a gear operator with a raised position in-dicator and two internal supervisory switches. Valvesshall have threaded or IPS grooved ends and shall
have blowout-proo stems and chrome-plated balls.They shall be UL listed, FM approved, and in compli-ance with MSS SP-110 or re protection service.
Butterf Valves 4 Inches to 12 InchesButterfy valves may be substituted or gate valveswhere appropriate. Valves shall be rated or 250-psi WWP and 175-psig working pressure, UL listed, FMapproved, and in compliance with MSS SP-67.
Valves urnished shall have a ductile iron (ASTM A536) body and may have ductile iron (ASTM A395)(nickel-plated) discs or aluminum bronze discs, de-pending on local water conditions. In addition, thewaer style or installation between class 125/150fanges or the lug style or grooved body may be speci-ed depending on the system’s needs.
Valves shall be equipped with weatherproo gear,operator rated or indoor and outdoor use with handwheel, and have a raised position indicator with twointernal supervisory switches.
Check Valves Valves 2½ inches and larger shall be 500-psi WWPand have a bolted bonnet, and the body and bonnetshall conorm to ASTM A126 class B cast iron, withfanged end composition Y-pattern, horizontal swing-type disc. They shall be UL listed, FM approved, and
in compliance with MSS SP-71 type 1 or re protec-tion service.
GLOSSARy
Ball valve A valve consisting o a single drilledball that is operated by a handle attached to thevertical axis o the ball, which permits fuid fowin a straight-through direction. The ball withinthe valve body may be rotated ully opened or ullyclosed by a one-quarter turn o the handle.
Body The part o a valve that attaches to the pipe-line or equipment—with screwed ends, fanged
ends, or soldered/welded joint ends—and enclosesthe working parts o the valve.
Bolted bonnet A type o bonnet constructed sothat it attaches to the valve body by means o a fanged, bolted connection. The whole bonnet as-sembly, including the hand wheel, stem, and disc,may be quickly removed by unscrewing the nutsrom the bonnet stud bolts.
Bonnet The part o the valve housing throughwhich the stem extends. It provides support and
protection to the stem and houses the stem pack-ing. It may be screwed or bolted to the body.
Buttery valve A type o valve consisting o a single disc that is operated by a handle attachedto the disc, which permits fuid fow in a straight-through direction. The valve is bidirectional. Thedisc within the valve body may be rotated ully
open or ully closed by a one-quarter turn o thehandle.
Cap The top part o the housing o a check valve(equivalent to the bonnet o a gate or globe valve),which may be either screwed or bolted onto themain body.
Check valve An automatic, sel-closing valve thatpermits fow in only one direction. It automaticallycloses by gravity when liquid ceases to fow in thatdirection.
Clapper A common term that is used to describethe disc o a swing-type check valve.
Disc The disc-shaped device that is attached to thebottom o a valve stem and is brought into contactwith or lited o the seating suraces to close oropen a globe valve or butterfy valve.
Full port A term meaning that the area throughthe valve is equal to or greater than the area o standard pipe.
Gate valve A valve that is used to open or close o the fow o fuid through a pipe. It is so named be-cause o the wedge (gate) that is either raised outo or lowered into a double-seated sluice to permit
ull fow or completely shut o fow. The passage-way through a gate valve is straight through, un-interrupted, and the ull size o the pipeline intowhich the valve is installed.
Gland bushing A metal bushing installed be-tween the packing nut and the packing to trans-mit the orce exerted by the packing nut againstthe packing.
Globe valve A valve that is used or throttling orregulating fow through a pipe. It is so named be-cause o the globular shape o the body. The discis raised o a horizontal seating surace to permit
fow or lowered against the horizontal seating sur-ace to shut o fow. The disc may be lited com-pletely to permit ull fow or lited only slightly tothrottle or regulate fow. The fow through a globevalve has to make two 90-degree turns.
Hand wheel The wheel-shaped turning device bywhich a valve stem is rotated, thus liting or lower-ing the disc or wedge.
Hinge pin The valve part that the disc or clappero a check valve swings.
Lit check valve A check valve using a disc thatlits o the seat to allow fow. When fow decreases,the disc starts closing and seals beore reverse fowoccurs.
Outside screw and yoke (OS&Y) A type o bon-net so constructed that the operating threads o the stem are outside the valve housing, where they
may be lubricated easily and do not come into con-tact with the fuid fowing through the valve.
Packing A general term describing any yielding material used to aect a tight joint. Valve packing is generally jam packing, or pushed into a stung box and adjusted rom time to time by tightening a packing gland or packing nut.
Packing gland A device that holds and compress-es the packing and provides additional compres-sion by manual adjustment o the gland as wearo the packing occurs. A packing gland may bescrewed or bolted in place.
Packing nut A nut that is screwed into place andpresses down on a gland bushing, which transmitsthe orce exerted by the packing nut to the pack-ing. It serves the same purpose as the packing gland.
Rising stem A threaded component that is un-screwed or screwed through the valve bonnet toopen or close a valve. The hand wheel may risewith the stem, or the stem may rise through thehand wheel.
Screwed bonnet A type o bonnet so constructedthat it attaches to the valve body by means o a
screwed joint. A bonnet may be attached to thebody by screwing over the body or inside the bodyor by means o a union-type screwed connection.
Solid wedge A wedge consisting o one solid pieceinto which the valve stem is attached, so it sealsagainst the valve seating suraces to ensure a tightseal when the valve is closed.
Split wedge A wedge consisting o two pieces intowhich the valve stem is screwed, so it expands thetwo pieces against the valve seating suraces to en-sure a tight seal when the valve is closed.
Standard port A term meaning that the area through the valve is less than the area o standardpipe.
Stem The usually threaded shat to which thehand wheel is attached at the top and the discor wedge at the lower end. The stem also may becalled the spindle.
Stop plug An adjusting screw that extends throughthe body o a check valve. It adjusts and controlsthe extent o movement o the disc or clapper.
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Swing check valve A check valve that uses a hinged disc or clapper to limit the direction o fow.The pressure exerted by the fuid fowing throughthe valve orces the disc away rom the seating surace. When the fow ceases, the clapper alls toits original position, preventing fow in the oppo-site direction.
Union A coupling tting consisting o three parts(shoulder piece, thread piece, and ring) that isused or coupling the ends o pipe sections. Adjoin-ing aces o shoulder and thread pieces are lappedtogether to orm a tight joint. Unions permit easydisconnection or repair and replacement o piping and ttings.
Union bonnet A type o bonnet so constructedthat the whole bonnet assembly, including thehand wheel, stem, and disc assembly, may be re-moved quickly by unscrewing the bonnet unionring rom the valve body.
Union ring A large nut-like component that se-cures the union thread and the union shoulder to-gether. It slips over and against the shoulder pieceand screws onto the union thread piece.
Union shoulder piece The part o the union as-tened to the pipe that retains the union ring.
Union threaded piece The part o the union that
is astened to the pipe and has external threadsover which the union ring is screwed to eect a coupling.
Wedge The wedge-shaped device that ts into theseating suraces o a gate valve and is drawn outo contact with the seating suraces to permit fowor is pushed down into contact with the seating suraces to close o fow with the valve. (See alsodisc.)
Pumps4The most common type o pump used in plumbing systems is the centriugal pump, although someapplications require other types. For plumbing, thecentriugal pump stands out because o its simpledesign and suitable head (pressure). Further, itsrotational speed matches that o commonly avail-
able electric motors; drive belts or gears are rarelyemployed. With small sizes, the motor shat is typi-cally coupled directly to the pump impeller, resulting in a compact design and a simple installation, evenor re pumps.
This chapter ocuses on centriugal pumps, butpumps in general are explored, including dierencesin pump types, perormance characteristics, applica-tions, installation, and environmental issues.
APPLICATIONSPump applications in plumbing include specialtypumps or liquid supplies, pressure boosters ordomestic water supply, similar supply pumps orre suppression, water circulation or temperaturemaintenance, and elevation increases or drainagesystems. Except or the circulation application, pumpsystems theoretically are open systems, meaning thatthe liquid is transerred rom one reservoir to anothero a higher elevation. The applications vary in thenature o the liquid, the duty—whether or daily useor or rare reghting use—and the magnitude o elevation changes.
PUMP BASICS
Machines that move water, or any liquid, are calledturbomachines. Commonly reerred to as pumps,these machines add energy to the liquid, resulting ina higher pressure downstream. This added energy iscalled head, which reers back to the days o dams andwater wheels. The descent o water was expressed asa level o energy per pound o water. The water de-scended adjacent to the dam through the water wheel,and the vertical distance between the water levels oneither side o the dam was measured. In contrast to
water wheels, all pumps add energy, but the amountis expressed in the same terminology.
In theory, i a suciently tall, open-top verticalpipe is mounted on a pipe both downstream and up-stream o a pump, the liquid level in both can be ob-served. The level downstream will be higher than the
level upstream. This dierence in elevation betweenthe two levels is called the total head or the pump. Another element o pump head is the dierence inelevation between the upstream pipe and the pump;a distinction is made i the upstream elevation isabove or below the elevation o the pump inlet.
Pump Tpes and ComponentsFor all pumps, the basic parts consist o a passage anda moving surace. The passage is simply reerred to asthe pump casing. A prime mover, such as an electricmotor but sometimes an engine, adds torque to themoving surace. Other parts include shat bearings
and various seals, such as the shat seal.Pumps may be categorized as positive displacement,
centriugal, axial, or mixed fow. Positive-displacementpumps deliver energy in successive isolated quantitieswhether by a moving plunger, piston, diaphragm, orrotary element. Clearances are minimized betweenthe moving and unmoving parts, resulting in onlyinsignicant leaks past the moving parts. Commonrotary elements include vanes, lobes, and gears.
When a pump with a rotating surace has signi-cant clearance between itsel and the stationary pas-sage, the pump does not have positive displacement.I the direction o discharge rom the rotating sur-
ace, called the impeller, radiates in a plane perpen-dicular to the shat, the pump is a centriugal pump.I the direction is inline with the shat, the pump isaxial. I the direction is partly radial and partly axi-al, the pump is mixed fow. Examples o a centriugalpump, an axial pump, and a positive-displacementpump, respectively, include an automobile waterpump, a boat propeller, and the human heart.
Compared to positive-displacement pumps, cen-triugal and axial pumps are simple and compact
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and do not have fow pulsations. Centriugal pumpsprovide greater total head than similarly sized axialpumps, but they provide lower fow. The operation o a centriugal pump includes the outward, radial pro- jection o the liquid rom the impeller as it rotates.In addition, i a gradual expanding passage is provid-ed ater the impeller, the high velocity is convertedto a high static pressure. This idea ollows the law o conservation o energy and is quantied in Bernoul-li’s equation. I the expanding passage wraps aroundthe impeller, it is called a volute.
The quantity and angle o the blades on the im-peller and the shape o the blades vary. They may betwo straight blades positioned radially, many curvedblades angled orward, or more commonly, manyblades angled backward to the direction o rotation. While orward blades theoretically impart greatervelocity, the conversion to pressure is unstable ex-cept within a narrow speed range.
Pipes generally connect to pumps with standardfanges, but they may also connect by pipe threads orsolder joints. The centerline o the inlet pipe may bealigned with the pump shat. Figure 4-1 shows thistype; it is reerred to as an end-suction design. Theoutlet generally alls within the plane o the impel-ler. I the inlet and outlet connections align as i in a continuation o the pipe run, as shown in Figure 4-2,the pump is reerred to as inline.
Casing materials are generally cast iron and, ordomestic water supply, cast bronze. Other materialsinclude stainless steel and various polymers. Impel-
ler materials also include cast iron, bronze, and vari-ous polymers. Pump bearings and motor bearingsvary between traditional sleeves and roller elementssuch as steel ball bearings. Bearings on each side o the impeller minimize shat stresses compared to a pair o bearings on one side. At the other extreme,the pump itsel has no bearings, and all hydraulicorces are applied to the motor bearings. The combi-nation o these materials, design eatures, and arrayo pump sizes results in pumps being the most var-ied o the world’s manuactured products.
The greatest pressure in any pumped system iswithin the pump casing, which includes the shat
seal. Another concern with this seal occurs when thepump is not operating, when a stored supply o pres-sure applies continuous static head against the seal.This seal traditionally has been designed with a fex-ible composite material stued around a clearancebetween the shat and the hub portion o the pumpcasing, reerred to as a stung box. A mechanicalarrangement applies pressure to the fexible mate-rial through routine adjustments. Some leakage isdeliberately required, so provisions or the tricklefow must be included, such as with the installationo a foor drain.
Another seal design consists o a simple O-ring.
More advanced seals include the mechanical sealand the wet rotor design. In a mechanical seal, theinterace o two polished suraces lies perpendicularto the shat. One is keyed and sealed to the shat,and the other is keyed and sealed to the pump cas-ing. Both are held together by a spring and a fexibleboot. Some pumps include two sets o these seals,and the space between them is monitored or leak-age. Oten, a special fow diversion continuouslyfushes the seal area.
Figure 4-1 Portion o a Close-Coupled Centriugal PumpWith an End-Suction Design
Figure 4-2 Inline Centriugal Pump with a Vertical ShatPhoto courtesy o Peerless Pump Co.
In the wet rotor design, the rotor winding o themotor and the motor bearings are immersed in thewater fow and are separated rom the dry statorby a thin, stationary, stainless steel shield called a canister. The shield imparts a compromise in themagnetic fux rom the stator to the rotor, so thesepumps are limited to small sizes.
DETERMINING PUMP EFFICIENCy High eiciency is not the only characteristic toexamine in selecting a pump. It is explored here,nonetheless, to demonstrate the impact o alterna-tives when various compromises are considered.
An ideal pump transers all o the energy rom a shat to the liquid; thereore, the product o torqueand rotational speed equals the product o mass fowand total head. However, hydraulic and mechanicallosses result in perormance degradation. Hydrauliclosses result rom riction within the liquid throughthe pump, impeller exit losses, eddies rom sudden
changes in diameter, leaks, turns in direction, orshort-circuit paths rom high-pressure sections tolow-pressure sections. Mechanical losses include ric-tion in bearings and seals. The amount o hydraulicand mechanical losses is rom 15 percent to 80 percentin centriugal pumps and lesser amounts or positive-displacement pumps.
Design eatures in centriugal pumps that mini-mize hydraulic losses include a generous passagediameter to reduce riction, an optimal impellerdesign, a gradual diameter change and directionchange, placement o barriers against short-circuits,and optimal matches o impeller diameters to pump
casings. The design o a barrier against short-circuitsincludes multiple impeller vanes, seals at the impel-ler inlet, and minimal space between the impellerand the pump casing. The seals at the impeller inletare commonly in the orm o wear rings. Enclosedimpellers, as shown in Figure 4-3, achieve higherheads because o the isolation o the inlet pressurerom the liquid passing through the impeller; thus,the original eciencies are maintained over thepump’s useul lie.
Equation 4-1 illustrates the relationship betweenfow, total head, eciency, and input power orpumps with cold water. For other liquids, the equa-
tion is appropriately adjusted.
Equation 4-1
P = Q × h [Q × h × 9.81]3,960 × e ewhere
P = Power through the pump shat, horsepower(W)
Q = Flow, gallons per minute (gpm) (L/s)h = Total head, eet (meters)e = Eciency, dimensionless
Impellers with diameters signicantly smallerthan an ideal design generally compromise ecien-cy. The eciency o centriugal pumps varies greatlywith head and fow. Hence, a pump with 85 percenteciency at one fow may be only 50 percent at one-third o that fow.
Axial fow directed into the impeller o a centriu-gal pump may come rom one side only (single-suc-tion pump, reer back to Figure 4-1) or both sides(double-suction pump, see Figure 4-4). The single-suction design creates axial orces on the pump shat.The double-suction design balances those orces. Inaddition, double-suction pumps have a slower inletvelocity, which helps prevent cavitation.
Since most pumps are driven by electric motors,a complete review o pump eciency should include
Figure 4-3 Enclosed Impeller
Figure 4-4 Centriugal Pump with aDouble-Suction Inlet Design
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consideration o motor eciency, which varies withtorque, type o motor, speed, type o bearings, andquality o electricity. Many ractional-horsepower,single-phase motors experience a dramatic loss o e-ciency at light loads. A three-phase motor achievespeak eciency at slightly less than ull load. High-speed motors and large motors oer greater e-ciencies than slower or smaller motors. Polyphase,permanent split-capacitor, and capacitor-start/ capacitor-run motors are more ecient than split-phase, capacitor-start/induction-run, and shadedpole motors.
A centriugal pump’s rst cost can be minimizedby designing or the best eciency points (BEP) o the operating fow and head. A lower total head alsoresults in less bearing and shat stresses, leading toa longer expected pump lie.
An appreciation o the benets o investing ineciency in a plumbing system can be realized byidentiying the magnitude o power in various parts
o a building. For example, a domestic water heater’senergy input may be 1,000,000 British thermal unitsper hour (Btuh) (293 kW), while its circulation pumpmay be 700 Btuh (205 W). Hence, in this situationan inecient pump is o little consequence. Exces-sive circulation increases standby losses, but a moreecient heat exchanger in the water heater will pro-vide the most tangible benet. While the importanceo a re pump or re suppression is paramount, e-ciency invested there is less important than a reli-able pump design.
CENTRIFUGAL PUMP
CHARACTERISTICSThe characteristics o centriugal pumps can be re-duced to two coecients and one value reerred to asthe specic speed. The coecients and a set o rela-tionships, called anity laws, allow similarly shapedcentriugal pumps to be compared. In general, thecoecients also apply to axial and mixed-fow pumps,as well as turbines and ans.
Deriving the coecients starts with the law o conservation o momentum. That is, the summationo orces on the surace o any xed volume equalsthe aggregate o angular-momentum vectors multi-plied by the fows at each o those vectors. Since the
applied energy into the liquid on the xed volumearound the impeller is only the tangential movemento the impeller, only the tangential velocity vectorsare considered. For constant density and or radialand tangential velocities at the inlet and outlet o animpeller, the momentum equation becomes:
Equation 4-2
T = d2 × r2 × vt2 × Q2 – d1 × r1 × vt1 × Q1
whereT = Torque, oot-pounds (N-m)d2 = Density at the outlet, pounds per cubic oot
(kg/m3)
r2 = Radius at the outlet, inches (mm)vt2 = Tangential velocity at the outlet, eet per
second (ps) (m/s)Q2 = Flow at the outlet, gpm (L/s)
d1 =
Density
at the inlet, pounds per cubic oot(kg/m
3)
r1 = Radius at the inlet, inches (mm)vt1 = Tangential velocity at the inlet, ps (m/s)Q1 = Flow at the inlet, gpm (L/s)
From Bernoulli’s equation o an ideal fow throughany type o pump, total head is a measure o powerper fow and per specic weight. Since power is theproduct o torque and rotational speed, the aboveequation can be related to the Bernoulli equation.For steady-state conditions, the inlet fow equals theoutlet fow. The relation becomes:
Equation 4-3
h = P = (r2 × vt2 – r1 × vt1) × nd × g × Q g
whereh = Total head created by the pump, eet (m)P = Power, horsepower (W)n = Rotational speed, revolutions per minute
(rpm) (radians per second)g = Gravity constant
With the velocity o the tip o a rotating surace atits outside radius designated as U, the equation is:
Equation 4-4
h =
U2 × vt2 – U1 × vt1
g For centriugal pumps, fow is proportional to the
outlet radial velocity. In addition, vt1 = 0 since inletfow generally is moving in an axial direction and notin a tangential direction. Thus:
Equation 4-5
h =
U2 × vt2
g Figure 4-5 shows the velocity vectors o the fow
leaving the impeller. Vector vr2 represents the velocityo the water in a radial direction, Vector X representsthe velocity o the water relative to the impeller blade,
and Vector Y represents the sum o X and U. Thus,it is possible to resolve these vectors into tangentialcomponents and derive the ollowing:
Figure 4-5 Net Fluid Movement From an ImpellerRepresented by Vector Y
Equation 4-6c
h =
U22[1 – (CQ) cot B]
g For a given fow, the vr2 /U2 ratio is constant and
is dened as a capacity coecient, CQ. For a givenimpeller design, CQ and Angle B are constant. Hence,[1 – (vr2 /U2) cot B] is constant and is dened as a headcoecient, CH. Equation 4-7 shows the relationship
between this coecient, the head, and the impeller’stip velocity.
Equation 4-7
CH =
h × g U2
2
With the various constants identied in Equa-tion 4-6c, the total head is directly proportional tothe square o the impeller’s tip velocity, U2. Recallthat the tip velocity is a product o the impeller’srotational speed and the impeller’s radius. Thus, thetotal head is proportional to the square o the impel-
ler’s radius or o its diameter, and it is proportionalto the square o the impeller’s rotational speed, inrpm (radians per second). This is the second pumpanity law.
Additionally, since fow is directly proportional toarea and velocity at any section through a pump, ata particular section the fow is proportional to thevelocity o the impeller’s tip. Hence, fow is propor-tional to the rotational speed o the impeller and tothe diameter o the impeller. This is the rst pumpanity law.
Since power is the product o fow and head, pow-er is directly proportional to the cube o the velocity.This is the third pump anity law.
Table 4-1 summaries the three pump anitylaws. Each unction is directly proportional to thecorresponding value in the other columns.
In addition, it is customary to combine fow andhead with the rotational speed and set exponentials,so this speed appears to the rst power. The result,nQ
0.5 /h
0.75, is called the specic speed o the pump.
When the fow rate, head, and a given pump speedare known, the specic speed can be derived, andthe design o an economical pump can be identied,whether centriugal, axial, or mixed fow. Specicspeed also allows a quick classication o a pump’secient operating range with a mere observation o the shape o the impeller.
The anity laws allow easy identication o pumpperormance when the speed changes or the impellerdiameter changes. For example, doubling the speed
or impeller diameter doubles the fow, increases thehead by our, and increases the required motor powerby eight.
PERFORMANCE CURVESSince centriugal pumps do not supply a nearly con-stant fow rate like positive-displacement pumps,characteristic pump curves are provided by manuac-turers to aid in selecting a pump. Under controlledconditions, such as with water at a certain tempera-ture, these curves are created rom measurements o impeller speed, impeller diameter, electric power, fow,and total head. The standard conditions are created
by such groups as the Hydraulic Institute. As can beobserved, the shape o the curve in Figure 4-6 agreeswith Equation 4-6c. This pump curve represents a particular impeller diameter measured at a constantspeed, with its total head varied and its resulting fow recorded. Eciency is plotted on many o these
Table 4-1 Centriugal Pump Anity Laws
FunctionTip
VelocityRotational Speed,rpm (radians/sec)
Impeller Radius (orDiameter), in. (mm)
Flow U n R
Head U2
n2
R2
Power U3
n3
R3
Figure 4-6 Typical Pump Curve Crossing a System Curve
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curves, and the BEP is sometimes marked. Additionalcurves usually include shat input power, measuredin horsepower (W), eciency, and net positive suctionhead (NPSH).
While a curve is plotted or a given pump andwith a given diameter impeller, a pump in operationunder a constant head and speed has one particularfow. The point on the pump curve o this fow andhead is reerred to as the duty point or system bal-ance point. The pump will provide that fow i thathead applies.
In plumbing, a particular fow may be requiredor a sump pump or hot water circulation pump. Indomestic water and re suppression supply systems,the head varies with the quantity o open aucets,
outlets, hose streams, or sprinkler heads. Further,the quantity o such open outlets varies with time.Thus, the duty point rides let and right along thecurve with time.
Another curve that represents the building’s dis-tribution piping at peak demand can be plotted on a pump curve. This second curve, called the system headcurve or building system curve, is shown in Figure 4-6.Equation 4-8 represents this amiliar curve, wherep1 represents a pressure gauge reading at the pumpinlet and p2 and h2 represent pressure and elevationhead respectively at a particular system location suchas at a remote xture. The last term represents theentire riction head in the piping between the twopoints including control valves, i any, at the pump.
The curve’s shape is parabolic. Thiscurve is applicable to any liquid thathas a constant absolute viscosityover a wide fow range (a Newtonianfuid).
Equation 4-8hp = (p2 – p1)/d + h2 + (L/D)(v
2 /2g)
At no fow, the riction term be-comes zero since velocity is zero,and the point where this curvecrosses the vertical axis is the sumo the remaining terms.
To select a pump, determine thepeak fow and use Equation 4-8 tocalculate the required pump head.The fow and head identiy the dutypoint. Most catalogues rom pump
manuacturers oer a amily o centriugal pumps in one diagram.Separate graphs, one or each pumphousing and shat speed, show thepump perormance or each o sev-eral impellers. Figure 4-7 illustratessuch a graph or a pump measuredat 1,750 rpm (183 radians per sec-ond). Pick a pump impeller that atleast includes the duty point. Anoptimal pump is one whose pumpcurve crosses this point. However,with most pump selections, the
pump curve crosses slightly abovethe point.
For example, i the duty pointis 100 gpm at 30 eet o head (6.31L/s at 9.14 m o head), the impel-ler number 694 in Figure 4-7 is a suitable choice because its pumpcurve (the solid line matched to694) crosses above the duty point.Power requirements are marked
Figure 4-7 Typical Pump Curves and Power Requirements
Figure 4-8 Blade Shape and Quantity Versus Perormance Curve
Source: Figures 4-7 and 4-8 courtesy o Weil Pump Company Inc.
in dashed lines in Figure 4-7. The pump’s motorsize, in horsepower or kilowatts, is identied by thedashed line above and to the right o the duty point. A more precise motor required can be estimated at1.6 hp (1.2 kW), but engineers typically pick the 2-hp(1.5-kW) motor size. Select the motor with a nomi-nal 1,800-rpm (188 radians per second) rotationalspeed. The pump’s eciency can be estimated i e-ciency curves are included on the chart. Comparing the eciencies o several pumps can lead to an idealchoice. Alternatively, the fow and head o the dutypoint can determine the ideal power requirement. A pump’s eciency is ound by dividing the idealpower, rom Equation 4-1, by the graphically shownpower. With this example, the eciency is 0.758/1.6= 47 percent.
The shape o a pump curve varies with the impel-ler design. A rapidly dropping headdue to increasing fow is character-ized by a steep curve. Flat curves
represent a slight variation romno fow to BEP, oten dened as 20percent. The latter is preerred inmost plumbing applications thatemploy one pump because o thenearly uniorm head. Figure 4-8shows steep and fat curves and thecorresponding blade designs.
A pump with a steep curve isadvantageous when a high head isrequired in an economical pumpdesign and the fow is o less con-sequence. For example, a sump
pump, which has a sump to collectpeak fows into its basin, may havea high static head. With a generousvolume in the sump, the total timeto evacuate the sump is secondary;thereore, the pump’s fow is o lessconcern than its head. Further, asthe inlet fow increases and the wa-ter level rises, the head reduces andthe pump fow increases.
A pump design with some slopein its curve is desired or parallelpump congurations. The sum o
the fows at each head results ina more fat curve. For control, thedrop in head as the demand in-creases may serve as an indicator tostage the next pump.
A pump with nearly verticalsteepness is desired or drainagepumps that are part o a system o pumps that discharge into a orcemain. This perormance character-
istic allows a nearly uniorm fow or a wide varia-tion o heads. Some centriugal and all positive-dis-placement pumps exhibit this characteristic.
STAGINGTo obtain greater total head, two pumps can be con-nected in series; that is, the discharge o one pumpbecomes the inlet o the other. As a convenience,pump manuacturers have created multistage pumpsin which two or more centriugal pumps are joinedin a series by combining all o the impellers on a common shat and arranging the casing to direct thefow o a volute into the eye o the next impeller (seeFigure 4-9).
Another way to obtain greater head is by using a regenerative turbine pump. Unlike other centriugalpumps, the outer edge o the impeller and its voluteare intentionally employed with higher velocities
by using recirculation o a portion o the fow rom the volute to pass just
inside the tip o the impeller. The closedimensions o these pumps limit theiruse to clean liquids.
Applications o high-head pumpsinclude water supplies in high-risebuildings, deep water wells, and repumps or certain automatic stand-pipe systems.
SPECIALTy PUMPSTo select a specialty pump, the ol-lowing must be considered: pressureincrease, range o fow, nature o the
energy source (electricity, air, manual,etc.), whether the liquid containsparticulates, whether pulses aretolerable, accuracy in dispensing, sel-priming requirement, whether thepump is submerged, and i the pumprequires an adaptation to its supplycontainer.
Domestic Booster Pumps A domestic booster pump system typi-cally uses multiple parallel centriugalpumps to increase municipal water
pressure or the building’s domesticwater distribution. Particular designissues such as sizing, pump redun-dancy, pressure-reducing valves, otherpump controls, adjustable-requencydrives, high-rise buildings, and breaktanks are described in Plumbing Engi-neering Design Handbook, Volume 2,Chapter 5: “Cold Water Systems.” Thesame issues apply or private watersystems that require a well pump.
Figure 4-9 Multistage or VerticalLineshat Turbine Pump
Photo courtesy o Peerless Pump Co.
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Fire PumpsThe water supply or re suppression requires a pumpthat is simple and robust. In addition, the slope o theperormance curve is limited by re pump standards.NFPA 20: Standard or the Installation o Station-
ary Fire Pumps or Fire Protection limits the curveto not less than 65 percent o the rated total head
or 150 percent o the rated fow. A variety o listing agencies monitor pump manuacturing to certiycompliance with one or more standards. The designo a single-stage or multistage centriugal pump gen-erally qualies. A double-suction centriugal pumpwith enclosed impeller, horizontal shat, wear rings,stung-box shat seals, and bearings at both endshistorically has been used. The pump inlet connectiongenerally is in line with the outlet connection.
A recent variation, or small re pumps, includesa vertical shat and a single-suction design with theimpeller astened directly to the motor shat. Pumpbearings, shat couplings, and motor mounts are
eliminated in this compact design.In applications or tank-mounted re pumps, the
impeller is suspended near the bottom o the tank,and the motor or other prime mover is located abovethe cover. Between the two is a vertical shat placedwithin a discharge pipe. NFPA calls these pumpsvertical lineshat turbine pumps. Flexibility in theirdesign includes multistaging, a wide range o tankdepths, and several types o prime movers.
Water Circulation PumpsMaintaining adequate water temperature in plumb-ing is achieved through circulation pumps. Applicable
generally or hot water, but equally eective or chilledwater to drinking ountains served by a remote chiller,the circulation pump maintains a limited temperaturechange. Heat transer rom hot water distributionpiping to the surrounding space is quantied oreach part o the distribution network. For a selectedtemperature drop rom the hot water source to theremote ends o the distribution, an adequate fowin the circulation can be determined rom Equation4-9. Since the nature o circulation is as i it were a closed system, pump head is simply the riction lossesassociated with the circulation fow.
For example, i it is determined that 1,000 Btuhtransers rom a length o hot water piping and nomore than 8°F is acceptable or a loss in the hot wa-
ter temperature, the fow is determined to be 1,000/ (500 × 8) = 0.250 gpm. In SI, i it is determined that293 W transers rom a length o hot water piping and no more than 4.4°C is acceptable or a loss in thehot water temperature, the fow is determined to be293/(4,187 × 4.4) = 0.0159 L/s.
Drainage Pumps
Where the elevation o the municipal sewer is insu-cient or i another elevation shortall occurs, pumpsare added to a drainage system. The issue may applyonly to one xture, one foor, or the entire building.Elevation issues usually apply to subsoil drainage, sothis water is also pumped. Lastly, i backfow is in-tolerable rom foor drains in a high-value occupancy,pumps are provided or the foor drains.
The terminology varies to describe these pumps,but typical names include sewage pump, sump pump,sewage ejector, lit station pump, efuent pump,bilge pump, non-clog pump, drain water pump, sol-ids-handling sewage pump, grinder pump, dewater-
ing pump, and wastewater pump.Drainage pumps generally have vertical shats,
cylindrical basins, and indoor or outdoor locations.Some pumps are designed to be submerged in theinlet basin, others in a dry pit adjacent to the basin,and in others the motor is mounted above with onlythe pump casing and impeller submerged. In anydesign, provision is required or air to enter or leavethe basin as the water level varies.
The nature o solids and other contaminants inthe water through these pumps necessitates severaltypes o pump designs. For minimal contaminants,the design may be with an enclosed impeller, wearrings, and clearance dimensions that allow ¾-inch(19-mm) diameter spheres to pass through. Such a pump may be suitable or subsoil drainage or orgraywater pumping.
For drainage fows rom water closets and simi-lar xtures, manuacturers provide pumps o twodesigns. One design uses an open recessed impel-ler, no wear rings, and clearance dimensions thatallow 2-inch (50-mm) diameter spheres to passthrough. The other, reerred to as a grinder pump(see Figure 4-10), places a set o rotating cutting blades upstream o the impeller inlet, which slice
solid contaminants as they pass through a ring thathas acute edges. Eciency is compromised in bothtypes or the sake o eective waste transport, inthe latter more so than in the ormer, but with thebenet o a reduced pipe diameter in the dischargepiping. Grinder pumps are available in centriugaland positive-displacement types.
The installation o a pump in a sanitary drainsystem includes a sealed basin and some vent pip-ing to the exterior or to a vent stack. In some cases,the pump can be above the water level, but only i a
Figure 4-10 Cross-Section o a Grinder Pump withCutting Blades at the Inlet
Photo courtesy o Ebara.
reliable provision is included in the design to primethe pump prior to each pumping event.
PUMP MAINTENANCEThe selection o a pump includes actors such as theneed to monitor, repair, or replace the pump. Pumpsin accessible locations can readily be monitored. Sen-sors on remote pumps, such as seal leak probes andbearing vibration sensors, assist in pump monitoring to prevent a catastrophic pump ailure.
Pump maintenance can be acilitated when dis-assembly requires minimal disturbance o piping or wiring. Disassembly may be with the casing splithorizontally along a horizontal shat or with the cas-ing split perpendicularly to the shat. The latter al-lows impeller replacement without disturbing thepipe connection to the pump body.
Complete pump replacement can be acilitatedwith adequate access, shuto valves, nearby mo-tor disconnects, minimal mounting asteners, di-
rect mounting o the motor on the pump housing (close-coupled pump), and pipe joints with boltedasteners. A simpler arrangement, commonly usedor submersible drainage pumps, allows removal o the pump rom the basin by merely liting a chain to
extract it. The lit or return is acilitated by specialguide rails, a discharge connection joint held tight bythe weight o the pump, and a fexible power cable.
ENVIRONMENTAL CONCERNSIn addition to any concerns about how a pump mayaect the environment, the environment may aectthe design requirement or a pump. An example o the ormer is a provision in an oil-lled submersiblepump to detect an oil leak, such as a probe in the spacebetween the shat seals that signals a breach o thelower seal. Another example is vibration isolation ora pump located near sensitive equipment.
The external environment can aect a pump inmany ways. For instance, a sewage ejector may besubjected to methane gas, causing a potential explo-sion hazard. Loss o power is a common concern, asare abrasive or corrosive conditions. The ormer canbe prevented with the inclusion o a parallel pumppowered by a separate battery, and correct material
selection can help prevent the latter. Other examplesinclude the temperature o the water through thepump, the temperature o the air around the pump,and the nature o any contaminants in the water.Sand and metal shavings are a concern with grinderpumps as they can erode the blades.
PUMP CONTROLSPump controls vary with the application. A smallsimplex sump pump may have a sel-contained motoroverload control, one external foat switch, an electricplug, and no control panel. A larger pump may havea control panel with a motor controller, run indicator
light, hand-o auto switch, run timer, audio/visualalarm or system aults, and building automationsystem interace.
A control panel should be certied as complying with one or more saety standards, and the panelhousing should be classied to match its installationenvironment. Motor control generally includes anelectric power disconnect and the related controlwiring, such as power-interrupting controls againstmotor overload, under-voltage, or over-current.
The largest pumps oten include reduced-voltagestarters. Duplex and triplex pump arrangementsinclude these control eatures or each pump as well
as an alternator device that alternates which pumprst operates on rising demand. A microprocessor maybe economically chosen or applications involving atleast a dozen sensor inputs.
A booster pump has additional controls such as lowfow, low suction pressure, high discharge pressure, a time clock or an occupancy schedule and possibly a speed control such as a variable-requency drive.
A circulation pump may include a temperaturesensor that shuts down the pump i it senses high
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temperature in the return fow, which presumablyindicates adequate hot water in each distributionbranch. A time clock or an occupancy scheduleshuts down the pump during o hours.
The controls or a re pump may include an au-tomatic transer between two power sources, enginecontrol i applicable, and pressure maintenancethrough a secondary pump, which is called a jockeypump. The control o a drainage pump includes one ormore foat switches and possibly a high water alarm.
INSTALLATIONPumping eectiveness and eciency require uniormvelocity distribution across the pipe diameter or basindimensions at the pump inlet. An elbow, increaserwith a sudden diameter change, check valve, and anyother fow disturbance at the pump inlet create anirregular velocity prole that reduces the fow andpossibly the discharge head. To avoid air entrapment,eccentric reducers with the straight side up are used
on inlet piping rather than concentric reducers.In addition to shuto valves, pump installationsmay include drain ports, pressure gauges, automaticor manual air release vents, and vibration isolationcouplings. Pressure gauges upstream and down-stream o the pump allow easy indication o therated pump perormance. Check valves are providedor each pump o duplex and similar multiple-pumparrangements, re pumps, and circulation pumps.
A re pump includes provisions or periodic fowtesting. Fire pumps also may include a pressure re-lie valve i low fows create high heads that exceedpipe material ratings.
A pump requires a minimum pressure at its inletto avoid cavitation. Destructive eects occur whena low absolute pressure at the entry to the impel-ler causes the water to vaporize and then collapseurther into the impeller. The resulting shock waveerodes the impeller, housing, and seals and overloadsthe bearings and the shat. The pockets o water va-por also block water fow, which reduces the pump’scapacity. Cavitation can be avoided by veriying Equation 4-10.
Equation 4-10
hr ≤ ha – hv + hs – h
wherehr = Net positive suction head required (obtained
rom the pump manuacturer), eet (m)ha = Local ambient atmospheric pressure
converted to eet (m) o waterhv = Vapor pressure o water at applicable
temperature, eet (m)hs = Suction head (negative value or suction
lit), eet (m)h = Friction head o piping between pump and
where hs is measured, eet (m)
Increasing hs resolves most issues regarding cavi-tation, generally by mounting the pump impeller aslow as possible. Note that hr varies with fow andimpeller diameter: ha = 33.96 eet (10.3 m) or anambient o 14.7 pounds per square inch (psi) (101kPa) and hv = 0.592 eet (0.180 m) or water at 60°F(15.5°C). Suction head, hs, may be the inlet pressureconverted to head, but it also may be the verticaldistance rom the impeller centerline to the suraceo the water at the inlet. The ambient head, ha , alsomay need adjusting or sewage pumps, with the ba-sin connected to an excessively long vent pipe. Re-ciprocating positive-displacement pumps have anadditional acceleration head associated with keeping the liquid lled behind the receding piston.
Submergence is a consideration or pumps joinednear or in a reservoir or basin. A shallow distancerom the pump inlet to the surace o the water maycreate a vortex ormation that introduces air into thepump unless the reservoir exit is protected by a wide
plate directly above. In addition to lost fow capacity,a vortex may cause fow imbalance and other harmto the pump. To prevent these problems, the basincan be made deeper to mount the pump lower, andthe elevation o the water surace can be unchangedto keep the same total head.
Redundancy can be considered or any pump ap-plication. The aggregate capacity o a set o pumpsmay exceed the peak demand by any amount; how-ever, the summation or centriugal pumps involvesadding the fow at each head to create a compositeperormance curve. Discretion is urther made tothe amount o redundancy, whether or each duplex
pump at 100 percent o demand or each triplex pumpat 40 percent, 50 percent, or 67 percent. For ecien-cy’s sake, a mix may be considered or a triplex, suchas 40 percent or two pumps and 20 percent or thethird pump.
GLOSSARy
Available net positive suction head The inher-ent energy in a liquid at the suction connection o a pump.
Axial ow When most o the pressure is developedby the propelling or liting action o the vanes on
the liquid. The fow enters axially and dischargesnearly axially.
Bernoulli’s theorem When the sum o three typeso energy (heads) at any point in a system is thesame in any other point in the system, assum-ing no riction losses or the perormance o extra work.
Brake horsepower (BHP)The total power requiredby a pump to do a specied amount o work.
Capacity coefcient The ratio o the radial veloc-ity o a liquid at the impeller to the velocity o theimpeller’s tip.
Churn The maximum static head o a pump—typi-cally the head when all fow is blocked.
Design working head The head that must be avail-able in the system at a specied location to satisy
design requirements.
Diuser A point just beore the tongue o a pumpcasing where all the liquid has been dischargedrom the impeller. It is the nal outlet o thepump.
Flat head curve When the head rises slightly asthe fow is reduced. As with steepness, the magni-tude o fatness is a relative term.
Friction head The rubbing o water particlesagainst each other and against the walls o a pipe,which causes a pressure loss in the fow line.
Head The energy o a fuid at any particular pointo a fow stream per weight o the fuid, generallymeasured in eet (meters).
Head coefcient Pump head divided by the squareo the velocity o the impeller tip.
Horsepower The power delivered while doing workat the rate o 500 oot-pounds per second or 33,000oot-pounds per minute.
Independent head Head that does not change withfow, such as static head and minimum pressure atthe end o a system.
Mechanical efciency The ratio o power outputto power input.
Mixed ow When pressure is developed partly bycentriugal orce and partly by the lit o the vaneson the liquid. The fow enters axially and discharg-es in an axial and radial direction.
Multistage pumps When two or more impellersand casings are assembled on one shat as a singleunit. The discharge rom the rst stage enters thesuction o the second and so on. The capacity isthe rating o one stage, and the pressure rating isthe sum o the pressure ratings o the individual
stages, minus a small head loss. Net positive suction head (NPSH) Static head,
velocity head, and equivalent atmospheric head ata pump inlet minus the absolute vapor pressure o the liquid being pumped.
Packing A sot semi-plastic material cut in ringsand snugly t around the shat or shat sleeve.
Potential head An energy position measured by thework possible in a decreasing vertical distance.
Pumps in parallel An arrangement in which thehead or each pump equals the system head andthe sum o the individual pump capacities equalsthe system fow rate at the system head.
Pumps in series An arrangement in which the totalhead/capacity characteristic curve or two pumpsin series can be obtained by adding the total heads
o the individual pumps or various capacities. Pump perormance curve A graphical illustration
o head horsepower, eciency, and net positivesuction head required or proper pump operation.
Radial ow When pressure is developed principallyby centriugal orce action. Liquid normally entersthe impeller at the hub and fows radially to theperiphery.
Required NPSH The energy in a liquid that a pumpmust have to operate satisactorily.
Shuto BHP One-hal o the ull load brake horse-
power.Slip A loss in delivery due to the escape o liquid
inside a pump rom discharge to suction.
Specifc speed An index relating pump speed, fow,and head used to select an optimal pump impeller.
Standpipe A theoretical vertical pipe placed at anypoint in a piping system so that the static head canbe identied by observing the elevation o the reesurace o the liquid in the vertical pipe. The con-nection o the standpipe to the piping system or a static head reading is perpendicular to the generalfow stream.
Static head The elevation o water in a standpiperelative to the centerline o a piping system. Anypressure gauge reading can be converted to statichead i the density o the liquid is known.
Static pressure head The energy per pound dueto pressure. The height a liquid can be raised by a given pressure.
Static suction head The vertical distance rom theree surace o a liquid to the pump datum whenthe supply source is above the pump.
Static suction lit The vertical distance rom the
ree surace o a liquid to the pump datum whenthe supply source is below the pump.
Steep head curve When the head rises steeply andcontinuously as the fow is reduced.
Suction head The static head near the inlet o a pump above the pump centerline.
Suction lit In contrast to suction head, this verti-cal dimension is between the pump centerline anda liquid’s surace that is below the pump.
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System head curve A plot o system head versussystem fow. System head varies with fow sinceriction and velocity head are both a unction o fow.
Total discharge head The sum o static head andvelocity head at a pump discharge.
Utility horsepower (UHP) Brake horsepower di-
vided by drive eciency.
Total head The total head at the pump dischargeminus suction head or plus suction lit.
Variable-speed pressure booster pumps A pumpused to reduce power consumption to maintain a constant building supply pressure by varying pumpspeeds through coupling or mechanical devices.
Velocity head The velocity portion o head with itsunits converted to an equivalent static head.
Water horsepower The power required by a pump
motor or pumping only.
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Piping Insulation5Insulation and its ancillary components are majorconsiderations in the design and installation o theplumbing and piping systems o modern buildings.Insulation is used or the ollowing purposes:
• Retardheatorcoolingtemperaturelossthrough
pipe• Eliminatecondensationonpiping
• Protectpersonnelby keeping the surfacetemperature o pipes low enough to touch
• Improvetheappearanceofpipewhereaestheticsare important
TERMINOLOGy To ensure an understanding o the mechanism o heat,
the ollowing denitions are provided.
British thermal unit (Btu) The heat required toraise the temperature o 1 pound o water 1°F.
Conductance Also known as conductivity, themeasurement o the fow o heat through an arbi-trary thickness o material, rather than the 1-inchthickness used in thermal conductivity. (See alsothermal conductivity.)
Convection The large-scale movement o heatthrough a fuid (liquid or gas). It cannot occurthrough a solid. The dierence in density between
hot and cold fuids produces a natural movemento heat.
Degree Celsius The measurement used in inter-national standard (SI) units ound by dividing theice point and steam point o water into 100 divi-sions.
Degree Fahrenheit The measurement used ininch-pound (IP) units ound by dividing the icepoint and steam point o water into 180 divisions.
Heat A type o energy that is produced by themovement o molecules. More movement producesmore heat. All heat (and movement) stops at abso-lute zero. It fows rom a warmer body to a coolerbody. It is calculated in such units as Btu, calories,or watt-hours.
Kilocalorie (kcal) The heat required to raise 1kilogram o water 1°C.
Thermal conductivity The ability o a specicsolid to conduct heat. This is measured in Britishthermal units per hour (Btuh) and is reerred toas the k-actor. The standard used in the measure-ment is the heat that will fow in one hour througha 1-inch-thick material, with a temperature di-erence o 1°F over an area o 1 square oot. Themetric equivalent is watts per square meter perdegree Kelvin (W/m
2 /°K). As the k-actor increases,
so does the fow o heat.
Thermal resistance Abbreviated R, the recipro-cal o the conductance value. (See conductance.)
Thermal transmittance Known as the U-actor,the rate o fow, measured in thermal resistance,through several dierent layers o materials takentogether as a whole. It is measured in Btuh persquare oot per degree Fahrenheit (Btuh/t
2 /°F).
THE PHySICS OF WATER VAPORTRANSMISSION Water vapor is present in the air at all times. A watervapor retarder does not stop the fow o water vapor.Rather, it serves as a means o controlling and reduc-ing the rate o fow and is the only practical solution tothe passage o water vapor. Its eectiveness dependson its location within the insulation system, which isusually as close to the outer surace o the insulationas practical. Water vapor has a vapor pressure that isa unction o both temperature and relative humidity.The eectiveness o an insulation system is best whenit is completely dry.
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The water vapor transmission rate is a measureo water vapor diusion into or through the totalinsulation system and is measured in perms. A permis the weight o water, in grains, that is transmittedthrough 1 square oot o 1-inch-thick insulation inone hour. A generally accepted value o 0.10 perms isconsidered the maximum rate or an eective vaporretarder. A ormula or the transmission o watervapor diusing through insulation systems is givenin Equation 5-1.
Equation 5-1
W = µAT∆PL
whereW = Total weight o vapor
transmitted, grains(7,000 grains = 1pound o water)
µ = Permeability o insulation, grains/ t2 /h/in. Hg ∆P/in.
A = Area o cross-sectiono the fow path,square eet
T = Time during whichthe transmissionoccurred, hours
∆P = Dierence o vaporpressure betweenends o the fow path,inches o mercury (in.Hg)
L = Length o fow path,
inches
TyPES OFINSULATIONInsulation manuacturers givetheir products dierent tradenames. The discussions thatollow use the generic namesor the most oten used ma-terials in the plumbing anddrainage industry. The insula-tion properties are based on theollowing conditions:
• Allmaterials have beentested to ASTM, NFPA, andUL standards.
• The temperatureatwhichthe thermal conductivity andresistance were calculated is75°F (24°C).
Insulation used or thechemical, pharmaceutical, and
ood-processing industries (or example) must be ableto withstand repeated cleaning by various methods.This is provided by the application o the proper jacketing material (discussed later), which shall beresistant to organism growth, smooth and white, re-sistant to repeated cleaning by the method o choiceby the owner, and nontoxic.
As with other building materials, insulation maycontribute to a re by either generating smoke (i theproduct is incombustible) or supporting combustion.Code limits or these actors have been established.These ratings are or complete insulation systemstested as a whole and not or individual components.
Figure 5-1 Insulating Around a Split Ring Hanger1. Pipe
2. Insulation—shown with actory-applied, non-metal jacket3. Overlap at logitudinal joints— cut to allow or hanger rod
4. Tape applied at butt joints— pipe covering section at hanger should extend a ewinches beyond the hanger to acilitate proper butt joint sealing
5. Insulation altered to compensate or projections on split ring hangers—i insulationthickness is serverely altered and let insucient or high-temperature applications
or condensation control, insulate with a sleeve o oversized pipe insulation6. Insulation applied in like manner around rod on cold installations
The code requirements or insulation are a famespread index o not more than 25 and a smoke-developed index o not more than 50. The standardsgoverning the testing o materials or fame spreadand smoke developed are ASTM E84 , NFPA 255 , andUL 723.
Fiberglass
Fiberglass insulation shall conorm to ASTM C547. It is manuactured rom glass ber bonded with a phenolic resin. The chemical composition o this resindetermines the highest temperature rating o this in-sulation. (Consult the manuacturer or exact gures.)
This insulation is tested to all below the index o 25or fame spread and 50 or smoke developed. It haslow water absorption and very limited to no combus-tibility. It has poor abrasion resistance.
Fiberglass is the most commonly used insulationor the retardation o heat loss rom plumbing linesand equipment. The recommended temperature rangeis rom 35°F to 800°F (1.8°C to 422°C), with ratingsdepending on the binder. It is available as pre-moldedpipe insulation, boards, and blankets. Typical k-actors range rom 0.22 to 0.26, and R values rangerom 3.8 to 4.5. Its density is about 3–5 pounds percubic oot (48–80 kilograms per cubic meter).
Fiberglass by itsel is not strong enough to stay on a pipe or piece o equipment, prevent the passage o watervapor, or present a nished appearance.Because o this, a covering or jacketmust be used.
Elastomeric
Elastomeric insulation, commonlycalled rubber, shall conorm to ASTMC534. This is a fexible, expanded oammade o closed-cell material manuac-tured rom nitrile rubber and polyvinylchloride resin. This insulation dependson its thickness to all below a specicsmoke-developed rating. All thicknesseshave a fame spread index o 25. It canabsorb 5 percent o its weight in waterand has a perm rating o 0.10. Its densityranges between 3 pounds per cubic ootand 6 pounds per cubic oot.
The recommended temperaturerange is rom –297°F to 220°F (–183°Cto 103°C). A typical k-actor is 0.27,and a typical R value is 3.6. It is recom-mended as preormed insulation or pipesizes up to 6 inches (DN 150) in ½-inch,¾-inch, and 1-inch thicknesses. It isalso available in 48-inch (1,200-mm)wide rolls and in sheet sizes o 36 × 48inches (900 × 1,200 mm). An adhesivemust be used to seal the seams and joints and adhere the insulation to the
equipment.Rubber insulation can be painted
without treatment. It is widely used inmechanical equipment rooms and pipe,and the ease o application makes it lesscostly. The recommended temperaturerange is rom –297°F to 220°F (–183°Cto 103°C)
Figure 5-2 Insulating Around a Clevis Hanger1. Pipe
2. Insulation—type specied or the line3. High-density insulation insert—extend beyond the shield to acilitate
together—cold application5. Jacketing—eld-applied metal shown
6. Metal shield7. Wood block or wood dowel insert
Source: MICA
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Cellular GlassCellular glass shall conorm to ASTM C552. Thisinsulation is pure glass oam manuactured withhydrogen sulde and has closed-cell air spaces. Thesmoke-developed rating is zero, and the fame spreadis 5. The recommended application temperature isbetween –450°F and 450°F (–265°C and 230°C), with
the adhesive used to secure the insulation to the pipeor equipment being the limiting actor. It has no waterretention and poor surace abrasion resistance.
Cellular glass is rigid and strong and commonlyused or high-temperature installations. It generallyis manuactured in blocks and must be abricatedby the contractor to make insulation or pipes orequipment. A saw is used or cutting. It has a typicalk-actor o 0.37 and an R value o 2.6. Its density is 8pounds per cubic oot.
It is resistant to common acids and corrosiveenvironments. It shall be provided with a jacket o some type.
Foamed PlasticFoamed plastic insulation is a rigid, closed-cell prod-uct, which shall conorm to the ollowing standardsdepending on the material. Polyurethane shall con-orm to ASTM C591 ; polystyrene shall conorm to ASTM C578 ; and polyethylene shall conorm to ASTMC1427. It is made by the expansion o plastic beadsor granules in a closed mold or using an extrusionprocess. The re spread index varies among manuac-turers, but its combustibility is high. Additives can beused to improve re retardancy. It is available moldedinto boards or pre-molded into pipe insulation.
Foamed plastic is most commonly used in 3-inchor 4-inch thickness to insulate cryogenic piping. Therecommended temperature range or installation isrom cryogenic to 220°F (103°C). The density variesrom 0.7 pound per cubic oot to 3 pounds per cubicoot. The k-actor varies between 0.32 and 0.20 de-pending on the density and age o the material. Theaverage water absorption is 2 percent.
Calcium SilicateCalcium silicate shall conorm to ASTM C533. It is a rigid granular insulation composed o calcium silicate,asbestos-ree reinorcing bers, and lime. This mate-rial has a k-actor o 0.38 and an R value o 2.
A mineral ber commonly reerred to as calsil,it is used or high-temperature work and does notnd much use in the plumbing industry except as a rigid insert or installation at a hanger to protect theregular insulation rom being crushed by the weighto the pipe.
Insulating CementInsulating cement is manuactured rom brous and/ or granular material and cement mixed with waterto orm a plastic substance. Sometimes reerred to asmastic, it has typical k-actors ranging between 0.65and 0.95 depending on the composition. It is wellsuited or irregular suraces.
JACKET TyPES A jacket is any material, except cement or paint, thatis used to protect or cover insulation installed on a pipe or over equipment. It allows the insulation tounction or a long period by protecting the underly-
Table 5-1 Heat Loss in Btuh/t Length o Fiberglass Insulation, ASJ Cover 150°F Temperature o Pipe
All-Service JacketKnown as ASJ, the all-service jacket is a laminationo brown (krat) paper, berglass cloth (skrim), and a metallic lm. A vapor retarder also is included. This jacket also is called an FSK jacket because o the -berglass cloth, skrim, and krat paper. It most oten isused to cover berglass insulation.
The berglass cloth is used to reinorce the kratpaper. The paper is generally a bleached, 30-pound(13.5-kg) material, which actually weighs 30 poundsper 30,000 square eet (2,790 m
2). The metallic oil is
aluminum. This complete jacket gives the re rating or the insulation system.
The jacket is adhered to the pipe with either sel-sealing adhesive or staples. The butt joint ends aresealed with adhesive, placed together, and then coveredwith lap strips during installation. Staples are usedwhen the surrounding conditions are too dirty or cor-rosive to use sel-sealing material. The staple holesshall be sealed with adhesive.
Aluminum Jacket Aluminum jackets shall conorm to ASTM B209. Theyare manuactured as corrugated or smooth and areavailable in various thicknesses ranging rom 0.010inch to 0.024 inch, with 0.016 inch being the mostcommon. The corrugated version is used where expan-sion and contraction o the piping may be a problem. Aluminum jackets also are made invarious tempers and alloys. A vaporretarder material can be applied toprotect the aluminum rom any cor-rosive ingredient in the insulation.
Fittings are abricated in the shop. Aluminum jackets may be secured
by one o three methods: by strapson 9-inch (180-mm) centers, by a proprietary S or Z shape, or by sheetmetal screws.
Stainless Steel JacketStainless steel jackets shall conormto ASTM A240. They are manuac-tured as corrugated or smooth andare available in various thicknessesranging rom 0.010 inch to 0.019inch, with 0.016 inch being the mostcommon. They are also available invarious alloy types conorming to ASTM A304 and can be obtained indierent nishes. A vapor retardermaterial can be applied, although itis not required or corrosive envi-ronments except where chlorine orfuorides are present.
Stainless steel jackets are used or hygienic purposesand are adhered in a manner similar to that used oraluminum.
Plastic and LaminatesPlastic jackets are manuactured rom polyvinylchloride (PVC), polyvinylidene fuoride (PVDF), acry-lonitrile butadiene styrene (ABS), polyvinyl acetate
(PVA), and acrylics. Thicknesses range rom 3 mils to35 mils. The local code authority shall be consultedprior to their use.
Laminates are manuactured as a composite thatis alternating layers o oil and polymer. Thicknessesrange rom 3 to 25 mils. The local code authority shallbe consulted prior to their use.
Both are adhered by the use o an appropriateadhesive.
Wire Mesh Wire mesh is available in various wire diameters andwidths. Materials or manuacture are Monel, stainless
steel, and Inconel. Wire mesh is used where a strong,fexible covering that can be removed easily is needed.It is secured with lacing hooks or stainless steel wirethat must be additionally wrapped with tie wire ormetal straps.
Lagging Lagging is the covering o a previously insulated pipe orpiece o equipment with a cloth or berglass jacket. Itis used where appearance is the primary consideration,since this type o jacket oers little or no additionalinsulation protection. This material also is used as a
combination system that serves as a protective coatand adhesive.
This jacket typically is secured to the insulationwith the use o lagging adhesive and/or sizing. It isavailable in a variety o colors and may eliminate theneed or painting.
HG = Heat gain/lineal oot (pipe) 28 t (fat) (Btu). ST = Surace temperature (°F).
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INSTALLATION TECHNIQUES
Insulation or Valves and FittingsThe ttings and valves on a piping system requirespecially ormed or made-up sections o insulation tocomplete the installation.
One type o insulation is the pre-ormed type thatis manuactured by specic size and shape to t over
any particular tting or valve. Such insulation isavailable in two sections that are secured with staples,adhesive, or pressure-sensitive tape depending on theuse o a vapor retarder. This is the quickest methodo installation, but the most costly.
Another system uses a pre-ormed plastic jacketthe exact size and shape o the tting or valve. A berglass blanket or sheet is cut to size and wrappedaround the bare pipe, and then the jacket is placedover the insulation. The exposed edges are tucked in,and the jacket is secured with special tacks with a barbthat prevents them rom pulling apart. The ends aresealed with pressure-sensitive tape.
For large piping, it is common to use straightlengths o berglass by mitering the ends and secur-ing them with a berglass jacket (lagging).
Insulation or Tanks Where berglass is specied, tanks are insulated us-ing 2×4-oot boards in the thickness required. Theboards are placed on the tank in an manner similarto brick laying. They are secured with metal bands. Wire is placed over the bands as a oundation orinsulating cement applied over the tank to give a nished appearance.
Where rubber is specied, the tank is coated with
adhesive, and the rubber sheets are placed on thetank. The edges are coated with adhesive to seal it.Painting is not required.
Insulation Around Pipe Supports As the installation on a project progresses, a contrac-tor must contend with dierent situations regarding the vapor retarder. Since the insulation systemselected shall be protected against the migration o water vapor into the insulation, the integrity o thevapor retarder must be maintained. Where a hangeris installed directly on the pipe, the insulation mustbe placed over both the pipe and the hanger. Figure
5-1 illustrates a split-ring hanger attached directlyon the pipe.
Since low-density insulation is the type most otenused, a situation arises wherein the primary consid-erations are keeping the vapor retarder intact andpreventing the weight o the pipe rom crushing theinsulation. Figure 5-2 illustrates several high-densityinsert solutions or a clevis hanger supporting aninsulated pipe.
The jacketing method shown in both gures canbe used interchangeably with any type o insulationor which it is suited.
SELECTING INSULATIONTHICKNESSSelecting the proper insulation thickness is aectedby the reason or using insulation:
1. Controlling heat loss rom piping or equipment
2. Condensation control
3. Personnel protection
4. Economics
Controlling Heat LossIncreased concern about conservation and energyuse has resulted in the insulation o piping to controlheat loss becoming one o the primary considerationsin design. Heat loss is basically an economic consid-eration, since the lessening o heat loss produces a
more cost-ecient piping system. The proper use o insulation can have dramatic results.
The insulation installed on domestic hot water, hotwater return, and chilled drinking water systems isintended to minimize heat loss rom the water. Sinceberglass insulation is the type most oten used, Table5-1 is provided to give the heat loss through verticaland horizontal piping as well as the heat loss throughbare pipe. Table 5-2 is given or piping intended to beinstalled outdoors.
When calculating the heat loss rom round sur-aces such as a pipe, the plumbing engineer shouldremember that the inside surace o the insulation
has a dierent diameter than the outside. Thereore,a means must be ound to determine the equivalentthickness that shall be used. This is done by the useo Table 5-3. To read this table, enter with the actualpipe size and insulation thickness, and then nd theequivalent thickness o the insulation.
Sotware endorsed by the U.S. Department o Energy and distributed by the North American In-sulation Manuacturers Association (NAIMA) thatwill calculate heat loss, condensation control, andenvironmental emissions is available at pipeinsula-tion.org.
Condensation Control As mentioned, water vapor in the air condenses on a cold surace i the temperature o the cold surace isat or below the dewpoint. I the temperature is abovethe dewpoint, condensation does not orm. The pur-pose o a vapor retarder is to minimize or eliminatesuch condensation. For this to be accomplished, the joints and overlaps must be sealed tightly. This is donethrough one o three methods:
Source: Certainteed.Notes: TH = Thickness o insulation (in.)HL = heat loss (Btu/h)LF = Heat loss per lineal oot o pipe (Btu/h)SF = Heat loss per square oot o outside insulation surace (Btu/h)ST = Surace temperature o insulation (°F)
5 IPS -10 (-23.3) 50 (10) 1 (25.4) 11.15 118.25 0.78aNo way to calculate slush. 32°F (0°C) ice value higher due to heat o usion.
bFlow is expressed as gal/h/t o pipe (12.4 Uhr-m).
Example: For 100 t. (30.5m) pipe run, multiply value shown by 100. This is the minimum continuous fow to keep water rom reezing.OD CT = outside diameter, copper tubeIPS = iron pipe size
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1. Rigid jackets such as metallic or plastic
2. Membranes such as laminated oils
3. Mastics applied over the pipe, either emulsion orsolvent type
Table 5-4 shows the dry-bulb dewpoint temperatureat which condensation orms. Table 5-5 is provided to
indicate the thickness o berglass insulation neededto prevent condensation with water at 50°F (10°C).
Personnel Protection When hot water fows through an uninsulated piping system, it is usually at a temperature that may scaldany person touching the pipe. Insulation is used tolower the surace temperatures o hot water pipes toprevent such harm. A surace temperature o 120°F(49°C) has been shown to not burn a person whotouches the pipe. Table 5-6 provides the thickness o berglass insulation and the surace temperature o the insulation. The thicknesses shown in this table
should be compared with those shown in Table 5-1 or5-2 to see which thickness is greater. The larger thick-ness should be used.
EconomicsThe two economic actors involved are the cost o theinsulation and the cost o energy. To calculate theenergy savings in nancial terms, the ollowing are
needed: service temperature o the surace, pipe sizeor surace dimensions, Btu dierence between the airand the surace (linear eet or square eet), eciencyo heating equipment, annual operating hours, andthe cost o uel.
I the plumbing designer wishes to make an eco-nomic comparison among various insulation systems,many ormulas and computer programs are availableor the purpose. Discussion o these methods is beyondthe scope o this chapter.
Figure 5-3 Temperature Drop o Flowing Water in a Pipeline
FREEZE PROTECTIONNo amount o insulation can prevent the reezing o water (or sewage) in a pipeline that remains dormantover a long period. Table 5-7 is provided as a directreading table or estimating the time it takes or dor-mant water to reeze. For some installations, it is notpossible or the water to remain dormant. I the water
is fowing, as it does in a drainage line, use Figure 5-3,a nomogram that gives the temperature drop o fow-ing water. I the contents cannot be prevented romreezing, the plumbing engineer can add hot water toraise the temperature, heat trace the line, or providesucient velocity to keep the contents rom reezing.
To calculate the fow o water in a line to preventreezing, use Equation 5-2.
TW = Water temperature, °FTA = Lowest air temperature, °F
D = Inside diameter o pipe, eet
INSULATION DESIGNCONSIDERATIONSFollowing are some general items to consider whendesigning the insulation or a plumbing system.
1. Insulation attenuates sound rom the fow o pipecontents. Where sound is a problem, such as intheaters, adding a mass-lled vinyl layer over theinsulation can lessen the sound.
2. Protecting health and saety when storing andhandling insulation and/or jacketing materials canbe alleviated by proper adherence to established
sae storage and handling procedures.3. The rate o expansion aects the eiciency o
the insulation over a long period. The dierencebetween the expansion o insulation and theexpansion o the pipe eventually leads to gaps aternumerous fexings.
4. Protect the insulation against physical damage byadding a strong jacket or delaying installation ona piping system. It has been ound that workmenwalking on the pipe pose the greatest danger.
5. I the insulation is to be installed in a corrosiveatmosphere, the proper jacket shall be installed to
withstand the most severe conditions.6. Union regulations should be reviewed to ensure that
the insulation contractor installs a jacket. Somemetal jackets above a certain thickness are installedby the general contractor.
7. Space conditions may dictate the use o oneinsulation system over another to t in a connedspace.
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Hangers andSupports6
Piping system supports and hangers perorm manyunctions—including supporting or anchoring piping systems, preventing pipe runs rom sagging, allow-ing or motion to alleviate breakage, and providing an adequate slope to accommodate drainage orfow—and they are an integral part o the plumbing
system. Choosing the correct supports and hangersis an important aspect o the design o a plumbing system, as improper specication can lead to ailure o the entire system. The designer must consider a mul-titude o environmental and physical characteristicsthat may interact with and aect the overall system,such as the quantity and composition o the fuidexpected to fow through the system, structural com-ponents, chemical interactions, metal atigue analysis,acoustics, and even electric current transerence. Thespecication must go beyond the support types andhanger distances prescribed in the plumbing codes.
In act, the designer may need to consult with otherengineering disciplines and with the pipe and pipesupport manuacturers or the correct materials tospeciy or particular applications.
HANGER AND SUPPORTCONSIDERATIONSThe most common hanger and support detail speciedon plans is a simple statement: “the piping shall besupported in a good and substantial manner in accor-dance with all local codes and ordinances.” However,the codes typically provide little help to the plumbing engineer. Their requirements are simple:
• Allwaterpipingshallbeadequatelysupportedtothe satisaction o the administrative authority.
• Pipingshallbesupportedfortheweightandthedesign o the material used.
• Supports, hangers,and anchors are devices forproperly supporting and securing pipe, xtures,and equipment.
• Suspendedpipingshallbesupportedatintervalsnot to exceed those shown in Table 6-1.
• Allpipingshallbesupportedinsuchamannerasto maintain its alignment and prevent sagging.
• Hangers and anchors shall be of sufcientstrength to support the weight o the pipe and itscontents.
A technical specication or perormance character-istic regarding piping support is an oten-overlookedpart o the plumbing system design. In addition toollowing the basic code requirements, the plumbing engineer must study, evaluate, and analyze the piping layout in relation to the structure and equipment, aswell as consider the totality o the piping systems thatwill be utilized and the surrounding environmentaland physical characteristics that will come to bearon the overall perormance o the completed system.
Given the wide variety o environmental and physicalcharacteristics around which projects are designed,it is not possible to provide an exhaustive listing o potential areas that need evaluation. However, somebasic considerations include the ollowing.
Loads What will the total load o the piping system be?First and oremost, basic engineering requires a perormance and load calculation to be conductedto determine the physical amount and weight o allspecic piping system elements. In this initial deter-mination, the engineer considers not only the weighto the piping itsel, but also that o all associated ele-
ments including valves, ttings, the bulk weight andfow characteristics o the substance to fow throughor be carried within the pipe, and thermal or acousti-cal insulation or other pipe-covering material.
Depending on the piping system’s location, oth-er natural and manmade orces that may create anadditional load on the piping system, such as rain,ice, and snow or piping systems exposed to naturalweather conditions, also must be considered. When a portion o the piping system will be exposed and rel-
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atively easy to reach, the engineer should give someconsideration to the potential or unintended uses,such as people hanging rom pipes or using them assupports or various items (e.g., plants, lights).
The chosen hanger, support, and anchor systemmust, at a minimum, accommodate the piping sys-tem load. Moreover, the plumbing engineer needs towork closely with the structural engineer to ensurethat the building’s structure will be able to supportthe load created by the attachment o the piping system. This load calculation also may incorporateother elements as indicated below.
Thermal Stresses What stresses and accompanying limitations willbe imposed on the piping system? Many external,internal, and thermal stresses and the accompanying movements that can occur need to be accommodatedby the hangers, supports, and anchors o a piping system. Hangers and supports must provide or
fexibility and axial (twisting), latitudinal, and lon-gitudinal motions.
Thermal events subject the piping system toboth internal and external infuences resulting incontractions and expansions, which can be gradualor sudden in their movements. Here again, naturaland manmade environments must be taken intoaccount. Whenever the piping system and its sur-rounding environment are subject to any heating orcooling events, the hangers and supports must beable to accommodate the contraction and expansioneects. In addition, the hangers must be able to ac-commodate the eects o heating and cooling eventsthat aect the substances being carried within thepiping system (e.g., certain liquids fow at dierentvelocities under dierent temperatures).
Even in a piping system with thermal consider-ations accounted or by design elements such as ex-pansion loops, the accompanying lateral movement
a. For spacing supports incorporating type 40 shields, see ANSI/MSS SP–58-2009, Table A3.
b. This table does not apply where span calculations are made or where there are concentrated loads between supports, such as fanges, valves, and specialties, etc. or changesin direction requiring additional supports.
c. Unbalanced orces o hydrostatic or hydrodynamic origin (thrust orces) unless restrained externally can result in pipe movement and separation o joints i the joints o thesystem are not o a restrained joint design. See ANSI/MSS SP-58-2009 Section 7.5.3
Extracted rom ANSI/MSS SP-58-2009 with permission o the publisher, Manuacturers Standardization Society o the Valve and Fittings Industry Inc. Note: The SP-58-2009“comprehensive” edition integrates the content o a revised MSS SP-58 with ANSI/MSS SP-69-2003, MSS SP-77-1995 (R 2000), MSS SP-89-2003, and MSS SP-90-2000 intoa single source document, enabling the user to speciy a minimum level o acceptance or pipe hanger design and perormance, in addition to dening the types o hangers andsupports. The aorementioned SP-69 will not be revised, and SP-77, 89, and 90 were withdrawn in 2010. The SP-58-2009 edition can ocially be utilized and reerenced in placeo the aorementioned Standard Practices.
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Chapter 6 — Hangers and Supports 117
should be accommodated by buttressing with theproper hangers and supports.
Pressure Fluctuations Just as with thermal stresses, pressure fuctuationsthat occur because o the substance being trans-ported within the piping system are accompaniedby contraction and expansion eects that need to be
accommodated by the proper hangers and supports.These pressure fuctuations are oten complex, as theyinvolve the conduct o fuids, gases, and semisolidsbeing transported in an enclosed environment.
Changes in pressure can create unrealized stress-es on the hangers and supports or the piping system.For instance, water hammer can cause movementand vibration within pipes that may cause the piping system to ail i it is too rmly or rigidly anchored. Water hammer can occur within any piping systemcarrying liquids when a signicant fuctuation o fow volume or pressure occurs or when a contami-nant substance, such as air, enters the piping.
The plumbing engineer must design a piping hanger and support system to handle extreme pres-sure fuctuations and also to ensure that the build-ing’s structure can handle the applied loads createdby the movement o the piping system.
Structural StressesPerhaps the most obvious o all external infuenceson a piping system is the structure to which thepiping system must be attached and pass through.Every natural and manmade material is subject tocontraction and expansion due to internal and exter-nal eects. Many o these structural stresses must
be accommodated by the plumbing engineer withinthe design o the hangers and supports or the piping system. Every building must be engineered to handlethe stresses o the basic structural components.
Anchors and supports o piping systems that ini-tially are attached to vertical metal structural com-ponents and transition to horizontal attachments toconcrete structural components must contend withthe contraction and expansion o the piping systemmaterials as well as the expansion and contraction o the structural elements. For example, the diametero the metal dome o the U.S. Capitol in Washing-ton, D.C. is known to expand by up to 6 inches when
heated by the sun during the summer.
Natural Environmental ConditionsThe susceptibility o a piping system to naturalconditions must be accounted or within the piping system and the accompanying hangers, supports, andanchors. The major eect o these natural environ-mental conditions is on the basic building structure.However, within structures designed to handle ex-treme natural phenomena, the piping system itsel must be hardened or conditioned.
Typical natural phenomena consist o seismicorces and sustained periods o high winds, includ-ing hurricanes and typhoons, which create majorstresses and loads on a building’s structure. For in-stance, an extreme high-rise building, such as theEmpire State Building in New York City, is knownto move 4 to 12 inches laterally in high winds. Inzones o known natural phenomena, such as areassusceptible to earth movement, the plumbing engi-neer must design the piping and support systems tosustain the shocks, stresses, and loads inherent withand applied by these extreme orces. The engineermust reer to applicable building codes to determinethe seismic design category or any mandated piping system support requirements.
While a plumbing system may not be expected tosurvive the complete destruction o a building’s struc-ture, it is expected to survive intact and working inthe event that the building structure itsel survives.
Reactivit and Conductivit
The hangers and supports vital to providing piping system integrity oten must also provide protectionrom unexpected natural and manmade activities,events, and phenomena totally unrelated to structure,stresses, loads, and similar engineering events. Just asthe engineer must consider the makeup o the interiorsuraces o the piping material, he also must considerthe exterior components o the piping system that willbe subject to environmental and manmade conditions.The hangers and supports must be actored into thisreactive equation.
Reactive conditions can consist o chemical reac-tions between unlike materials or the introductiono a reactive substance or electrical conductivity thatcan occur between dierent materials due to electri-cal “leakage” onto a piping system. These reactiveand conductivity concerns can be unobtrusive andunexpected. Regardless, they can be the cause o un-expected ailure in the hangers or supports o thepiping system.
This type o ailure can be especially acute in unex-pected areas. Chemical umes, salt water, and clean-ing liquids can cause a chemical reaction betweena hanger or support and a pipe o diering metals.Initial indicators o potential ailure can be seen in
corrosion or in the compounds produced by chemicalreaction that attach to the hangers and supports ininhospitable environments such as boiler rooms orspecialty gas and liquid systems.
It is vital that such reactive conditions be consid-ered and that the engineer speciy compatible pipeand support materials or provide or protective coat-ings or materials. It is especially important to en-sure that the interior portions o hangers, supports,and clamps that come in contact with piping also aresubject to the protective coatings; otherwise, they
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will be prone to ailure as the material is destroyedrom the inside out.
Similarly, electrical current seepage or leakage cancause unexpected but known eects between two dis-similar materials. The plumbing engineer may needto evaluate the potential or this electrical leakage,especially in common raceways where piping andconduit are placed side by side, and provide suitableprotection via the hangers and supports. A commonexample o this is the galvanic corrosion that occursin copper pipe when steel hangers are used.
AcousticsFor certain structures, the engineer may need toconsider various acoustical aspects related to piping systems. In general, two signicant types o acousti-cal annoyances must be considered. The rst is noisesuch as the sound o liquid rushing through a pipe ora harmonic resonance that makes a pipe “ring.” Inthese instances, the engineer must ensure that thepiping system and the accompanying supports receive
proper insulation.The second type o acoustic eect that must be
considered is that created by vibration and movementwithin the piping system. This acoustic anomaly re-quires a hanger and support system that oers a com-bination o three-dimensional fexibility to accountor lateral, longitudinal, and axial movements o thepiping system and a sound- and vibration-insulating material or anchor integrated into the hanger.
Manmade Environmental ConditionsThe plumbing engineer also should be cognizant o any manmade environmental conditions that can a-
ect the piping system. These created conditions cancause uncalculated stresses and loads on the systemand lead to premature ailure. Created environmentalconditions that can result in resonance or vibrationaecting interior structural systems include majorhighway arteries with signicant automotive and trucktrac; airport takeo and landing patterns; nearbyconstruction; underground digging; and undergroundtrac such as subways and railroad tunnels.
HANGER AND SUPPORTSELECTION AND INSTALLATIONThe old adage “the whole is only as strong as its
individual parts” applies directly to piping hangersand supports. Countless environmental and physi-cal conditions as discussed above can be consideredwhen choosing the correct hanger, support, or anchor.Nothing, however, substitutes or experience andknowledge. The engineer should work directly withthe pipe manuacturer regarding the proper spacing criteria and hanging methods or the pipe that isto be specied. While the number o variables thatcan be examined in choosing hangers and supports
or a plumbing system has no limits, practicalityand resource limitations also must be taken intoconsideration.
Hanger TpesHangers, supports, and clamps come in a wide varietyo materials, shapes, and sizes (see Figure 6-1). Whilethe major purpose o the hangers shown is to support
the loads and stresses imposed on a piping system,specication o the correct hanger is a vital componentor the overall structural integrity o the building itsel. The structure must be able to handle the loadsand stresses o the piping system, and the hanger andsupport system must be engineered to provide fex-ibility, durability, and structural strength.
Selection CriteriaTo ensure proper hanger and support selection, theplumbing engineer must determine or be cognizant o the degrees o reedom that will be necessary withinthe piping system due to its operating characteris-
tics. These degrees o reedom need to be consideredin a three-dimensional space to account or lateral,horizontal, vertical, and axial movements and fuc-tuations.
The most typical selection criterion used is theone most closely associated with the type o pipe ma-terial and the temperature fuctuations within thesystem. This simple selection process requires thecorrect hanger choice to be made rom Table 6-2.Then, based on that hanger choice and the tempera-ture o the overall piping system, Table 6-3 can beused to select the appropriate hanger.
However, this selection process relies on averages
and standards. It does not take into account all o the three-dimensional fuctuations and movementsthat, depending on the structure and the associatedor potential stresses and loads, will aect the overallplumbing system.
Tables 6-2 and 6-3 should be used as guidelinesor selecting the most suitable type o hanger orthe support requirement at each incremental stepo the design process. These tables oer the basicso hanger selection—a variety o hanger choices andthe material composition most suited or the tem-perature characteristics that will aect the piping
System Class Temperature Rating, °F (°C)Hot A-1 120 to 450 (49 to 232)
Hot A-2 451 to 750 (233 to 399)
Hot A-3 Over 750 (over 400)
Ambient B 60 to 119 (16 to 48)
Cold C-1 33 to 59 (1 to 15)
Cold C-2 –20 to 32 (–29 to O)
Cold C-3 –39 to –20 (–39 to –29)
Cold C-4 –40 and below (–40 and below)
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Figure 6-1 Types o Hangers and SupportsExtracted rom ANSI/MSS SP-58-2009 with permission o the publisher, Manuacturers Standardization Society o the Valve and Fittings Industry Inc.
Figure 6-1 Types o Hangers and Supports (continued)Extracted rom ANSI/MSS SP-58-2009 with permission o the publisher, Manuacturers Standardization Society o the Valve and Fittings Industry Inc.
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system. What these tables cannot do is substitute orthe engineering and design processes that determinethe proper hanger selection based on the environ-mental and physical infuences that will aect thedierent elements o the piping system under vary-ing conditions. The most instructive aspect o Table6-3 is ound in the notes at the end o the table (seenotes b, c, and e).
Hanger and Support Spacing Ater the appropriate hanger components have beenselected or the type o piping system and the type o building or structural support available, the plumbing engineer must identiy the spacing appropriate to thetype o pipe used. Table 6-1 provides support criteria orsome o the most common pipe materials. However, theplumbing engineer must ensure that the design criteria is in compliance with local code requirements.
Just as with Table 6-3, it needs to be noted thatTable 6-1 provides guidelines only based on piping systems under ideal circumstances with little envi-ronmental or physical infuences. Thereore, thesespacing guidelines are at the upper end o the speci-cations. That is, they should be considered themaximum spacing or hangers and supports.
For proper hanger spacing, the engineer mustevaluate and take into account the three-dimensionalfuctuations and movements as well as the environ-mental and physical infuences that will aect theentirety o the plumbing system. Proper spacing isa unction o stress, vibration, and the potential ormisuse (e.g., exposed piping used as a ladder, sca-olding, or exercise equipment). Spacing depends onpipe direction changes, structural attachment ma-terial and anchor points, additional plumbing sys-tem loadings—such as valves, fanges, lters, accessports, tanks, motors, pipe shielding, insulation, anddrip, splash, and condensate drainage—and other
specialty design requirements.
Table 6-5 Load Ratings o Carbon Steel Threaded HangerRods
1. For materials other than carbon steel, see requirements o ANSI/MSS SP-58-2009,Section 4.8 and Table A2.
2. Tabulated loads are based on a minimum actual tensile stress o 50 ksi (345 MPa)divided by a saety actor o 3.5, reduced by 25%, resulting in an allowable stress o10.7 ksi. (The 25% reduction is to allow or normal installation and service conditions.)
3. Root areas o thread are based on the ollowing thread series: diam. 4 in. and below:coarse thread (UNC); diam. above 4 in.: 4 thread (4-UN).
Extracted rom ANSI/MSS SP-58-2009 with permission o the publisher, ManuacturersStandardization Society o the Valve and Fittings Industry Inc.
Table 6-4 Recommended Minimum Rod Diameter orSingle Rigid Rod Hangers
Types o Pipe
Steel Water ServiceSteel Vapor Service
Ductile Iron PipeCast Iron Soil
Copper Water ServiceCopper Vapor Service
Glass, PlasticFiberglass Reinorced
NominalPipe or
Tubing Size Nominal Rod Diam. Nominal Rod Diam.
in. (mm) in. (mm) in. (mm)¼(6) 3 ⁄ 8(M10) 3 ⁄ 8(M10)3 ⁄ 8(10) 3 ⁄ 8(M10) 3 ⁄ 8(M10)
½(15) 3 ⁄ 8(M10) 3 ⁄ 8(M10)
¾(20) 3 ⁄ 8(M10) 3 ⁄ 8(M10)
1 (25) 3 ⁄ 8(M10) 3 ⁄ 8(M10)
1¼(32) 3 ⁄ 8(M10) 3 ⁄ 8(M10)
1½(40) 3 ⁄ 8(M10) 3 ⁄ 8(M10)
2 (50) 3 ⁄ 8(M10) 3 ⁄ 8(M10)
2½(65) ½(M12) ½(M12)
3 (80) ½(M12) ½(M12)
3½(90) ½(M12) ½(M12)
4 (100) 5 ⁄ 8(M16) ½(M12)
5 (125) 5 ⁄ 8(M16) ½(M12)
6 (150) ¾(M20) 5 ⁄ 8(M16)
8 (200) ¾(M20) ¾(M20)
10 (250) 7 ⁄ 8(M20) ¾(M20)
12 (300) 7 ⁄ 8(M20) ¾(M20)
14 (350) 1 (M24)
16 (400) 1 (M24)18 (450) 1 (M24)
20 (500) 1¼ (M30)
24 (600) 1¼ (M30)
30 (750) 1¼ (M30)
Notes:
1.For calculated loads, rod diameters may be sized in accordance with MSS SP-58Tables 2 and 2M provided Table 1 and Section 7.2.1 o MSS SP-58 are satised.
2.Rods may be reduced one size or double rod hangers. Minimum rod diameter shall be3 ⁄ 8 in. (M10).
Extracted rom ANSI/MSS SP-58-2009 with permission o the publisher, ManuacturersStandardization Society o the Valve and Fittings Industry Inc.
ANCHORINGThe strength, saety, and integrity o a plumbing system depend on the hangers or supports that arespecied. However, it is not enough to simply speciy a hanger or support—another important considerationis how it is anchored. A hanger or support will per-orm only up to the capability o its attachment to
a structural element. At a minimum, the plumbing engineer needs to ensure close coordination betweenthe plumbing system design and that o the otherdesign engineers, including iron and concrete struc-tural engineers, to ensure properly spaced and appliedhangers and supports and their anchors.
Anchoring hangers and supports requires di-erent methods depending on the structural ele-ments, transitions rom vertical and horizontal
suraces, and diering materials (e.g., rom steelto concrete). Perhaps the most dicult hanger andsupport attachment requirement is that to concretein an existing structure. It might be necessary orthe plumbing engineer to contact the original con-crete designer or supplier or involve an experiencedhanger manuacturer or contractor or the properanchoring o the hangers and supports.
The extent o detail required within the plumb-ing system design depends on the project’s param-eters and the practicality and responsibility o theengineer to the overall building assembly. It mightbe in the plumbing engineer’s scope to establishloading, shear, and stress specications or the hang-er and support anchoring structure. Depending onthe structure, the requirements and specicationsor the hanger and support anchors vary widely. Forinstance, anchoring to wood involves a signicantlydierent process than anchoring to steel. In the lat-ter case, welding specications may need to be in-
cluded and bonding material compatibility ensured. Anchoring to concrete requires the use o implantedanchors during the pouring o the concrete or subse-quent attachment using anchor bolts and plates.
Anchor TpesFigure 6-2 shows some common materials and devicesoten used or anchoring hangers and supports; how-ever, a wide variety o anchor bolts, screws, washers,nuts, rods, plates, and strengtheners is available.Figure 6-3 shows additional supports that might bepreerred by the engineer in very particular circum-stances.
Table 6-4 shows the pipe hanger rod size or a single rigid rod hanger; however, care should betaken to observe the loading associated with specialconditions that may induce a load beyond the hangerrod strength. Moreover, lateral stress and axial ten-sion aect the choice o rod size and material. SeeTable 6-5 or load ratings o threaded hanger rodsand Table 6-6 or minimum design load ratings orrigid pipe hanger assemblies. These tables show ac-ceptable standards or hanger materials, but it is im-portant to check a particular manuacturer’s speci-cations as well. See Table 6-7 or sample design loadtables or a manuacturer’s concrete inserts. In the
overall engineered design, load and stress calcula-tions or multiple hanger and support assembliesand the use o multiple anchor assemblies (such asconcrete rod inserts) require additional evaluationand analysis to properly incorporate the eects o a distributed load.
SLEEVESPipes oten must pass through walls, foors, and otherpenetrations. I unlike materials come into contact,the potential chemical reactions between them can
Table 6-6 Minimum Design Load Ratings or Pipe HangerAssemblies (applicable to all components o complete assembly,including pipe attachment, rod, xtures, and building attachment)
Nominal Pipe or Tube Size Min. Design Load Ratings atNormal Temp. Range
b
in. (mm) lb (kg)3 ⁄ 8(10) 150(0.67)
½(15) 150(0.67)
¾(20) 150(0.67)
1 (25) 150(0.67)
1¼ (32) 150(0.67)
1½ (40) 150(0.67)
2 (50) 150(0.67)
2½ (65) 150(0.67)
3 (80) 200(0.89)
3½ (90) 210(0.93)
4 (100) 250(1.11)
5 (125) 360(1.60)
6 (150) 480(2.14)
8 (200) 760(3.38)
10 (250) 1120(4.98)
12 (300) 1480(6.58)
14 (350) 1710(7.61)
16 (400) 2130(9.47)
18 (450) 2580(11.48)
20 (500) 3060(13.61)
24 (600) 3060(13.61)
30 (750) 3500(15.57)
Notes:
a. See MSS SP-58-2009 Section 4 or allowable stresses and temperatures.
b. Normal temperature range is –20 to 650°F (–29 to 343°C) or carbon steel, –20 to 450°F(–29 to 231°C) or malleable iron, and –20 to 400°F (–29 to 204°C) or gray iron.
c. See MSS SP-58-2009 Section 7.2.1 or minimum rod diameter restrictions.
d. For loads greater than those tabluated, hanger component load ratings shall beestablished by the manuacturer. Design shall be in accordance with all criteria asoutlined in MSS SP-58-2009.
e. Pipe attachment ratings or temperature ranges between 650 and 750°F (343 and 398°C)shall be reduced by the ratio o allowable stress at service temperature to the allowablestresses at 650°F (343°C).
. For services over 750°F (398°C), attachments in direct contact with the pipe shall bedesigned to allowable stresses listed in MSS SP-58-2009, Tables A2 and A2M.
Extracted rom ANSI/MSS SP-58-2009 with permission o the publisher, ManuacturersStandardization Society o the Valve and Fittings Industry Inc.
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Table 6-7(A) Sample Design Load Tables or Manuacturer’s Concrete Inserts
damage the pipe, structure, or both. Likewise, whena pipe passes through a penetration, what happens i the structure collapses on or damages the pipe? Forthis reason, the plumbing engineer must provide pro-tection o the pipes using pipe sleeves. Pipe sleeves canbe constructed o a variety o materials that shouldbe selected based on the application as well as thematerials o the structure and the pipe.
HANGER, SUPPORT, AND ANCHORMATERIALS An almost unlimited variety o materials can be usedor producing hangers, supports, and anchors. Withthe increased use o plastic, berglass, and otherlightweight and corrosion-resistant pipe materials hascome an increased availability o matching hangersand supports. The plumbing engineer must matchand coordinate the various materials available. Dueto possible chemical reactions and galvanic eects,it is very important to match the composition o the
hanger, support, and anchor materials to the composi-tion o the piping system material.
GLOSSARy
Acceleration limiter A device—hydraulic, me-chanical, or spring—used to control acceleration,shock, and sway in piping systems.
Access channel A conduit or channel cast in placewithin concrete structural elements that providesor the passing through o pipe. It is placed hori-zontally throughout a concrete structure to acili-tate uture access.
Access opening An opening or conduit cast inplace within concrete structural elements thatprovides or the passing through o pipe. The mosttypical usage is or short vertical conduit in con-crete slabs to eliminate the subsequent drilling o core holes.
Accumulator A container, used in conjunctionwith a hydraulic cylinder or rotating vane deviceor the control o shock or sway in piping systems,that is used to accommodate the dierence in fuidvolume displaced by the piston. It also serves as a continuous supply o reserve fuid.
Threaded Stand Pipe
Multiuse Plate
Anchor Base Plate
Concrete Deck Inserts
Threaded Side Beam Bracket
Concrete Rod Attachment Plate
Concrete Clevis Plate with Pin
Concrete Single Lug Plate
Welding Lug
Weld Beam Attachment with Pin
Figure 6-2 Types o Hanger and Support Anchors (continued)
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All Steel Ceiling Plate
Top Beam “C” Clamp
Reversible C-Type Beam Clamp
Steel “C” Clamp
Top Beam Clamp
Bar Joist Hanger
Center Load Beam Clamp
Adjustable Beam Attachment
Adjustable Side Beam Clamp
Adjustable Beam Clamp
Beam Clamps
Cable Sway Braces
Sway Brace Attachments
Sway Brace Attachments: Bar Joists
Figure 6-2 Types o Hanger and Support Anchors (continued)
Adjustable Mechanical or automated movementproviding or linear adjustment capability (regard-less o the plane or dimension). Adjustment maybe mechanical, such as a threaded rod, or assistedwith vacuum or air pressure.
Adjustment device A component that providesor adjustability. (See adjustable.)
Ater cold pull elevation The mechanical draw-ing view incorporating additional piping elementsduring installation that will be necessary or ther-mal fuctuations once the piping system is hot.
Alloy A chrome-moly material (oten less than 5percent chrome) used to resist the eects o hightemperatures (750°F to 1,100°F [399°C to 593°C]). Alloys are used as pipe, hanger, support, and an-chor materials.
Anchor To asten or hold a material or device toprevent movement, rotation, or displacement at
the point o application. Also an appliance used inconjunction with piping systems to asten hang-ers and supports to prevent movement, rotation,or displacement.
Figure 6-3 Hanger and Support Anchors or Particular ApplicationsSource: Support details courtesy o Holdrite®
Lavatory or Sink Water Closet (or other single pointconnection)
Horizontal pipingUrinal (Drinking Fountain/Electric Water
Cooler Similar)
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Anchor bolt A astener (e.g., bolt or threaded rod)that is used to attach or connect materials, devices,or equipment. Oten reers to the bolt that is em-bedded in concrete or passed through an opening in steel that is used to attach a hanger or supportto a concrete or steel structure.
As built The actual installation o construction or
conguration placement. Assembly A pre-ormed arrangement or a gath-
ered collection o various appliances and compo-nents used to carry, hold, and/or restrain devices,equipment, or a piping system load in tension.
Auxiliary stop A supplemental restraint thattemporarily locks or holds in place movable parts.Oten used in conjunction with spring devices,such as a spring hanger, to provide or a xed po-sition enabling a load to be transerred to a sup-porting structure in a desired placement during construction or installation.
Axial brace An assembly or bracket device usedto resist twisting or to restrain a piping run in theaxial direction.
Band or strap hanger An appliance or deviceused as a hanger or support or pipe that providesor vertical adjustment. It also is used to connectpipe to a hanger assembly.
Base support A device that carries a load rom be-neath and is used to carry a load’s weight in com-pression.
Beam clamp A mechanical device used to con-
nect, as a hanger or support, or to hold part o a piping system to a structural beam element (typi-cally a steel beam). A clamp rmly holds multiplematerials or devices together and does not requirewelding.
Bearing plate See slide plate and roll plate.
Bent An assembly or rame consisting o two ver-tical members joined by one or more horizontalmembers used or the support o a piping systemto a structural element.
Bolting The use o bolts, studs, and nuts as as-teners.
Brace, brace assembly A pre-ormed applianceor assembly consisting o various componentsthat, depending on its location, is used to hold and/ or restrain a piping system rom horizontal, verti-cal, and lateral orces.
Brace, hanger, or support drawing The me-chanical drawing detailing the elements and com-ponents o an assembly or rame structure thatincorporates a bill o material, load and movementdata, and both general and specic identication.
Bracket A pre-ormed support or astener, usu-ally constructed in a cantilevered manner, with orwithout additional diagonal structural membersor load stability, designed to withstand a gravityload and horizontal and vertical orces.
C clamp A pre-ormed appliance in a C shape thatattaches to a fange or other part o a structural
member and acts as an anchor or a hanger, sup-port, or other device such as a threaded rod.
Cable A component used to brace structural assem-blies and piping systems (also called wire rope).
Cable sway brace Components added to a stan-dard pipe support or hanger system to limit swayduring movement such as during a seismic event.The components include cable, pipe attachments,and attachment to the structure. Cable bracing re-quires two attachment locations as it works undertension only and not tension and compression likerigid bracing.
Cantilever A projecting structural element ormember supported at only one end.
Center beam clamp A jaw-type mechanical de-vice used to connect, as a hanger or support, orused to hold part o a piping system to a structuralbeam element (typically a steel beam). It is usedwith I beams and wide fange beams to provide a centered beam connection.
Channel clamp A mechanical device with a chan-nel adapter and hook rod that provides an o-cen-ter attachment to the bottom fange o a channelbeam or a hanger, support, or other part o a pip-
ing system.
Clamp A mechanical device used to connect, as a hanger or support, or hold part o a piping systemto a structural beam element. (A clamp rmly holdsmultiple materials or devices together and doesnot require welding.) See beam clamp, C clamp,channel clamp, double bolt pipe, three-bolt clamp,double-bolt riser, riser clamp, and pipe clamp.
Clevis A connector device or metal shackle withdrilled ends to receive a pin or bolt that is used orattaching or suspending parts.
Clevis hanger A support device providing verticaladjustment consisting o a clevis-type top bolted toa ormed steel bottom strap.
Cold elevation See design elevation and atercold pull elevation.
Cold hanger location The location o the pipehangers, supports, and assemblies o the installedpiping system in reerence to the building’s struc-ture and structural elements prior to the invoking o an operating environment.
Cold load The stress or loading put on a piping system prior to the occurrence o a normal orsteady-state operating environment (as measuredat ambient temperature). The cold load equals theoperating load plus or minus load variations.
Cold setting The position at which a mechanicalcontrol device indicator, such as that on a spring
hanger, is set to denote the proper nonoperating position installation setting o the unit.
Cold shoe A T-section hanger or support with in-tegrated insulation that has been designed or coldtemperature piping system application.
Cold spring The act o pre-stressing a piping sys-tem during installation to condition it or minimalfuctuations, expansions, and other reactions whenthe nished piping system and related equipmentare used in the designed operating environment.
Colored fnish A generic term to describe vari-ous color nishes that are used as an identier
or product compatibility. For example, a copper-colored nish on connectors or piping denotes thatthe product was sized or copper tubing.
Commercial piping system A piping system lo-cated in a commercial building structure that gen-erally includes re protection, plumbing, heating,and cooling piping systems.
Component Any individual item, appliance, ordevice that is combined with others to create anassembly or is part o a whole.
Concrete astener A device installed in or at-
tached to concrete by various means (oten pre-cast, drilled, or epoxied) to which a pipe hanger orsupport can be attached.
Concrete insert, concrete insert box An anchordevice cast in place in concrete and provides or a hanger, support, rod, or similar attachment. Theinsert provides load assistance to a piping systemand has nominal lateral adjustment.
Continuous insert An anchoring device in theorm o a channel (which can be o varying lengths)that is cast in place in a concrete structure andprovides or multiple hangers, supports, rods, or
similar attachments. The insert provides load as-sistance to a piping system and has the capabilityor lateral adjustments.
Constant support hanger A mechanical spring-coil device that provides constant support or a piping system while permitting some dimensionalmovement.
Constant support hanger indicator A deviceattached to the movable arm o a constant supporthanger that measures vertical pipe movement.
Copper plating See plating.
Corrosion The process that describes the oxida-tion o a metal that is weakened or worn down bychemical action.
Cut short The shortening or lengthening o a sec-tion o pipe to provide or reduced fuctuations,expansions, and other reactions when the nished
piping system and related equipment are used inthe designed operating environment.
DWV Drain, waste, and venting.
Deadweight load The combination o all stressor loading put on a piping system that takes intoconsideration only the weight o the piping system,including the pipe, hangers, supports, insulation,and pipe contents.
Design elevation The overall mechanical draw-ing view o the piping system as designed.
Design load The combination o all stress or load-
ing put on a piping system as dened in the engi-neered drawing or as part o the engineered designspecication.
Deviation A measurement o dierence oten ex-pressed as a percentage. It oten is used to describethe accuracy dierence between actual and speci-ed perormance criteria.
Double acting A descriptor or a mechanical de-vice that provides resistance in both tension andcompression cycles.
Double-bolt pipe clamp See three-bolt pipeclamp.
Drag The retarding orce that acts on a portiono a hydraulic or mechanical device as it movesthrough fuid, gas, or other riction-generating substances. It also reers to the orce required toextend and retract a hydraulic or mechanical ele-ment o a hanger or support device during activa-tion at low velocity.
Dual-use brace A single brace that can be usedas both a longitudinal and lateral brace in a singlelocation.
Dynamic orce or dynamic loading The addi-
tional loading and stress conditions that must betaken into consideration over and above a steady-state condition.
Dynamic load The temporary stress or loading put on a piping system as the result o internal orexternal orces that create movement or motion inthe system.
Elbow lug An elbow-shaped device with a pipeconnector welded to it or use as an attachment.
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Electrogalvanized A protective coating o elec-troplated zinc. (See also galvanized.)
Electroplated Plating by using an electro-deposi-tion process. (See also plating.)
Electrolysis The producing o chemical changesdue to the dierences in electrical potential be-tween dissimilar materials in the presence o mois-ture. (See also corrosion.)
Elevation A mechanical drawing view that is a geometrical projection as seen on a vertical plane.
Embedded A device or astener that is cast inplace in a concrete structure.
Engineered drawing A mechanical drawing thatdetails the elements and components o a piping system and incorporates a bill o material, loadand movement data, location inormation, andboth general and specic identication.
Engineered hanger assembly A mechanical
drawing that details the elements and componentso a hanger assembly and incorporates a bill o ma-terial, load and movement data, location inorma-tion, and both general and specic identication.(See also semi-engineered hanger assembly.)
Erected elevation See design elevation.
Extension riser clamp An attachment device orthe support o vertical piping that provides or thetranser o the piping load to the bearing suraceto which the clamp is attached.
Eye rod A bolt or rod with a circular or pear-shaped end that permits other components or de-vices to be attached by means o a bolt or pin. Theeye may be orged, welded, or nonwelded.
Eye socket An appliance that provides or the at-tachment o a threaded bolt or rod to the bolt orrod o another component or device.
Fabrication A term used to reer to a part con-structed or manuactured out o standard parts orraw materials.
Fabricated steel part A component that is con-structed rom standard shapes o steel plate.
Fabricator A business engaged in the abrication
o parts.
Forged clevis A connector device, a clevis, thathas been ormed as one piece (i.e., orged).
Four-way brace An assembly consisting o lateraland longitudinal bracing that is designed to con-trol back-and-orth movement in our directions.
Framing steel A structural steel member, normal-ly less than 10 eet in length, used between existing
members as a means o providing or the attach-ment o a hanger or support or a piping system.
Friction load The stress or loading put on a pip-ing system as the result o rictional orces thatexist between dierent suraces that are in con-tact with each other, such as moving or sliding suraces.
Galvanized A zinc coating applied to steel to pro-tect against oxidation and other chemical actions.
Gang hanger A hanger assembly utilizing a com-mon cross-member to provide support or parallelruns or banks o piping.
Guide A device used to permit pipe movement ina predetermined direction while restraining move-ment in other directions.
Hanger A device that is suspended rom a struc-ture and used to carry or support a load.
Hanger assembly A general term used to describe
a series o assembled components that make up a device that is connected to or suspended rom a structure and is used to carry or support a loadin tension or carry a load under compression. Thedevice may be designed to prevent, resist, or limitmovement, or it may be used to permit movementin a predetermined direction while restraining movement in other directions.
Hanger drawing See brace, hanger, or supportdrawing.
Hanger loads See pipe hanger loads.
Hanger rod A round steel bar, normally threaded,used to connect components or hangers and sup-ports.
Heavy bracket A bracket used or the support o heavy loads. (See bracket.)
Hinged pipe clamp Also known as a split ring,a hinged attachment device that permits instal-lation beore or ater piping is in place and usedprimarily on noninsulated piping.
Horizontal traveler A hanger or support devicethat accommodates horizontal piping movement.
Hot-dip galvanized A corrosion protection coat-
ing o zinc applied to steel or other metals.
Hot elevation The mechanical drawing view o a piping system as it will appear in its ull operating environment.
Hot hanger location The location o the pipehangers, supports, and assemblies o the installedpiping system in reerence to the building’s struc-ture and structural elements within the operating environment.
Hot load The stress or loading put on a piping system as the result o a normal or steady-stateoperating environment. (See operating load.)
Hot setting The position at which a mechanicalcontrol device indicator, such as that on a spring hanger, is set to denote the proper operating posi-tion setting o the unit.
Hot shoe A T-section hanger or support with in-tegrated insulation that has been designed or hottemperature piping system application.
HVAC Heating, ventilation, and air-conditioning.
Hydraulic snubber See hydraulic sway brace.
Hydraulic sway brace A hydraulic cylinder orrotating vane device used to control shock or swayin piping systems, while allowing or normal ther-mal expansion.
Hydrostatic load The stress or loading put on a piping system as the result o hydrostatic testing.
(See hydrostatic test load.)
Hydrostatic lock The condition wherein a sup-plemental restraint temporarily locks or holds inplace moveable parts during a hydrostatic test. Itoten is used in conjunction with spring devices,such as a spring hanger, to provide or a xed po-sition enabling a load to be transerred to a sup-porting structure in a desired placement during construction or installation.
Hydrostatic test A pre-operational test wherebythe piping system is subjected to a pressurized fu-id in excess o the specied operational pressure to
ensure the integrity o the system.
Hydrostatic test load The temporary loading condition consisting o the total load weight o thepiping (gravitational load), insulation, and testfuid or piping systems subjected to hydrostatictests.
Industrial piping system A piping system locat-ed in an industrial complex that generally includesre protection, plumbing, heating, and cooling piping systems and also incorporates process, vac-uum, air, steam, or chemical piping systems.
Insert An anchor device that is cast in place in a concrete structure and provides or a hanger, sup-port, rod, or similar attachment. Inserts provideload assistance to a piping system and have nomi-nal lateral adjustment.
Insert box See concrete insert.
Insert nut A emale threaded anchor device thatis locked into position as part o an insert and thatreceives a threaded rod or bolt.
Institutional piping system A piping system lo-cated in an institutional environment or building structure that generally includes re protection,plumbing, heating, and cooling piping systems, aswell as process, vacuum, air, or chemical gas pip-ing systems.
Insulated pipe support A hanger or support
with an integrated insulation insert designed oruse with insulated pipe.
Insulation protection saddle A device used toprevent damage to the insulation on a pipe at thesupport point.
Integral attachment When connector pieces anddevices have been welded together as hangers andsupports or an assembly.
Intermediate anchor An attachment point usedto control the distribution, loading, and movementon a fexible piping system.
Invert A drawing elevation view rom the bottomor underneath.
Jacket A metal covering placed around the insula-tion on a pipe to protect it against damage.
Knee brace A diagonal structural member used totranser load or provide stability.
Lateral brace A brace designed to restrain a pip-ing system against transverse loads.
Lateral stability The state or degree o control o a piping system transverse to the run o the pipe.
Light bracket A bracket used or the support o
light loads. (See bracket.) Limit stop An internal device built into a me-
chanical device to prevent the overstressing o a spring coil, overtravel, or release o a load.
Liner Material placed between hangers, supports,or an assembly to protect a piping system romdamage or other undesirable eects.
Load adjustment scale A scale used on a me-chanical device to indicate the load adjustment.
Load bolt or pin A bolt or pin used to support theweight or load carried by a hanger or assembly.
Load coupling An adjustment device used to con-nect hanger and support components.
Load indicator A pointer, dial, or gauge or read-ing or determining the settings and changes o a device.
Load rated The rating o a particular size o com-ponent or assembly to withstand a specied orcewith a saety actor applied.
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Load scale A measurement pointer, dial, or gaugeattached to a device to provide a means o deter-mining the static or dynamic aspects o a supportedload.
Load variation The dierence in the elevationsat a support point between the time o installation(cold) and actual operating (hot) environment.
Load See pipe hanger load.
Location See pipe hanger location.
Lock up The operational period when a hydraulic,mechanical, or spring device used to control shockand sway in piping systems is actuated.
Longitudinal brace A brace designed to restraina piping system against axial loads.
Lug A welded appliance to provide an attachmentpoint to a structural member or piping.
Mechanical snubber See mechanical sway brace.
Mechanical sway brace A mechanical device usedto control shock or sway in piping systems, whileallowing or normal thermal expansion.
Medium bracket A bracket used or the support o moderate loads. (See bracket.)
Metric hanger A hanger or support that conormsto metric measurements and, where appropriate,contains a metric threaded connection.
Mill galvanized A corrosion-protection coating o zinc applied at the point o abrication.
Multiple support See gang hanger.
Negligible movement The calculated minimummovement at a support point or the portion o a piping system with inherent fexibility.
Nominal size The identied size, which may varyrom the actual size.
Nonintegral attachment When connector piecesand devices do not require being welded together ashangers and supports or an assembly.
Nut, insert See insert nut.
Oset A relative displacement between a struc-tural attachment point and a piping system that is
incorporated into the design to accommodate move-ment.
Operating load The stress or loading put on a pip-ing system as the result o a normal or steady-stateoperating environment.
OSHPD Caliornia Oce o Statewide Health Plan-ning and Development, which provides servicesthat include the ecient processing o approvals orhealth acility construction. OSHPD is a national
leader in seismic restraint guidelines and require-ments.
Pipe attachment Any component or device used toconnect a pipe to a hanger, support, or assembly.
Pipe brace See brace.
Pipe channel A conduit or channel cast in place
within concrete structural elements that providesor the passing through o pipe. It is placed horizon-tally throughout a concrete structure to acilitateuture access.
Pipe clamp A bolted clamp attachment that con-nects a pipe to a hanger, support, assembly, or struc-tural element.
Pipe clip An attachment appliance used to connecta pipe directly to a structural element, also reerredto as a strap or pipe clamp.
Pipe covering protection saddle A protectivecovering used to prevent damage to insulation sur-
rounding a pipe at hanger and support points.
Pipe elevation See design elevation, erected eleva-tion, ater cold pull elevation, and cold elevation.
Pipe hanger An appliance or device attached to orsuspended rom a structural element that is used tosupport a piping system load in tension.
Pipe hanger assembly An assembly o hangersused to hold a piping system.
Pipe hanger drawing A mechanical drawing thatdetails the elements and components o a piping system and incorporates a bill o material, load and
movement data, location inormation, and both gen-eral and specic identication. (See also engineereddrawing and semi-engineered drawing.)
Pipe hanger location See location types: coldhanger location and hot hanger location.
Pipe hanger plan and pipe hanger plan loca-tion The engineered design and elevations that
ully detail the hangers, supports, and anchors o a piping system. Mechanical drawings include appro-priate osets as a result o movement and displace-ment expectations.
Pipe insulation shield A rigid insert appliancedesigned to protect pipe insulation passing throughhangers, supports, and assemblies.
hot load, hydrostatic load, operating load, seismicload, thermal load, thrust load, trip-out load, wa-ter hammer load, and wind load.
Pipe opening An opening, conduit, or channelcast in place within concrete structural elementsthat provides or the passing through o pipe. Themost typical usage is or short vertical conduit in
concrete slabs to eliminate the subsequent drilling o core holes.
Pipe rack A structural rame that is used to sup-port piping systems. (See assembly.)
Pipe roll A pipe hanger or support that utilizes a roller or bearing device to provide the ability orlateral axial movement in a piping system.
Pipe saddle support A pipe support that utilizesa curved section or cradling the pipe.
Pipe shoe A hanger or support (typically T shaped)attached to a pipe to transmit the load or orces to
Pipe sleeve An opening, conduit, or channel castin place within concrete structural elements thatprovides or the passing through o pipe. The mosttypical usage is or short vertical conduit in con-crete slabs to eliminate the subsequent drilling o core holes. However, conduit or channel may beplaced horizontally throughout a concrete struc-ture to acilitate uture access.
Pipe sleeve, pipe sleeve hanger or support An
appliance or device that surrounds a pipe and con-nects to a hanger or support to provide or align-ment and limited movement.
Pipe slide A hanger or support that incorporatesa slide plate to accommodate horizontal pipemovement.
Pipe strap An attachment appliance used to con-nect a pipe directly to a structural element. (Seepipe clip and pipe clamp.)
Pipe support A device or stanchion by which a pipe is carried or supported rom beneath. In thisposition, the pipe load is in compression.
Pipe system load See specic load types: coldload, deadweight load, design load, dynamic load,riction load, hot load, hydrostatic load, operating load, seismic load, thermal load, thrust load, trip-out load, water hammer load, and wind load.
Plate lug See lug.
Plating An electroplating process whereby a me-tallic coating (e.g., copper, chrome, or zinc) is de-posited on a substrate.
Point loading The point o application o a loadbetween two suraces. It typically describes theload point between a curved and a fat surace.
Preset Prior installation adjustment o hangers,supports assemblies, equipment, and devices.
Protection saddle A saddle that provides a pro-tective covering or coating to prevent damage to
pipe or to the insulation surrounding a pipe athanger and support points.
Protection shield An appliance, which may berigid or fexible, designed to protect pipe or insula-tion at contact points with hangers and supports.
Random hanger A hanger or support that re-quires eld abrication and the exact location,shape, and type o which are let to the discretiono the installer.
Reservoir An attachment or separate containerused in conjunction with a fuid- (or gas-) using
device (e.g., hydraulic) that provides a means tostore or hold a supply o liquid (or gas) to provideor a reserve or otherwise ensure or an adequateor continuous supply o fuid (or gas).
Restraint An appliance, device, or equipment thatprevents, resists, or limits unplanned or randommovement.
Restraining control device A hydraulic, me-chanical, spring, or other rigid or fexible hanger,support, or device used to control movement.
Resilient support A hanger, support, or devicethat provides or vertical, horizontal, lateral, or
axial movement.
Retaining strap An appliance or device used inconjunction with clamps and other componentsto secure hangers and supports to structural ele-ments.
Rigid sway brace Components added to a stan-dard pipe support or hanger system to limit swayduring movement such as a seismic event. Thecomponents include solid strut or pipe, pipe at-tachments, and attachment to the structure. Rigidbracing only requires one attachment per locationbecause it works under tension and compression.
Rigid hanger A hanger or support that controlsor limits vertical and horizontal movement.
Rigid support See rigid hanger.
Rigging Devices, including chain, rope, and cable,used to erect, support, and manipulate.
Ring band An appliance or device consisting o a strap (steel, plastic, or other material) ormed ina circular shape with an attached knurled swivelnut used or vertical adjustment.
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Riser An upright or vertical member, structural orotherwise.
Riser clamp An appliance or device used to pro-vide connections to and support or upright or ver-tical members, structural or otherwise.
Riser hanger A hanger or support used in con- junction with a riser.
Rod A slender bar typically considered to have a circular cross-section, available in a variety o ma-terials. (See threaded rod.)
Rod coupling An appliance or device used to jointwo rods. (See threaded rod coupling.)
Rod hanger A hanger or support that has an inte-grated rod as part o its construction.
Rod stiener An appliance or device used to pro-vide additional rigidity to a rod.
Roll stand A pipe roll mounted on a stand andused or support.
Roll and plate A combination o a pipe roll anda slide plate used or minimal lateral and axialmovement where minimal or no vertical adjust-ment is required.
Roll hanger An appliance or device that utilizes a pipe roll or lateral and axial movement when usedto carry a load in suspension or tension.
Roll plate A fat appliance, typically a steel or al-loy plate, that permits movement and/or acilitatesa sliding motion. (See slide plate.)
Roll trapeze A combination device utilizing a pipe
roll and a trapeze hanger.
Saddle A curved appliance or device designed tocradle a pipe and used in conjunction with a hang-er or support.
Saety actor The ultimate strength o a materialdivided by the allowable stress. It also reers to theultimate strength o a device divided by the ratedcapacity.
Scale plate A device attached to hangers, sup-ports, and assemblies to detect changes in load ormovement.
Seismic control device An appliance or deviceused to provide structural stability in the event o a change in the steady-state environment aecting a building’s structure, such as would occur with a natural event such as an earthquake or other vio-lent action.
Seismic load The temporary stress or loading put on a piping system as the result o a changein the steady-state environment aecting a build-ing’s structure, such as would occur with a natural
event such as an earthquake or other violent ac-tion.
Semi-engineered drawing A mechanical draw-ing that details the elements and components o a piping system and incorporates a bill o material,load and movement data, and other general iden-tication.
Semi-engineered hanger assembly A mechani-cal drawing that details the elements and compo-nents o a hanger assembly and incorporates a billo material, load and movement data, and othergeneral identication.
Service conditions Description o the operating environment and operating conditions, including operating pressures and temperatures.
Shear lug An appliance or device used primarilyto transer axial stress (shear stress) and load to a support element.
Shield See protection shield.Side beam bracket A bracket designed to be
mounted in a vertical position by attachment to a structural element. This bracket provides mount-ing capability or a hanger or support.
Side beam clamp A beam clamp that providesor an o-center attachment to the structural ele-ment.
Signifcant movement The calculated move-ment at a proposed support point or a hanger orsupport.
Single acting A descriptor or a mechanical de-vice that provides resistance in either tension orcompression cycles, but not both. (See double act-ing.)
Single pipe roll A pipe roll used in a trapezehanger.
Sleeper A horizontal support, usually located atgrade.
Slide plate A fat appliance, typically a steel or al-loy plate, which permits movement and/or acili-tates a sliding motion.
Sliding support An appliance or device that pro-
vides or rictional resistance to horizontal move-ment.
Slip ftting An appliance or device used to helpalign and provide or limited movement o a pipe.This device is used as an assembly component.
Snubber A hydraulic, mechanical, or spring deviceused to control shock and sway; a shock absorber.
Special component An appliance or device that isdesigned and abricated on an as-required basis.
Spider guide An appliance or device used with in-sulated piping to maintain alignment during axialexpansion and contraction cycles.
Split ring See hinged pipe clamp.
Spring cushion hanger A simple, noncalibrated,single-rod spring support used to provide a cush-ioning eect.
Spring cushion roll A pair o spring coils withretainers or use with a pipe roll.
Spring hanger An appliance or device using a spring or springs to permit vertical movement.
Spring snubber See spring sway brace.
Spring sway brace A spring device used to con-trol vibration or shock or to brace against sway.
Stanchion A straight length o structural mate-rial used as a support in a vertical or upright posi-tion.
Stop An appliance or device used to limit move-ment in a specic direction.
Strap An attachment appliance used to connect a pipe directly to a structural element. (See pipe clipand pipe clamp.)
Stress analysis An analytical report that evalu-ates material, structural, or component stress lev-els.
Strip insert See continuous insert.
Structural attachment An appliance or deviceused to connect a hanger, support, or assembly to
a structural element.Strut A rigid tension/compression member.
Strut clamp An appliance or device used to se-cure a pipe to a strut.
Support A device that attaches to or rests on a structural element to carry a load in compression.
Support drawing See brace, hanger, or supportdrawing.
Suspension hanger See pipe hanger.
Sway brace See lateral brace or restraining con-trol device.
Swivel pipe ring See ring band.
Swivel turnbuckle An appliance or device thatprovides fexibility and linear adjustment capabil-ity used in conjunction with hangers and supports.(See turnbuckle.)
Thermal load The stress or loading put on or in-troduced to a piping system as the result o regularor abrupt changes in the steady-state temperature
o the pipe contents or the surrounding environ-ment.
Threaded rod A steel, alloy, plastic, or other ma-terial rod threaded along its ull length. Threadsmay be rolled or cut.
Threaded rod coupling An appliance or deviceused to join two threaded rods.
Three-bolt pipe clamp A pipe clamp normallyused or horizontal insulated piping that utilizesbolts to attach the clamp to the pipe and a sepa-rate load bolt to transer the piping weight to theremainder o the pipe hanger assembly rom a point outside the insulation (previously known asa double-bolt pipe clamp).
Top beam clamp A mechanical device used toconnect, as a hanger or support, or used to holdpart o a piping system to the top o a structuralbeam element (typically a steel beam). A clamprmly holds multiple materials or devices together
and does not require welding.
Thrust load The temporary stress or loading puton a piping system as the result o a change in thesteady-state operating environment o the pipecontents due to regular or abrupt changes associ-ated with equipment or mechanical devices suchas the discharge rom a saety valve, relie valve,pump ailure, or ailure o some other mechanicaldevice or element.
Transverse brace See lateral brace.
Trapeze hanger A pipe hanger consisting o par-
allel vertical rods connected at their lower endsby a horizontal member that is suspended roma structural element. This type o hanger oten isused where an overhead obstruction is present orwhere insucient vertical space is available to ac-commodate a more traditional hanger or support.
Travel device A hanger or support device that ac-commodates piping movement.
Travel indicator See constant support hangerindicator and variable spring hanger indicator.
Travel scale A device attached to a spring unit tomeasure vertical movement.
Travel stop A device that temporarily locks move-able parts in a xed position, enabling a load tobe transerred to a supporting structural elementduring installation and testing phases.
Trip-out load The temporary stress or loading put on a piping system as the result o a changein the steady-state fow o the pipe contents due tothe change associated with equipment or mechani-cal devices such as a turbine or pump.
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Turnbuckle A device with one let-hand emalethreaded end and one right-hand emale threadedend, used to join two threaded rods and providelinear adjustment.
Two-way brace A brace designed to control move-ment in two directions. (See lateral brace and lon-gitudinal brace.)
U-bolt A U-shaped rod with threaded ends thatts around a pipe and is attached to a structuralelement or a supporting member.
Vapor barrier An uninterrupted, nonpermeablematerial used as a cover or insulated pipe to ex-clude moisture rom the insulation.
Variability The load variation o a variable-spring hanger divided by the hot load expressed as a per-centage.
Variable-spring hanger A spring coil device thatproduces varying support while permitting verti-
cal movement.Variable-spring hanger indicator A device at-
tached to a variable-spring hanger that measuresvertical pipe movement.
Velocity limited A term relating to snubbers inwhich velocity is the means o control.
Vibration control device An appliance used toreduce and/or control the transmission o vibra-tion to structural elements.
Vibration isolation device See vibration controldevice.
Water hammer load The temporary stress orloading put on a piping system as the result o a
change, abrupt or otherwise, in the steady-statefow o the pipe contents.
Welded beam attachment A U-shaped, fat-barappliance, normally welded to a steel beam, usedto connect a hanger, support, or assembly.
Welded pipe attachment The use o a weld to at-tach a pipe to a hanger, support, or assembly.
Weldless eye nut A orged steel appliance thatprovides an attachment point or a threaded hang-er rod to a bolt or pin connection.
Wire hook A type o hanger or support that is sim-
ply a bent piece o heavy wire.
Wind load The temporary or steady-state stressor loading put on or added to a piping system asthe result o a change in environmental conditionssuch as increased steady state or alternating airmovement. Usually reers to piping systems in en-vironmentally exposed conditions.
Vibration Isolation7In modern commercial construction, due to spacerestrictions, HVAC and plumbing system-relatedequipment oten is placed near occupied space, butsuch equipment generates noise and vibration whilerunning that is irritating or unacceptable to tenants.In the past, a very critical installation on an upper
foor could be achieved by allowing not more than 10percent vibration transmission. Thick, sti concretefoors and walls in old buildings could withstand andabsorb such signiicant machinery vibration andnoise. However, today’s lighter structures are not ascapable o shielding equipment vibration, and designsrequire a greater precision to allow no more than a 1 percent or 2 percent transmissibility. Installationsthat were satisactory in the past are no longer ac-ceptable by modern standards. Noise levels now mustbe controlled to the extent that equipment noise doesnot add to the noise level o any building area.
Tests have been conducted to establish accept-able noise criteria or dierent types o occupancies.These noise criteria (NC) curves take into consider-ation an individual’s sensitivity to both the loudnessand requency o noise. This studied criteria is veryprevalent in more sensitive environments such asschools, hospitals, and perormance venues wherethe disturbance hinders the acceptable environment. A similar criterion in vibration analysis shows thatin certain acilities, such disturbance has a dramaticeect on the neurological path-re o tenants.
The only acceptable solution is to analyze thestructure and equipment, not just as individual pieces,
but as a total system during design. Every elementmust be careully considered to ensure a satisactoryend product. It is impossible to separate vibrationand noise issues, but taking a conscientious designapproach can eliminate most problems.
TERMINOLOGy Following are some common actors ound in vibrationisolation theory ormulas.
Vibration Isolator A vibration isolator is a pliant, or resilient, materialthat is placed between the equipment or machineryand the building structure to create a low, naturalrequency support system or the equipment. Com-mon materials are cork, elastomers, neoprene rubber,and steel springs.
Static DefectionStatic defection (d) refects how much the isolatordefects under the weight o the equipment. It ismeasured in inches (mm).
Natural Frequenc Natural requency ( n) is the requency at which thevibration isolator naturally oscillates when com-pressed and released rapidly. It is measured in cyclesper minute (cpm) (Hz).
Disturbing Frequenc
Generated by the equipment, disturbing requency ( d)is the lowest requency o vibration. It is measured incycles per minute (cpm) (Hz).
Resonant AmplicationResonant amplication occurs when the natural re-quency o the isolators and the disturbing requencyequal one another.
Transmissibilit Also known as requency or eciency quotient (Eq),transmissibility is the ratio ( d / n) o the maximumorce to the supporting structure, due to the vibrationo a machine, to the maximum machine orce.
Percent transmissibility (T) is the percentage o the maximum orce given to the building’s structurethrough the isolators.
Damping Damping is the capacity o a material to absorb vibra-tion by essentially acting as the brakes or equipmentmounted on isolators by reducing or stopping motionthrough riction or viscous resistance.
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THEORy OF VIBRATION CONTROL A very simple equation is used to determine thetransmission o steady-state vibration, the constantlyrepeating sinusoidal wave orm o vibration gener-ated by such equipment as compressors, engines,and pumps.
Equation 7-1
T =Ft
=1
Fd ( d / n)2– 1
whereT = TransmissibilityFt = Force transmitted through the resilient
mountingsFd = Unbalanced orce acting on the resiliently
supported system d = Frequency o disturbing vibration, cpm (Hz) n = Natural requency o the resiliently
mounted system, cpm (Hz)
This equation is exact or steel springs becausethey have straight-line load defection characteristicsand negligible damping. When the equation is used ororganic materials, the ollowing corrections normallygive conservative results: For rubber and neoprene,use 50 percent o the static defection when calculating the natural requency, and or cork, use 1.5 times thenatural requency determined by actual test.
The natural requency o a resiliently mountedsystem is the requency at which it will oscillate byitsel i a orce is exerted on the system and thenreleased. The natural requency o the resilientlymounted system can be calculated using the ollow-
ing equation. Equation 7-2
n =188
(1/d)½
whered = Static defection o the resilient mounting,
inches (mm)
When using Equation 7-2 in international stan-dard (SI) units, the 188 multiplying actor should bechanged to 947.5.
The static defection can be obtained rom the ol-
lowing expression. Equation 7-3
d = W
k
whereW = Weight on the mounting, pounds (kg)k = Stiness actor o the mounting o
defection, pounds per inch (kg/mm)
The natural requency o a resiliently mountedsystem can be illustrated by suspending a weight roma very long rubber band. I the weight is pulled downslightly and released, it will oscillate up and down atthe natural requency o the system. A longer rubberband will produce more defection than a shorter one.Systems with more defection have lower naturalrequencies than those with less defection. The im-portance o this can be seen by examining Equation7-1 rewritten in the ollowing orm.
Equation 7-4
Ft = Fd [ 1 ]( d / n)
2– 1
A system may have up to six natural requencies.In the practical selection o machine mountings, i thevertical natural requency o the system is decreasedto allow or a low transmissibility, the horizontal androtational natural requencies generally will be lower
than the vertical and can be disregarded, except ormachines with very large horizontal, unbalancedorces or with large unbalanced moments, such ashorizontal compressors and large two-, three-, and ve-cylinder engines.
Obviously, the transmitted orce should be mini-mized. Since the disturbing orce is a unction o themachine’s characteristics and cannot be reduced,except by dynamic balancing o the machine—orby reducing the operating speed, which is seldompractical—the transmitted orce can be reduced onlyby minimizing the unction 1/[( d / n)
2– 1].
This can be accomplished only by increasing the
requency ratio ( d / n). However, since the disturbing requency is xed or any given machine and is a unc-tion o the revolutions per minute (rpm), it seldomcan be changed. The only remaining variable is themounting natural requency. Reducing the naturalrequency by increasing the static defection o theresilient mountings reduces the vibration transmis-sion. This explains why the eciency o machinerymountings increases as their resiliency and defectionincrease.
Figure 7-1 shows the eect o varying requencyratios on the transmissibility. Note that or requencyratios less than two, the use o mountings actually
increases the transmissibility above what wouldresult i no isolation were used and the machinewere bolted down solidly. In act, i careless selectionresults in a mounting with the natural requencyequal to or nearly equal to the disturbing requency,a very serious condition called resonance occurs. InEquation 7-4, the denominator o the transmissibil-ity unction becomes zero, and the transmitted orcetheoretically becomes innite. As the requency ratio
Figure 7-1 Transmissibility vs. Frequency RatioNote: This curve applies to steel spring isolators and other materials with very little damping.
increases beyond two, the resilientmountings reduce the transmittedorce.
Figure 7-2 shows a chart that canbe used to select the proper resilientmountings when the ollowing jobcharacteristics are known: weight
per mounting, disturbing requency,and design transmissibility. The chartshows the limitations o the various types o isolationmaterials, data that is particularly helpul in selecting the proper media.
TyPES OF VIBRATION AND SHOCKMOUNTINGS
Cork Cork is the original vibration and noise isolation ma-terial and has been used or this purpose or at least100 years. The most widely used orm o cork todayis compressed cork, which is made o pure granuleso cork without any oreign binder and is compressedand baked under pressure to an accurately controlleddensity. Cork can be used directly under machines, butits widest applications are under concrete oundations.It is not aected by oils, acids normally encountered,or temperatures between 0°F and 200°F (-17.8°C and93.3°C) and does not rot under continuous cycles o moistening and dryness. However, it is attacked bystrong alkaline solutions.
Cork under concrete oundations still giving goodservice ater 20 years indicates that the material hasa long, useul lie when properly applied. Cork is airly
good as a low-requency shock absorber, but its use as a
vibration isolator is limited to requencies above 1,800cpm. Cork has good sound insulation characteristics.Because o the large amount o damping in cork, thenatural requency cannot be computed rom the staticdefection and must be determined in tests by vibrat-ing the cork under dierent loads to determine theresonance requency, which establishes the naturalrequency o the material. The limiting values or corkgiven in Figure 7-2 were determined in this manner.
Elastomers and Neoprene RubberElastomers having very good sound insulation char-acteristics are acceptable or low-requency shock
absorption and are useul as vibration isolators orrequencies above 1,200 cpm. Static defection typicalto elastomers is rom 0.05 inch to 0.15 inch (1 mm to4 mm). Typical elastomer mountings are illustrated inFigure 7-3. The temperature range o natural rubberis 50°F to 150°F (10°C to 65.6°C), and that o neopreneis 0°F to 200°F (-17.8°C to 93.3°C).
Neoprene rubber is recommended or applicationswith continuous exposure to oil. Special elastomercompounds are available to meet conditions beyondthose cited. Elastomers tend to lose resiliency as theyage. The useul lie o elastomer mountings is aboutseven years under nonimpact applications and about
ve years under impact applications, thoughthey retain their sound insulation value ormuch longer. Individual molded elastomermountings generally are economical onlywith light- and medium-weight machines,since heavier capacity mountings approachthe cost o the more ecient steel spring isolators. Pad-type elastomer isolation hasno such limitations.
Steel Spring IsolatorsSteel spring isolators provide the most e-cient method o isolating vibration and
shock, approaching 100 percent eective-ness. The higher eciency is due to thegreater defections they provide. Standardsteel spring isolators, such as those shownin Figure 7-4, provide defections up to 5inches (127 mm) compared to about ½ inch(12.7 mm) maximum or rubber and othermaterials. Special steel spring isolators canprovide defections up to 10 inches (254 mm).Since the perormance o steel springs ol-
Table 7-1 The Relative Eectiveness o Steel Springs, Rubber, and Cork inthe Various Speed Ranges
Range RPM Springs Rubber CorkLow Up to 1200 Required Not recommended Unsuitable except or shock
a
Medium 1200–1800 Excellent Fair Not recommended
High Over 1800 Excellent Good Fair to good or critical jobsa
For noncritical installations only; otherwise, springs are recommended.
Figure 7-3 Typical Elastomer and Elastomer-Cork Mountings: (A) Compression and Shear Elastomer Floor Mounting; (B)Elastomer Hanger or Suspended Equipment and Piping; (C) Elastomer/Cork Mounting; (D) Elastomer/Cork Mounting with
Built-In Leveling Screw
(A)
(C)
(B)
(D)
Figure 7-4 Typical Steel Spring Mounting
lows the vibration control equations very closely, theirperormance can be predetermined very accurately,eliminating costly trial and error, which is sometimesnecessary in other materials.
Steel spring isolators are available in static defec-tions rom 0.75 inch to 6.0 in (19 to 152 mm), yielding natural requencies rom 4 Hz to 1.3 Hz with open steel
spring isolators. (Restrained steel spring isolators havedierent capacity levels than open steel spring isola-tors.) Most steel spring isolators are equipped withbuilt-in leveling bolts, which eliminates the need orshims when installing machinery. The more ruggedconstruction possible in steel spring isolators providesor a long lie, usually equal to that o the machine itsel.Since high-requency noises sometimes tend to bypasssteel springs, rubber sound isolation pads usually areused under spring isolators to stop such transmissioninto the foor on critical installations.
Table 7-1 tabulates the useul ranges o cork, rubber,and steel springs or dierent equipment speeds.
APPLICATIONSProperly designed mountings permit the installa-tion o heavy mechanical equipment in penthousesand on roos directly over oces and sleeping areas.Such upper-foor installations oer certain operating economies and release valuable basement space orgaraging automobiles. However, when heavy machineryis installed on upper foors, great care must be taken
to prevent vibration transmission, which oten showsup many foors below when a wall, ceiling, or even a lighting xture has the same natural requency as thedisturbing vibration. The result o such resonancevibration is a very annoying noise.
Ecient mountings permit lighter, more economicalconstruction o new buildings and prevent diculties
when machinery is installed on concrete-lled, ribbed,metal deck foors. They also permit the installation o heavy machinery in old buildings that were not origi-nally designed to accommodate such equipment.
Vibration and noise transmission through piping is a serious problem. When compressors are installedon resilient mountings, provision should be made orfexibility in the discharge and intake piping to reducevibration transmission. This can be accomplished ei-ther through the use o fexible metallic hose (whichmust be o adequate length and very careully installedin strict accordance with the manuacturer’s specica-tions) or by providing or fexibility in the piping itsel
by running the piping or a distance equal to 15 pipediameters, both vertically and horizontally, beoreattaching the piping to the structure. Additional pro-tection is provided by suspending the piping rom thebuilding on resilient mountings.
Eective vibration control or machines is usuallyquite inexpensive, seldom exceeding 3 percent o the
equipment cost. In many cases, resilient mountingspay or themselves immediately by eliminating specialmachinery oundations or the need to bolt equipmentto the foor. It is much cheaper to prevent vibration andstructural noise transmission by installing mountingswhen the equipment is installed than it is to go backlater and try to correct a aulty installation. Resilientmachinery mountings should not be considered a panacea or noise transmission problems. They havea denite use in the overall solution o noise problems,and their intelligent use can produce gratiying resultsat low cost.
The purpose o a grease interceptor is to interceptand collect grease rom a commercial or institutionalkitchen’s wastewater passing through the device,thereby preventing the deposition o pipe-clogging grease in the sanitary drainage system and ensuring ree fow at all times. Grease interceptors are installed
in locations where liquid wastes contain grease. Thesedevices are required to receive the drainage romxtures and equipment with grease-laden wasteslocated in ood preparation acilities such as restau-rants, hotel kitchens, hospitals, school kitchens, bars,actory caeterias, and clubs. Fixtures and equipmentinclude pot sinks, soup kettles or similar devices, wokstations, foor drains or sinks into which kettles aredrained, automatic hood wash units, pre-rinse sinks,and dishwashers without grinders. Residential dwell-ings seldom discharge grease in such quantities as towarrant a grease interceptor.
Grease interceptors typically come in one o twobasic types. The rst type is called a hydromechani-cal grease interceptor (HGI), previously reerredto as a grease trap. These are preabricated steelmanuactured units, predominately located indoorsat a centralized location in proximity to the xturesserved or at the discharging xture point o use. Theyare relatively compact in size and utilize hydraulicfow action, internal bafing, air entrainment, and a dierence in specic gravity between water and FOG(ats, oils, and grease) or the separation and retentiono FOG rom the xture waste stream. The standardgoverning the installation, testing, and maintenance
o HGIs is PDI G101: Testing and Rating Procedure or Hydro Mechanical Grease Interceptors.
The second type is the gravity grease interceptor(GGI). These are engineered, preabricated, or eld-ormed concrete-constructed units that typically arelocated outside due to their large size and receive FOGdischarge waste rom all required xtures within a given acility. These units essentially utilize gravityfow and retention time as the primary means o separating FOG rom the acility waste stream priorto it entering the municipal drainage system. The
standard or the design and construction o gravitygrease interceptors is IAPMO/ANSI Z1001: Preabri- cated Gravity Grease Interceptors.
Other FOG retention and removal equipment canbe categorized as grease removal devices (GRDs) andFOG disposal systems (FDSs).
Note: It is important or the plumbing engineerto understand that the topic o FOG retention andremoval is a continuing and ever-changing evolutiono both technology and the latest equipment availableat the time. Types o interceptors currently on themarket may be proprietary in nature and may includeeatures specically inherent to one particular manu-acturer. The purpose o the equipment descriptionscontained in this chapter is to expose the reader to thebasic types o FOG treatment equipment presentlyavailable as they currently are dened and listedwithin model codes. The text is not intended to imply
that any one particular type o device is superior toanother or a given application. That being the case,the plumbing engineer must exercise care whenproposing to speciy FOG treatment equipment thatcould be considered proprietary, in conjunction with a government-controlled or publicly unded project thatmay prohibit the speciying o such equipment due toa lack o competition by other manuacturers.
PRINCIPLES OF OPERATIONMost currently available grease interceptors oper-ate on the principle o separation by fotation alone(GGI) or fuid mechanical orces in conjunction with
fotation (HGI).The perormance o the system depends on the
dierence between the specic gravity o the waterand that o the grease. I the specic gravity o thegrease is close to that o the water, the globules willrise slowly. I the density dierence between thegrease and the water is larger, the rate o separationwill be aster.
Since the grease globules’ rise rate is inverselyproportional to the viscosity o the wastewater, therate o separation will be aster when the carrier
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fuid is less viscous and vice versa. Grease globulesrise more slowly at lower temperatures and morerapidly at higher temperatures. Grease, especiallywhen hot or warm, has less drag, is lighter thanwater, and does not mix well with water. The nalvelocity or a spherical particle, known as its foating velocity, may be calculated using Newton’s equationor the rictional drag with the driving orce, shownin Equation 8-1.
Equation 8-1
Cd A p v2
= (p1 – p) g V 2
This yields the ollowing mathematical relation-ship:
Equation 8-2
v =√4 g p1 – p
D3 Cd p
whereCd = Drag coecient A = Projected area o the particle, pD
2 /4 or a
spherev = Relative velocity between the particle and
the fuidp = Mass density o the fuid
p1 = Mass density o the particleg = Gravitational constant, 32.2 t/s/sD = Diameter o the particleV = Volume o the particle, 13pr
3or a sphere
(r = radius o the particle)
Experimental values o the drag coecient havebeen correlated with the Reynolds number, a di-
mensionless term expressing the ratio o inertia andviscous orces. (Note: Equation 8-2 applies to particleswith diameters 0.4 inch [10 mm] or smaller andinvolving Reynolds numbers less than 1. For largerdiameters, there is a transition region; thereater,Newton’s law applies.) The expressionor the Reynolds number, R = r v D/m,contains, in addition to the parametersdened above, the absolute viscosity.The drag coecient has been demon-strated to equal 24/R (Stokes’ law). When this value is substituted or Cd inEquation 8-2, the result is the ollowing (Reynolds number < 1):
Equation 8-3
v =g (p1 – p) D
2
18m
The relationship in Equation 8-3,which identies the principle o separa-tion in a gravity grease interceptor, hasbeen veried by a number o investiga-tions or spheres and fuids o various
types. An examination o this equation shows that thevertical velocity o a grease globule in water dependson the density and diameter o the globule, the densityand viscosity o the water, and the temperature o the water and FOG material. Specically, the greaseglobule’s vertical velocity is highly dependent on theglobule’s diameter, with small globules rising muchmore slowly than larger ones. Thus, larger globuleshave a aster rate o separation.
The eect o shape irregularity is most pronouncedas the foating velocity increases. Since grease par-ticles that need to be removed in sanitary drainagesystems have slow foating velocities, particle irregu-larity is o small importance.
Figure 8-1 shows the settling velocities o discretespherical particles in still water. The heavy lines areor settling values computed using Equation 8-3 andor drag coecients depending on the Reynolds num-ber. Below a Reynolds number o 1, the settlement isaccording to Stokes’ law. As noted above, as particle
sizes and Reynolds numbers increase, there is rsta transition stage, and then Newton’s law applies. At water temperatures other than 50°F (10°C), theratio o the settling velocities to those at 50°F (10°C)is approximately (T + 10)/60, where T is the watertemperature. Sand grains and heavy foc particlessettle in the transition region; however, most o theparticles signicant in the investigation o watertreatment settle well within the Stokes’ law region.Particles with irregular shapes settle somewhat moreslowly than spheres o equivalent volume. I thevolumetric concentration o the suspended particlesexceeds about 1 percent, the settling is hindered to
the extent that the velocities are reduced by 10 per-cent or more.
Flotation is the opposite o settling insoar as thedensities and particle sizes are known.
Figure 8-1 Rising and Settling Rates in Still Water
Retention PeriodThe retention period (P) is the theoretical time thatthe water is held in the grease interceptor. The volumeo the tank or the required retention period can becomputed as ollows:
Equation 8-4
V = QP7.48
As an example o the use o Equation 8-4, or a retention period (P) equal to two minutes and a fowrate (Q) o 35 gallons per minute (gpm), the tankvolume is:
V = (35 x 2) / 7.48 = 9.36 t3
Retention periods should be based on peak fows. InInternational Standard (SI) units, the denominator inEquation 8-4 becomes approximately unity (1).
Flow-Through PeriodThe actual time required or the water to fow throughan existing tank is called the fow-through period. How closely this fow-through period approximatesthe retention period depends on the tank. A well-designed tank should provide a fow-through periodo at least equal to the required retention period.
Factors Aecting Flotation in the IdealBasin When designing the ideal separation basin, ourparameters dictate eective FOG removal rom thewater: grease/oil droplet size distribution, dropletvelocity, grease/oil concentration, and the condition o the grease/oil as it enters the basin. Grease/oil can bepresent in ve basic orms: oil-coated solids, ree oil,mechanically emulsied, chemically emulsied, anddissolved. When designing the ideal basin, consideronly ree grease/oil.
The ideal separation basin is one that has no
turbulence, short-circuiting, or eddies. The lowthrough the basin is laminar and distributed uni-ormly throughout the basin’s cross-sectional area.The surace-loading rate is equal to the overfow rate.Free oil is separated due to the dierence in specicgravity between the grease/oil globule and the water.Other actors aecting the design o an ideal basinare infuent concentration and temperature.
It is important to evaluate and quantiy a basindesign both analytically and hydraulically. Figure8-2 shows a cross-section o a basin chamber. Thebasin chamber is divided into two zones: liquid treat-ment zone and surace-loading area (grease/oil mat).The mat zone is that portion o the basin where theseparated grease/oil is stored. L is the length o thechamber or basin, and D is the liquid depth or themaximum distance the design grease/oil globule mustrise to reach the grease mat. Vh is the horizontalvelocity o the water, and Vt is the vertical rise rateo the design grease/oil globule.
As noted, the separation o grease/oil rom waterby gravity dierential can be expressed mathemati-cally by Stokes’ law, which can be used to calculate therise rate o any grease/oil globule on the basis o itssize and density and the density and viscosity o the
water. (See Figure 8-1 or the rise rate versus globulesize at a xed design temperature.)
The primary unction o a grease interceptor is toseparate ree-foating FOG rom the wastewater. Sucha unit does not separate soluble substances, and itdoes not break emulsions. Thereore, it never shouldbe specied or these purposes. However, like any set-tling acility, the interceptor presents an environmentin which suspended solids are settled coincident withthe separation o the FOG in the infuent.
Figure 8-2 Cross-Section o a Grease Interceptor Chamber
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The ability o an interceptor to perorm its primaryunction depends on a number o actors. These in-clude the type and state o FOG in the waste fow, thecharacteristics o the carrier stream, and the designand size o the unit. Due to the reliance on gravitydierential phenomena, there is a practical limita-
tion to interceptor eectiveness. In terms o grease/ oil globule size, an interceptor will be eective over a globule diameter range having a lower limit o 0.015centimeter (150 microns).
Gravity separation permits the removal o particlesthat exhibit densities dierent rom their carrierfuid. Separation is accomplished by detaining thefow stream or a sucient time to permit particles toseparate out. Separation, or retention, time (T) is thetheoretical time that the water is held in the basin. A basin must be designed such that even i the grease/ oil globule enters the chamber at the worst possiblelocation (at the bottom), there will be enough time or
the globule to rise the distance needed or capture (seeFigure 8-3). I the grease/oil globule rate o rise (Vt)exceeds the retention time required or separation,the basin will experience pass-through or short-circuiting. Retention time can be expressed as:
Equation 8-5
V = QT
whereV = Volume o basinQ = Design fowT = Retention time
As previously noted, particles that rise to the sur-
ace o a liquid are said to possess rise rates, whileparticles that settle to the bottom exhibit settling rates. Both types obey Stokes’ law, which establishesthe theoretical terminal velocities o the rising and/ or settling particles. With a value o 0.015 centimeteror the diameter (D) o the globule, the rate o rise o oil globules in wastewater may be expressed in eetper minute as:
Equation 8-6
Vt =0.0241 (Sw – So)
u
whereVt = Rate o rise o oil globule (0.015 centimeter
in diameter) in wastewater, eet per minuteSw = Specic gravity o wastewater at design
temperature o fowSo = Specic gravity o oil in wastewater at design
temperature o fowu = Absolute viscosity o wastewater at design
temperature, poises
Grease Interceptor Design EampleThe ollowing example illustrates the application o the above equations or the design o a grease inter-ceptor.
Without additional data describing the distribu-tion o oil droplets and their diameters within a
representative wastewater sample, it is not possibleto quantitatively predict the eect that increasedinterceptor size or reduced low and subsequentincreased retention time within the grease intercep-tor will have on the efuent concentration o theinterceptor. However, experimental research on oildroplet rise time (see Table 8-1) illustrates the e-ect that increased interceptor size or reduced fowand subsequent increased retention time within thegrease interceptor will have on oil droplet removal.Following the logic in Table 8-1 allows the designerto improve the grease interceptor by increasing theinterceptor volume or reducing fow and subsequentlylowering horizontal velocity and increasing retentiontime within the grease interceptor.
a decrease in the overfow rate might have the sameeect. A fotation test might determine the point o agglomeration or a known water sample.
PRACTICAL DESIGN While acquaintance with the theory o fotation isimportant to the engineer, several actors have pre-
vented the direct application o this theory to thedesign o grease interceptors. Some turbulence isunavoidable at the inlet end o the tank. This eectis greatly reduced by good inlet design (including bafing) that distributes the infuent as uniormly aspracticable over the cross-section o the tank. Thereis also some intererence with the streamline fow at
the outlet, but this condition is less pronouncedthan the inlet turbulence and is reduced only byusing overfow weirs or bafes. Density currentsare caused by dierences in the temperature,the density o the incoming wastewater, and theinterceptor’s contents. Incoming water has moresuspended matter than the partially claried con-tents o the tank. Thereore, the infuent tends toorm a relatively rapid current along the bottomo the tank, which may extend to the outlet. Thiscondition is known as short-circuiting and occurseven with a uniorm collection at the outlet end.
Flocculation o suspended solids has been
mentioned. Its eects, however, are dicult topredict.
In general, the engineer depends on experienceas well as the code requirements o the variouslocal health departments or the preerred reten-tion and overfow rates. Depth already has beendiscussed as having some eect on the tank’s e-ciency. A smaller depth provides a shorter pathor the rising particle to settle, which gives thebasin greater eciency as the surace-loading rates match the overfow rates based on a givenretention time. The tank’s inlets and outlets re-quire careul consideration by the designer. The
ideal inlet reduces the inlet velocity to preventthe pronounced currents toward the outlet, dis-tributes the inlet water as uniormly as practicalover the cross-section o the tank, and mixes theinlet water with the water already in the tank toprevent the entering water rom short-circuiting toward the outlet.
GREASE INTERCEPTOR TyPES
Hdromechanical Grease InterceptorsFor more than 100 years, grease interceptors havebeen used in plumbing drainage systems to prevent
grease accumulations rom clogging interconnect-ing sanitary piping and sewer lines. However, itwasn’t until 1949 that a comprehensive standardor the basic testing and rating requirements orhydromechanical grease interceptors was devel-oped. This standard is known as PDI G101. It hasbeen widely recognized and is reerenced in mostplumbing codes, replicated in ASME A112.14.3:Grease Interceptors, reerred to in manuactur-ers’ literature, and included in the basic testing and rating requirements o Military Specication
Figure 8-4 (A) Hydromechanical Grease Interceptor; (B) Timer-controlled Grease Removal Device; (C) FOG Disposal System
MIL-T-18361. A speciying engineer or purchaser o a hydromechanical grease interceptor can be assuredthat the interceptor will perorm as intended whenit has been tested, rated, and certiied in conor-mance with PDI G101, ASME A112.14.3, and ASME A112.14.4: Grease Removal Devices.
Conventional manually operated hydromechanicalinterceptors (see Figure 8-4A) are extremely popularand generally are available with a rated fow capacityup to 100 gpm (6.31 L/s) or most applications. Forfow rates above 100 gpm (6.31 L/s), large capacityunits up to 500 gpm (31.5 L/s) commonly are used.The internal designs o these devices are similar. Theinlet bafes, usually available in various styles andarrangements, act to ensure at least 90 percent e-ciency o grease removal through the HGI, per PDIG101 testing requirements or units o 100 gpm andless. Care should be taken to avoid long runs o pipebetween the source and the interceptor to avoid FOGaccumulation and mechanical emulsication prior to
entering the interceptor.Grease removal rom manually operated hydrome-
chanical grease interceptors is typically perormed byopening the access cover and manually skimming theaccumulated grease rom the interior water surace(along with the removal o a perorated lter screenor cleaning i so equipped).
Semiautomatic UnitsSemiautomatic units are typically a hydromechanicalinterceptor design, with FOG accumulation on thesurace o the water inside the interceptor. However,these types o HGIs are not used as widely as theyonce were due in part to advances in grease retentionequipment technology. In addition, the FOG removalprocess involves the running o hot water throughthe interceptor to raise the water level and orce theFOG into the draw-o recovery cone or pyramid andthen out through the attached draw-o hose to a FOGdisposal container until the running water becomesclear. As compared to the operational qualities o theinterceptor types and technologies currently avail-able, this process wastes potable water at a time whenwater conservation should be o critical concern to theplumbing engineer, especially in certain areas o thecountry where the cost o water may be at a premium
or a acility owner.SeparatorsGrease separators are available rom some manuac-turers. They separate FOG-laden wastes dischargedrom xtures via gravity action. These types o devicesare similar to HGIs in their construction, unction,and cleaning. Unlike HGIs, they are not PDI G101certied and do not contain or rely on external fowcontrol devices or proper unctioning. Internally,they are constructed in such a way that there is no
straight-through travel o wastewater rom inlet tooutlet. Flow through the unit is directed in a specicpattern and/or use o components (engineered bythe device manuacturer) as required to minimizefow velocities and allow or the proper separation o FOG material rom the wastewater. Provided that thedevice has been properly sized and installed correctly,the inlet simply closes when the separator’s holding capacity is reached i short-circuiting devices or meth-ods have not been otherwise utilized. As such, thistype o device has essentially a built-in fow controland needs no external fow control. These devices canbe selected where allowable by local authorities andwhere the installation o a PDI G101-certied deviceis not required or approval.
Grease Removal DevicesGrease removal devices are typically hydromechanicalinterceptors that incorporate automatic, electricallypowered skimming devices within their design. Thetwo basic variations o this type o interceptor are
timer-controlled units and sensor-controlled units.In timer-controlled units (see Figure 8-4B), FOG
is separated by gravity fotation in the conventionalmanner, at which point the accumulated FOG isskimmed rom the surace o the water in the inter-ceptor by a powered skimming device and activatedby a timer on a time- or event-controlled basis.
The skimmed FOG is essentially scraped or wipedrom the skimmer surace and directed into a trough,rom which it drains through a small pipe rom theinterceptor into a disposal container located adjacentto the interceptor. Most GRDs are tted with an elec-tric immersion heater to elevate the temperature inthe interceptor to maintain the contained FOG in a liquid state or skimming purposes.
A variation o this type o interceptor utilizes a FOG removal pump that is positioned in a tray insidethe interceptor and controlled rom a wall unit thatcontains a timer device. The pump is attached to a small translucent tank with a drain outlet that islocated adjacent to the interceptor.
To operate these units, a timer is set to turn onthe skimmer or FOG removal pump within a selectedperiod. In a short time, the accumulated FOG isdrained into the adjacent container, to be disposed o
in a proper manner.Sensor-controlled units employ computer-con-
trolled sensors or probes, which sense the presence o FOG and automatically initiate the draw-o cycle ata predetermined percentage level o the interceptor’srated capacity. FOG is then drawn rom the top o the FOG layer in the interceptor. The draw-o cyclecontinues until the presence o water is detected bythe sensor, which stops the cycle to ensure that onlywater-ree FOG is recovered. I required, an immer-sion heater is activated automatically at the onset o
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the draw-o cycle to liquey FOG in the interceptor.In addition, i either the unit’s grease collection res-ervoir (where the recovered grease is stored pending removal) or the interceptor itsel is near capacity withpotential overloading sensed, warning measures andunit shutdown are activated automatically.
When GRDs are considered or installation,the manuacturer should be consulted regarding electrical, service, and maintenance requirements.The plumbing engineer must coordinate these re-quirements with the appropriate trades to ensurea proper installation. Furthermore, owing to theserequirements, it is essential that those responsibleor operating GRDs be trained thoroughly in theiroperation.
FOG Disposal Sstems A FOG disposal system is very similar to a hydro-mechanical interceptor in its operation. However, inaddition to reducing FOG in efuent by separation,it automatically reduces FOG in efuent by mass
and volume reduction, without the use o internalmechanical devices or manual FOGremoval. This system is specically en-gineered, and one type is congured tocontain microorganisms that are usedto oxidize FOG within the interceptorto permanently convert the FOG mate-rial into the by-products o digestion, a process otherwise reerred to as bioreme-diation. (It should be noted that this isalso the same process used by municipalwastewater treatment plants.) OtherFOG disposal systems utilize thermal orchemical methods o oxidation.
Figure 8-4C is an example o a bioremediation type o interceptor. Theinterceptor is divided into two mainchambers, separated by bafes at theinlet and outlet sides. The bafe locatedat the inlet side o the interceptor actsto distribute the infow evenly across thehorizontal dimension o the interceptor.However, unlike conventional HGIs, a media chamber is its main compartment,which contains a coalescing media that
is engineered to cause FOG to rise along the vertical suraces o the media struc-ture, where it comes into contact withmicroorganisms inhabiting a bioilmattached to the media. A wall-mountedshel located above the interceptor sup-ports a metering pump, timer, controls,and a bottle lled with a bacteria cultureprovided by the system manuacturer.
As the FOG material collects in thebiolm, bacteria rom the culture bottle
(injected by the metering pump) break the bondsbetween atty acids and glycerol and then the bondsbetween the hydrogen, carbon, and oxygen atomso both, thereby reducing FOG volume. Drainagecontinues through the media chamber around theoutlet bafe, where it then is discharged to the sani-tary system.
Though FOG disposal systems signicantly reducethe need or manual FOG removal or the handling o mechanically removed FOG materials, the needor monitoring efuent quality, routine maintenanceto remove undigested materials, and inspections toensure all components are clean and unctioning properly are required and should be perormed on a regular basis.
Furthermore, it is essential that the plumbing en-gineer coordinate all electrical and equipment spaceallocation requirements with the appropriate tradesto allow or the proper installation and unctioning o a FOG disposal system.
Gravit Grease InterceptorsGravity grease interceptors commonly are made o 4-inch (101.6-mm) minimum thickness concrete walls,with interior concrete barriers that act to sectional-ize the interior into multiple chambers that dampenfow and retain FOG by fotation. Figure 8-5A showsa typical installation. However, standards allow other
materials such as berglass, plastic, and protectedsteel. Generally, these units are used outside buildingsas inground installations rather than as inside sys-tems adjacent to or within kitchen areas. These unitsgenerally do not include the draw-o or fow-controlarrangements common to hydromechanical units.
The unit should be installed as close to the sourceo FOG as possible. I this cannot be achieved due toeld conditions or other site constraints, a heat tracesystem can be installed along the drain piping thatis routed to the inlet side o the GGI to help keep theFOG-laden waste rom solidiying beore it enters theinterceptor. Increasing the slope o the drain piping to
the interceptor also can be considered in lieu o heattracing where allowable by local codes and authoritieshaving jurisdiction.
I a unit is located in a trac area, care must betaken to ensure that the access covers are capableo withstanding any possible trac load. It is alsoimportant that the interceptor be located in such a way as to allow easy cleanout.
Preabricated GGIs also tend to be internallyand externally congured with unique, pre-installedeatures designed to meet the local jurisdictionalrequirements o any given project location. Theplumbing engineer must veriy the local requirements
to which these units must conorm to ensure properunit selection.
Field-ormed concrete gravity grease interceptorsare basically identical to the preabricated units asdescribed above, with the exception that they usu-ally are constructed at the project site. Though likelymore expensive to install than a preabricated unit,one reason or its installation could be unique projectsite constraints. For example, a GGI may need to beinstalled in a very tight area, too close to existing property lines or adjacent structures to allow hoist-ing equipment the necessary access to an excavatedarea that otherwise would be sucient or a standardpreabricated GGI installation.
Following is a list o recommended installationprovisions or preabricated and eld-ormed GGIslocated outside a building.
• Theunitshouldbeinstalledasclosetothesourceo FOG as possible. I this cannot be achieved dueto eld conditions or other site constraints, a heattrace system can be installed along the drain pip-ing that is routed to the inlet side o the GGI.
• Theinuentshouldentertheunitatalocationbe-low the normal water level or near the bottom o the GGI to keep the surace as still as possible.
• The inlet and the outlet of the unit should beprovided with cleanouts or unplugging both thesewers and the dip pipes.
• Theefuentshouldbedrawnfromnearthebot-
tom o the unit, via a dip pipe, to remove as muchfoating grease and solids as possible.
• A largemanhole, or removable slab, should beprovided or access to all chambers o the greaseinterceptor or complete cleaning o both thefoating and the settled solids.
• Adifferenceinelevationbetweentheinletandtheoutlet o 3 to 6 inches (76.2 to 152.4 mm) shouldbe provided to ensure fow through the greaseinterceptor during surge conditions without the
waste backing up in the inlet sewer. As the greasebegins to accumulate, the top o the grease layerwill begin to rise above the normal water level ata distance o approximately 1 inch (25.4 mm) oreach 9 inches (228.6 mm) o grease thickness.
• Afterinstallation,testingoftheGGIforleakageshould be a specication requirement prior to -nal acceptance.
In addition to concrete GGIs, gravity grease inter-ceptors in the orm o preabricated round, cylindricalprotected steel tanks are also available (see Figure8-5B). These units oten are reerred to as passive
grease interceptors, but they all into the same cat-egory as gravity grease interceptors because theyoperate in virtually the same manner. Interceptors o this type are available with single and multiple cham-bers (depending on local jurisdictional requirements),with internal bafes, vent connections, and manholeextensions as required to allow or proper operation.They are manuactured in single- and double-wallconstruction and can be incorporated with steam orelectric heating systems to help acilitate FOG separa-tion and extraction rom the unit.
Protected steel tank GGIs are built to UL specica-tions or structural and corrosion protection or both
the interior and the exterior o the interceptor. The ex-terior corrosion protection is a two-part, polyurethane,high-build coating with interior coating options o polyurethane, epoxy, or a proprietary material (depend-ing on infuent wastewater temperature, wastewatercharacteristics, etc.). When protected steel tank GGIsare considered or installation, the manuacturershould be consulted regarding venting and hold-downrequirements or buoyancy considerations.
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INSTALLATIONMost local administrative authorities require in their jurisdictions’ codes that spent water rom ood servicextures and equipment producing large amounts o FOG discharge into an approved interceptor beoreentering the municipality’s sanitary drainage system.These requirements (generally code and pretreatment
regulations, with pretreatment coordinators having the nal word) can include multi-compartment potsinks, pre-rinse sinks, kettles, and wok stations, aswell as area foor drains, grease-extracting hoodsinstalled over rying or other grease-producing equip-ment, and dishwashing equipment.
I foor drains are connected to the interceptor, theengineer must give special consideration to other ad- jacent xtures that may be connected to a commonline with a foor drain upstream o the interceptor.Unless fow control devices are used on high-volumextures or multiple xtures fowing upstream o thefoor drain connection, fooding o the foor drain can
occur. A common misapplication is the installationo a fow control device at the inlet to the intercep-tor that may restrict high-volume xture dischargeinto the interceptor, but foods the foor drain on thecommon branch. Floor drains connected to an inter-ceptor require a recessed (beneath the foor) inter-ceptor design.
An acceptable design concept is to locate the in-terceptor as close to the grease-producing xtures aspossible. Under-the-counter or above-slab intercep-tor installations are oten possible adjacent to thegrease-producing xtures. This type o arrangementoten avoids the individual venting o the xtures,
with a common vent and trap downstream o thegrease interceptor serving to vent the xtures andthe grease interceptor together. Thereore, a p-trap isnot required on the xture outlet. However, providedthis particular arrangement is allowed by governing codes and local jurisdictions, special attention shouldbe paid to air inlet sources or the air-injected fowcontrol i no p-trap is attached to the xture outlet toavoid circuiting the building vent to the xture.
I the grease interceptor is located ar rom thextures it serves, the grease can cool and solidiy inthe waste lines upstream o the grease interceptor,
causing clogging conditions or requiring more re-quent cleaning o the waste lines. However, a heattrace system can be installed along the main wasteline that is routed to the inlet side o the interceptorto help keep the FOG-laden waste rom solidiying beore it enters the interceptor. Long horizontal andvertical runs also can cause mechanical emulsica-tion o entrained FOG, which makes it dicult toseparate.
Some practical considerations are also importanti an interceptor is to be located near the xturesit serves. I the interceptor is an under-the-counter,above-the-slab device, the engineer should leaveenough space above the cover to allow completecleaning and FOG removal rom the unit.
Some ordinances also require that interceptorsnot be installed where the surrounding tempera-tures under normal operating conditions are lessthan 40°F (4.4°C).
Some administrative authorities prohibit the dis-charge o ood waste disposers through HGIs andGRDs because o the clogging eect o ground-upparticles. Other jurisdictions allow this setup, pro-vided that a solids interceptor or strainer basket isinstalled upstream o these devices to remove anyood particulates prior to entering the interceptor.It is recommended that ood waste disposers be con-nected to HGIs and GRDs (in conjunction with a sol-ids strainer) when allowed by the authority having
jurisdiction due to the act that disposer waste dis-charge is a prime carrier o FOG-laden material.
The same situation is similar with respect todishwashers. Some administrative authorities pro-hibit the discharge o dishwasher waste to HGIs andGRDs, while other jurisdictions allow it, providedthat the dishwashers are without pre-rinse sinks. Itis recommended that dishwashers not be connectedto HGIs or GRDs. Although the high discharge wastetemperature rom a dishwasher may be benecial tothe FOG separation process by helping maintain theFOG in a liquid state, the detergents used in dish-washing equipment can inhibit the device’s ability to
separate FOG altogether, which allows FOG to passthrough the device where it eventually can revert toits original state and cause problems within the mu-nicipal sanitary system.
FLOW CONTROLFlow control devices are best located at the outlet o the xtures they serve. However, fow control ttingsare not common or foor drains or or xtures thatwould food i their waste discharge was restricted(such as a grease-extracting hood during its fushing cycle).
A ew precautions are necessary or the proper
application o fow control devices. The engineershould be sure that enough vertical space is availablei the fow control device is an angle pattern witha horizontal inlet and a vertical outlet. A commondiculty encountered is the lack o available heightor an above-slab grease interceptor adjacent to thexture served when the vertical height needed orthe drain outlet elbow, pipe slope on the waste armrom the xture, vertical outlet fow control tting,
and height rom the grease interceptor inlet to thefoor are all compensated.
The air intake (vent) or the fow control tting may terminate under the sink as high as possible toprevent overfow or terminate in a return bend atthe same height on the outside o the building. Whenthe xture is individually trapped and back-vented,air intake may intersect the vent stack. All instal-lation recommendations are subject to the approvalo the code authority. The air intake allows air tobe drawn into the fow control downstream o theorice bafe, thereby promoting air-entrained fowat the interceptor’s rated capacity. The air entrainedthrough the fow control also may aid the fotationprocess by providing a liting eect or the rising grease.
It is particularly important to install the greaseinterceptor near the grease-discharging xturewhen fow control devices are used because o thelower fow in the waste line downstream o the fow
control device. Such fow may not be enough to en-sure sel-cleaning velocities o 3 eet per second (ps)(0.9 m/s).
While fow control is necessary to ensure thatan interceptor will meet PDI G101 standards andunction as designed, it should be stated that theycan also be problematic due to their nature and pur-pose. Along with the issues previously mentioned,these devices clog airly rapidly i not maintained ona regular basis due to their construction. It is notuncommon or these devices to be removed entirelyand discarded by acility maintenance personnel inan eort to alleviate clogging and minimize mainte-
nance expenses. Whether legal or not, this deeatsthe purpose o having the device in the rst place,resulting in an interceptor installation that may notunction as intended.
An alternative to utilizing a fow control devicemay be to select an interceptor whose fow charac-teristics exceed the design fow rate established ora acility or xture. In the case o a single xture orpoint-o-use application, Equation 1-11 rom Plumb-ing Engineering Design Handbook, Volume 1 couldbe used to determine the actual fow rate o a x-ture. The subsequent selection o an interceptorwould then be o a capacity greater than that o the
discharge fow rate o the xture to ensure properoperation and removal o FOG. The same method ora central interceptor installation could be used or a group o xtures, except that the Manning ormula could then be used to determine the necessary infu-ent fow rate. While either method typically resultsin the selection o an interceptor that is somewhatoversized, the elimination o a fow control deviceand longer durations between interceptor cleanings
could be achieved, thus osetting initial installationcost over time.
GUIDELINES FOR SIZINGThe ollowing recommended sizing procedure orgrease interceptors may be used as a general guidelineor the selection o these units. The engineer shouldalways consult the local administrative authoritiesregarding variations in the allowable drain-downtimes acceptable under the approved codes. Calcula-tion details and explanations o the decision-making processes have been included in ull in the examplesas an aid to the engineer using these guidelines inspecic situations.
Example 8-1
Assume an HGI or a GRD or a single-xture installa-tion with no fow control. Size the grease interceptoror a three-compartment pot (scullery) sink, with eachcompartment being 18 × 24 × 12 inches.
1. First, determine the sink volume:Cubic contents o one sink compartment =
18 × 24 × 12 = 5,184 in.3
Cubic contents o three sink compartments =
3 × 5,184 = 15,552 in.3
Contents expressed in gallons =
15,552 in.3 /231 = 67.3 gallons
2. Then add the total potable water supply that couldbe discharged independent o a xture calculatedabove, including manuacturer-rated appliancessuch as water-wash exhaust hoods and disposers(i allowed to discharge to the interceptor).
3. Next, determine the xture load. A sink (or x-ture) seldom is lled to the brim, and dishes, pots,or pans displace approximately 25 percent o thewater. Thereore, 75 percent o the actual xturecapacity should be used to establish the drainageload:
0.75 × 67.3 gal = 50.8 gal
4. Calculate the fow rate based on drain time, typi-cally one minute or two minutes. The fow ratesare calculated using the ollowing equation:
Drainage load, in gallons / Drainage load, inminutes
Thereore, the fow rate or this example wouldbe:
50 gpm (3.15 L/s) or one-minute drainage or 25gpm (1.58 L/s) or two-minute drainage.
5. Last, select the interceptor. Choose between a hydromechanical interceptor with a rated ca-pacity o 50 gpm or one-minute fow or 25 gpmor two-minute fow or a gravity interceptor
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with a capacity o 1,500 gallons (50-gpm fowrate × 30-minute detention time).
Local administrative authorities having jurisdic-tion should be consulted as they may dictate a spe-cic ormula or sizing criteria that would ultimatelydetermine the specic fow parameters or whichthe interceptor could be selected. It is extremely im-
portant to determine not only the governing modelcode requirements regarding specic interceptor cri-teria, but also local jurisdictional requirements pro-mulgated by the pretreatment authority since theysometimes contradict each other, especially wherelocal jurisdictions adopt certain amendments andregulations that may supersede any model code re-quirements.
Grease extraction water-wash hood equipmentmay be used. It should be noted that while these sys-tems are used in some cases, grease hoods that incor-porate troughs that entrap grease, which are slopedto drip cups at the ends o the hood, are used quite
prevalently. These cup drains are removed by hand,and the FOG material contained is disposed o in a proper manner and never discharges to the intercep-tor. It is important to veriy which types o systemswill be used with respect to grease hood equipmentprior to the selection o the interceptor so the propercapacity can be determined.
It also should be noted that the phrase “sizing aninterceptor” is used throughout the industry quiteloosely. However, grease interceptors are not sized.They are selected based on specic fow parametersand requirements as determined by the plumbing engineer during the design process or each indi-vidual acility. Furthermore, the design fow ratesand pipe sizing criteria or ood preparation acilitiesshould not be determined by using the xture unitmethod typically used or other types o acilitiesdue to the act that the probability o simultaneoususe actors associated with xture unit values do notapply in ood preparation acilities where increasedand continuous fow rates are encountered. Also, theacility determines the peak fows used to select theproper interceptor or the intended application, notthe other way around (i.e., a single acility does notdischarge at a multitude o dierent fow rates de-
pending on which particular type o interceptor isbeing considered or installation.)Lastly, in certain projects the plumbing engineer
may be called on to select an interceptor in whichthe fow rates or a acility are not readily quanti-able at the time o design, such as or a uture ex-pansion, restaurant, or ood court area within a newdevelopment. In this case, tables or ormulas canbe used in an eort to help quantiy the maximumfow rate that will be encountered or a specic pipesize at a given slope and velocity that ultimately dis-
charges to the interceptor. This inormation can beused to select the proper interceptor capacity or theintended fow rates anticipated.
CODE REQUIREMENTSThe necessity or the plumbing engineer to veriy allstate and local jurisdictional requirements prior tothe start o any ood service acility design cannotbe emphasized enough. Although state and modelplumbing codes provide inormation with respectto interceptor requirements and regulations, localhealth departments and administrative authoritieshaving jurisdiction have likely established their ownset o guidelines and requirements or an intercep-tor on a specic project and, thereore, also shouldbe consulted at the start o the design. It is up to theplumbing engineer to pull together the various agencyrequirements in an eort to design a code-compliantsystem, while incorporating any additional governing requirements and regulations.
Following are itemized lists incorporating the ma- jor provisions o the model plumbing codes and areincluded herein as an abbreviated design guide orthe engineer when speciying sizing. It is importantto review the applicable code in eect in the area orany variation rom this generalized list.
UPC Requirements or Interceptors
1. Grease interceptors are not required in individualdwelling units or residential dwellings.
2. Water closets, urinals, and other plumbing x-tures conveying human waste shall not drain intoor through any interceptor.
3. Each xture discharging into an interceptor shallbe individually trapped and vented in an approvedmanner.
4. Grease waste lines leading rom foor drains, foorsinks, and other xtures or equipment in serving establishments such as restaurants, caes, lunchcounters, caeterias, bars, clubs, hotels, hospitals,sanitariums, actory or school kitchens, or otherestablishments where grease may be introducedinto the drainage or sewage system shall be con-nected through an approved interceptor.
5. Unless specically required or permitted by the
authority having jurisdiction, no ood waste dis-posal unit or dishwasher shall be connected toor discharge into any grease interceptor. Com-mercial ood waste disposers shall be permittedto discharge directly into the building drainagesystem.
6. The waste discharge rom a dishwasher may bedrained into the sanitary waste system through a gravity grease interceptor when approved by theauthority having jurisdiction.
7. Flow control devices are required at the drainoutlet o each grease-producing xture connectedto a hydromechanical grease interceptor. Flowcontrol devices having adjustable (or removable)parts are prohibited. The fow control device shallbe located such that no system vent shall be be-tween the fow control and the interceptor inlet.(Exception: Listed grease interceptors with inte-
gral fow controls or restricting devices shall beinstalled in an accessible location in accordancewith the manuacturer’s instructions.)
8. A vent shall be installed downstream o hydrome-chanical grease interceptors.
9. The grease collected rom a grease interceptormust not be introduced into any drainage piping or public or private sewer.
10. Each gravity grease interceptor shall be so in-stalled and connected that it shall be at all timeseasily accessible or inspection, cleaning, and re-moval o intercepted grease. No gravity grease in-
terceptor shall be installed in any part o a build-ing where ood is handled.
11. Gravity grease interceptors shall be placed asclose as practical to the xtures they serve.
12. Each business establishment or which a grav-ity grease interceptor is required shall have aninterceptor that shall serve only that establish-ment unless otherwise approved by the authorityhaving jurisdiction.
13. Gravity grease interceptors shall be located so asto be readily accessible to the equipment requiredor maintenance and designed to retain grease
until accumulations can be removed by pumping the interceptor.
IPC Requirements or HdromechanicalGrease Interceptors
1. Grease interceptors are not required in individualdwelling units or private living quarters.
2. A grease interceptor or automatic grease removaldevice shall be required to receive the drainagerom xtures and equipment with grease-ladenwaste located in ood preparation areas such asrestaurants, hotel kitchens, hospitals, schoolkitchens, bars, actory caeterias, and clubs. The
xtures include pre-rinse sinks, soup kettles orsimilar devices, wok stations, foor drains or sinksto which kettles are drained, automatic hood washunits, and dishwashers without pre-rinse sinks.
3. Where ood waste disposal units are connectedto grease interceptors, a solids interceptor shallseparate the discharge beore connecting to theinterceptor. Solids interceptors and grease inter-ceptors shall be sized and rated or the dischargeo the ood waste grinder.
4. Grease interceptors shall be equipped with de-vices to control the rate o water fow so that thewater fow does not exceed the rated fow. Thefow control device shall be vented and terminatenot less than 6 inches above the food rim levelor be installed in accordance with manuacturer’sinstructions.
5. Hydromechanical grease interceptors shall havethe minimum grease retention capacity or thefow-through rates indicated in Table 8-2.
OPERATION AND MAINTENANCEOperational methods can create problems or the en-gineer even i all o the design techniques or greaseinterceptors presented have been observed. Failing to scrape dinner plates and other ood waste-bearing utensils into the ood waste disposer prior to loading them into dishwasher racks means that the liquidwaste discharged rom the dishwasher to the greaseinterceptor also carries solid ood particles into the
grease interceptor unit. The grease interceptor is nota ood waste disposer.
Another common problem is insucient greaseremoval. The period between removals diers oreach interceptor type and is best let to the expe-rience o licensed proessional cleaning services.However, i the fow rate o the unit is constantlyexceeded (no fow control) with high-temperaturewater, such as a heavy discharge rom a dishwasher,the grease in the unit may periodically be liqueedand washed into the drainage system downstream
Table 8-2 Minimum Grease
Retention CapacityTotal Flow-
Through Rating(gpm)
Grease RetentionCapacity(pounds)
4 8
6 12
7 14
9 18
10 20
12 24
14 28
15 30
18 36
20 40
25 50
35 70
50 100
75 150
100 200
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Keeping a fuid isolated in a complex piping networkin a modern building may seem like a straightorwardproposition. However, such eorts all short unless alldetails are addressed thoroughly. Plumbing conveysone o society’s most cherished commodities, saewater, to be used or personal hygiene and consump-
tion, or industry, or medical care, and or landscapeirrigation. Thus, a clear and distinct barrier betweenpotable water and pollution, toxic substances, ordisease-causing microbes is required. Good plumb-ing practices also call or similar controls related tograywater.
A cross-connection control (CCC) is a piping designor device, oten combined with requent monitoring,that prevents a reverse fow o water at a cross-connec-tion, or the point in the water supply where the waterpurity level is no longer known because o the transi-tion rom an enclosed streamline o water to another
surace, basin, drain system, pipe system, or piping beyond the control o the water purveyor. Examples o potential cross-connections include plumbing xtures,hose bibbs, appliance connections, hydronic watersupply connections, re sprinkler and standpipe wa-ter supply connections, water supply connections toindustrial processes, laundries, medical equipment,ood service equipment, HVAC equipment, swimming pool water makeup, water treatment backwash, trapprimers, irrigation taps, dispensers that dilute theirproduct with water, pressure-relie valve dischargepiping, and drain-fushing water supply. However, a cross-connection is not necessarily hard piped. Rather,
because o the nature o fuid mechanics, it also couldbe where the end o a water supply pipe is suspendedbelow the rim o a xture or foor drain.
HyDROSTATIC FUNDAMENTALS
A cross-connection hazard is relative to the natureo the contaminants likely to be present in the en-vironment o the cross-connection. To understandthe hazards o cross-connections and the associatedcontrol methods, a knowledge o hydrostatics is es-sential since the pressure at any point in a static water
system is a unction only o the water’s depth. Thisrelationship is understood by considering that at anypoint, the weight o water above it is the product o its volume and its specic weight. Specic weight issimilar to density; however, it is dened as weight perunit volume rather than mass per unit volume. Like
density, it varies slightly with temperature.To derive the pressure relationship in a hydrostatic
fuid, consider the volume o the fuid at a given depthand a horizontal area at that depth. The pressure isthe weight divided by the area. Hence,
I 1 cubic oot o water is 62.4 lb and 1 square ooto area is 144 in
2, then p = h × 62.4/144 = 0.433h.
For absolute pressure in a water supply, the localatmospheric pressure is added to the gauge pressure.For example, in Figure 9-1, i the local atmosphericpressure is 14.7 psi, the absolute pressure at the top o the column is ound rom [(0.433)(-23)] + 14.7 = 4.73psia. Note that atmospheric pressure is not constant.
Rather, it varies with the weather, geographic loca-tion, and the eects o HVAC systems.
Hydrodynamics, or additional orces related to themomentum rom moving water, aect the magnitudeo a reverse fow and the transient nature o a fow de-mand. Pressure reversals at booster pump inlets andcirculator pump inlets may cause other hydrodynamicissues. These pressure eects are superimposed on hy-drostatic pressures. Nonetheless, impending reversalsgenerally are aected by hydrostatics only.
Cross-ConnectionControl9
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As an example, consider a 100-oot (30.5-m) tallwater supply riser pipe with 20 pounds per squareinch gauge (psig) (138 kPa) at its top. From Equation9-1, the pressure at the base o the riser will be 63.3psig (436 kPa). I an event causes a 30-psig (207-kPa)pressure loss, the pressure at the top xture will be-10 psig (-69 kPa gauge), or 4.7 pounds per squareinch absolute (psia) (32 kPa absolute). This vacuumwill remain in the piping until any aucet, fush valve,or other valve is opened on the riser.
CAUSES OF REVERSE FLOW Cross-connection control methods must be appliedbetween varying water supplies to prevent pollu-tion or a contaminant rom inadvertently entering the potable water supply. A general water supply isrepresented in Figure 9-2. Although it shows onlyour endpoints, you can expand it to any number o endpoints with any arrangement o pipes o dierentelevations and lengths. Hence, the network o pipesmay represent a small network, such as a residence,
or it may represent a large network, such as a building complex or a major city.
At each endpoint in a plumbing water supply,any o ve general details, such as shown in Figure9-3, may be connected. Elevation is represented bythe vertical lines. For illustration purposes, no CCCis included. An example o Figure 9-3(a) is a waterstorage tank with an open or vented top, such as a city water tower. Figure 9-3(b) could be a pressurevessel such as a boiler, Figure 9-3(c) a plumbing basin,Figure 9-3(d) a hose immersed in a plumbing basinor a supply to a water closet with a fushometer, andFigure 9-3(e) a re suppression system, a hydronicsystem, or a connection point or process piping oror a building’s water distribution in contrast to thestreet distribution.
I you include a pump anywhere in a network,an elevated reservoir can illustrate the eect o thepump. The pump’s discharge head is equivalent to thesurace elevation level o the reservoir relative to thepiping system discharge level.
Figure 9-1 Hydrostatics Showing Reduced AbsolutePressure in a Siphon
Figure 9-2 Pipe Network With Four Endpoints
Figure 9-3 Five Typical Plumbing Details Without Cross-Connection Control
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Chapter 9 — Cross-Connection Control 161
All discussions o CCC include identication o back-pressure and back-siphonage. Back-pressureis the pressure at a point in a water supply systemthat exists i the normal water supply is cut o oreliminated. Back-siphonage is an unintended siphonsituation in a water supply with the source reservoirbeing a xture or other source with an unknown levelo contamination. A siphon can be dened as a benttube ull o water between two reservoirs under atmo-spheric pressure, causing fow in the reservoirs despitethe barrier between them.
For example, the maximum back-pressure at thebase o the riser in Figure 9-3(a), or a reservoir otherthan the normal water supply, occurs i the tank shownis lled to its rim or overfow outlet. In Figure 9-3(d),fow rom the basin may occur i the water supply iscut o or eliminated and i the water elevation is nearor above the pipe outlet. This reverse fow, or siphonaction, is caused by atmospheric pressure against theree surace o the water in the basin.
In a network, when the law o hydrostatics isgenerally applied to the reservoir with the highestelevation, the network’s pressure distribution is
identiable, and the direction o fow can be knownthrough general fuid mechanics. In an ideal case,the presence o that reservoir generally keeps thedirection o fow in a avorable direction. However,the connection o a supply reservoir is vulnerable toany cause or a pressure interruption, and the normalnetwork pressure distribution may be disturbed. Forexample, when a valve anywhere in a general systemisolates a part o the system away rom the supplyreservoir, another part o the isolated section maybecome the water source, such as any xture, equip-ment, or connected system. Reer back to Figure 9-2.I endpoint 2 is the city water supply and endpoint4 is a closed-loop ethylene glycol system on a roo, i the city supply is cut o, the glycol may reely eedinto endpoints 1 and 3.
Other pressure interruptions include broken pipes,broken outlets, air lock, pressure caused by thermalenergy sources, malunctioning pumps, malunction-ing pressure-reducing valves, and uncommon water
discharges such as a major reghting event.Because it cannot be predicted where a valve may
close or where another type o pressure interruptionmay occur, each water connection point becomesa potential point or reverse fow. Thus, everyxture, every connected piece o equipment, andevery connected non-plumbing system becomesa point o reverse fow. Containers o any liquidthat receive water rom a hose or even a spout o inadequate elevation potentially may fow in a reverse direction. Submerged irrigation systemsor yard hydrants with a submerged drain pointpotentially may fow soil contaminants into the
water supply system. Hence, the saety o a watersupply distribution depends on eective control ateach connection point. The saety is not ensured i the eectiveness o one point is unknown despitecontrols at all other points.
Further, control methods today do not detector remove the presence o contaminants. A con-trol device added to hot water piping supplying a laboratory will not be eective i the circulationreturn brings contaminated hot water out o thelaboratory.
A manually closed water supply valve is notconsidered a cross-connection control, even i
the valve is bubble-tight and well supervised.Ordinary check valves also are not considereda cross-connection control. The history o suchgood intentions or equipment connections orwater ll into processing operations has notbeen suciently eective as compared to cross-connection control.
In addition, as a measure o containment, a control device in the water service is a primarycandidate to isolate a hazard within a building.
Table 9-1 Plumbing System Hazards
Direct Connections Potential Submerged Inlets
Air-conditioning, air washerAir-conditioning, chilled waterAir-conditioning, condenser waterAir lineAspirator, laboratoryAspirator, medicalAspirator, herbicide and ertilizer
ANSI A 112.2.1 Air Gap BS and BP High Twice eective opening;not less than 1 inch abovefood rim level
C Lavatory, sink or bathtubspouts, Residentialdishwasher (ASSE 1006)and clothes washers (ASSE1007)
ASSE 1001 Pipe-appliedvacuum breaker BS Low 6 inches above highestoutlet; vertical position only I Goosenecks and appliancesnot subject to backpressure or continuouspressure
ASSE 1011 Hose bibbvacuum breaker
BS Low Locked on hose bibbthreads; at least 6 inchesabove grade
I Freeze-resistanttype required
Hose bibbs, hydrants, andsillcocks
ASSE 1012c
Dual-checkvalve withatmosphericvent
BS and BP Low tomoderate
Any position; drain pipedto foor
C Air gap requiredon vent outlet;vent piped tosuitable drain
makers; dental chairs;miscellaneous aucetapplications; sot drink,coee, and other beveragedispensers; hose sprayson aucets not meetingstandards
ASSE 1056 Spill-resistantindoor vacuumbreaker
BS High 12–60 inches abovehighest outlet; vertical only
C Testing annually(minimum);overhaul veyears (minimum)
Degreasers; laboratories;photo tanks; Type I lawnsprinkler systems andswimming pools (must belocated outdoors)
aBS = Back-siphonage; BP = Back-pressure
bI = Intermittent; C = Continuous
cA tab shall be axed to all ASSE 1012 and 1024 devices indicating installation date and the ollowing statement: “FOR OPTIMUM PERFORMANCE AND SAFETY, IT IS RECOMMENDED THAT THISDEVICE BE REPLACED EVERY FIVE (5) YEARS.”
Table 9-2 Application o Cross-Connection Control Devices
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• ASSE 1006: Perormance Requirements or Residential Use Dishwashers
• ASSE 1007: Perormance Requirements or Home Laundry Equipment
Barometric Loop
The design o a barometric loop requires part o theupstream supply pipe to be adequately above the re-ceiving basin. The minimum height is derived romEquation 9-1. For an atmospheric pressure o 31 inch-es (788 mm) o mercury, h = 35.1 eet (10.8 m). Thetechnique, shown in Figure 9-4, is eective becausethe room’s atmospheric pressure is not sucient to
push a column o water up that much elevation. Active TechniquesMechanisms in an active control device prevent re-verse fow either by allowing fow in one direction onlyor by opening the pipe to atmospheric pressure. Theormer generally is categorized as a back-pressurebackfow preventer, which typically utilizes a disc thatlits rom a seat to maintain normal fow. The latteris generally a vacuum breaker, which has greaterapplication restrictions. A device o either broadcategory uses a specially designed, abricated, tested,and certied assembly. For high hazard applications,the assembly oten includes supply and dischargevalves and testing ports. For various applications,Tables 9-3 and 9-4 list several back-pressure backfowpreventer standards and vacuum breaker standardsrespectively.
Examples o locating back-pressure backlowpreventers that are required or eective cross-con-nection control in Figure 9-3(a), (b), and (e) are shownwith a small square in corresponding applications inFigure 9-5(a), (b), and (e). The hydrostatic pressureo the water downstream o the backfow preventer
Figure 9-6 Example o Cross-Connection Controls in aBuilding
must be resisted by the active control in the evento water supply pressure ailure. Figure 9-6 showsseveral backfow preventers as isolation at xturesand equipment as well as hazard containment at thewater service.
Types o back-pressure backlow preventersinclude double-check valve assemblies, reduced-pres-sure principle backfow preventers, and dual checkswith atmospheric vents. Types o vacuum breakersinclude atmospheric, pressure, spill-resistant, hose
connection, and fush valve.
Double Check Valve Assembly
This control, with its two check valves, supplyvalves, and testing ports, can eectively isolatea water supply rom a low hazard system suchas a re standpipe and sprinkler system. Thedesign includes springs and resilient seats (seeFigure 9-7). Some large models, called detec-tor assemblies, include small bypass systemso equivalent components and a meter, whichmonitors small water usages associated withquarterly testing o a re sprinkler system.
A small version o a double check orcontainment CCC has been developed orresidential water services.
Reduced-Pressure Principle Backow Preventer
This control is similar to the double checkvalve but employs added eatures to isolatea water supply rom a high hazard. An alter-nate name is reduced-pressure zone backfowpreventer, or RPZ. A heavier spring is usedon the upstream check valve, which causesa pronounced pressure drop or all portionso the piping system downstream. A relie port between the check valves opens to theatmosphere and is controlled by a diaphragm.
Each side o the diaphragm is ported to eachside o the upstream check valve (see Figure9-8). A rated spring is placed on one side o the diaphragm. An articial zone o reducedpressure across the check valve is created bytorsion on the check valve spring. Pressureon the inlet side o the device is intended toremain a minimum o 2 psi (13.8 kPa) higherthan the pressure in the reduced-pressurezone. I the pressure in the zone increases towithin 2 psi (13.8 kPa) o the supply pressure,the relie valve will open to the atmosphereto ensure that the dierential is maintained.
This circumstance occurs i the downstreamequipment or piping has excessive pressure.It also occurs i the upstream check valve ailsor i the water supply is lost.
These devices are designed to be in-line, testable, and maintainable. They areequipped with test cocks and inlet and outletshuto valves to acilitate testing and main-tenance and an air gap at the relie port. Thedevice should be installed in an accessibleFigure 9-7 Double Check Valve
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location and orientation to allow or testing andmaintenance. Like the double check valve detectorassembly, this backfow preventer is available as a detector assembly.
Dual Check with Atmospheric Vent
This control is similar to the reduced-pressure prin-ciple type, but the diaphragm design is replaced by
a piston combined with the downstream check valve(see Figure 9-9). It eectively isolates a water sup-ply rom a low hazard such as beverage machinesand equipment with nontoxic additives. The unc-tion o its design is not suciently precise or highhazards. The relie port is generally hard-piped withits air gap located remotely at a similar or lowerelevation.
A vacuum breaker is o a similar design, but it iselevation-sensitive or eective isolation o a hazard.Permitted maximum back-pressure ranges rom 4.3psig (29.7 kPa) to zero depending on the type.
Atmospheric Vacuum Breaker
This control, with a single moving disc, can eectivelyisolate a water supply rom a low hazard system. Without this control in Figure 9-3(d), a reverse fowwill occur rom the basin i the fuid level in the basinis near or above the pipe discharge, the water supplypressure is lost, and the highest elevation o the pip-ing above the fuid level is less than that needed or a barometric loop. The reverse fow, reerred to as back-siphonage, is caused by atmospheric pressure againstthe surace o the fuid, which pushes the fuid up thenormal discharge pipe and down into the water sup-ply. Static pressure or any point in the basin and in
the pipe, ater discounting pipe riction, is a unctiononly o elevation. Above the fuid surace elevation,
this pressure is less than atmospheric; that is, it is a vacuum. The reverse fow thereore is stopped i thevacuum is relieved by opening the pipe to atmosphere.Figure 9-10 illustrates the vent port and the disc thatcloses under normal pressure.
Pressure-Type Vacuum Breaker
This control is similar to the atmospheric vacuum
breaker but employs one or two independent spring-loaded check valves, supply valves, and testing ports.It is used to isolate a water supply rom a high hazardsystem.
Spill-Resistant Vacuum Breaker
This control is similar to the pressure-type vacuumbreaker, but it employs a diaphragm joined to thevacuum breaker disc. It is used to isolate a watersupply rom a high hazard system and to eliminatesplashing rom the vent port.
Hose Connection Vacuum Breaker
This control is similar to the atmospheric vacuum
breaker in unction but varies in design and applica-tion. The disc is more elastic, has a pair o sliced cutsin the center, and deorms with the presence o watersupply pressure to allow the water to pass through thecuts (see Figure 9-11). The deormation also blocksthe vent port. A more advanced orm employs twodiscs, and the design allows perormance testing.
Flush Valve Vacuum Breaker
This control is similar to the hose connection vacuumbreaker in unction but varies somewhat in the designo the elastic part.
Hbrid Technique
A hybrid o passive and active controls is the breaktank. Consisting o a vented tank, an inletpipe with an air gap, and a pump at thedischarge, a break tank provides eectivecontrol or any application ranging roman equipment connection to the waterservice o an entire building. Its initial andoperating costs are obviously higher thanthose o other controls.
INSTALLATION All cross-connection controls requirespace, and the active controls require
service access. In addition, an air gapcannot be conned to a sealed space orto a subgrade location, and it requiresperiodic access or inspection. A vacuumbreaker may ail to open i it is placedin a ventilation hood or sealed space. A backfow preventer is limited to certainorientations.
I a water supply cannot be interruptedor the routine testing o a control device,Figure 9-8 Reduced-Pressure Principle Backfow
a pair o such devices is recommended. Some manu-acturers have reduced the laying length o backfowpreventers in their designs. Backfow preventers withrelie ports cannot be placed in a subgrade structurethat is subject to fooding because the air gap couldpotentially be submerged. Thus, backfow preven-ters or water services are located in buildings andabovegrade outdoors. Where required or climaticreasons, heated enclosures can be provided. Features
include an adequate opening or the relie port fowand large access provisions.
Manuacturers o reduced-pressure principlebackfow preventers recommend an inline strainerupstream o the backfow preventer and a drain valvepermanently mounted at the strainer’s upstreamside. Periodic fushing o the screen and upstreampiping should include brisk opening and closing to jarpotential debris and fush it away beore it can enterthe backfow preventer. Manuacturers also have in-corporated fow sensors and alarm devices that canprovide warnings o malunctions.
I special tools are required to service and maintainan active control device, the specication should re-quire the tools to be urnished with and permanentlysecured to the device.
Installation ShortallsThough relatively simple, air gaps have some shortalls.Namely, the structure o the outlet must be sucientlyrobust to withstand abuse while maintaining the gap.
The general openings around the air gap must not becovered. The rim o the basin must be wide enoughto capture attendant splashing that occurs rom astdischarges. The nature o the rim must be adequatelyrecognized so the gap is measured rom a valid eleva-tion. That is, i the top edge o the basin is not practical,the invert o a side outlet may be regarded as the validelevation. Similarly, the rim o a standpipe inside thebasin may be regarded as the valid elevation. In eitherdesign, the overfow and downstream piping must beevaluated to consider i it will handle the greatest inletfow likely to occur. A common design o potable waterlling a tank through an air gap that is below the tankrim, but where the tank has an overfow standpipe, isthe design ound in water closet tanks. The generousstandpipe empties into the closet bowl so the air gapis never compromised.
Vacuum breakers also have several shortalls. A valve downstream o the vacuum breaker will sendshock waves through the vacuum breaker every timethe valve closes. This causes the disc to drop during the percussion o the shock wave, which momentarilyopens the vent port, allowing a minute amount o waterto escape. The design o vacuum breakers is sensitiveto the elevation o the breaker relative to the elevation
o the water in the basin. A vacuum breaker mountedtoo low may allow back-siphonage because the vacuumis too low or the disc to respond.
With back-pressure backfow preventers, a foordrain or indirect waste receptor is required, whichcomplicates its installation, especially in renovationwork and or water services. An air gap is requiredor the relie port, which has its own set o shortalls.Lastly, the public’s perception o backfow preventers ismuddled by conusing regulations, misunderstandings
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when they ail, and modications o the air gap whennuisance splashing occurs.
For the reduced-pressure principle backfow preven-ter, its testing disrupts the water service. In addition,it requires space or its large size and its accessibilityrequirement. Another hazard exists with this backfowpreventer in re protection supplies because o the ad-ditional pressure drop in the water supply in contrastwith a single check valve. Reduced-pressure principlebackfow preventers also represent a signicant foodhazard during low-fow conditions i the upstreamcheck has a slight leak because the pressure will equal-ize, which opens the relie to the supply pressure.
The vent openings o both active devices and airgaps are prone to splashing and causing wet foors.Each drain with its rim above the foor should be ac-companied by a nearby foor drain or indirect wastedrain.
In addition to noise, energy consumption, andmaintenance, break tanks allow the opportunity or
microbial growth. Chlorine eventually dissipates inthe open air above the water level i consumptionis modest. Lastly, an obstructed overfow pipe mayrender the air gap ineective.
Existing water distribution systems and con-nection points commonly have installation aults.These range rom submerged inlets in xtures ortanks, direct connections to equipment or the sani-tary drain system, tape wrapped around air gaps tolimit splashing, and the discharge o relie pipes be-low foor drain rims. In retrotting existing build-ings with backfow prevention on the water services,complete knowledge o the building’s water uses is
essential. This must be conrmed by a eld surveyand reviewed by the building’s operating person-nel. Usually the existing building conditions presenteven greater challenge in providing backfow pre-vention. Existing buildings may require additional,more costly, equipment to accommodate the installa-tion o the backfow prevention equipment.
With new construction, the installation o backfowprevention could result in increased drainage costs orRPZ relies and the associated water pumping. Whenproviding RPZ-type devices or new constructioninside the building, the ideal location is abovegradeon the main foor to minimize the possibility o sub-
merging the relie port. However, on many buildings,this is a dicult location to obtain since the mainfoor is prime space reserved or building operationalunctions. I the RPZ must be installed in the spacebelowgrade, drainage provisions must be consideredand designed to accommodate the maximum possibledischarge fow. In small basements, the fooding po-tential is greater and, thereore, must be evaluatedmore careully. In all basements, drainage provisions
must include emergency power or pumping as wellas constantly monitored food alarms.
QUALITy CONTROL
Product Standards and ListingsFor quality assurance in cross-connection control,standard design and device testing have been part o
the manuacturing and sale o active control devices.In addition, the product is urnished with an identiy-ing label o the standard, and the model number isurnished in a list that is published by a recognizedagency.
Field Testing Frequent testing, such as upon installation, uponrepairs, and annually, provides additional qualityassurance.
Tests or a pressure-type vacuum breaker and a spill-resistant vacuum breaker include observing theopening o the air-inlet disc and veriying the check
valve(s). The air-inlet disc shall open at a gauge read-ing o not less than 1 psig (6.9 kPa) measured witha pressure gauge mounted on the vacuum breakerbody. To test the check valve, open the downstreampiping and mount a sight glass, open to atmosphereat its top, upstream o the check valve and purge it o air. Then open the supply valve and close it when 42inches (1,070 mm) o water are in the sight glass. Thewater level in the sight glass o a properly unctioning device will drop as water escapes past the check valve,but it will not drop below 28 inches (710 mm) aboveits connection point.
Tests or a reduced-pressure principle backfow
preventer include verication o each check valve,the downstream shuto valve, and operation o therelie valve. On a properly unctioning device withall air purged, upstream pressure is deliberatelyapplied downstream o the second check valve, andthe pressure dierential across it is held when thedownstream shuto is both open and closed. In thenext test, a pressure dierential is observed across theupstream check valve. A deect in the check valve seatwill prevent a dierential rom being held. In the lasttest, a bypass on the test instrument is opened slowlyto begin equalizing the pressure across this checkvalve, and the pressure dierential, or a properly
unctioning device, is noted as not being less than 3psi (20.7 kPa) when fow is rst observed rom therelie port.
Regulator Requirements Authorities having jurisdiction create and enorcelegally binding regulations regarding the applica-tions o cross-connection control, the standards andlistings or passive and active controls, and the typesand requencies o eld testing. The authority mayrequire evidence o eld testing by keeping an instal-
lation record o each testable device and all tests o the device.
Authorities having jurisdiction typically are wa-ter purveyors, plumbing regulation ocials, healthdepartment ocials, or various qualied agents incontract with government regulators. Regulationso cross-connection control are generally part o a plumbing code, but they may be published by a localhealth department or as the requirements o a mu-nicipal water service connection.
GLOSSARy
Absolute pressure The sum o the indicatedgauge pressure and the atmospheric local pressure.Hence, gauge pressure plus atmospheric pressureequals absolute pressure.
Air gap A separation between the ree-fowing discharge end o a water pipe or aucet and thefood level rim o a plumbing xture, tank, or anyother reservoir open to the atmosphere. Generally,to be acceptable, the vertical separation betweenthe discharge end o the pipe and the upper rimo the receptacle should be at least twice the di-ameter o the pipe, and the separation must be a minimum o 1 inch (25.4 mm).
Air gap, critical The air gap or impending re-verse fow under laboratory conditions with stillwater, with the water valve ully open and one-hal atmospheric pressure within the supply pipe.
Air gap, minimum required The critical air gapwith an additional amount. It is selected based onthe eective opening and the distance o the outletrom a nearby wall.
Approved Accepted by the authority having juris-diction as meeting an applicable specication stat-ed or cited in the regulations or as suitable or theproposed use.
Atmospheric pressure Equal to 14.7 psig (101kPa) at sea level.
Atmospheric vacuum breaker A device thatcontains a moving foat check and an internal airpassage. Air is allowed to enter the passage whengauge pressure is zero or less. The device should
not be installed with shuto valves downstream.The device typically is applied to protect againstlow hazard back-siphonage.
Auxiliary water supply Any water supply on oravailable to the premises other than the purvey-or’s approved public potable water supply.
Backow An unwanted fow reversal.
Backow preventer A device that prevents back-fow. The device should comply with one or more
recognized national standards, such as those o ASSE, AWWA, or the University o Southern Cali-ornia Foundation or Cross-Connection Controland Hydraulic Research, and with the require-ments o the local regulatory agency.
Back-pressure Backfow caused by pressure thatexceeds the incoming water supply pressure.
Back-siphonage A type o backfow that occurswhen the pressure in the water piping alls to lessthan the local atmospheric pressure.
Barometric loop A abricated piping arrangementrising at least 35 eet at its topmost point above thehighest xture it supplies. It is utilized in watersupply systems to protect against back-siphonage.
Containment A means o cross-connection con-trol that requires the installation o a back-pres-sure backfow preventer in the water service.
Contaminant A substance that impairs the quality
o the water to a degree that it creates a serioushealth hazard to the public, leading to poisoning or to the spread o disease.
Cross-connection A connection or potential con-nection that unintentionally joins two separatepiping systems, one containing potable water andthe other containing pollution or a contaminant.
Cross-connection control Active or passive con-trols that automatically prevent backfow. Suchcontrols include active and passive devices, stan-dardized designs, testing, labeling, and requentsite surveys and eld testing o mechanical de-
vices.Cross-connection control program A program
consisting o both containment and point-o-usexture or equipment isolation. The containmentprogram requires a control installed at the pointwhere water leaves the water purveyor’s systemand enters the consumer side o the water meter. The isolation program requires an ongoing sur-vey to ensure that there have been no alterations,changes, or additions to the system that may havecreated or recreated a hazardous condition. Isola-tion protects occupants as well as the public.
Double check valve assembly A device that con-sists o two independently acting spring-loadedcheck valves. They typically are supplied with testcocks and shuto valves on the inlet and outletto acilitate testing and maintenance. The deviceprotects against both back-pressure and back-si-phonage; however, it should be installed only orlow hazard applications.
Double check valve with intermediate atmo-
spheric vent A device having two spring-loaded
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check valves separated by an atmospheric ventchamber.
Dual check valve assembly An assembly o two in-dependently operating spring-loaded check valveswith tightly closing shuto valves on each side o the check valves, plus properly located test cocksor the testing o each check valve.
Eective opening The diameter or equivalent di-ameter o the least cross-sectional area o a aucetor similar point at a water discharge through anair gap. For aucets, it is usually the diameter o the aucet valve seat.
Fixture isolation A method o cross-connectioncontrol in which a backfow preventer is located tocorrect a cross-connection at a xture location orequipment location. Such isolation may be in addi-tion to containment.
Flood level rim The elevation at which wateroverfows rom its receptacle or basin.
Flushometer valve A mechanism energized bywater pressure that allows a measured volume o water or the purpose o fushing a xture.
Free water surace A water surace in which thepressure against it is equal to the local atmospher-ic pressure.
Hose bibb vacuum breaker A device that is per-manently attached to a hose bibb and acts as anatmospheric vacuum breaker.
Indirect waste pipe A drainpipe that fows intoa drain system via an air gap above a receptacle,
interceptor, vented trap, or vented and trappedxture.
Joint responsibility The responsibility sharedby the purveyor o water and the building owneror ensuring and maintaining the saety o the po-table water. The purveyor is responsible or pro-tecting their water supply rom hazards that origi-nate rom a building. The owner is responsible orensuring that the building’s system complies withthe plumbing code or, i no code exists, within rea-sonable industry standards. The owner is also re-sponsible or the ongoing testing and maintenance
o backfow devices that are required to protect thepotable water supply.
Negligent act An act that results rom a ailureto exercise reasonable care to prevent oreseeablebackfow incidents rom occurring or when anoth-er problem is created when correcting a potentialproblem. For example, i a closed system is createdby requiring a containment device without consid-ering how such a device will alter the hydrodynam-ics within the system, and this causes the rupture
o a vessel such as a water heater, this could beconsidered negligent.
Plumbing code A legal minimum requirement orthe sae installation, maintenance, and repair o a plumbing system, including the water supply sys-tem. Where no code exists, good plumbing practiceshould be applied by ollowing reasonable industry
standards. Pollutant A oreign substance that, i permitted
to get into the public water system, will degradethe water’s quality so as to constitute a moderatehazard or to impair the useulness or quality o the water to a degree that is not an actual hazardto public health but adversely and unreasonablyaects the water or domestic use.
Potable water Water that is urnished by the wa-ter purveyor with an implied warranty that it issae to drink. The public is allowed to make the as-sumption that it is sae to drink by the water pur-
veyor or regulatory agency having jurisdiction. Pressure-type vacuum breaker A device that
contains two independently operating valves, a spring-loaded check valve, and a spring-loadedair inlet valve. The device has test cocks or inlinetesting and two tightly sealing shuto valves to a-cilitate maintenance and testing. It is used only toprotect against back-siphonage.
Proessional An individual who, because o hisor her training and experience, is held to a higherstandard than an untrained person. The proes-sional is exposed to liability or their actions or
inaction. Reasonable care Working to standards that are
known and accepted by the industry and applying those standards in a practical way to prevent in- jury or harm via predictable and oreseeable cir-cumstances.
Reduced-pressure principle backow preven-ter A device consisting o two separate and inde-pendently acting spring-loaded check valves, with a dierential pressure-relie valve situated betweenthe check valves. Since water always fows roma zone o high pressure to a zone o low pressure,
this device is designed to maintain a higher pres-sure on the supply side o the backfow preventerthan is ound downstream o the rst check valve.This ensures the prevention o backfow. Thisdevice provides eective high hazard protectionagainst both back-pressure and back-siphonage.
Residential dual check An assembly o twospring-loaded, independently operating checkvalves without tightly closing shuto valves andtest cocks. Generally, it is employed immediately
downstream o a residential water meter to act asa containment device.
Special tool A tool peculiar to a specic deviceand necessary or the service and maintenance o that device.
Spill-resistant vacuum breaker A device con-taining one or two independently operated spring-
loaded check valves and an independently oper-ated spring-loaded air inlet valve mounted on a diaphragm that is located on the discharge side o the check(s). The device includes tightly closing shuto valves on each side o the check valves andproperly located test cocks or testing.
Survey A eld inspection within and around a building, by a qualied proessional, to identiy andreport cross-connections. Qualication o a proes-sional, whether an engineer or licensed plumber,
includes evidence o completion o an instructionalcourse in cross-connection surveying.
Vacuum A pressure less than the local atmospher-ic pressure.
Vacuum breaker A device that prevents back-siphonage by allowing sucient air to enter thewater system.
Water service entrance That point in the owner’swater system beyond the sanitary control o thewater district, generally considered to be the out-let end o the water meter and always beore anyunprotected branch.
Water supply system A system o service anddistribution piping, valves, and appurtenances tosupply water in a building and its vicinity.
Many types o possible pathogenic organ-isms can be ound in source water. Theseinclude dissolved gases, suspended mat-ter, undesirable minerals, pollutants, andorganic matter. These substances can beseparated into two general categories:
chemical and biological. They generallyrequire dierent methods o remediation.No single ltration or treatment processsatises all water-conditioning require-ments.
Surace water may contain more o these contaminants than groundwater,but groundwater, while likely to containless pathogens than surace water, maycontain dissolved minerals and have un-desirable tastes and odors. Water providedby public and private utilities is regarded
to be potable, or adequately pure orhuman consumption so long as it meetsthe standards o the U.S. EnvironmentalProtection Agency’s Sae Drinking Water Act and the local health ocial. However,such water still might contain some levelso pathogens and other undesirable com-ponents. Even i the water quality wouldnot cause a specic health threat to thegeneral public, it may not be suitable orbuildings such as hospitals and nursing homes that house populations that may bevulnerable. Moreover, it may not be pure
enough or certain industrial, medical, orscientic purposes.
Impure water damages piping andequipment by scoring, scaling, and cor-roding. Under certain conditions, watercontaining particles in suspension erodesthe piping and scores moving parts. Watercontaining dissolved acidic chemicals insucient quantities dissolves the metalsuraces with which it comes in contact.Pitted pipe and tank walls are common
WaterTreatment10
Table 10-1 Chemical Names, Common Names, and Formulas
Chemical Name Common Name FormulaBicarbonate (ion) — HCO3
–
Calcium (metal) — Ca2+
Calcium bicarbonate — Ca(HCO3)2
Calcium carbonate Chalk, limestone, marble CaCO3
Calcium hypochlorite Bleaching powder, chloride o lime Ca(ClO)2
Chlorine (gas) — Cl2Calcium sulate — CaSO4
Calcium sulate Plaster o paris CaSO4.½H2O
Calcium sulate Gypsum CaSO4.2H2O
Carbon Graphite C
Carbonate (ion) — CO32-
Carbon dioxide — CO2
Ferric oxide Burat ochre Fe2O3
Ferruous carbonate — FeCO3
Ferrous oxide — FeO
Hydrochloric acid Muriatic acid HCl
Hydrogen (ion) — H+
Hydrogen (gas) — H2
Hydrogen sulde — H2S
Iron (erric ion) — Fe3+
Iron (errous ion) — Fe2+
Magnesium bicarbonate — Mg(HCO3)2
Magnesium carbonate Magnesite MgCO3
Magnesium oxide Magnesia MgO
Magnesium sulate — MgSO4
Magnesium sulate Epsom salt MgSO4.7H2O
Manganese (metal) — Mn
Methane Marsh gas CH4
Nitrogen (gas) — N2
Oxygen (gas) — O2
Potassium (metal) — K
Potassium permanganate Permanganate o potash KMnO4
Sodium (metal) — Na
Sodium bicarbonate Baking soda, bicarbonate o soda NaHCO3
Sodium carbonate Soda ash Na2CO3
Sodium carbonate Sal soda Na2CO3.10H2O
Sodium chloride Salt NaCl
Sodium hydroxide Caustic soda, lye NaOH
Sodium sulate Glauber’s salt Na2SO4.10H2O
Sulate (ion) — SO42–
Suluric acid Oil o vitrol H2SO4
Water — H2O
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maniestations o the phenomenon called corrosion.Scaling occurs when calcium or magnesium com-pounds in the water (in a condition commonly knownas water hardness) become separated rom the waterand adhere to the piping and equipment suraces. Thisseparation is usually induced by a rise in temperaturebecause these minerals become less soluble as thetemperature increases. In addition to restricting fow,scaling damages heat-transer suraces by decreasing heat-exchange capabilities. The result o this condi-tion is the overheating o tubes, ollowed by ailuresand equipment damage.
Changing the chemical composition o the waterby means o mechanical devices (lters, soteners,demineralizers, deionizers, and reverse osmosis) iscalled external treatment because such treatment isoutside the equipment into which the water fows.Neutralizing the objectionable constituents by adding chemicals to the water as it enters the equipment isreerred to as internal treatment. Economic consid-
erations usually govern the choice between the twomethods. Sometimes it is necessary to apply morethan one technology. For instance, a water sotenermay be required to treat domestic water, but a reverseosmosis system may be needed beore the water is sentto HVAC or medical equipment. Another example isthe need or an iron prelter to remove large iron par-
ticles to protect a reverse osmosis membrane, whichwould be damaged by the iron particles.
For reerence, the chemical compounds commonlyound in water treatment technologies are tabulatedin Table 10-1. Table 10-2 identies solutions to listedimpurities and constituents ound in water.
BASIC WATER TyPESFollowing are the basic types o water. Keep in mindthat these terms oten have multiple meanings de-pending on the context or the discipline being used.
Raw WaterRaw water, or natural water, is ound in the environ-ment. Natural water is rainwater, groundwater, wellwater, surace water, or water in ponds, lakes, streams,etc. The composition o raw water varies. Oten rawwater contains signicant contaminants in dissolvedorm such as particles, ions, and organisms.
Potable Water
Potable water as dened in the International Plumb-ing Code is water ree rom impurities present inamounts sucient to cause disease or harmul physi-ological eects and conorming to the bacteriologicaland chemical quality requirements o the publichealth authority having jurisdiction. The U.S. EPA Sae Drinking Water Act denes the requirementsor water to be classied as potable. Potable water is
Table 10-2 Water Treatment—Impurities and Constituents, Possible Eects and Suggested Treatments
Possible Eectsa
Treatment
S c a l e
C o r r o s i o n
S l u d g e
F o a m i n
P r i m i n g
E m b r i t l e m e n t
N o n e ( I n e r t )
S e t t i n g , c o a g u l a t i o n ,
f l t r a t i o n , e v a p o r a t i o n
S e t t i n g , c o a g u l a t i o n ,
f l t r a t i o n , e v a p o r a t i o n , i o n
e x c h a n g e
S o t e n i n g b y c h e m i c a l s ,
i o n e x c h a n g e m a t e r i a l s ,
e v a p o r a t o r s
S o t e n i n g b y h e a t e r s ,
c h e m i c a l s , i o n e x c h a n g e
m a t e r i a l s , e v a p o r a t i o r s
N e u t r a l i z i n g , o l l o w e d b y
s o t e n i n g o r e v a p o r a t i o
n
E v a p o r a t i o n a n d
d e m i n e r a l i z a t i o n b y i o n
-
e x c h a n g e m a t e r i a l
D e - a e r a t i o n
C o a g u l a t i o n , f l t r a t i o n ,
e v a p o r a t i o n
C o n s t i t u e n t s
Suspended solids X X X X X
Silica — SiO2 X X
Calcium carbonate — CaCO3 X X
Calcium bicarbonate — Ca(HCO3)2 X X
Calcium Sulate — CaSO4 X X X
Calcium chloride — CaCl2 X X
Magnesium carbonate — MgCO3 X X
Magnesium bicarbonate — Mg(HCO3)2 X X
Magnesium chloride — MgCl2 X X X
Free acids — HCI, H2SO4 X X
Sodium chloride — NaCl X X
Sodium carbonate — Na2CO3 X X X X
Sodium bicarbonate — NaHCO3 X X X X
Carbonic acid — H2CO3 X X
Oxygen — O2 X X
Grease and oil X X X X X
Organic matter and sewage X X X X X
aThe possibility o the eects will increase proportionately to an increase in the water temperature.
oten ltered, chlorinated, and/or otherwise treatedto meet these standards or drinking water.
Process WastewaterCooling tower water is classied as a process wastewa-ter. Cooling tower water can scale and corrode. Whenlet untreated, cooling tower water can encouragebacteria growth and the subsequent health risks. As
with many process wastewaters, cooling tower wateris monitored and controlled or pH, algae, and totaldissolved solids.
Sot and Hard WaterSot water contains less than 60 parts per million(ppm) o dissolved calcium or magnesium.
Hard water contains dissolved minerals such ascalcium or magnesium in varying levels. As dened bythe U.S. Geological Survey, water containing 61–120ppm o dissolved minerals is considered moderatelyhard, and water containing 121–180 ppm o dissolvedminerals is considered hard. Water containing greater
than 181 ppm o dissolved minerals is considered veryhard. (Note: pH and temperature aect the behavioro dissolved minerals and should be considered in thedesign o systems containing hard water.)
Deionized WaterDeionized water has been stripped o mineral ionssuch as cations rom sodium, iron, calcium, and cop-per as well as anions o chloride and sulate. However,the deionization process does not remove viruses,bacteria, or other organic molecules. Deionized wateris specied in ranges o conductivity.
Distilled Water
Distilled water also meets the requirements o thelocal health department as well as the Sae Drinking Water Act. Distilling water involves removing theimpurities by boiling and collecting the condensing steam into a clean container. Distilled water has manyapplications, and distillation is commonly the processused to provide bottled water or consumption.
Puried WaterPuried water meets the requirements o the localhealth department as well as the Sae Drinking Water Act. It is mechanically processed or laboratory orpotable water use.
Pure water is a relative term used to describe wa-ter mostly ree rom particulate matter and dissolvedgases that may exist in the potable water supply. Purewater is generally required in pharmacies, centralsupply rooms, laboratories, and laboratory glassware-washing acilities. The two basic types o pure waterare high-purity water, which is ree rom minerals,dissolved gases, and most particulate matter, andbiopure water, which is ree rom particulate matter,minerals, bacteria, pyrogens, organic matter, and mostdissolved gases.
Water purity is most easily measured as specicresistance in ohm-centimeters (Ω-cm) or expressed asparts per million o ionized salt (NaCl). The theoreti-cal maximum specic resistance o pure water is 18.3megaohm-centimeters (MΩ-cm) at 25°C, a purity thatis nearly impossible to produce, store, and distribute.It is important to note that the specic resistance o water is indicative only o the mineral content andin no way indicates the level o bacterial, pyrogenic,or organic contamination.
The our basic methods o producing pure waterare distillation, demineralization, reverse osmosis,and ltration. Depending on the type o pure waterrequired, one or more o the methods will be needed.Under certain conditions, a combination o methodsmay be required. These processes are explained indetail later in the chapter.
WATER CONDITIONS ANDRECOMMENDED TREATMENTS
Turbidit Turbidity is caused by suspended insoluble matter,including coarse particles that settle rapidly in stand-ing water. Amounts range rom almost zero in mostgroundwater and some surace supplies to 60,000nephelometric turbidity units (NTU) in muddy,turbulent river water. Turbidity is objectionable orpractically all water uses. The standard maximumor drinking water is 1 NTU (accepted by industry),which indicates quite good quality. Turbidity exceed-ing 1 NTU can cause health concerns.
Generally, i turbidity can be seen easily, it will clog pipes, damage valve seats, and cloud drinking water.For non-process water, i turbidity cannot be seen, itshould present ew or no problems.
Turbidity that is caused by suspended solids in thewater may be removed rom such water by coagula-tion, sedimentation, and/or ltration. In extremecases, where a lter requires requent cleaning dueto excessive turbidity, it is recommended that engi-neers use coagulation and sedimentation upstream o the lter. Such a device can take the orm o a basinthrough which the water can fow at low velocities tolet the turbidity-causing particles settle naturally.
For applications where water demand is high and
space is limited, a mechanical device such as a clarierutilizing a chemical coagulant may be more practical.This device mixes the water with a coagulant (such aserric sulate) and slowly stirs the mixture in a largecircular container. The coarse particles drop to thebottom o the container and are collected in a sludgepit, while the ner particles coagulate and also dropto the bottom o the container. The claried waterthen leaves the device ready or use or urther treat-ment, which may include various levels o ltrationand disinection.
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The water provided by municipalities is usuallylow enough in turbidity and organic constituents topreclude the use o lters, clariers, or chlorinators. As always, however, there are exceptions to the rule. When dealing with health and saety or with theoperating eciency o machinery, engineers alwaysmust consider the occasional exception.
HardnessThe hardness o water is due mainly to the presenceo calcium and magnesium cations. These salts, inorder o their relative average abundance in water,are bicarbonates, sulates, chlorides, and nitrates.They all produce scale.
Calcium salts are about twice as soluble as mag-nesium salts in natural water supplies. The presenceo bicarbonates o calcium and magnesium producesa condition in the water called temporary hardnessbecause these salts can be easily transormed into a calcium or magnesium precipitate plus carbon dioxidegas. The noncarbonic salts (sulates, chlorides, and ni-
trates) constitute permanent hardness conditions.Hardness is most commonly treated by the sodium-
cycle ion exchange process, which exchanges thecalcium and magnesium salts or very soluble sodiumsalts. Only calcium and magnesium (hardness ions) inthe water are aected by the sotening process, whichproduces water that is non-scale orming. I the oxy-gen or carbon dioxide content o the water is relativelyhigh, the water may be considered aggressive.
The carbonic acid may be removed by aerationor degasication, and the remaining acids may beremoved by neutralization, such as by blending hy-drogen and sodium cation exchanger water. Anothermethod o neutralizing the acid in water is by adding alkali. The advantage o the alkali neutralizationmethod is that the cost o the sodium cation exchangesotener is eliminated. However, the engineer maywant to weigh the cost o chemicals against the costo the sodium ion exchange unit.
Aeration and Deaeration As hardness in water is objectionable because it ormsscale, high oxygen and carbon dioxide contents arealso objectionable because they corrode iron, zinc,brass, and several other metals.
Free carbon dioxide (CO2) can be ound in most
natural water supplies. Surace waters have the low-est concentration, although some rivers may containas much as 50 ppm. In groundwater, the CO2 contentvaries rom almost zero to concentrations so high thatthe carbon dioxide bubbles out when the pressure isreleased.
Carbon dioxide also orms when bicarbonates aredestroyed by acids, coagulants, or high temperatures.The presence o CO2 accelerates oxygen corrosion.
Carbon dioxide can be removed rom water by anaeration process. Aeration is simply a mechanicalprocess that mixes the air and the water intimately.It can be done with spray nozzles, cascade aerators,pressure aerators, or orced drat units. When thisaeration process is complete, the water is relativelyree o CO2 gas.
Water with a high oxygen content can be extremelycorrosive at elevated temperatures. Oxygen (O2) canbe removed rom the water by a deaeration process.Oxygen becomes less and less soluble as the watertemperature increases; thus, it is removed easily romthe water by bringing the water to its boiling point.
Pressure and vacuum deaerators are available. When it is necessary to heat the water, as in boilers,steam deaerators are used. Where the water is usedor cooling or other purposes where heating is notdesired, vacuum units may be employed.
With aerators and deaerators in tandem, waterree o CO2 and O2 is produced.
MineralsPure water is never ound in nature. Natural watercontains a series o dissolved inorganic solids, whichare largely mineral salts. These mineral salts are in-troduced into the natural water by a solvent action asthe water passes through (or across) the various lay-ers o the Earth. The types o mineral salts absorbedby natural water depend on the chemical contento the soil through which the natural water passesbeore it reaches the consumer. This may vary romarea to area. Well water diers rom river water, andriver water diers rom lake water. Two consumersseparated by a ew miles may have water supplies o very dissimilar characteristics. The concentrationsand types o minerals in the same water supply evenmay vary with the changing seasons.
Many industries can benet greatly by being sup-plied with high-grade pure water. These industriesare nding that they must treat their natural watersupplies in various ways to achieve this condition.The recommended type o water treatment dependson the chemical content o the water supply and therequirements o the particular industry. High-gradepure water typically results in greater economy o production and better products.
Beore the advent o the demineralization process,the only method used to remove mineral salts romnatural water was distillation. Demineralization has a practical advantage over distillation. The distillationprocess involves removing the natural water rom themineral salts (or the larger mass rom the smallermass). Demineralization is the reverse o distillation:it removes the mineral salts rom the natural water.This renders demineralization the more economicalmethod o puriying natural water in most cases.
Many industries today are turning to demineraliza-tion as the answer to their water problems.
The stringent quality standards or makeup wateror modern boilers are making demineralizers andreverse osmosis a must or these users. Modern plat-ing practices also require the high-quality water thatdemineralization produces.
CHLORINATIONChlorination o water is most commonly used todestroy organic (living) impurities. Organic impuri-ties all into two categories: pathogenic, which causedisease such as typhoid and cholera, and nonpatho-genic, which cause algae and slime that clog pipes andvalves, discolor water, and produce undesirable odors.These pathogenic and nonpathogenic organisms canbe controlled saely by chlorine with scienticallyengineered equipment to ensure constant and reliableapplications. An intelligent choice o the treatmentnecessary cannot be made until a laboratory analy-
sis o the water has determined its quality and thequantities o water to be used are known. I micro-organisms are present in objectionable amounts, a chlorination system is required.
Chlorination traditionally has been used or thedisinection o drinking water. However, the initialinvestment required to properly chlorinate a potablewater supply has, in many cases, restricted its use tothe large water consumer or to cities, which have theadequate nancial support and sucient manpowerto properly maintain the chlorination system. Anotherdrawback to the use o chlorine as a disinectant is
that the transportation and handling o a gas chlori-nation system are potentially dangerous. When thesaety procedures are ollowed, however, there are ewproblems than with either liquid or solid products.
Chemically, chlorine is the most reactive halo-gen and is known to combine with nitrogenous andorganic compounds to orm weak bactericidal com-pounds. Chlorine also combines with hydrocarbonsto orm potentially carcinogenic compounds (triha-lomethanes).
When chlorine is added to the water, hypochlorousand hydrochloric acids are ormed. Hydrochloric acidis neutralized by carbonates, which are naturallypresent in the water. The hypochlorous acid providesthe disinecting properties o chlorine solutions. Parto the hypochlorous acid is used quickly to kill (bythe oxidation process) the bacteria in the water. Theremaining acid keeps the water ree o bacteria untilit reaches the point o ultimate use.
This residual hypochlorous acid can take two
orms. It may combine with the ammonia present inalmost all waters to orm a residual, or chloramine,that takes a relatively long time to kill the bacteria,but it is very stable. Thus, when a water system islarge, it is sometimes desirable to keep a combinedresidual in the system to ensure saety rom thetreatment point to the arthest end use. I enoughchlorine is added to the system, more hypochlorousacid than can combine with the ammonia in the wa-ter is present. The excess hypochlorous acid is calledree residual. It is quite unstable, but it kills organicmatter very quickly. Though the time it takes or this
Figure 10-1 Automatic ChlorinatorsNotes: The system illustrated in (A) maintains a given residual where the fow is constant or where it changes only gradually. The direct residual control is most eective on
recirculated systems, such as condenser cooling water circuits and swimming pools. The desired residual is manually set at the analyzer. The fow is chlorinated until the residualreaches a set upper limit. The analyzer starts the chlorinator and keeps it operating until the residual again reaches the established upper limit. In (B) the compound loop controlsthe chlorinator output in accordance with two variables, the fow and the chlorine requirements. Two signals (one rom the residual analyzer and another rom the fow meter), whensimultaneously applied to the chlorinator, will maintain a desired residual regardless o the changes in the fow rates or the chlorine requirements.
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water to pass rom the treatment plantto the point o ultimate use is short,only ree residual can ensure that allbacteria will be killed. Maintaining anadequate ree residual in the water isthe only way to ensure that the wateris sae. Its presence proves that enoughchlorine was originally added to disin-ect the water. I no residual is present,it is possible that not all o the bacteria in the water were killed; thereore,more chlorine must be added.
Chlorine gas or hypochlorite solu-tions can be readily and accuratelyadded to the water at a constant rate orby proportional eeding devices oeredby a number o suppliers. Large mu-nicipal or industrial plants use chlorinegas because it is less expensive thanhypochlorite solutions and convenient.
Chlorinators, such as those shown in Figure 10-1,inject chlorine gas into the water system in quantitiesproportional to the water fow.
For the treatment o small water supplies, hy-pochlorite solutions sometimes are ound to be moreadvantageous. In eeding hypochlorite solutions,small proportioning chemical pumps, such as the oneillustrated in Figure 10-2, may be used to inject thehypochlorite solution directly into the pipelines orthe reservoir tanks.
CLARIFICATIONTurbid water has insoluble matter suspended in it.
As turbidity in the water increases, the water looksmore clouded, is less potable, and is more likely toclog pipes and valves.
Particles that are heavier than the fuid in whichthey are suspended tend to settle due to gravity ac-cording to Stokes’ law:
Equation 10-1
v=kd
2(S1 – S2)
z
where v = Settling velocity o the particle
k = Constant, usually 18.5d = Diameter o the particleS1 = Density o the particleS2 = Density o the fuidz = Viscosity o the fuid
From Equation 10-1, it can be seen that the set-tling velocity o the particle decreases as the density(S2) and the viscosity (z) o the fuid increase. Becausethe density and viscosity o the water are unctions o its temperature, it is readily understood why, or ex-ample, the rate o the particle settling in the water at
a temperature o 32°F is only 43 percent o its settling rate at 86°F. Thereore, the removal o water turbidityby subsidence is most ecient in the summer.
Where the water turbidity is high, ltration alonemay be impractical due to the excessive requirementsor backwash and media replacement. Subsidence isan acceptable method or the clarication o waterthat permits the settling o suspended matter.
Although water fow in a horizontal plane doesnot seriously aect the particle’s settling velocity, anupward fow in a vertical plane prevents particle set-tling. The design o settling basins should, thereore,keep such intererences to a minimum. For practicalpurposes, the limit or solids removal by subsidence
is particles o 0.01 millimeter or larger in diameter.Smaller particles have such a low rate o settling thatthe time required is greater than can be allowed.Figure 10-3 shows a typical design o a settling basin.Obviously, when a large volume o water is being handled, the settling basin occupies a large amounto space. Also, it can present saety and vandalismproblems i not properly protected.
Where space is limited, a more practical approachmight be the use o a mechanical clarier that employschemical coagulants (see Figure 10-4). Such devicescan be purchased as packaged units with simplein-and-out connections. Many chemical coagulants
currently are available, including aluminum sulate,sodium aluminate, ammonium alum, erric sulate,and erric chloride. Each coagulant works betterthan the others in certain types o water. However,no simple rules guide the engineer in the choice o the proper coagulant, coagulant dosages, or coagu-lant aids. Water analysis, water temperature, typeo clarication equipment, load conditions, and enduse o the treated water are some o the actors thatinfuence the selection o the proper coagulant. A ew
Backwashing As the suspended particles removed rom the wateraccumulate on the lter material, it should be cleanedto avoid any excessive pressure drops at the outletand the carryover o turbidity. The need or cleaning,particularly in pressure lters, is easily determinedthrough the use o pressure gauges, which indicate
the inlet and outlet pressures. Generally, when thepressure drop exceeds 5 pounds per square inch (psi),backwashing is in order.
In this process (see Figure 10-7), the ltered wateris passed upward through the lter at a relativelyhigh fow rate o 10–20 gpm per square oot. The bedshould expand at least 50 percent, as illustrated inFigure 10-8. This process keeps the grains o the ltermedium close enough to rub each other clean, but itdoes not lit them so high that they are lost down thedrain. Backwashing can be automated by employing pressure dierential switches (electronically, hydrau-lically, or pneumatically) to activate the diaphragm
or control valves that initiate the backwash cycle ata given pressure drop.
Some problems connected with lter beds are il-lustrated in Figures 10-9 through 10-11. Extremelyturbid water or insucient backwashing causes ac-cumulations called mudballs (see Figure 10-9). I notremoved, mudballs result in uneven ltration andshort lter runs and encourage ssures. When thelter bed surace becomes clogged with these depositsand simple backwashing does not remove them, thelter may need to be taken out o service and drainedand the deposits removed by hand skimming, or thelter must be rebedded.
When ssures occur in the sand bed (see Figure10-10), the cause usually can be traced to one or a combination o three items: the inlet water is notbeing distributed evenly or is entering at too higha velocity; backwash water is not being distributedevenly or is entering at too high a velocity; or mudballshave stopped the passage o water through certainareas and raised velocities in others. The lter mustbe drained and opened and the lter medium cleanedand reoriented.
Gravel upheaval (see Figure 10-11) usually iscaused by violent backwash cycles during which wateris distributed unevenly or velocities are too high. I not corrected, ssures are encouraged, or worse, ltermedia is allowed to pass into the distribution systemwhere it may seriously damage valves and equipmentas well as appear in potable water.
Diatomaceous Earth FiltersThe use o diatomaceous earth as a water-ltering medium achieved prominence during the 1940s asa result o the need or a compact, lightweight, andportable ltering apparatus.
The water enters the lter vessel and is drawnthrough a porous supporting base that has beencoated with diatomaceous earth. Filter cloths, porousstone tubes, wire screens, wire wound tubes, andporous paper lter pads are some o the support basematerials most commonly used today. Figure 10-12illustrates a typical lea design lter.
Figure 10-9 Mudballs
Figure 10-11 Gravel Upheaval
Figure 10-10 Fissures
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Diatomaceous earth, or silica (SiO4), is producedrom mineral deposits ormed by diatoms, or ossilized
plants that are similar to algae. Deposits o diatomshave been ound as much as 1,400 eet in thickness.Commercial lter aids are produced rom the crudematerial by a milling process that separates the dia-toms rom one another. The nished product is in theorm o a ne powder.
When diatomaceous earth orms a cake on thesupport base, a lter o approximately 10 percentsolids and 90 percent voids is achieved. The openingsin this lter are so small that even most bacteria arestrained out o the water. However, the openings inthe support base are not small enough initially toprevent the passage o individual diatomite particles.
Some o these diatomite particles pass through thesupport base during the precoating operation. How-ever, once the ormation o the coating is complete,the interlocked mass o diatomite particles preventsany urther passage o the particles.
Commercial diatomaceous earth is manuacturedin a wide range o grades with diering ltration ratesand dierences in the clarity o the ltered water. Theadvantages o diatomaceous earth lters, as comparedto pressure sand lters, are a considerable savingsin the weight and required space, a higher degree o ltered water clarity and purity in the outgoing water,and no required coagulant use. One disadvantage isthat only waters o relatively low turbidity can beused eciently. It is not advisable to use these lterswhere incoming water turbidities exceed 100 ppm,since low-eciency, short lter runs will result. Otherdisadvantages are that the initial and operating costsusually ar exceed those o conventional sand ltersand that the incidence o high pressure drop acrossthe unit (as much as 25 to 50 psi) and intermittentfows cause the lter cake to detach rom the supportbase.
DEMINERALIZATIONSometimes called deionization, demineralizationproduces high-purity water that is ree rom miner-als, most particulate matter, and dissolved gases.Depending on the equipment, the treated water canhave a specic resistance o 50,000Ω to nearly 18 MΩ.However, it can be contaminated with bacteria, pyro-
gens, and organics, as these can be produced insidethe demineralizer itsel. Demineralized water can beused in most laboratories, in laboratory glassware-washing acilities as a nal rinse, and as pretreatmentor still eed water.
The typical demineralizer apparatus consists o either a two-bed unit with a resistivity range o 50,000Ω to 1 MΩ or a mixed-bed unit with a resistivity rangeo 1 MΩ to nearly 18 MΩ. The columns are o an inertmaterial lled with a synthetic resin that removesthe minerals by an ionization process. Since the unitruns on pressure, a storage tank is not required orrecommended, as bacteria may grow in it. A demin-
eralizer must be chemically regenerated periodically,during which time no pure water is being produced.I a continuous supply o water is needed, a backupunit should be considered, as the regeneration processtakes several hours. An atmospheric, chemical-resis-tant drain is needed, and higher-pressure water isrequired or backwash during regeneration.
I deionized water is required in a small amountand the acility does not want to handle the regener-ant chemicals and/or the regenerant wastewater, itmay contract with a deionized water service providerto supply the acility with the quality and quantity o deionized water required. The service deionized wa-
ter (SDI) provider urnishes the acility with servicedeionized water exchange tanks to supply the quality,fow rate, and quantity o water required. When thetanks are exhausted, the SDI provider urnishes a newset o tanks. The SDI provider takes the exhaustedtanks back to its acility or regeneration.
Ion Echange According to chemical theory, compounds such asmineral salts, acids, and bases break up into ions whenthey are dissolved in water. Ions are simply atoms,singly or in groups, that carry an electric charge. Theyare o two types: cation, which is positively charged,
and anion, which is negatively charged. For example,when dissolved in water, sodium chloride (NaCl)splits into the cation Na
+and the anion Cl
–. Similarly,
calcium sulate (CaSO4) in solution is present as thecation Ca
2+and the anion SO4
2–. All mineral salts in
water are in their ionic orm.Synthetic thermosetting plastic materials, known
as ion exchange resins, have been developed toremove these objectionable ions rom the solutionand to produce very high-purity water. These resins
are small beads (or granules) usually o phenolic, orpolystyrene, plastics. They are insoluble in water,and their basic nature is not changed by the processo ion exchange. These beads (or granules) are veryporous, and they have readily available ion exchangegroups on all internal and external suraces. Theelectrochemical action o these ion exchange groupsdraws one type o ion out o the solution and puts a dierent one in its place. These resins are o threetypes: cation exchanger, which exchanges one positiveion or another, anion exchanger, which exchangesone negative ion or another, and acid absorber, whichabsorbs complete acid groups on its surace.
A demineralizer consists o the required numbero cation tanks and anion tanks (or, in the case o monobeds, combined tanks) with all o the necessaryvalves, pipes, and ttings required to perorm thesteps o the demineralization process or the cationresin, as well as an acid dilution tank material orthe cation resin and an acid dilution tank, as suluric
acid is too concentrated to be used directly. I hydro-chloric acid is to be used as a cation regenerant, thismix tank is unnecessary since the acid is drawn indirectly rom the storage vessel. A mixing tank orsoda ash or caustic soda, used in anion regeneration,is always provided.
Since calcium and magnesium in the raw regener-ant water precipitate the hydroxide (or carbonate)salts in the anion bed, the anion resin must be re-generated with hardness-ree water. This conditionmay be accomplished either with a water sotener(which may be provided or this purpose) or by use o the efuent water rom the cation unit to regenerate
the anion resin. The use o a sotener decreases theregeneration time considerably, as both units may beregenerated simultaneously rather than separately.
Provided with each unit is a straight reading vol-ume meter, which indicates gallons per run as well asthe total volume put through the unit. Also providedwith each unit is a conductivity and resistivity indi-cator used to check the purity o the efuent waterat all times. This instrument is essentially a meteror measuring the electrical resistance o the treatedwater leaving the unit. It consists o two principalparts: the conductivity cell, which is situated in theefuent line, and the instrument box to which the
conductivity cell is connected.The conductivity cell contains two electrodes
across which an electric potential is applied. Whenthese poles are immersed in the treated water, theresistance to the fow o the electricity between thetwo poles (which depends on the dissolved solidscontent o the water) is measured by a circuit in theinstrument. The purity o the water may be checkedby reading the meter. When the purity o the wateris within the specic limits, the green light glows.
When the water becomes too impure to use, the redlight glows. In addition, a bell may be added that ringswhen the red light glows to provide an audible as wellas a visible report that the unit needs regeneration.This contact also can close an efuent valve, shitoperation to another unit i desired, or put the unitinto regeneration.
ControlsSeveral types o controls are currently availableto carry out the various steps o regeneration andreturn to service. The two most common arrange-ments ollow:
• TypeA:Thisconsistsofcompletelyautomatic,individual air- or hydraulic-operated diaphragmvalves controlled by a sequence timer, andregeneration is initiated via a conductivitymeter. This arrangement provides maximumfexibility in varying amounts and concentrationso regenerants, length o rinsing, and all othersteps o the operating procedure. The diaphragm
valves used are tight seating, oering maximumprotection against leakage and thus contaminationwith minimal maintenance.
• TypeB:Thisconsists ofmanually operatedindividual valves. This system combines maximumlexibility and minimal maintenance with aneconomical rst cost. It typically is used on largerinstallations.
Figure 10-13 Ion ExchangeVessel—Internal Arrangement
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Internal Arrangements
The internal arrangements o the vessels are similaror all types o controls. The internal arrangementused on medium to large units is shown in Figure10-13. Smaller units have simpler arrangementssince the distribution problems are less complex. Thepositive and thorough distribution o regenerants,rinse, and wash waters to achieve maximum eciencyprovides economy and reliability.
Ion Exchange Water Soteners
A typical hydrogen-sodium ion exchange plant isshown in Figure 10-14. This process combines sodium-cycle ion exchange sotening with hydrogen-cycle
cation exchange.The sodium ion exchange process is exactly the
same as a standard ion exchange water sotener.The hardness (calcium and magnesium) is replacedwith sodium (non-scaling). The alkalinity (bicarbon-ates) and other anions remain as high as in the rawwater.
The cation exchanger is exactly the same as theone used with demineralizers; thereore, its efuentcontains carbonic acid, suluric acid, and hydrochloricacid. Sodium ion exchange units are operated in par-
allel, and their efuentsare combined. Mineralacids in the hydrogenion exchange eluentneutralize the bicarbon-ates in the sodium ionexchange eluent. Theproportions o the twoprocesses are varied toproduce a blended efu-ent having the desiredalkalinity. The carbondioxide is removed by a degasier. The efuent issot, low in solids, and asalkaline as desired.
In the sodium ionexchange sotener plusacid addition process (seeFigure 10-15), the acid
directly neutralizes thebicarbonate’s alkalinityto produce a sot, low-al-kaline water. The carbondioxide produced is re-moved by a degasier. Thechie disadvantages o thisprocess are that the totaldissolved solids are notreduced and control o theprocess is dicult.
In a sodium ion ex-change sotener plus
chloride dealkalizer process, water passes irstthrough the sodium ion exchange sotener, whichremoves the hardness, and then through a chloridedealkalizer, which is an ion exchanger that operatesin the chloride cycle. The bicarbonates and sulatesare replaced by chlorides. The resin is regeneratedwith sodium chloride (common salt). The equipmentis the same as that or sodium ion soteners. Thisprocess produces sot, low-alkaline water. Total dis-solved solids are not reduced, but the chloride levelis increased. The chie advantages o this processare the elimination o acid and the extreme simplic-ity o the operation. No blending or proportioning is
required.In some cases, the anion resin can be regenerated
with salt and caustic soda to improve capacity andreduce the leakage o carbon dioxide.
WATER SOFTENING Water sotening is required or practically all commer-cial and industrial building water usage. Generallyspeaking, almost any building supplied with waterhaving a hardness o 3.5 grains per gallon (gpg) or
Figure 10-15 Sodium Cycle Sotener Plus Acid Addition
more should have a water sotener. This is true eveni the only usage o the water other than or domesticpurposes is or heating because the principal threatto water heater lie and perormance is hard water. Approximately 85 percent o the water supplies inthe United States have hardness values above the3.5 gpg level.
However, it is not good practice to speciy a watersotener to supply the heating equipment only anddisregard the sotening needs or the balance o thecold water usage in the building. A typical exampleo this condition is a college dormitory. Many xturesand appliances in a dormitory in addition to the hotwater heater require sot water, including the piping itsel, fush valve toilets, shower stalls, basins, andlaundry rooms. Many xtures and appliances that usea blend o hot and cold water experience scale buildupand staining, even when the hot water is sotened.
One o the most common reasons or installing water sotening equipment is to prevent hardness
scale buildup in piping systems, valves, and otherplumbing xtures. Scale builds up continually and ata aster rate as the temperature increases. The graphin Figure 10-16 illustrates the degree o scale depositand the rate increase as thetemperature o the water iselevated on water having a hardness o 10 gpg. For watero 20-gpg hardness, scale de-posit values can be multipliedby two. Although the rate o scale deposit is higher as thetemperature increases, sig-
nicant scale buildup occurswith cold water. Thus, thecold water scale, while taking a longer period to build up, isnevertheless signicant.
Water SotenerSelectionThe actors the designershould consider in sizing water soteners include theollowing: low rate, sot-ener capacity, requency o
regeneration, single ver-sus multiple systems, spacerequirements, cost, and op-erating eciency.
Flow Rate
Ater determining the totallow rate requirements orthe building, including allequipment, the engineer canconsider the size o the water
sotener. The unit selected should not restrict thewater fow rate beyond the pressure loss that thebuilding can withstand, based on the pressures avail-able at the source and the minimum pressure neededthroughout the entire system. A water sotener thatmeets both fow rate and pressure drop requirementsshould be selected.
The sotener system also should be capable o providing the design fow rates within the desiredpressure drop. This means not only that the pipeand valve sizes must be adequate, but also that thewater sotener tank and its mineral must be capable o handling the fows while providing the sot water. Thewater sotener design should be based on hydraulicand chemical criteria.
Good design practices or general use dictate thatservice fow rates through the water sotener be ap-proximately 1–5 gpm per cubic oot with mineral beddepths o 30 inches or more. Based on these acceptedpractices, the water sotener is generally able to
handle peak fows or short periods.Standard sotener units are designed or a pressure
dierential o approximately 15 psi, the most com-mon dierential acceptable or building design. Thus,
Figure 10-16 Lime Deposited rom Water o 10 Grains Hardness as a Function oWater Use and Temperature
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Chapter 10 — Water Treatment 187
sotening mineral is used. This amount is based on therecommended depth o the mineral (normally 30–36inches) and the proper ree-board space above themineral (the space required or the proper expansiono the mineral during backwashing). Thus, rom theunit initially selected, a standard capacity is known.
The capacity o a water sotener is its total hard-ness exchange ability, generally expressed in termso grains exchange. The normal capacity o availablesotening mineral (resins) is 20,000–30,000 grains oreach cubic oot o mineral. Thus, the total capacity
or the water sotener is obtained by multiplying thisvalue by the number o cubic eet o mineral in thewater sotener. The hardness o the raw water mustbe ascertained. By dividing the water hardness (grainsper gallon), expressed as CaCO3 equivalent, into thetotal sotener capacity (grains), the designer can de-termine the number o gallons o sot water that theunit will produce beore requiring regeneration.
Knowing (or estimating) the total gallons o waterused per day indicates the requency o regeneration.Most oten, it is best to have a slight reserve capacityto accommodate any small increases in water usage.
Sotening is not really a orm o water puricationsince the unction o a sotener is to remove only thehardness (calcium and magnesium) rom the waterand substitute, by ion exchange, the soter element o sodium. Soteners requently are used in hard waterareas as pretreatment to distillation to simpliy main-tenance. They are oten necessary as a pretreatmentto deionizers and reverse osmosis, depending on the
analysis o the eed water and the type o deionizer.The ollowing steps should be taken prior to select-
ing a water sotener.
1. Perorm a water analysis by analyzing the waterwith a portable test kit, obtaining a water analysisrom the local authorities, or sending a watersample to a qualied water testing lab.
2. Determine the water consumption using sizing charts or consumption gures rom water bills orby taking water meter readings.
3. Determine continuous and peak fow rates using the xture count fow rate estimating guide to
determine the required fow rate, obtaining fowrate gures or the equipment to be serviced, or bytaking water meter readings during peak periodso water consumption.
4. Determine the water pressure by installing a pressure gauge. I there is a well supply, check thepump’s start and stop settings.
5. Determine the capacity: gallons per day × grainsper gallon = grains per day.
6. Select the smallest unit that can handle themaximum capacity required between regenerationswith a low salt dosage. Avoid sizing equipment with
the high dosage unless there is reason to do so,such as a high-pressure boiler.
Example 10-2
For example, the capacity required is 300,000grains. What size unit should be selected?
A 300,000-grain unit will produce this capacitywhen regenerated with 150 pounds o salt.
A 450,000-grain unit will produce this capacitywhen regenerated with 60 pounds o salt.
Table 10-3 Water Consumption Guide
ApartmentsOne-bedroom units 1.75 people/apartment
Two-bedroom units Three people/apartment
Three-bedroom units Five people/apartment
Full line 60 gpd/person
Hot only 25 gpd/person
One bath 1.5 gpm/apartment
Two baths 2.5 gpm/apartment
Barber shops 75 gpm/chair
Beauty shops 300 gpd/person
Bowling alleys 75 gpd/lane
Factories (not including process waters)With showers 35 gpd/person/shit
Without showers 25 gpd/person/shit
Farm animals
Dairy cow 35 gpd
Bee cow 12 gpd
Hog 4 gpd
Horse 12 gpd
Sheep 2 gpd
Chickens 10 gpd/100 birdsTurkeys 18 gpd/100 birds
Hospitals 225 gpd/bed (Estimate air-conditioning and laundryseparately.)
Motels (Estimate the restaurant, bar, air-conditioning,swimming pool, and laundry acilities separately, and add these
to the room gallonage or total consumption.)Full line 100 gpd/room
Hot only 40 gpd/room
Mobile home courts Estimate 3.75 people/home,and estimate 60 gpd/person.(Outside water or sprinkling,washing cars, etc., should bebypassed.)
RestaurantsTotal (ull line) 8 gal/meal
Food preparation (hot and cold) 3 gal/meal
Food preparation (hot only) 1.5 gal/meal
Cocktail bar 2 gal/person
Rest homes 175 gpd/bed (Estimate laundryseparately.)
SchoolsFull line 20 gpd/student
Hot only 8 gpd/student
Trailer parks 100 gpd/space
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Chapter 10 — Water Treatment 189
Salt Reccling SstemsTo increase the eciency o the water sotener interms o salt consumption and water usage during the regeneration cycle, one option to consider is theuse o a salt recycling system. It is essentially a hard-ware modication available or both new and existing water soteners that immediately reduces the amount
o salt needed to regenerate a sotener by 25 percent,without any loss o resin capacity or treated waterquality. It works best with water sotener equipmentthat utilizes a nested diaphragm valve congurationas seen in Figure 10-19. It is not recommended orwater soteners that utilize a top-mounted, multi-portmotorized control valve.
The salt recycling process adds a brine reclaimstep to the regeneration process ater the brine drawhas occurred. During brine reclaim, used dilute brinefow is diverted rom the drain and routed back to thebrinemaker tank where it is stored and resaturatedor later use, thereby saving both salt and water. The
salt savings occur because the make-up water to thebrinemaker contains approximately 25 percent o the salt needed or the next regeneration. Thereore,only 75 percent o “new” salt is dissolved or thenext regeneration. Water savings occur because therecycled brine is not discharged to drain but is usedto make up the brine solution or the next regenera-tion. The eective salt dosage or the water soteneris unchanged; thereore, the 25 percent salt savingscan be realized in sotener systems that use bothmaximum and minimum salt dosages.
The hardware package consists o a diverter valve(see Figure 10-19) in the drain line that routes the
recycled brine to the brinemaker tank and a modi-
ed control system that incorporates the extra brinereclaim step.
Salt Storage Options A ew options or salt storage are available. Salt blocksand bags o salt, or beads, may not be suitable or largesystems in which dozens or even hundreds o poundsmay be needed on a daily basis. These systems may
require bulk salt storage and delivery systems, con-sisting o an aboveground storage tank that is loadeddirectly rom salt trucks. The salt then is conveyedthrough piping to the brine tank. This system maybe wet or dry.
Underground storage tanks almost always requirethe salt to be premixed with water in the storagetank. It then can be piped to the brine tank as a brinesolution and mixed down to the desired concentra-tion levels.
DISTILLATIONDistillation produces biopure water that is ree rom
particulate matter, minerals, organics, bacteria, py-rogens, and most dissolved gases and has a minimumspecic resistance o 300,000 Ω-cm. Until recentadvances in the industry, the use o distilled waterwas limited to hospitals and some pharmaceuticalapplications. Now, in hospitals, schools with sciencedepartments, laboratories, and industries other thanpharmaceuticals, distilled water is vital to manyoperational unctions. When used in healthcare acili-ties, biopure water is needed in the pharmacy, centralsupply room, and any other area where patient con-tact may occur. Biopure water also may be desired inspecic laboratories at the owner’s request and as a nal rinse in a laboratory glassware washer.
date
Project name
Location
Type o acility
What is water being used or?
Water analysis: (express in gr./ gal. or ppm as CaCo3)
Total hardness
Sodium
Total dissolved solids
Sodium to hardness ratioIron
Flow rate (gpm) peak Normal Average
Allowable pressure loss System inlet pressure
Operating hours/day Gallons/day
Inuent header pipe size
Electrical characteristics
Type o operation
Special requirement or options (ASME, lining, accessories)
Space limitation L W H
Figure 10-17 Water Sotener Survey Data
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Chapter 10 — Water Treatment 191
The Distillation ProcessThe typical water distillation system consists o anevaporator section, internal bafe system, water-cooled condenser, and storage tank. The heat sources,in order o preerence based on economy and main-tenance, are steam, electricity, and gas. (Gas is not a good choice.) The still may be operated manually orautomatically. The distilled water may be distributedrom the tank by gravity or by a pump. A drain isrequired. On stills larger than 50 gallons per hour(gph), a cooling tower should be considered or thecondenser water.
The principles o distillation are quite simple. Thewater passes through two phase changes, rom liquidto gas and back to liquid (see Figure 10-20). All thesubstances that are not volatile remain behind in theboiler and are removed either continuously or inter-mittently. Water droplets are prevented rom coming up with the water vapor by proper design o the still,which takes into account the linear velocity, and byuse o an appropriate system o bafes.
Although distillation removes nonvolatile sub-stances suciently, the volatile substances in the eedwater cause more problems. These, mainly carbondioxide, which are already present in the eed water
or are ormed by the decomposition o bicarbonates,can be removed by keeping the distillate at a relativelyhigh temperature because carbon dioxide is less sol-uble at high temperatures. Ammonia (NH3) is muchmore soluble in water than carbon dioxide, and itstendency to redissolve is much higher as well. More-over, the ionization constant o ammonium hydroxide(NH4OH) is much greater than that o carbonic acid(H2CO3), which means that equal amounts o ammo-nia and carbon dioxide show dierent conductivities
(that or ammonia is much higher than thator carbon dioxide).
The purity o the distillate is usuallymeasured with a conductivity meter, and a resistivity o 1 MΩ—or a conductivity o 1microsiemen (µS)—is equivalent to approxi-mately 0.5 ppm o sodium chloride. Mosto the conductivity is accounted or by thepresence o carbon dioxide (and ammonia)and not by dissolved solids. The questionarises: Which is preerred, 1 MΩ resistivityor a maximum concentration o dissolvedsolids? It is quite possible that a distillatewith a resistivity o 500,000 Ω (a conduc-tivity o 2 µS) contains ewer dissolvedsolids than a distillate with a resistivity o 1,000,000 Ω (1 µS).
A problem in distillation can be scaleormation. Scale orms either by the de-composition o soluble products o insoluble
substances or because the solubility limito a substance is reached during the concentration.Solutions to this problem include the ollowing:
• Softeningofthefeedwater,thatis,removingallcalcium and magnesium ions. However, this does
Figure 10-19 Water Sotener with Salt Recycling System
Figure 10-20 Distillation
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not remove the silica, which then may orm a hard,dense scale that is very dicult to remove.
• Removalofthealkalinity(bicarbonates).Whenoriginally present, sulate and silica still orm a harder scale than a carbonate scale.
• Removalofallormostofthedissolvedsubstances.This can be done by demineralization with ion
exchangers or by reverse osmosis.It may sound oolish to remove the impurities rom
the water beore distilling the water. However, keep inmind that distillation is the only process that produceswater guaranteed to be ree o bacteria, viruses, andpyrogens. It may pay to have pretreatment beore a still to cut down on maintenance (descaling), down-time, and energy consumption and to have bettereciency, capacity, and quality. Pretreatment mayrequire a higher initial investment, but the supplierwho has the experience and technology in all watertreatment systems can give unbiased advice—that is,
to oer a systems approach instead o pushing onlyone method.Distilled water is oten called hungry water. This
reers to the act that distilled water absorbs in solu-tion much o the matter, in any phase, with which itcomes in contact. It becomes important, thereore, toselect a practical material or the production, storage,and distribution o distilled water. Years o experienceand research have shown that pure tin is the mostpractical material or the production, storage, anddistribution o distilled water due to its inert charac-teristic. It is the least soluble. (Other materials, suchas gold, silver, and platinum, have equal or superior
qualities but are not considered or obvious reasons.) A secondary but almost equal advantage o tin is itsrelatively low porosity, which virtually eliminates thepossibility o particle entrapment and growth in pores.In a good water still, thereore, all o the suraces thatcome in contact with the pure vapors and distillateshould be heavily coated with pure tin. Likewise, thestorage tank should be heavily coated or lined withpure tin on all interior suraces. Tinned stills andstorage tanks are not signicantly more expensivethan glass ones in all but the smallest sizes.
Titanium is being strongly considered as a prom-ising material or distillation equipment. Although
some stills have been made o titanium, it is moreexpensive than tin and has not yet been proven su-perior.
Distillation Equipment Applications andSelectionIn the construction o buildings requiring distilledwater, the selection o the appropriate equipment isusually the responsibility o the plumbing engineer.Beore the proper equipment can be selected, the ol-lowing actors should be considered:
• Thequantityofdistilledwaterthatwillberequiredper day (or per week) by each department
• Thepurityrequirementsofeachdepartment
• Thespaceavailablefortheequipment
• Theavailabilityofpower
Regarding the rst two items, the engineer should
obtain the anticipated quantity and purity require-ments rom all department heads who require distilledwater.
In this section, it is assumed that less than 1,000gallons per day (gpd) o distilled water is required. Thesingle-eect still operated at atmospheric pressure isgenerally the most practical and widely used. For theconsumption o larger quantities o distilled water,consideration may be given to other types o stills(such as the multiple-eect and vapor-compressionstills). These stills have advantages and disadvantagesthat should be studied when conditions warrant.
Centralized vs. Decentralized Systems
The choice between central distillation equipmentand individual stills in each department is a mattero economics. In the case o central distillation, theactors to consider are the distances involved in piping the water to the various departments—hence, the costo the appropriate piping and, possibly, the pumping requirements. The original and maintenance costs o multiple individual stills can be high. In the majorityo installations, the use o one or two large, centrallylocated stills with piped distribution systems hasproven more practical and economical than a numbero small, individual stills.
Stills While a well-designed still can produce pure distilledwater or most purposes, the distilled water to beused by a hospital or intravenous injections or by a pharmaceutical company manuacturing a productor intravenous injections must be ree o pyrogens(large organic molecules that cause individuals togo into shock). For such uses, a still with specialbafes to produce pyrogen-ree distilled water mustbe specied.
Other types o stills are designed to meet variouspurity requirements. The recommendations o themanuacturer should be obtained to speciy the propertype o still or a specic application.
Due to the amount o heat required in the opera-tion to change the water into steam, it is impracticalto make large-capacity, electrically heated and gas-heated stills. All stills larger than 10 gph, thereore,should be heated by steam. For each gallon per houro a still’s rated capacity, steam-heated stills requireapproximately 1/3 boiler horsepower, electricallyheated stills need 2,600 watts, and gas-red stills need14,000 British thermal units per hour.
The still must be well designed and bafed to eectan ecient vapor separation without the possibilityo carryover o the contaminants and to ensure opti-mum removal o the volatile impurities. It is equallyimportant that the materials used in construction o the still, storage reservoir, and all components coming in contact with the distilled water do not react withthe distilled water.
Distribution Systems
Cost can be a signicant actor in the distributionsystem, particularly i it is extensive. The distribu-tion system can consist o 316 stainless steel, CPVCSchedule 80, and polyvinylidene fuoride (PVDF). Thettings should be o the same material.
The purity requirements should be consideredand a careul investigation made o the propertiesand characteristics o the materials being considered.Many plastics have a relatively porous surace, whichcan harbor organic and inorganic contaminants. Withsome metals, at least trace quantities may be imparted
to the distilled water.
Storage Reservoir
The storage reservoir used or distilled water should bemade o a material that is suited or the application andsealed with a tight cover so that contaminants rom theatmosphere cannot enter the system. As the distilledwater is withdrawn rom the storage tank, air mustenter the system to replace it. To prevent airbornecontamination, an ecient lter should be installed onthe storage tank so that all air entering the tank maybe ltered ree o dust, mist, bacteria, and submicronparticulate matter, as well as carbon dioxide.
Figure 10-21 illustrates a typical air lter. Thisair lter (both hydrophilic and hydrophobic) removesgases and airborne particles down to 0.2 µ. Puriedair leaves at the bottom. The rectangular chamberis a replaceable lter cartridge. A and B are intakebreather valves, and C is an exhaust valve.
As a urther saeguard against any possiblecontamination o the distilled water by biologicalimpurities, an ultraviolet light can be attached tothe inside o the cover (not very eective) and/orimmersed in the distilled water (also not very eec-tive) or in the fow stream to eectively maintain itssterility. Ultraviolet lighting should be given strong
consideration or hospital and pharmaceutical instal-lations, as well as or any other applications wheresterility is important.
Example 10-3
Assume that a total o 400 gpd o distilled water isrequired by all departments. A ully automatic stilland storage tank combination should be used in thisapplication. Fully automatic controls stop the stillwhen the storage tank is ull and start the still whenthe level in the storage tank reaches a predetermined
low level. In addition, the evaporator is fushed outeach time it stops. A 30-gph still (with a 300-gallonstorage tank) produces more than the desired 400gpd. Because the still operates on a 24-hour basis, asthe storage tank calls or distilled water (even i nodistilled water is used during the night), 300 gallonsare on hand to start each day. As water is withdrawnrom the storage tank, the still starts and replenishesthe storage tank at a rate o 30 gph.
In this example, the storage tank volume, in gal-lons, is 10 times the rated capacity o the still. Thisis a good rule o thumb or a ully automatic still andstorage tank combination. A closer study o the pat-tern o the anticipated demands may reveal unusualpatterns, which may justiy a larger ratio.
Purity Monitor
One requently used accessory is the automatic puritymonitor. This device tests the purity o the distilledwater coming rom the still with a temperature-compensated conductivity cell. This cell is wired to
a resistivity meter that is set at a predeterminedstandard o distilled water commensurate with thecapability o the still. I or any reason the purity o the distilled water is below the set standard, the sub-standard water does not enter the storage tank andis automatically diverted to waste. At the same time,a signal alerts personnel that the still is producing substandard water so an investigation may be made asto the cause. Simple wiring may be used to make the
Figure 10-21 Typical Air Filter
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Chapter 10 — Water Treatment 195
is the most powerul oxidizer that can be saely usedin water treatment.
Ozone requently is used to treat wastewater and asa disinectant and oxidant or bottled water, ultrapurewaters, swimming pools, spas, breweries, aquariums,cooling towers, and many other applications. Ozoneis not able to produce a stable residual in a distribu-tion system. However, ozone can lower the chlorinedemand and thus the amount o chlorine required andthe chlorinated by-products.
Ozone systems can be big enough to serve centralplants or municipalities. Figure 10-22 shows an ex-ample o a large-scale system. Figure 10-23 shows a simplied plan view o such a system.
Ultraviolet Light TreatmentUltraviolet light is electromagnetic radiation, orradiant energy, traveling in the orm o waves. A short-range (UVC) wavelength is considered a germi-cidal UV. When ultraviolet light o a sucient energylevel is absorbed into matter, it causes a chemical or
physical change. In the case o microorganisms, ultra-violet light is absorbed to a level that is just enoughto physically break the bonds in DNA to prevent liereproduction. Thereore, ultravi-olet light is a mechanism capableo disinecting water. The mostwidely used source o this lightis low-pressure mercury vaporlamps emitting a 254-nanometer(nm) wavelength. However, 185nm can be used or both disinec-tion and total oxidizable carbonreduction. The dosage requiredto destroy microorganisms isthe product o light intensityand exposure time. The expo-sure requirements or dierentmicroorganisms are well docu-mented by the EPA. Ultravioletbulbs are considered to provide8,000 hours o continuous useand to not degrade to morethan 55 percent o their initialoutput.
When ultraviolet equipment
is sized, the fow rate and qual-ity o the incoming water mustbe taken into consideration. Itis generally necessary to lterthe water beore the ultravioletequipment. Sometimes it may benecessary to lter downstream o the ultraviolet equipment with0.2-µ absolute lter cartridgesto remove dead bacteria and cellragments.
Ultraviolet equipment oten is used in drinking water, beverage water, pharmaceutical, ultra-purerinse water, and other disinection applications.
To validate eectiveness in drinking water systems,the methods described in the U.S. EPA’s Ultraviolet Disinection Guidance Manual is typically used. Forwastewater systems, the National Water ResearchInstitute’s Ultraviolet Disinection Guidelines or
Drinking Water and Water Reuse is typically used,specically in wastewater reclamation applications.
Reverse OsmosisReverse osmosis produces a high-purity water thatdoes not have the high resistivity o demineralizedwater and is not biopure. Under certain conditions,it can oer economic advantages over demineralizedwater. In areas that have high mineral content, it canbe used as a pretreatment or a demineralizer or stillwhen large quantities o water are needed. Reverseosmosis is used primarily in industrial applications andin some hospitals and laboratories or specic tasks. It
also is used by some municipalities and end users orthe removal o dissolved components or salts.
Figure 10-22 Schematic Diagram o a Large-Scale Ozone System
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Several types o reverse osmosis units are available.Basically, they consist o a semipermeable membrane,and water is orced through the membrane under highpressure. A drain and storage tank are required withthis system.
RO is a relatively simple concept. When equalvolumes o water are separated by a semipermeable
membrane, osmosis occurs as pure water perme-ates the membrane to dilute the more concentratedsolution (see Figure 10-24). The amount o physicalpressure required to equalize the two volumes aterequilibrium has been reached is called the osmoticpressure. I physical pressure is applied in excess o theosmotic pressure, reverse osmosis (see Figure 10-25)occurs as water passes back through the membrane,leaving contaminants such as dissolved salts, organics,and colloidal solids concentrated upstream. In practice,the concentrate is diverted to drain, thus rejecting contaminants rom the system altogether. The con-tinuous fushing process o the membrane preventsa phenomenon known as concentration polarization,which is a buildup o the polarized molecules on themembrane surace that urther restricts fow in a short period.
For dependable long-term perormance, RO equip-ment or large-volume applications should be o allstainless steel ttings and bowls. Such a system shoulduse solid-state controls (with simple indicator lightsand gauges) plus a conductivity meter that readsthe tap and permeates water quality. High-pressure
relie devices and low-pressure switches protect themembrane and the pump rom any prelter block-age and accidental eed water shuto. A water-saverdevice that completely shuts o water fow when thestorage tank is ull but allows an hourly washing o the membrane is essential.
Three types o semipermeable membranes are
manuactured rom organic substances: tubularmembrane, cellulose-acetate sheet membrane, andpolyamide-hollow ber membrane. They may be usedor similar applications, assuming that the proper pre-treatment or each is urnished. In properly designedand maintained systems, RO membranes may lasttwo or three years.
RO Membranes
The current technology o RO developed rapidly asone specic application o the larger technology o synthetic membranes. Several code requirementshad to be met beore these membranes could be con-
sidered practical or economical or water puricationprocesses.
First, the membrane had to be selective—that is,it had to be capable o rejecting contaminants and yet still be highly permeable to water. This conditionmeant that it had to have a consistent polymericstructure with a pore size in the range o the smallestcontaminant molecules possible.
Second, the membrane had to be capable o sus-tained high fux rates to be economical and practicalin water applications. This condition meant that the
Figure 10-23 Simplied Plan View o Ozone SystemSource: Ozone Technology, Inc. All rights reserved. Pressureless Ozone Water Purication Systems is a trademark o Ozone Technology, Inc. Copyright, 2006.
produced at high fow rates as needed, thus eliminat-ing the need to store it.
Laboratory-grade water is less rigorously dened,but it still reers to water rom which one or moretypes o contaminants have been removed. This deni-tion should be distinguished rom other processes thatexchange one contaminant or another, such as watersotening (in which calcium and magnesium saltsare removed by exchanging them with sodium salts).The reverse osmosis, deionization, and distillationprocesses are all capable o producing laboratory-grade water.
The quality o the laboratory-grade water producedby several methods o central-system water produc-tion is shown in Table 10-4. The RO and distillationprocesses remove more than 99 percent o all bacte-ria, pyrogens, colloidal matter, and organics abovemolecular weight 200. These methods remove thedissolved inorganic material, such as multivalent ions,calcium, magnesium, carbonates, and heavy metals to
the level o 98 percent, while monovalent ions, suchas sodium, potassium, and chloride, are removed tothe level o 90 percent to 94 percent by RO and 97percent by distillation.
Large-scale deionization processes achieve simi-lar levels o inorganic ion removal, but they do notremove bacteria, pyrogens, particles, and organics.Bacteria, in act, can multiply on the resins, result-ing in an increase in biological contaminants overnormal tap water.
It should be stressed that the degrees o waterpurity shown in Table 10-4 are obtainable only romwell-cleaned equipment that is perorming to itsoriginal specications. Maintaining this condition orthe deionization process means that the resins mustbe replaced (or regenerated) regularly and that theinternal components o the still must be thoroughlycleaned. I a still is not properly and regularly cleaned,the residual contaminants can cause the pH valueo the end product water to all as low as 4. Reverseosmosis is the only one o the methods that uses a reject stream to continuously remove the residualcontaminants. Regularly scheduled prelter changesand system maintenance are, o course, necessary tomaintain the desired water quality.
Applications or RO
The quality and cost o RO water make RO a strong competitor or distillation and deionization in manyapplications. Table 10-5 compares the three methodso water purication or several research and indus-
trial applications.Frequently, the user needs both laboratory-grade
and reagent-grade waters to meet a wide range o needs. Figure 10-26 shows two ways o approaching this situation. Alternative A consists o a central ROsystem rom which the water is piped to a point-o-use polishing system to be upgraded to reagent-gradewater. This approach utilizes the economics o a large central RO system while ensuring the highestreagent-grade purity at those use points that requireit. Alternative B employs smaller point-o-use RO
Figure 10-26 Approaches to Providing Laboratory-Grade and Reagent-Grade Water: (A) RO WaterPuried Centrally and Transported by Pipe to Points o Use Then Polished, (B) RO System Coupled with
Deionization System Totally at the Point o Use, Eliminating Piping
systems with point-o-use polishing, which eliminateslengthy distribution piping, a potential source o recontamination. Both alternatives include a nal
polishing by activated carbon, mixed-bed deioniza-tion, and 0.2-µ membrane ltration. In each case,laboratory-grade water is readily available directlyrom the RO system. Moreover, the transportation andstorage o the reagent-grade water are avoided.
NanoltrationNanoltration (NF) is a cross-fow membrane ltra-tion system that removes particles in approximatelythe 300–1,000 molecular weight range, rejecting se-lected ionic salts and most organics. Nanoltrationrejects the dissociated inorganicsalts that are polyvalent, such as
calcium, magnesium, and sulate,while passing monovalent salts,such as sodium and chloride. There-ore, nanoltration oten is calleda sotening membrane system.Nanoltration operates at low eedpressures. The equipment is similarto that or reverse osmosis.
UltraltrationUltraltration (UF) is a membraneiltration system that separatesliquids and solids. This separationprocess is used in industry andresearch to puriy and concentratemacromolecular solutions, especiallyprotein solutions. It provides ltra-tion in the range o 0.0015 µ to 0.1 µ, or approximately 1,000–100,000molecular weight. Ultraltrationin an industrial application oten isused to separate oil and water as incutting solutions, mop water, andcoolants.
Copper-Silver IonizationCopper-silver ionization is a nota ltration system, but a methodo injecting positive ions into thewater stream. The positive cationsattach to the negative anions o organic pathogens, destroying
their cell structures. It is used toeliminate Legionella and otherwaterborne organisms; thus, thesesystems are used extensively inhospitals and healthcare centers.Figure 10-27 shows the basic sys-tem components.
GLOSSARy
Absorption The process o tak-ing up a substance into the physi-
cal structure o a liquid or solid by a physical orchemical action but without a chemical reaction.
Adsorption The process by which molecules, col-loids, and/or particles adhere to suraces by physi-cal action but without a chemical reaction.
Algae A microscopic plant growth that may beound in some well waters in certain areas o thecountry. This plant growth may collect on the resinin the water conditioner, resulting in poor opera-tion because o restricted water fow. Chlorinationand dechlorination control this problem and pro-tect plumbing lines and xtures.
Table 10-5 Applications o Puried Water
Water Use
Method o Purication
RO Distilled DeionizedGeneral process use Yes Yes Yes
USP XXIII water or injection Yes (must meetpuried water
standard)
Yes No
Hemodialysis Yes No Yes (exceptor pyrogens,bacteria, and
organics)
Figure 10-27 Silver Ionization Unit and Control Panel
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Chapter 10 — Water Treatment 201
Countercurrent regeneration During the re-generation o a water conditioner, in all steps o the regeneration cycle, when the fow is in the op-posite direction o the service fow.
Cross-ow membrane fltration The separa-tion o the components o a fuid by a semiperme-able membrane such as reverse osmosis, nanol-
tration, ultraltration, and microltration.Cubic oot o mineral A measurement o the
high-capacity resin or ion exchange mineral usedin a water sotener.
Cycle The length o time a water sotener will op-erate without backwashing and/or regeneration.
Cycle operation Usually the sequence o valveoperations on automatic water soteners. A two-cycle valve is a device in which upfow brining iscombined with the backwash cycle, sacricing theperormance on both the backwashing and thebrining. The ve-cycle valve perorms each es-
sential regeneration step separately, providing a longer lie, more ecient service, and better per-ormance.
Diatom An organism commonly ound in wa-ters and considered by health ocials to be non-harmul. Diatoms occasionally may impart objec-tionable odors, and their calcied skeletons makechalk and provide a diatomite powder used orswimming pool eatures.
Dissolved iron Iron that is dissolved in water.The dissolved, or errous, iron is highly soluble inmost waters, and the undissolved, or erric, iron is
almost always insoluble in water.
Dissolved solids The residual material remain-ing ater a ltered solution evaporates.
Distributor A device used within a sotener tankto distribute the fow o the water throughout thetank and to prevent the resin rom escaping intothe lines. Sometimes called a strainer.
Down ow Usually designates the down directionin which the water fows during the brine cycle o manual and semiautomatic water soteners.
Drain valve (drain line) A valve or line em-
ployed to direct or carry the backwash water, usedregenerant, and rinse water to the nearest drain o the waste system.
Euent The water moving away rom, or out o, a water conditioner.
Endotoxin A heat-resistant pyrogen ound in thecell walls o viable and nonviable bacteria. Ex-pressed as EDU units.
Exhaustion In water sotening or ion exchange,the point where the resin no longer can exchangeadditional ions o the type or which the processwas designed.
Ferric iron The insoluble orm o iron. Ferrousiron in water is readily converted to erric iron byexposure to oxygen in the air.
Ferrous iron The soluble orm o iron.
Filter-ag A ceramic-like, insoluble, granular ma-terial used in a clarier to physically separate thesuspended matter in some water supplies. It back-washes reely with less water than sand and othersimilar lter materials.
Filtration The process o passing a fuid througha lter material or the purpose o removing tur-bidity, taste, color, or odor.
Floc The suspended particles in water that havecoagulated into larger pieces and may orm a mat
on the top o the mineral or resin bed in a waterconditioner and reduce or impair the ecient op-eration o the equipment.
Flow rate In water treatment, the quantity o wa-ter fowing, in a unit o time, oten given in gallonsper minute or gallons per hour.
Flow regulator A mechanical or automatic de-vice used in water treatment equipment to regu-late the fow o the water to a specied maximumfow rate.
Flux In cross-fow ltration, the unit membranethroughput, expressed as volume per unit o time
per area, such as gallons per day per square oot.
Free board The space above a bed o ion exchangeresin or mineral in a water sotener tank that al-lows or the unobstructed expansion o the bedduring the backwash cycle.
Grains capacity The amount o hardness min-eral (calcium or magnesium) that is removed by a water sotener mineral or resin within a speciedlength o time or by a specic quantity o resin.
Grains per gallon A common basis o reporting water analysis. One grain per gallon equals 17.1parts per million. One grain is 1/7,000 o a pound.
Hardness The compounds o calcium and magne-sium that are usually present in hard water.
Hardness leakage The presence o hardnessminerals (calcium and magnesium) ater the wa-ter has passed through the sotener due to hard-ness retained in the resin bed rom the previousservice run. The amount o leakage expected in a properly operating system is directly proportional
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to the salt rate and the total dissolved solids in theincoming water. While some leakage is normal, ex-cessive leakage usually indicates aulty regenera-tion.
High-capacity resin A manuactured material,in the orm o beads or granules, that has thepower to take hardness-orming ions and give up
sotness-orming ions and the reverse cycle there-o. Sometimes called ion exchange resin.
High purity A term describing highly treated wa-ter with attention to microbiological reduction orelimination, commonly used in the electronic andpharmaceutical industries.
Hydrogen sulfde A highly corrosive gas that o-ten is ound in water supplies. Water containing hydrogen sulde gas has a characteristic rottenegg odor.
Inuent The water moving toward, or into, a wa-ter sotener.
Inlet or outlet valve A gate valve on the inlet oroutlet piping o a water conditioner.
Installation sequence In water treatment appli-cations, the proper procedure or installing equip-ment when more than one piece o water treat-ment equipment is needed to properly conditionthe untreated water.
Ion An electrically charged atom or molecule.
Ion exchange The replacement o one ion by an-other. In the sotening process, the sodium in thesotener resin is exchanged or calcium, magne-
sium, iron, and manganese (i present).
Iron An element common to most undergroundwater supplies, though not present in the largequantities that calcium and magnesium can be.Even small amounts o iron are objectionable inthe water system.
Limestone A common rock composed primarilyo calcium. It combines with carbon dioxide pres-ent in groundwater to orm calcium carbonate andcauses hardness o water.
Magnesium An element that, along with calcium,is responsible or the hardness o water.
Natural water Water containing dissolved inor-ganic solids, mostly mineral salts, which are in-troduced into the water by a solvent action as thewater passes through, or across, various layers o the Earth.
Nitrate A naturally occurring orm o nitrogenound in soil and groundwater. High nitrate levels,generally 10 parts per million or more, can cause
a condition known as blue baby that inhibits thetranser o oxygen through the lung tissue to thebloodstream, resulting in oxygen starvation.
Ohm A unit o measurement. One ohm (1Ω) equals0.5 × 10
–6parts per million or 10
–6microsiemens.
Parts per million A common method o report-ing water analyses. 17.1 ppm equals 1 grain per
gallon. Parts per million is commonly consideredequivalent to milligrams per liter.
pH value A number denoting the alkaline or acid-ic nature o water (or a solution). The pH scaleranges rom 0 to 14, with 7 being the accepted neu-tral point. A pH value below 7 indicates acidity,and values above 7 indicate alkalinity.
Precipitate A solid residue ormed in the processo removing certain dissolved chemicals out o a solution.
Pressure drop A decrease in water pressure, typi-
cally measured in pounds per square inch. Regeneration A process that rereshes the resin
bed in a water sotener to remove any hardnessions collected in the resin.
Resin A synthetic polystyrene ion exchange mate-rial (oten called high-capacity resin).
Rinse Part o the regeneration cycle o a watersotener where reshwater is passed through a water sotener to remove the excess salt (sodiumchloride) prior to placing the water sotener intoservice.
Salt A high-grade sodium chloride o a pellet orbriquette type used or regenerating a water sot-ener.
Service run The operating cycle o a water sot-ener, during which the hard water passes throughthe ion exchange resin and enters the service linesas sot water.
Sodium An element usually ound in water supplies(depending on local soil conditions) that is a basicpart o common salt (sodium chloride).
Sot water Water without hardness material,which has been removed either naturally or
through ion exchange.Sulate A compound commonly ound in waters in
the orm o calcium sulate (CaS04) or magnesiumsulate (MgS04).
Suspension The oreign particles carried (but notdissolved) in a liquid, like rusty iron in water.
Tannin An organic color or dye, not a growth,sometimes ound in waters. (The latter is the resulto decomposition o wood buried underground.)
Titration A laboratory method o determining the presence and amount o chemical in a solution,such as the grains hardness (calcium and magne-sium) o water.
Total dissolved solids All dissolved materials inthe water that cannot be removed by mechanicalltration, generally expressed in terms o parts
per million.Turbidity A term used to dene the degree o
cloudiness o water due to undissolved materialssuch as clay, silt, or sand. It is measured in neph-elometric turbidity units.
Upow The upward direction in which water fowsthrough the water conditioner during any phase o the operating cycle.
Virus A tiny organism that is smaller than bacte-ria and resistant to normal chlorination. Virusescause diseases, such as poliomyelitis and hepatitis(both o which are transmitted primarily through
All piping materials undergo dimensional changesdue to temperature variations in a given system. Theamount o change depends on the material character-istics (the linear coecient o thermal expansion orcontraction) and the amount o temperature change.The coecient o expansion or contraction is dened
as the unit increase or decrease in length o a mate-rial per 1°F increase or decrease in temperature.Coecients o thermal expansion or contraction ora number o commonly used pipe materials are shownin Table 11-1. These coecients are in accordancewith ASTM D696 and are based on completely unre-strained specimens.
I the coecient o thermal expansion or contrac-tion is known, the total change in length may becalculated as ollows:
Equation 11-1
L2 – L1 =αL1 (T2 – T1)
whereL1 = Original pipe length, eetL2 = Final pipe length, eetT1 = Original temperature, °FT2 = Final temperature, °F
α= Coecient o expansion or contraction, oot/ oot/°F
A typical range o temperature change in a hotwater piping system is rom 40°F entering water to120°F distribution water, or an 80°F temperature di-erential. Total linear expansion or contraction or a 100-oot length o run when subject to an 80°F change
in temperature can be calculated or the usual piping materials in a hot water system. A typical range o temperature in a drain, waste, and vent (DWV) systemis rom 100°F (the highest temperature expected) to50°F (the lowest temperature expected), or a 50°Ftemperature dierential.
THERMAL STRESSTo not exceed the maximum allowable strain in thepiping, the developed length can also be calculatedrom the ollowing equation.
Equation 11-2
∆=PL
3
3EI
where ∆
= Maximum defection at the end o a cantilever beam, inches
P = Force at end, poundsL = Length o pipe subjected to fexible stress,
inchesE = Flexural modulus o elasticity, pounds per
square inch (psi)I = Moment o inertia, inches
4
For pipes in which the wall thickness is not largewith respect to the outside diameter, the moment o inertia and the sectional modulus can be calculatedas ollows:
For thin-walled pipes, the maximum allowablestress and the maximum allowable strain can becalculated as ollows:
S =4PL
πD2t
ε=πD
2St
4L
whereS = Maximum ber stress in bending = M/Z, psi
M = Bending moment = PL, inch-poundsD = Outside diameter, inches
ε= Strain
Substituting the maximum allowable stress andthe maximum allowable strain into Equation 11-2,
ThermalEpansion11
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the development length o piping can be estimatedby Equations 11-3 and 11-4 respectively.
Equation 11-3
L =(3ED∆
)½
2S
Equation 11-4
L =(3D∆
)½
2ε
Equation 11-3 is used when the maximum allow-able stress is xed, and Equation 11-4 is used whenthe maximum allowable strain is xed. When Equa-tion 11-4 is used, the fexural modulus o elasticitymust be known. In cases where the modulus o thespecic compound is not available, the ollowing ap-proximately average values are usually adequate:
Material E at 73˚F(psi)
S at 73˚F(psi)*
Steel 30,000,000 16,450
Copper (type L) 17,000,000 6,000
Brass (red) 17,000,000 6,000
ABS 1210 250,000 1,000
ABS 1316 340,000 1,600
PVC 1120 420,000 2,000
PVC 1220 410,000 2,000
PVC 2110 340,000 1,000
PB 2110 38,000 1,000
PE 2306 90,000 630
PE 3306 130,000 630
PE 3406 150,000 630
CPVC 4120 423,000 2,000*ASME B31 values
Equation 11-3 can be actored to yield the ollow-ing equation:
Equation 11-5
L =(3E
)( D∆ )½
2S
where E and S = Constants or any given material
L is measured in eet.
Using the values or E and S in the above table,Equation 11-3 or Equation 11-5 reduces to the ol-lowing:
• Steel pipe: L = 6.16 (D∆)½
• Brass pipe: L = 7.68 (D∆)½
• Copper pipe: L = 7.68 (D∆)½
• ABS 1210: L = 1.61 (D∆)½
• ABS 1316: L = 1.49 (D∆)½
• PVC 1120: L = 1.48 (D∆)½
• PVC 1220: L = 1.46 (D∆)½
• PVC 2110: L = 1.88 (D∆)½
• PB 2110: L = 0.63 (D∆)½
• PE 2306: L = 1.22 (D∆)½
• PE 3306: L = 1.47 (D∆)½
• PE 3406: L = 1.57 (D∆)½
• CPVC 4120: L = 1.48 (D∆)½
Many computer programs are available that read-ily solve these equations as well as address the variousinstallation congurations. Also, reer to the manu-acturer o the material that is being used or specicinormation regarding expansion and contraction.
Provisions must be made or the expansion andcontraction o all hot water and circulation mains,risers, and branches. I the piping is restrained rommoving, it will be subjected to compressive stress ona temperature rise and to tensile stress on a tempera-ture drop. The pipe itsel usually can withstand thesestresses, but ailure requently occurs at pipe jointsand ttings when the piping cannot move reely. Thetwo methods commonly used to absorb pipe expansionand contraction without damage to the piping areexpansion loops and osets and expansion joints.
Epansion Loops and OsetsThe total movement to be absorbed by any expan-sion loop or oset oten is limited to a maximumo 1½ inches or metallic pipes. Thus, by anchoring at the points on the length o run that produce 1½-inch movement and placing the expansion loops or
joints midway between the anchors, the maximummovement that must be accommodated is limited to¾ inch. The piping conguration used to absorb themovement can be in the orm o a U bend, a single-elbow oset, a two-elbow oset, or a three-, ve-, orsix-elbow swing loop. In the great majority o piping systems, the loop or joint can be eliminated by tak-ing advantage o the changes in direction typicallyrequired in the layout.
Table 11-2 provides the total developed lengthrequired to accommodate a 1½-inch expansion. (Thedeveloped length is measured rom the rst elbow to
the last elbow, as shown in Figure 11-1.)Epansion JointsExpansion loops and osets should be used whereverpossible; however, when movements are too large andnot enough space is available to provide an expansionloop (especially or risers in high-rise buildings), ex-pansion joints can be used.
It should be noted that expansion joints are me-chanical devices that present a ailure risk. I notinstalled properly with guides and anchors, they can
Table 11-3 Approximate Sine Wave Conguration With Displacement
Flexible PipeMaximum Temperature Variation (Between Installation and Service), °F
10 20 30 40 50 60 70 80 90 100
Loop Length, t Oset or Contraction, in.20 3 4 5 6 7 8 9 10 11 12
50 7½ 10 12½ 15 17½ 20 22½ 25 27½ 30
100 15 20 25 30 35 40 45 50 55 60
Rigid Pipe
Maximum Temperature Variation (Between Installation and Service), °F10 20 30 40 50 60 70 80 90 100
Loop Length, t Oset or Contraction, in.20 1½ 2 2½ 3 3½ 4 4½ 5 5½ 6
50 3¾ 5 6¼ 7½ 8¾ 10 11¼ 12½ 13¾ 15
100 7½ 10 12½ 15 17½ 20 22½ 25 27½ 30
Note: °C = (F – 32) /1.8mm = in. × 25.4m = t × 0.3048
long stacks are installed. Three methods o accommo-dating expansion or contraction are described below.
1. Osets may be provided. The developed length o the oset that should be provided can be calculatedin accordance with the appropriate ormula. Forexample, or a 50°F temperature dierential inthe straight run, the amount to be accommodated
at the branch connection is approximately ⅜ inch.To accommodate this amount o expansion, thebranch pipe must have sucient developed lengthto overcome a bending twist without being subjectedto excessive strain.
2. Where allowed by applicable codes, expansion jointsmay be used.
3. Engineering studies have shown that by restraining the pipe every 30 eet to prevent movement,satisactory installations can be made. Tensile orcompressive stresses developed by contractionor expansion are readily absorbed by the piping without any damage. Special stack anchors are
available and should be installed according to themanuacturer’s recommendations.
THERMOPLASTIC PIPINGThermoplastic piping (ABS, PVC, PE, and CPVC)expands and contracts in reaction to temperaturechanges at a much aster rate, up to 10 times aster,than metallic pipe. Because o this, some manuactur-
ers o plastic piping use a maximum allowable straino 0.005 inch per inch. When this is the case, Equation11-4 reduces to:
L = 1.44 (D∆)½
Use o plastic piping in high-rise buildings inparticular requires careul calculations to minimizeexpansion and contraction.
UNDERGROUND PIPINGUnderground piping temperature changes are lessdrastic than aboveground piping changes becausethe piping is not exposed to direct heating rom solarradiation, the insulating nature o the soil preventsrapid temperature changes, and the temperature o the transported medium can have a stabilizing eecton the pipe’s temperature.
Contraction or expansion o fexible pipe can beaccommodated by snaking the pipe in the trench. Anapproximate sine wave conguration with a displace-ment rom the centerline and a maximum oset asshown in Table 11-3 accommodate most situations.The installation should be brought to the service tem-perature prior to backlling. Ater increased length istaken up by snaking, the trench can be backlled inthe normal manner.
Up to 3-inch nominal size, rigid pipe can be handledby snaking in the same manner used or fexible pipe.
Osets and loop lengths under specic temperaturevariations are shown in Table 11-3. For distances o less than 300 eet, 90-degree changes in direction takeup any expansion or contraction that occurs.
For larger sizes o pipe, snaking is not practical orpossible in most installations. In such cases, the pipeis brought to within 15°F o the service temperature,and the nal connection is made. This can be accom-plished by shade backlling, allowing the pipe to coolat night and then connecting early in the morning,or cooling the pipe with water. The thermal stressesproduced by the nal 15°F service temperature areabsorbed by the piping.
ExPANSION TANKS When water is heated, it expands. I this expansionoccurs in a closed system, dangerous water pressurescan be created. A domestic hot water system can be a closed system when the hot water xtures are closedand the cold water supply piping has backfow preven-
ters or any other device that can isolate the domestichot water system rom the rest o the domestic watersupply, as shown in Figure 11-2(A).
These pressures can quickly rise to a point atwhich the relie valve on the water heater unseats,thus relieving the pressure, but at the same timecompromising the integrity o the relie valve, asshown in Figure 11-2(B). A relie valve installed on a water heater is not a control valve, but a saety valve.It is not designed or intended or continuous usage.Repeated excessive pressures can lead to equipmentand pipe ailure and personal injury.
When properly sized, an expansion tank connected
to the closed system provides additional system vol-ume or water expansion while ensuring a maximumdesired pressure in a domestic hot water system. Itdoes this by utilizing a pressurized cushion o air(see Figure 11-3). The ollowing discussion explainshow to size an expansion tank or a domestic hot
water system and the theory behind the design andcalculations. It is based on the use o a diaphragm orbladder-type expansion tank, which is the type mostcommonly used in the plumbing industry. This typeo expansion tank does not allow the water and airto be in contact with each other.
Epansion o Water
A pound o water at 140°F has a larger volume thanthe same pound o water at 40°F. To put it anotherway, the specic volume o water increases with anincrease in temperature. I the volume o water at a specic temperature condition is known, the expan-sion o water can be calculated as ollows:
Vew = Vs2 – Vs1
whereVew = Expansion o water, gallonsVs1 = System volume o water at
temperature 1, gallonsVs2 = System volume o water at
temperature 2, gallons
Vs1 is the initial system volume and can be deter-mined by calculating the volume o the domestic hotwater system. This entails adding the volume o thewater-heating equipment to the volume o the piping and any other part o the hot water system.
Vs2 is the expanded system volume o water at thedesign hot water temperature. Vs2 can be expressedin terms o Vs1. To do that, look at the weight o thewater at both conditions.
The weight (W) o water at temperature 1 (T1)equals the weight o water at T2, or W 1 = W 2. At T1, W 1 = Vs1 /vsp1, and similarly at T2, W 2 = Vs2 /vsp2,
where vsp equals the specic volume o water at thetwo temperature conditions. (See Table 11-4 or spe-cic volume data.) Since W 1 = W 2, then:
Vs1=
Vs2
vsp1 vsp2
Solving or Vs2:
Vs2 = Vs1( vsp2)vsp1
Earlier it was stated that Vew = Vs2 – Vs1. Sub-stituting Vs2 rom above, it can be calculated thatsince
Vs2 = Vs1( vsp2), thenvsp1
Vew = Vs1( vsp2 ) – Vs1 , orvsp1
Equation 11-6
Vew = Vs1( vsp2 )vsp1 – 1
Table 11-4 Thermodynamic Properties o Water at aSaturated Liquid
Temp., °FSpecic Volume,
t3 /lb
40 0.01602
50 0.01602
60 0.0160470 0.01605
80 0.01607
90 0.01610
100 0.01613
110 0.01617
120 0.01620
130 0.01625
140 0.01629
150 0.01634
160 0.01639
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Chapter 11 — Thermal Expansion 211
Example 11-1
A domestic hot water system has 1,000 gallons o water. How much will the 1,000 gallons expand roma temperature o 40°F to a temperature o 140°F?
From Table 11-4, vsp1= 0.01602 (at 40°F) and vsp2 = 0.01629 (at 140°F). Utilizing Equation 11-6,
Vew = 1,000
(0.01629
)=
16.9 gallons0.01602 – 1
Note that this is the amount o water expansionand should not be conused with the size o the expan-sion tank needed.
Epansion o Material Will the expansion tank receive all o the water expan-sion? The answer is no, because not just the water isexpanding. The piping and water-heating equipmentexpand with an increase in temperature as well. Anyexpansion o these materials results in less o the wa-ter expansion being received by the expansion tank. Another way o looking at it is as ollows:
Venet = Vew – Vemat
whereVenet = Net expansion o water received by the
expansion tank, gallonsVew = Expansion o water, gallons
Vemat = Expansion o material, gallons
To determine the amount o expansion each mate-rial experiences per a certain change in temperature,look at the coecient o linear expansion or that ma-terial. For copper, the coecient o linear expansionis 9.5 × 10
–6inch/inch/°F, and or steel it is 6.5 × 10
–6
inch/inch/°F. From the coecient o linear expansion,
a material’s coecient o volumetric expansion can bedetermined. The coecient o volumetric expansionis three times the coecient o linear expansion:
ß= 3α
whereß = Volumetric coecient o expansion
α= Linear coecient o expansion
Thus, the volumetric coeicient or copperis 28.5 × 10
–6gallon/gallon/°F, and or steel it is
19.5 × 10–6
gallon/gallon/°F. The material will expandproportionally with an increase in temperature.
Equation 11-7
Vemat = Vmat × ß (T2 – T1)
Making the above substitution and solving or Venet,
A domestic hot water system has a water heater madeo steel with a volume o 900 gallons. It has 100 eeto 4-inch piping, 100 eet o 2-inch piping, 100 eeto 1½-inch piping, and 300 eet o ½-inch piping. All o the piping is copper. Assuming that the initialtemperature o the water is 40°F and the nal tem-perature o the water is 140°F, (1) how much will eachmaterial expand, and (2) what is the net expansion o water that an expansion tank will see?
1. Utilizing Equation 11-7 or the steel (materialno. 1), Vmat1 = 900 gallons and Vemat1 = 900(19.5 × 10
–6)(140 – 40) = 1.8 gallons.
For the copper (material no. 2), rst look at Table11-5 to determine the volume o each size o pipe:
4 inches = 100 x 0.67 = 67 gallons
2 inches = 100 x 0.17 = 17 gallons 1½ inches = 100 x 0.10 = 10 gallons
½ inch = 300 x 0.02 = 6 gallons
Total volume o copper piping = 100 gallons
Utilizing Equation 11-7 or copper, Vmat2 = 100gallons and Vemat2 = 100 (28.5 × 10
–6)(140 – 40)
= 0.3 gallon.
2. The initial system volume o water (Vs1) equals Vmat1 + Vmat2, or 900 gallons + 100 gallons.From Example 11-1, 1,000 gallons o watergoing rom 40°F to 140°F expands 16.9 gallons.Thus, utilizing Equation 11-8, Venet = 16.9 –(1.8 + 0.03) = 15 gallons. This is the net amounto water expansion that the expansion tank willsee. Once again, note that this is not the size o the expansion tank needed.
Bole’s Law Ater determining how much water expansion theexpansion tank will see, it is time to look at howthe cushion o air in an expansion tank allows thedesigner to limit the system pressure.
Table 11-5 Nominal Volume o Piping
Pipe Size, in.Volume o Pipe, gal/linear
t o pipe½ 0.02
¾ 0.03
1 0.04
1¼ 0.07
1½ 0.10
2 0.172½ 0.25
3 0.38
4 0.67
6 1.50
8 2.70
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Boyle’s law states that at a constant temperature,
the volume occupied by a given weight o perectgas (including or practical purposes atmosphericair) varies inversely as the absolute pressure (gaugepressure + atmospheric pressure). It is expressed bythe ollowing:
Equation 11-9
P1 V 1 = P2 V 2
whereP1 = Initial air pressure, pounds per square inch
absolute (psia)V 1 = Initial volume o air, gallonsP2 = Final air pressure, psia
V 2 = Final volume o air, gallonsHow does this law relate to sizing expansion tanks
in domestic hot water systems? The air cushion inthe expansion tank provides a space into which theexpanded water can go. The volume o air in thetank decreases as the water expands and enters thetank. As the air volume decreases, the air pressureincreases.
Utilizing Boyle’s law, the initial volume o air (i.e.,the size o the expansion tank) must be based on (1)initial water pressure, (2) desired maximum waterpressure, and (3) change in the initial volume o theair. To utilize the above equation, realize that thepressure o the air equals the pressure o the waterat each condition, and make the assumption that thetemperature o the air remains constant at condition1 and condition 2 in Figure 11-4. This assumption isreasonably accurate i the expansion tank is installedon the cold water side o the water heater. Remember,in sizing an expansion tank, the designer is sizing a tank o air, not a tank o water.
Reerring to Figure 11-4, at condition 1 the tank’sinitial air pressure charge, P1, equals the incoming
water pressure on the other side o the diaphragm.
The initial volume o air in the tank, V 1, is also thesize o the expansion tank. The nal volume o air inthe tank, V 2, also can be expressed as V 1 less the netexpansion o water (Venet). The pressure o the air atcondition 2, P2, is the same pressure as the maximumdesired pressure o the domestic hot water system atthe nal temperature, T2. P2 should always be lessthan the relie valve setting on the water heater.
Utilizing Boyle’s law, P1 V 1 = P2 V 2. Since V 2 = V 1 – Venet, then:
P1 V 1 = P2 (V 1 – Venet)
P1 V 1 = P2 V 1 – P2 Venet
(P2 – P1)V 1 = P2 Venet
V 1 =P2 Venet
P2 – P1
Multiplying both sides o the equation by (1/P2)/ (1/P2), or by 1, the equation becomes:
Equation 11-10
V 1 = Venet
1 – (P1 / P2)
whereV 1 = Size o expansion tank required to
maintain the desired system pressure, P2,gallons Venet = Net expansion o water, gallons
P1 = Incoming water pressure, psia (Note: Absolute pressure is gauge pressure plusatmospheric pressure, or 50 psig = 64.7psia.)
P2 = Maximum desired pressure o water, psia
Example 11-3
Looking again at the domestic hot water systemdescribed in Example 11-2, i the cold water supply
pressure is 50 psig and the maximum desired waterpressure is 110 psig, what size expansion tank isrequired?
Example 11-2 determined that Venet equals 15gallons. Converting the given pressures to absoluteand utilizing Equation 11-10, the size o the expansiontank needed can be determined as:
V 1 = 15 = 31 gallons1 – (64.7/124.7)
Note: When selecting the expansion tank, makesure the tank’s diaphragm or bladder can accept 15gallons o water (Venet).
SUMMARy Earlier in this section, the ollowing were estab-lished:
In Equation 11-6, Vs1 was dened as the systemvolume at condition 1. Vs1 also can be expressed interms o Vmat:
Vs1 = Vmat1 + Vmat2
Making this substitution and combining the equa-tions provides the ollowing two equations, whichare required to properly size an expansion tank or a domestic hot water system.
Equation 11-11
Venet = (Vmat1 + Vmat2) ( vsp2
)–vsp1 – 1
[Vmat1 × ß1(T2 – T1) + Vmat2 × ß2(T2 – T1)]
Equation 11-10
V 1 = Venet
1 – (P1 / P2)
where Venet = Net expansion o water seen by the
expansion tank, gallons Vmat = Volume o each material, gallons
vsp = Specic volume o water at each condition,cubic eet per pound ß = Volumetric coecient o expansion o each
material, gallon/gallon/°FT = Temperature o water at each condition, °FP = Pressure o water at each condition, psia
In the early 1900s, Halsey Willard Taylor and LutherHaws both invented their own version o the drinking ountain. Haws later patented the rst drinking aucet(see Figure 12-1) in 1911. While the original xturessupplied room-temperature water, demand or chilledwater led to the development o a unit that used large
blocks o ice to chill the water. A later evolution wasa cumbersome foor-standing unit with a belt-drivenammonia compressor used to chill the water.
Today, a plethora o types and aesthetically pleas-ing models o water coolers satises even the mostdemanding applications. The industry is ocused onproviding the highest quality o water while using theleast amount o foor space, allowing water coolersto be installed in heavy-trac areas while satisying code and end-user requirements.
WATER AND THE HUMAN BODy The importance o nutrients is judged by how long the human body can unction without them. Water isessential because humans can subsist or only about
a week without it. It constitutes approximately 75percent o the human body and on average it takeseight cups o water to replenish the water a bodyloses each day.
Water has two primary tasks in the metabolicprocess: It carries nutrients and oxygen to dierent
parts o the body through the bloodstream and lym-phatic system, and it allows the body to remove toxinsand waste through urine and sweat. Furthermore, itregulates body temperature, cushions joints and sottissues, and lubricates articulations, hence balancing the unctions o the body.
Considering the importance o water to the humanbody, the plumbing designer should keep in mind thatthe plumbing codes are nothing more than minimumrequirements; thereore, the designer should evaluatei the code requirements will be sucient to satisythe building occupants’ water needs.
UNITARy COOLERS A mechanically rerigerated drinking-water coolerconsists o a actory-made assembly in one structure.This cooler uses a complete mechanical rerigerationsystem to cool potable water and provide such wateror dispensing by integral and/or remote means.
Water coolers dier rom water chillers. Watercoolers are used to dispense potable water, whereaswater chillers are used in air-conditioning systems orresidential, commercial, and industrial applicationsand in cooling water or industrial processes.
The capacity o a water cooler is the quantity
o water cooled in one hour rom a specied inlettemperature to a specied dispensing temperature,expressed in gallons per hour (gph) (L/h). Standardcapacities o water coolers range rom 1 gph to 30 gph(3.8 L/h to 114 L/h).
Ratings Water coolers are rated on the basis o their continu-ous fow capacity under specied water temperatureand ambient conditions (see Table 12-1). ARI 1010:Sel-Contained, Mechanically Rerigerated Drinking
Figure 12-1 Early Drinking FaucetSource: Haws Corp.
Potable WaterCoolers and
Central WaterSstems12
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Water Coolers provides the gen-erally accepted rating conditionsand reerences test methods asprescribed in ANSI/ASHRAE 18: Methods o Testing or Rating Drinking-Water Coolers with
Sel-Contained Mechanical Re- rigeration.
Water Cooler TpesThe three basic types o watercoolers are:
• Bottled water cooler (seeFigure 12-2), which uses a bottle, or reservoir, to storethe supply o water to becooled and a aucet or similarmeans to ll glasses, cups, orother containers. It also includes a wastewater re-ceptacle. The designer should always check withthe authority having jurisdiction to ensure that a
bottled water cooler satises the local minimumplumbing xture requirements.
• Pressure-typewatercooler(seeFigures12-3and12-4), which is supplied with potable water un-
der pressure and in-cludes a wastewaterreceptacle or meanso disposing water to
a plumbing drainage system. Such coolers can usea aucet or similar means to ll glasses or cups, aswell as a valve to control the fow o water as a projected stream rom a bubbler so water may be
consumed without the use o a glass or cup.
• Remote-typecooler,whichisafactory-assembledsingle structure that uses a complete mechani-cal rerigeration system. Its primary unction isto cool potable water or delivery to a separatelyinstalled dispenser.
Not utilizing precooler 90 (32.2) 80 (26.7) 50 (10) 165 (73.9) NoneCompartment type cooler During the standard capacity test, there shall be no melting o ice
in the rerigerated compartment, nor shall the average temperatureexceed 46°F (7.8°C).
Source: ARI Standard 1010, reprinted by permission.
Note: For water-cooled condenser water coolers the established fow o water through the condenser shall not exceed 2.5times the base rate capacity, and the outlet condenser water temperature shall not exceed 130°F (54.4°C). The base ratecapacity o a pressure water cooler having a precooler is the quantity o water cooled in 1 h, expressed in gallons perhour, at the standard rating conditions, with 100% diversion o spill rom the precooler.
aThis temperature shall be reerred to as the “standard rating temperature” (heating).
Figure 12-2 Bottled Water Cooler
Figure 12-4 Pressure-Type PedestalWater Cooler
Source: Halsey Taylor
Figure 12-3 Wheelchair-AccessiblePressure-Type Water Cooler
Chapter 12 — Potable Water Coolers and Central Water Systems 217
In addition to these three basic types, water cool-ers are categorized by specialized conditions o use,additional unctions they perorm, or the type o installation, as described below.
Special-Purpose Water Coolers
Explosion-proo water coolers are constructed orsae operation in hazardous locations (volatile atmo-
spheres), as classied in Article 500 o the NationalElectrical Code.
Vandal-resistant water coolers are made or heavy-use applications such as in schools or prisons.
Extreme climate water coolers include rost re-sistance or occasional cold temperatures and reezeprotection or those used during sustained cold tem-peratures.
A caeteria-type cooler is supplied with waterunder pressure rom a piped system and is intended
primarily or use in caeterias and restaurants to dis-pense water rapidly and conveniently into glasses orpitchers. It includes a means or disposing wastewaterto a plumbing drainage system.
A drainless water cooler is a pressure-type coolersupplied by ¼-inch tubing rom an available watersupply and does not have a waste connection. As withthe bottled water cooler, a drip cup sits on a pressureswitch to activate a solenoid valve on the inlet sup-ply to shut o the supply by the weight o the waterin the cup.
Water coolers that accommodate wheelchairs areavailable in several styles. In the original design, thechilling unit was mounted behind the backsplash,with a surace-mounted bubbler projecting 14 inchesrom the wall, enabling a person in a wheelchair toroll under the xture. In today’s wheelchair-accessibleunits, the chilling unit is located below the level o thebasin (see Figures 12-3 and 12-5), with the bubblerprojecting rom the wall at such a height that a person
in a wheelchair can roll under it. Dual-height designs(see Figures 12-6 and 12-7), also known as barrier-ree, are the most popular designs today. These unitsrecognize the needs o able-bodied individuals, thosewith bending diculties, and those in wheelchairs ata consolidated location. In ully recessed accessibledesigns, or barrier-ree inverted, the chilling unit ismounted above the dispenser to allow a recess underthe ountain or wheelchair access. When using this
Figure 12-5 Wheelchair-Accessible UnitSource: Halsey Taylor
Figure 12-6 Dual-Height DesignSource: Halsey Taylor
Figure 12-7 Dual-Height Design with Chilling UnitMounted Above Dispenser
Source: Haws Corp.
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Figure 12-8 Fully RecessedWater Cooler
Source: Halsey Taylor
style, the designer should ensure thatthe grill vanes go upward and that therecess is o sucient depth and widthor a person in a wheelchair. (For ad-ditional inormation on ADA-compliantxtures, reer to Plumbing Engineering
Design Handbook, Volume 1, Chapter 6,
“Plumbing or People with Disabilities”and ICC/ANSI A117.1: Accessible andUseable Buildings and Facilities. Childrequirements are based on the nal rul-ing o the U.S. Access Board.)
The dierent types o water coolerinstallations include the ollowing:
• Freestanding(seeFigure12-4)
• Wall hung (see Figures 12-3, 12-5,and 12-6)
• Fullyrecessed(seeFigure12-8),al-lowing an unobstructed path
• Fullyrecessedwithaccessories(seeFigure 12-9)
• Fullyrecessedbarrier-free(seeFig -ure 12-10), or wheelchair access
Options and AccessoriesThe designer should consider all ac-cessories and options to satisy projectrequirements. Water coolers are avail-able with several dierent options:
• Activation devices, such as hands-ree, sensor-operated, oot pedals, orpush bottoms and push bars
• Glassorpitcherllers,suchaspushlever or push down
• Bottle llers, an industry responseto new trends that aim to eliminateplastic water bottles (see Figure 12-12)
• Iceand/orcupdispensers,hotwaterdispensers, water lters, and reriger-ated compartments
• Cane apron, an accessorydesigned
to bring wall-hung, dual-mount watercoolers into ADA compliance
• Bubblers, including standard, van-dal resistant, and fexible, which is con-structed o pliable polyester elastomerthat fexes on impact beore returning to its original position to help protectagainst accidental injuries. Flexiblebubblers usually contain an antimicro-bial agent blended into the plastic to
Figure 12-9 Fully Recessed Water Coolerwith Accessories
Source: Halsey Taylor
Figure 12-10 Fully Recessed,Barrier-Free Water Cooler
Source: Oasis
Figure 12-11 Semi-Recessed orSimulated Recessed Water Cooler
Chapter 12 — Potable Water Coolers and Central Water Systems 219
prevent bacteria rom multiplying on the suraceo the bubbler.
Water Cooler Components Water coolers may contain any o the ollowing com-ponents (see Figure 12-13):
1. Antimicrobial saety
2. Stainless steel basin3. Activation, such as push button, push bar, or in-
rared
4. Stream height regulator, which automaticallymaintains a constant stream height
5. Water system, manuactured o copper compo-nents or other lead-ree materials
6. Compressor and motor
7. Non-pressurized cooling tank
8. Fan motor and blade
9. Condenser coil, n or tube type
10. Drier, which prevents internal moisture romcontaminating the rerigeration system
11. Drain outlet with 1¼-inch slip-joint tting
12. Preset cooler control
13. Water inlet connection (not shown), which ac-
cepts ⅜-inch outside diameter tubing or hookupto incoming water line
14. Inline strainer (not shown)
15. Water ltration
Stream RegulatorsSince the principal unction o a pressure-type water
cooler is to provide a drinkable stream o cold waterrom a bubbler, it usually is provided with a valve tomaintain a constant stream height, independent o supply pressure. A fow rate o 0.5 gallon per minute(gpm) (0.03 L/s) rom the bubbler generally is acceptedas providing an optimum stream or drinking.
REFRIGERATION SySTEMS As stipulated in the Montreal Protocol o 1987 andsubstantially amended in 1990 and 1992, HFC-134a rerigerant replaced the use o chlorofuorocarbons(CFCs), which have been implicated in the acceler-ated depletion o the ozone layer. HFC-134a is a
commercially available, environmentally acceptablehydrofuorocarbon (HFC) commonly used as a rerig-erant in HVAC systems.
Hermetically sealed motor compressors commonlyare used or alternating-current (AC) applications,both 50 hertz (Hz) and 60 Hz. Belt-driven compressorsgenerally are used only or direct-current (DC) and25-Hz supply. The compressors are similar to those
Figure 12-12 Bottle FillerSource: Elkay
Figure 12-13 Water Cooler Accessories
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used in household rerigerators and range rom 0.08horsepower (hp) to 0.5 hp (0.06 kW to 0.37 kW).
Forced air-cooled condensers are most commonlyused. In coolers rated less than 10 gallons per hour(gph) (38 L/h), natural convection, air-cooled (static)condensers sometimes are included. Water-cooledcondensers o tube-on-tube construction are used onmodels intended or high ambient temperatures orwhere lint and dust in the air make air-cooled typesimpractical.
Capillary tubes are used almost exclusively or re-rigerant fow control in hermetically sealed systems.
Pressure-type coolers oten are equipped withprecoolers to transer heat rom the supply waterto the wastewater. When drinking rom a bubblerstream, the user wastes about 60 percent o the coldwater down the drain. In a precooler, the incoming water is put in a heat exchange relationship withthe wastewater. Sometimes the cold wastewater alsois used to subcool the liquid rerigerant. A precooler
with this arrangement is called an economizer. Cool-ers intended only to dispense water into cups arenot equipped with precoolers since no appreciablequantity o water is wasted.
Most water coolers manuactured today consist o an evaporator ormed by rerigerant tubing bondedto the outside o a water circuit. The water circuit isusually a tank or a coil o large tubing. Materials usedin the water circuit are usually nonerrous or stain-less steel. Since the coolers dispense water or humanconsumption, sanitary requirements are essential (seeUL 399: Drinking Water Coolers).
Water coolers that also provide a rerigerated
storage space, commonly reerred to as compartmentcoolers, have the same control compromises commonto all rerigeration devices that attempt two-temper-ature rerigeration using a single compressor. Mostbottle-type compartment coolers are provided with thesimplest series system, one in which the rerigeranteeds rst to a water-cooling coil and then through a restrictor device to the compartment. When the com-pressor operates, both water cooling and compartmentcooling take place. The thermostat usually is locatedto be more aected by the compartment temperature,so the amount o compressor operation and watercooling available depends considerably on the usage
o the compartment.Some compartment coolers, generally pressure
types, are equipped with more elaborate systems,ones in which separate thermostats and solenoidvalves are used to switch the rerigerant fow rom a common high side to either the water-cooling evapora-tor or the compartment evaporator. A more recentlydeveloped method o obtaining the two-temperatureunction uses two separate and distinct systems, each
having its own compressor, high side, rerigerantfow-metering device, and controls.
WATER CONDITIONINGMost water coolers are classied by UL in accordancewith NSF/ANSI 61: Drinking Water System Compo-nents—Health Eects and the Sae Drinking Water Act, which protects public health by regulating thenation’s public drinking water and its sources. Also,this legislation makes proessional engineers, contrac-tors, architects, building owners, and maintenancesta responsible or the quality o water dispensedrom the equipment and xtures they provide.
The eects o lead are devastating to the humanbody, as it accumulates on vital organs and alters theneurological system. Children are particular sensitiveto lead because their bodies and vital organs are stilldeveloping. Even in low concentrations, lead can hin-der growth and cause learning disabilities. High leadlevels also can cause seizures, unconsciousness, and,
Chapter 12 — Potable Water Coolers and Central Water Systems 221
In cases where the quality o a building’s watersupply is a concern, manuacturer units can beequipped with lead-reduction systems designed toremove cysts, lead particles, and chlorine. Methodsto avoid and remove lead beore it enters the wateror the cooler include the ollowing:
• Lead-absorbentlters,forinstallationonthein-
coming water to the cooler• Reverseosmosis(RO)systems,whichcanbebuilt
into the water cooler
• Lead-free plumbing products complying withNSF/ANSI 61 Annex G and NSF/ANSI 372: Drinking Water System Components—Lead Con-tent
CENTRAL SySTEMS A central chilled drinking water system typically isdesigned to provide water at 50°F (10°C) to the drink-ing ountains. Water is cooled to 45°F (7.2°C) at the
central plant, thus allowing or a 5°F (2.8°C) increasein the distribution system. System working pressures
generally are limited to 125 pounds per square inchgauge (psig) (861 kPa). (The designer should checkthe local code or the maximum pressure allowed.) A central chilled drinking water system should beconsidered in any building, such as a multistory ocebuilding, where eight or more drinking ountains arestacked one above the other.
Components A central chilled drinking water system consists o thechilling unit, distribution piping, drinking ountains,and controls.
Chilling Unit
The chiller may be a built-up or actory-assembledunit, but most installations use actory-assembledunits. In either case, the chiller consists o the ol-lowing:
• Adirect-expansionwatercooleroftheshell-and-tube type, with a separate eld-connected stor-age tank or an immersion-type coil installed inthe storage tank. I a separate tank is used, a circulating pump normally is needed to circulatethe water between the evaporator and the tank.Evaporator temperatures o 30°F to 34°F (-1.1°Cto 1.1°C) are used.
• An adequately sized storage tank to accommo-date the fuctuating demands o a multiple-outletsystem. Without a tank or with a tank that is too
small, the fuctuations will cause overloading or short-cycling, causing excessive wear on theequipment. The tank must be o nonerrous con-struction. The evaporator mounted in the tankshould be o the same construction as the tank toreduce galvanic action.
• Circulatingpumps,normallyofthebronze-tted,close-coupled, single-stage type with mechanicalseals. For systems designed or 24-hour opera-tion, duplex pumps are installed, with alternating controls allowing each pump to be used 12 hoursper day.
• Controls consisting of high- and low-pressure
cutouts, reeze protection, and thermostatic con-trol to limit the temperature o the water leaving the chiller. A fow switch or dierential pressurecontrol also should be provided to stop the com-pressor when there is no fow through the cooler. Another desirable item is a time switch that canbe used to operate the plant during periods o building occupancy.
Figure 12-15 Downeed Central System
1ST FLOOR
2ND FLOOR
3RD FLOOR
4TH FLOOR
5TH FLOOR
6TH FLOOR
BALANCINGVALVE
MECHANICALPENTHOUSE
BASEMENT
DRINKINGFOUNTAIN
(TYPICAL)
CIRCULATINGWATER
RETURN
RECIRCULATINGPUMP
CHILLERSTORAGE TANK
AIRVENT
CHILLEDWATER
SUPPLY
WATERFILTER
(OPTIONAL)
DOMESTICWATERSUPPLY
DRINKINGFOUNTAIN
(TYPICAL)
7TH FLOOR
8TH FLOOR
9TH FLOOR
10THFLOOR
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Distribution Piping System
The distribution piping delivers chilled water to thedrinking ountains. Systems can be upeed as shownin Figure 12-14 or downeed as shown in Figure 12-15. The piping can be copper, brass, or plastic (CPVC,PP, or PEX) designed or a working pressure o 125psig (861 kPa).
The makeup cold water lines are the same mate-rial as the distribution piping. When the water supplyhas objectionable characteristics, such as high ironor calcium content, or contains odorierous gases insolution, a lter should be installed in the makeupwater line.
Insulation is necessary on all distribution pip-
ing and the storage tanks. The insulation should beglass ber or closed cell oam insulation—such asthat normally used on chilled-water piping—with a conductivity ( k) o 0.22 (32) at a 50°F (10°C) meantemperature and a vapor barrier jacket, or equal. Allvalves and piping, including the branch to the xture,should be insulated. The waste piping rom the drink-ing ountain, including the trap, should be insulated.This insulation is the same as is recommended or useon cold water lines.
Drinking Fountains
Any standard drinking ountain (see Figure 12-16)can be used in a central drinking water system.However, the automatic volume or stream regulatorprovided with the ountain must be capable o provid-ing a constant stream height rom the bubbler withinlet pressures up to 125 psig (861 kPa).
Sstem Design Rerigeration
For an oce building, a usage load o 5 gph (19 L/h)per ountain or an average corridor and oce is nor-mal. The water consumption or other occupancies isgiven in Table 12-2. Table 12-3 is used to convert theusage load in gph (L/h) to the rerigeration load inBritish thermal units per hour (Btuh) (W). The heatgain rom the distribution piping system is based ona circulating water temperature o 45°F (7.2°C). Table12-4 lists the heat gains or various ambient tempera-tures. The length o all lines must be included when
calculating the heat gain in the distribution piping.Table 12-5 tabulates the heat input rom variouslysized circulating pump motors.
The total cooling load consists o the heat removedrom the makeup water, heat gains rom the piping,heat gains rom the storage tank, and heat inputrom the pumps. A saety actor o 10 to 20 percent isadded beore selecting a condensing unit. The size o the saety actor is governed by usage. For example,in a building with weekend shutdowns, the highersaety actor allows pickup when reopening the build-ing on Monday morning when the total volume o water in the system would need to be cooled to the
operating temperature. Since the water to the chilleris a mixture o makeup and return water, the chillerselection should be based on the resultant mixedwater temperature.
Circulating Pump
The circulating pump is sized to circulate a minimumo 3 gpm (0.2 L/s) per branch or the gpm (L/s) neces-sary to limit the temperature rise o the circulatorywater to 5°F (2.8°C), whichever is greater. Table 12-6lists the circulating pump capacity needed to limit thetemperature rise o the circulated water to 5°F (2.8°C).I a separate pump is used to circulate water between
the evaporator and the storage tank, the energy inputto this pump must be included in the heat gain.
Storage Tank
The storage tank’s capacity should be at least 50percent o the hourly usage. The hourly usage maybe selected rom Table 12-2.
Distribution Piping
General criteria or sizing the distribution piping or a central chilled drinking water system are asollows:
Bubbler Service: PersonsServed Per Gallon (Liter) oStandard Rating Capacity
Cup Service: PersonsServed Per Gallon (Liter)o Base Rate Capacity
Oces 12 (3) 30 (8)Hospitals 12 (3) —
Schools 12 (3) —
Light manuacturing 7 (2) —
Heavy manuacturing 5 (2) —
Hot heavy manuacturing 4 (1) —
Restaurants 10 (3)
Caeterias 12 (3)
Hotels (corridors) —
Required Rated Capacity per Bubbler, gph (L/h)
One Bubbler Two or More BubblersRetail stores, hotel lobbies,oce building lobbies
12 (3) 5 (20) 5 (20)
Public assembly halls,amusement parks, airs, etc. 100 (26) 20–25(80–100) 15 (60)
Theaters 19 (5) 10 (40) 7.5 (30)
Source: Reprinted rom ARI Standard 1010, by permission.
Note: Based on standard rating conditions, with delivered water at 50°F (10°C).
• Limitthemaximumvelocity ofthewaterin thecirculating piping to 3 eet per second (ps) (0.9m/s) to prevent the water rom having a milky ap-pearance.
• Avoid excessive frictionhead losses. The energynecessary to circulate the water enters the wateras heat and requires additional capacity in the wa-
ter chiller. Accepted practice limits the maximumriction loss to 10 eet (3 m) o head per 100 eet(30 m) o pipe.
• Dead-endpiping,suchasthatfromthemainriserto the ountain, should be kept as short as possi-ble, and in no event should it exceed 25 eet (7.6 m)in length. The maximum diameter o such dead-end piping should not exceed⅜-inch (9.5-mm) ironpipe size (IPS), except on very short runs.
• Sizepipingonthetotalnumberofgallonscircu-lated. This includes gallons consumed plus gallonsnecessary or heat leakage.
General criteria or the design layout o piping or a central chilled drinking water system are as ollows:
• Keeppiperunsasstraightaspossiblewithamini-mum number o osets.
• Use long sweepttingswherever possible tore-duce riction loss.
• Ingeneral,limitthemaximumpressuredevelopedin any portion o the system to 80 psi (552 kPa). I the height o a building should cause pressures inexcess o 80 psi (552 kPa), divide the building intotwo or more systems.
• Ifmorethanonebranchlineisused, installbal-ancing cocks on each branch.
• Provide a pressure relief valve and air vents athigh points in the chilled water loop.
The ollowing example illustrates the calculationsrequired to design a central chilled drinking watersystem.
Example 12-1
Design a central drinking water system or the build-ing in Figure 12-15. The net foor area is 14,600 squareeet (1,356 square meters) per foor, and occupancyis assumed to be 100 square eet (9.3 m
2) per person.
Domestic water is available at the top o the building,with 15-psig (103-kPa) pressure. Applicable codes are
the Uniorm Plumbing Code and the Uniorm Build-ing Code.
First calculate the number o drinking ountainsrequired. The occupancy is 146 people per loor(14,600/100). The Uniorm Building Code requiresone ountain on each foor or every 75 people, so
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146/74 = 1.94 ountains per foor. Thereore, use twoountains per foor, or a total o 20 ountains.
Determination o heat gain in piping requires pipesizes, but these sizes cannot be accurately knownuntil the heat gains rom the makeup water, piping,storage tank, and pumps are known. Thereore, as-sume 1-inch (25-mm) diameter chilled water risers,circulation line, and distribution piping to the risers.Then, the heat gains in the piping system are as ol-lows (rom Table 12-4):
Total piping heat gain = 3,249 Btuh (953 W)The water that must be cooled and circulated is
at a minimum o 3 gpm (11.4 L/h) per riser, or a totalo 6 gpm (22.7 L/h).
Next, calculate the rerigeration load due to thecirculating pump input. The pump head can be de-termined rom data given in Table 12-7 and Figure
12-15. The results o the calculations are given inTable 12-8, with the indicated pumping requirementsbeing 6 gpm (22.7 L/h) at a 25.77-oot (7.85-m) head.Data rom one manuacturer indicates that a ¾-hp
(0.56-kW) motor is needed. From Table 12-5, the heatinput o the pump motor is 1,908 Btuh (559 W).
Finally, calculate the rerigeration load due to thestorage tank heat gain. The tank is normally sizedor 50 percent o the total hourly demand. Thus, or100 gph (379 L/h), a 50-gallon (190-L) tank would beused. This is approximately the capacity o a standard16-inch (406-mm) diameter, 60-inch (1,524-mm) long tank. Assume 1½-inch (38-mm) insulation, 45°F(7.2°C) water, with the tank in a 90°F (32.2°C) room. Assume an insulation conductivity o 0.13 Btuh persquare oot
(0.4 W/m
2). The surace area o the tank
is about 24 square eet (2.2 m2). Thus, the heat gain
is 24 x 0.13 x (90 – 45) = 140 Btuh (41 W).Thus, the load summary is as ollows:
Item Heat Gain, Btuh (W)Makeup water 25,000 (7,325)
Piping 3,240 (949)
Pump heat input 1,908 (559)
Storage tank 140 (41)
Subtotal 30, 288 (8,874)20 percent saety actor 6,050 (1,773)
Required chiller capacity 36,338 (10,647)
Installation
A supply stop should be used so the unit may be ser-viced or replaced without shutting down the watersystem. Also, the designer should consult local, state,and ederal codes or proper mounting height.
STANDARDS, CODES, ANDREGULATIONS Whether a sel-contained (unitary) cooler or a central
chilled water system, most mechanical installationsare subject to regulation by local codes. They mustcomply with one or more plumbing, rerigeration,electrical, and accessibility codes. The majority o such local codes are based on model codes preparedby associations o nationally recognized experts.
Table 12-4 Circulating System Line Loss
Pipe Size, in.(mm)
Btu/h per FtPer °F
(W/°C/m)
Btu/h per 100 Ft (W per 100 m)[45°F (7.2°C) Circulating Water]
1. Capacities are in gph per 100 t (L/h per 100 m) o pipe including all branchlines necessary to circulate to limit temperature rise to 5°F (2.8°C) [water at45°F (7.2°C)].
2. Add 20% or a saety actor. For pump head, gure longest branch only. Installpump on the return line to discharge into the cooling unit. Makeup connectionshould be between the pump and the cooling unit.
Table 12-5 Circulating Pump Heat Input
Motor, Hp (kW) ¼ (0.19) 1 ⁄ 3(0.25) ½ (0.37) ¾ (0.56) 1 (0.75)
Note: Table gives loss o head in eet (meters) due to riction per 100 t (30 m) o smooth straight pipe.
Municipalities choose one o these model codes andmodiy it to suit local conditions. For this reason, it isimportant to reer to the code used in the locality andto consult the authority having jurisdiction.
Local rerigeration codes vary considerably. TheUniorm Building Code sets up guide regulations per-taining to the installation o rerigeration equipment.It is similar in most requirements to ANSI/ASHRAE15: Saety Standard or Rerigeration Systems, withsome notable exceptions. Thereore, it is important
to careully apply the local code in the design o thererigeration portion o a chilled drinking water sys-tem. Other local codes that merit careul review arethe electrical regulations as they apply to controls,disconnection switches, power wiring, and ASMErequirements or tanks and piping.
In addition to ARI 1010 and ANSI/ASHRAE 18,UL 399 covers saety and sanitation requirements.Federal Specication WW-P-541: Plumbing Fixtures,among others, usually is prescribed by governmentpurchasers.
NSF/ANSI 61 is intended to cover specic materi-als or products that come into contact with drinking water, drinking water treatment chemicals, or both.The ocus o the standard is the evaluation o contami-nants or impurities imparted indirectly to drinking water.
A ew states, including Caliornia, Vermont,Maryland, and Louisiana, have enacted “lead-ree”legislation applicable to any product that dispensesor conveys water or human consumption. (Note that
this does not replace NSF/ANSI 61 requirements.)Federal legislation revising the denition or “leadree” within the Sae Drinking Water Act as it pertainsto pipe, pipe ttings, and xtures will go into eecton January 4, 2014.
Many local plumbing codes apply directly to watercoolers. Primarily, these codes are directed towardeliminating any possibility o cross-connection be-tween the potable water system and the wastewater(or rerigerant) system. Thereore, most coolers aremade with double-wall construction to eliminate thepossibility o confict with any code.
Table 12-8 Pressure Drop Calculations or Example 12-1
Froma
Pipe Length, t (m)Water Flow,
gpm (L/h)Selected gpm
Size, in.
Pressure Drop, t (m) CumulativePressure Drop,
t (m)Actual Equivalentb
100 t Actual tA to B 30(9) 45(14) 6(23) 1 5.0(1.5) 2.25 (0.7) 2.25(0.7)
B to D 180(55) 270(82) 3(11.5) 1 1.3(0.4) 3.5 (1.1) 5.75(1.8)
D to A 270(82) 406(124) 6(23) 1 5.0(I.5) 20.02 (6.1) 25.77(7.9)
a Reer to Figure 12-15.bIncrease 50% to allow or ttings. I an unusually large number o ttings is used, each should be considered or its actual contribution to pressure drop.
Pretreatment o eluent prior to discharge is a requirement established by ederal legislation andimplemented by ederal regulations and state andlocal legislation. Pretreatment requirements ap-ply to both direct discharges (i.e., to drain elds,streams, lakes, and oceans) and indirect discharges
as in collection systems leading to treatment works.Pretreatment is required o all industrial discharges,which includes all discharges other than those roma domestic residence.
Pretreatment can involve the removal o metals,adjustment o pH, and removal o organic compounds.CFR Title 40: Protection o Environment, publishedby the U.S. Environmental Protection Agency (EPA),denes pretreatment as “the reduction o the amounto pollutants, or the alteration o the nature o pol-lutant properties in wastewater prior to or in lieu o discharging or otherwise introducing such pollutants
into a POTW [publicly owned treatment works]. Thereduction or alteration may be obtained by physical,chemical, or biological processes, process changes, orby other means, except as prohibited.”
Bioremediation is a pretreatment method thatsimultaneously removes a pollutant rom the wastestream and disposes o it by altering its chemical orphysical structure such that it no longer depreci-ates water quality (in the case o direct discharges)or causes intererence or pass-through (in the caseo indirect discharges). Generally speaking, biore-mediation can be described as the action o living organisms on organic or inorganic compounds to
reduce in complexity or destroy the compound. Typi-cally, bioremediation processes are conducted at thesource o the pollutant to avoid transporting largequantities o polluted wastewater or concentrationso pollutants. The most common application o biore-mediation to plumbing systems is or the disposal o ats, oils, and grease (FOG).
PRINCIPLE OF OPERATIONBioremediation systems, as described here, do notinclude the practice o adding enzymes, bacteria, nu-
trients, or combinations thereo (additives) to greasewaste drainage, grease traps, or grease interceptors.The use o additives in conventional apparatus is a cleaning method resulting in the removal o FOGrom the apparatus and its deposition downstream.Recombined FOG is usually a dense orm, which is
more dicult to remove rom sewer mains and litstations than the substance not altered by the ap-plication o additives.
Bioremediation systems are engineered systemscontaining the essential elements o a bioreactorthat can be operated by the kinetic energy impartedrom fowing water or mechanically agitated by vari-ous pumping and aeration methods. Bioremediationsystems can be aerobic (requiring oxygen or themetabolic activity o the organisms), anaerobic (notrequiring oxygen), or a combination o both. The typeo bioremediation system employed is determined
mainly by the target compound and the organismsnecessary to metabolize that compound. In the caseo FOG, typically the application o bioremediationis aerobic. Figure 13-1 shows a kinetically operatedaerobic bioremediation system.
Central to the operation o all on-site bioremedia-tion systems applied to FOG are:
• Separation, or the removal o FOG rom thedynamic waste fow
• Retention, allowing the cleaned wastewater toescape, except or the static water content o thedevice
• Disposal, or the metabolic disassembly o FOGto its elements o hydrogen, oxygen, and carbon,usually in the orm o water and carbon dioxide
Incidental to the application o a bioremediationsystem to FOG are:
• Sizing, or the calculation o the potential maximumfow over a designated interval
• Food solids removal rom the liquid wastestream
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• Placement, to minimize the length o untreatedgrease waste piping
SeparationSeparation o FOG with the greatest eciency, mea-sured as the percentage o FOG present in the wastestream and the time necessary to eect separation,is essential to the accomplishment o retention and
disposal. The standards or this measurement arePDI G101, PDI G102, and ASME A112.14.6. Separa-tion can be eected by simple gravity fotation, inwhich case the device must be o sucient volumeto provide the proper retention time and quiescenceto allow ascension o suspended FOG (see Chapter8). Separation also can be eected by coalescence,coagulation, centriugation, dissolved air fotation,and skimming. In these instances, or a given fow,the device is typically smaller in dimension than inthe gravity fotation design.
Because ood particles generally have a specicgravity greater than 1 and are oleophilic, the pres-ence o ood particles materially intereres with theecient separation o FOG rom the waste stream.Food grinders typically are not used upstream o bioremediation systems or this reason and becauseo the increased biological oxygen demand (BOD) thatthe additional waste places on the system.
RetentionThe retention o FOG in a bioremediation systemis essential to its disposal by a reduction in its con-stituent elements. Retention is acilitated by bafes,
compartmentalization, or sedimentation, depending on the system design. Because only 15 percent o sus-pended FOG (at a specic gravity o 0.85) is above thewater’s surace, bioremediation systems that retainFOG a greater distance rom dynamic fows generallyhave greater retention eciencies and capacities thanthose that rely on suspension alone.
DisposalThe disposal o FOG by biochemical processes withinan on-site system is the most distinguishing eatureo bioremediation systems. The organisms respon-sible or metabolizing the FOG may be endemic tothe waste stream or, more likely, seeded by means o a timed or fow-sensitive metering device. Crucial toa disposal unction equal to ongoing separation andretention rates is a sucient population o organismsin contact with the FOG. While this is a unction o sizing (see the section on sizing guidelines later in thischapter), it is also a unction o system design.
The mechanism typically utilized to provide a stable, structured population o organisms in a biore-mediation system is a biolm, which is a controlledbiological ecosystem that protects multiple specieso organisms rom washouts, biocides, and changing environmental conditions in the bioremediation sys-tem. Biolm orms when bacteria adhere to suracesin aqueous environments and begin to excrete a slimy,glue-like substance that can anchor them to manymaterials, such as metals, plastics, soil particles,medical implants, and tissue.
Figure 13-1 Kinetically Operated Aerobic Bioremediation System
Chapter 13 — Bioremediation Pretreatment Systems 229
Biolms are cultivated on structures o variouscongurations o the greatest possible surace area pergiven volume. The structure or structures generallyare reerred to as media. The media may be xed (i.e.,stationary relative to the device and the waste fow),moved by a mechanism such as a series o rotating discs or small, ball-shaped elements, or moved ran-domly by the energy o the waste stream fow and/orpump or aerator agitation.
The organisms inhabiting a biolm reduce theFOG to carbon dioxide and water through a processcalled beta oxidation, in which atty acid chains areshortened by the successive removal o two carbonragments rom the carboxyl end o the chain. Biore-mediation systems utilizing structured biolms aremuch more resistant to the eects o biocides, deter-gents, and other chemicals requently ound in kitchenefuent than systems using planktonic application o organisms. The eciency o bioremediation systemsin terms o disposal depends on the total surace area
o the media relative to the quantity o FOG separatedand retained, the viability and species diversity o thebiolm, system sizing, and installation.
FLOW CONTROLFlow control is sometimes used with bioremediationsystems depending on system design. When fowcontrol devices are prescribed by the manuacturer,generally they are best located near the discharge o the xtures they serve. However, because bioreme-diation systems are engineered systems, the use andplacement o system elements are prescribed by themanuacturer. In instances in which elements o a
bioremediation system may be common to the plumb-ing industry, the manuacturer’s prescription or theapplication o those elements to the system shall pre-vail over common practice or code requirements.
SIZING GUIDELINESThese guidelines are intended as a tool or the engi-neer to quantiy the maximum hydraulic potentialrom a given acility. Typically, xture unit equiva-lency prediction sizing methods and other estimationtools based on utilization rate weighted actors arenot acceptable sizing tools or bioremediation sys-tems. Bioremediation systems must be capable o
accommodating maximum hydraulic events withoutexperiencing upset, blockage, or pass-through.
The sizing procedure is as ollows:
1. Fixture inventory: Itemize every xture capableo liquid discharge to the grease waste piping system including but not limited to sinks, hoods,ware washers, foor sinks and drains, and kettles.Grinder pulpers are generally not discharged tobioremediation systems. Review the manuactur-er’s requirements or each particular system.
2. Capacity calculation: Calculate the capacity o liquid-retaining devices such as sinks as ollows:
Length × Width × Depth = Capacity, in cubicinches
Capacity × Number o compartments = Total ca-pacity, in
cubic inches
Total cubic capacity ÷ 231 = Gallons capacity
Gallons capacity × 0.75 (ll actor) = Rated dis-charge, in gallons per minute (gpm)
(Note: I a two-minute drain duration is used, di-vide the rated discharge by two.)
3. Rated discharges: Fixtures such as ware wash-ers with a manuacturer’s rated water consump-tion or single discharge rate are calculated at thegreater rate.
4. Floor sinks and drains: Floor sinks and drainsgenerally are rated at 4 gpm. Count the numbero foor drains and sinks not receiving indirect
discharges rom the xtures calculated above andmultiply by our to determine the gpm potential.I this number exceeds the total supply to the a-cility, select the smaller o the two numbers.
5. Loading infuences: Some manuacturers mayprescribe multipliers or various acility char-acteristics such as cuisine to accommodate an-ticipated increased organic content per gallon o calculated discharge. Reer to the manuacturer’srequirements or specic systems.
DESIGN STANDARDSEach manuacturer o a bioremediation system has
specic design elements to establish tness or thepurpose o its particular design. Certain undamen-tal materials and methods utilized in the design andmanuacture o bioremediation systems are indicatedby the ollowing standards:
• ASME A112.14.6: FOG (Fats, Oils, and Greases) Disposal Systems
• ASTM C33: Standard Specifcation or Concrete Aggregates
• ASTM C94: Standard Speciication or Ready Mixed Concrete
• ASTM C150: Standard Specifcation or Portland
Cement
• ASTM C260: Standard Speciication or Air- Entraining Admixtures or Concrete
• ASTM C618: Standard Specifcation or Coal Fly Ash and Raw or Calcined Natural Pozzolan orUse in Concrete
• PDI G101: Testing and Rating Procedure or Hydro Mechanical Grease Interceptors
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• PDIG102:Testing and Certifcation or Grease Interceptors with FOG Sensing and Alarm Devices
• ACI 318: Bu ilding Code Requirements o rStructural Concrete
• IAPMO PS 1: Tank Risers
• UL 5085-3: Low Voltage Transormers—Part 3:Class 2 and Class 3 Transormers
• AASHTO H20-44
• U.S. EPA Test Method 1664
MATERIALS
ConcreteI concrete is used as the container material ora bioremediation system, the concrete and rein-orcement should be o sucient strength to resiststresses caused during handling and installationwithout structural cracking and be o such corro-
sion-resistant quality to resist interior and exterioracids that may be present. Concrete should have a minimum compressive strength o 3,500 pounds persquare inch (psi) (24,132 kPa) and a maximum water-cementing materials ratio o 6 gallons per sack o cement. Concrete should be made with Type II or V,low-alkali Portland cement conorming to ASTM C150and also should include the sulate expansion optionas specied in Table 4 o ASTM C150 or Type II or V. Concrete should contain 4 to 7 percent entrainedair utilizing admixtures conorming to ASTM C260.Concrete aggregates should conorm to ASTM C33.I ready-mix concrete is used, it should conorm to
ASTM C94. Fly ash and raw or calcined natural pozzo-lan, i used as mineral admixture in Portland cementconcrete, should conorm to ASTM C618.
Stainless SteelStainless steel used in bioremediation systems shouldbe o type 316 or o some other type with equal orgreater corrosion resistance.
Fiberglass-Reinorced PolesterBioremediation systems constructed principally o berglass-reinorced polyester should comply with theminimum requirements expressed or septic tanks inSection 5 o IAPMO PS 1.
PolethleneBioremediation systems constructed principallyo polyethylene should comply with the minimumstandards expressed or septic tanks in Section 5 o IAPMO PS 1.
STRUCTURAL CONSIDERATIONSBioremediation systems should be designed to handleall anticipated internal, external, and vertical loads.
Bioremediation system containers, covers, andstructural elements that are intended or burial and/ or trac loads should be designed or an earth loado not less than 500 pounds per square oot (24 kPa)when the maximum coverage does not exceed 3 eet(0.9 meter). Each system and cover should be struc-turally designed to withstand all anticipated earthor other loads and should be installed level and on a solid surace.
Bioremediation systems, containers, covers, andstructural elements or installation in trac areasshould be designed to withstand an AASHTO H20-44 wheel load and an additional 3-oot (0.9-m) earthload with an assumed soil weight o 100 pounds persquare oot (4.8 kPa) and a fuid equivalent sidewallpressure o 30 pounds per square oot (1.4 kPa).
Internal construction o separations, coalescing suraces, bafes, and structures that may compart-mentalize fuids should be designed to withstandthe maximum expected hydrostatic pressure, which
includes the pressure exerted by one compartmentat maximum capacity with adjacent compartmentsempty. The internal structures should be o suitable,sound, and durable materials consistent with indus-try standards.
In buried applications, bioremediation systemsshould have sae, reasonable access or prescribedmaintenance and monitoring. Access could consisto horizontal manways or manholes. Each accessopening should have a leak-resistant closure thatcannot slide, rotate, or fip. Manholes should extendto grade, have a minimum diameter o 20 inches (0.5m) or be 20 × 20 inches (0.5 × 0.5 m) square, and
should comply with IAPMO PS 1 Section 4.7.1.Bioremediation systems should be provided with
drawings as well as application and disposal unc-tion details. Descriptive materials should be com-plete, showing dimensions, capacities, fow rates,structural and process ratings, and all applicationand operation acts.
DIMENSION AND PERFORMANCECONSIDERATIONSBioremediation systems dier regarding type andoperating method, but all should have a minimumvolume-to-liquid ratio o 0.4 gallon per 1-gpm fow
rating and a minimum retention ratio o 3.75 poundso FOG per 1-gpm fow. The inside dimension betweenthe cover and the dynamic water level at ull-ratedfow should be a minimum o 2 inches (51 mm). Whilethe air space should have a minimum volume equal to10.5 percent o the liquid volume, air management andventing shall be prescribed by the manuacturer.
The bioremediation system’s separation and re-tention eciency rating should be in accordance
Chapter 13 — Bioremediation Pretreatment Systems 231
with PDI G101. Bioremediation systems shouldshow no leakage rom seams, pinholes, or other im-perections.
Perormance testing o bioremediation systemsshould demonstrate perormance equal to or exceed-ing manuacturer claims and should have a minimumdischarge FOG content not to exceed 100 milligramsper liter. Perormance testing should be conductedonly by accredited, third-party, independent labora-tories in accordance with current scientic methodsand EPA analysis procedures.
INSTALLATION AND WORKMANSHIPInstallation should be in accordance with the manu-acturer’s requirements. Bioremediation systemsshould be ree o cracks, porosity, fashing, burrs,chips, and lings or any deects that may aect per-ormance, appearance, or serviceability.
Plumbing engineers are not the green police. Theirprimary responsibility is serving the client who hiresthem to design a specic set o plumbing systems.However, plumbing engineers can try to educateclients and help them appreciate the immediate andlong-term benets o sustainable design, and as a
result o these eorts, more projects are going green.In act, many authorities having jurisdiction requiresome o the practices discussed in this chapter.
By incorporating sustainable design practicesinto their projects, plumbing engineers can helpclients save water, energy, and money, as well aspotentially obtain Leadership in Energy and En-vironmental Design (LEED) certication. All par-ties benet by increasing the eciency o buildings. Also, it is essential to make eorts to preserve someo the natural resources that are being fushed awayevery day. Some o these design considerations are
mandated by ederal law. Some may be legislatedin the uture. Others provide immediate nancialbenets, and many provide health benets. Sustain-able design practices are constantly evolving, andit is up to each individual to investigate emerging technologies and choose the best systems or theirclients.
WHAT IS SUSTAINABLE DESIGN?Sustainable design is not a new concept. It has beendone or decades. In some cases, current sustainabledesign practices actually return to old technologiesthat were abandoned when petroleum products be-
came so available and cheap. However, sustainabledesign has taken on new meaning with the popularityo green building. Plumbing engineers should alwaysconsider the eciency o the systems they design orany project and utilize the sustainable technologiesthat are appropriate or each project’s needs. Whilesome sustainable practices help achieve LEED certi-cation, many do not, but certication should not bethe only objective.
In a 1987 report, the Brundtland Commission,ormerly known as the U.N. World Commission on
the Environment and Development, dened sus-tainable development as “development that meetsthe needs o the present without compromising theability o uture generations to meet their needs.”Sustainable development also might be described asdesign and construction practices that signicantly
reduce or eliminate the negative impact o buildingson the environment and occupants in ve broad ar-eas: sustainable site planning, saeguarding waterand water eciency, energy eciency and renewableenergy, conservation o materials and resources, andindoor environmental quality.
ASSESSMENT AND VALIDATIONNumerous organizations worldwide provide rat-ing and accreditation processes or various types o construction. The Building Research EstablishmentEnvironmental Assessment Method (BREEAM) isthe European equivalent to the U.S. Green Building Council’s LEED program.
The USGBC and LEEDThe U.S. Green Building Council is a nonprot co-alition o leaders rom across the building industrywho promote buildings that are environmentallyresponsible, protable, and healthy places to liveand work. The purpose o this organization is to in-tegrate building industry sectors and lead a markettransormation—including the education o owners
and practitioners.LEED stands or Leadership in Energy and Envi-
ronmental Design. The LEED certication program
encourages a whole-building approach. It promotesand guides a collaborative process o integrated designand construction. Rating systems are available ornew construction, existing building operations andmaintenance, core and shell, commercial interiors,schools, retail, homes, healthcare, and neighborhooddevelopment.
LEED helps plumbing engineers design systemsthat optimize environmental and economic actors,increasing eiciency in these areas. LEED also
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provides recognition o quality buildings and environ-
mental stewardship through third-party validation o achievement and ederal, state, and local governmentincentives.
The our levels o LEED certication are Certied,Silver, Gold, and Platinum. Note that the certicationlevels are subject to change and refect the currentsystem. Always double-check which system and ver-sion applies to each particular project. For the latestinormation on LEED systems and certication, visitusgbc.org.
The LEED program is broken into categories inwhich numerous credits can be obtained. The programocuses on sustainable sites, water eciency, energy
and the atmosphere, materials and resources, indoorenvironmental quality, and innovation in design. Theplumbing systems that plumbing engineers design canhelp obtain credits in many o the categories.
REAL-LIFE FINANCIAL BENEFITSThe most common objections to building green are theperceived high cost o LEED documentation and high-er design and construction costs. While it is estimatedthat construction costs may increase 3 percent or a
LEED-certied building,the construction cost o a typical oce building hasbeen shown to be about2 percent o the totallietime cost, assuming a 20-year liespan, andabout 5 percent or oper-ation and maintenance,whereas the people in-habiting the building may account or as muchas 92 percent o the totalcost through salaries andbenets.
Increased sustain-ability in plumbing sys-tem designs can havedirect nancial rewards.Some o the ways that
sustainable design prac-tices can provide tan-gible nancial benetsare through reducedoperating and mainte-nance costs, as well asreduced insurance andliability through the im-proved health o occu-pants, greater occupantsatisaction, improvedperormance o occu-pants, reduced absentee-
ism, lower environmental impacts, and streamlinedregulatory approvals. Sustainable design also leadsto higher building valuations. The rule o thumb isto divide the reduction in annual operating costs by10 percent to get the increased value o the build-ing, which may be up to $4 in increased valuation orevery $1 spent. Green buildings also typically enjoyhigher visibility and marketability.
HOW PLUMBING SySTEMSCONTRIBUTE TO SUSTAINABILITy
Domestic Water Use Reduction orIrrigation
Some LEED credits are related to irrigation. A build-ing can earn points by reducing or eliminating theamount o domestic water required or irrigation andlandscaping. How can this be accomplished? Methodsor earning these credits include many design choices,such as utilizing plantings that do not require water-ing other than the rain that they receive naturally,using rainwater to sustain the landscaping, and cap-turing and reusing wastewater rom the building,such as condensate waste, or landscaping needs.
Table 14-1 Treatment Stages or Water Reuse
Level 1 ComponentsNonpotable systems needing limited treatment• Catchmentushing• Largecontaminateremoval• Sedimentltration
Level 3 ComponentsPotable water or human consumption• Alloftheprevioussteps• Automatedsystemtestingofpre-potableincomingwater• Increasedlevelofltration• Increasedlevelofdisinfectionprocesses• Automatedsystemoftestingthewateraftertreatment
to conrm water quality meets the standards or humanconsumption
Domestic Water Use Reduction orFituresTo earn LEED points or plumbing xtures, the proj-ect team must demonstrate that the domestic waterrequired or the plumbing xtures was reduced. Speci-ying low-fow xtures in lieu o conventional xturescan easily accomplish this objective or most projects.
The standards used as the reerence, or baseline, areper the requirements o the Energy Policy Act o 1992.This includes 1.6-gallon-per-fush (gp) toilets, 1-gp urinals, 2.5-gallon-per-minute (gpm) aucets, and2.5-gpm showerheads. Note that fush xtures arerated in gp, and fow xtures are rated in gpm. Thesexture types have dierent characteristics and needto be addressed relative to their unctionality.
Some o the reduced-consumption xtures include1.28-gp toilets; 0.5-gp, 0.125-gp, and waterlessurinals; 0.5-gpm aucets; 1.6-gpm kitchen aucets;and 2-gpm, 1.8-gpm, 1.5-gpm, and even 1-gpm show-erheads. Which xtures are best? It depends on the
project. This is a decision that must be made by theplumbing designer in conjunction with the architect,taking into consideration the needs o the owner.Some o the considerations may be site-specic. Forinstance, waterless urinals may be a good choice inareas that have little or no water supply. 0.125-gp urinals may be more appropriate or other projects.
Another water-saving technique is vacuum-operated waste transport systems. They are used oncruise ships and in some prisons. The water closetsrequire only 0.5 gp, but additional energy is requiredto operate the vacuum pumping system. This drainagesystem relies on a mechanical device requiring power
to operate, which adds another po-tential weak point to the system.
Wastewater Management Wastewater management must bepart o a total sustainable building strategy. This includes consider-ation o the environmental impactso wastewater: the quality, quantity,and classication o wasted mattermust be taken into account. Thewastewater expelled rom buildingsis a combination o biodegradable
waste, reusable waste, storm waterruno, and non-degradable waste.The biodegradable waste can beconsidered a source o nutrientsthat can go back into nature bybioremediation methods. Manynon-degradable wastes can be recy-cled. Some by-products may requirehandling as hazardous materials.
Storm water runo can be recycled and used to reducedomestic water consumption.
Wastewater reclamation and reuse systems canbe categorized into the ollowing levels (see Table14-1).
• Level 1—Nonpotable systems needinglimitedtreatment: Rainwater and condensate waste
collection systems shall be provided or irrigationand cooling use. Provide a collection tank,circulating pump, and point o connection orlandscaping, coordinating with the landscape andheating, ventilating, and air-conditioning (HVAC)contractors. Recovery and delivery systems shouldinclude redundant tanks and other equipment toacilitate cleaning and maintenance. Domesticwater makeup also should be included oremergency use and when supplementary water isrequired. Excess water production rom Level 1shall be conveyed to Level 2.
• Level 2—Low-level potable systems: Level 2 systems
shall collect water rom graywater processing, aswell as rom Level 1 production surpluses. Eachsystem should include redundant tanks and otherequipment to acilitate cleaning and maintenance.Domestic water makeup also should be includedor emergency use and when supplementary wateris required. Each graywater system shall includelters, an ultraviolet (UV) system, tanks, pumps,etc., all o which must be indicated on the plumbing drawings. The graywater reuse xtures may returntheir waste to a black water treatment system.This type o system typically treats suspended
Figure 14-1 Typical Small Rainwater Cistern System Diagram
solids, odors, and bacteria in water to be reusedor toilet fushing.
• Level 3—Potable water or human consumption:Level 3 consists o both public domestic waterand water rom Level 1 and Level 2 systems, withadditional treatment. Water shall be collected romthe public water utility, as well as rom Level 1 and
Level 2 production surpluses. The Level 1 and 2water must be processed with UV, reverse osmosis(RO), ozone, and ltering systems similar to Level2, but monitored to EPA or NSF Internationalstandards or the local equivalents. Each systemshall include lters, a UV or similar system, tanks,
pumps, etc., all o which must be indicated on theplumbing drawings.
• Level 4—Black water or nonpotable systems:Level 4 includes water not meant or humanconsumption without urther processing. It canbe used or toilet fushing and laundry acilities.This system must include redundancy. Water shall
be collected rom the graywater system, as wellas rom Level 1 and Level 2 production surpluses.Each system shall be provided with emergencydomestic water makeup. Each system shall includelters, a UV system, tanks, pumps, etc., all o whichmust be indicated on the plumbing drawings.
Table 14-2 Rainwater Treatment Options
Treatment Method Location Result
Screening
Lea screens and strainers Gutters and downspoutsPrevents leaves and debris romentering tank
SettlingSedimentation Within tank Settles out particulates
Activated charcoal Beore tap Removes chlorine*
FilteringRoo washers Beore tank Removes suspended material
Chlorination$1/month manual dose or$600–3,000 or automaticdosing system
Include monitoring withautomatic dosing
Less eective in highturbidity; should bepreltered
Excessive chlorine levelshave been linked to healthissues and damage tocopper piping systems
Source: Texas Guide to Rainwater Harvesting, 2nd
edition, Texas Water Development Board
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• Level 5—Black water or potable systems: Level 5includes water not meant or human consumptionor contact without additional treatment. It consistso black water that has been collected and treated.Each system shall include membrane ilters,bio-chambers, a UV system, tanks, pumps, etc.,as indicated on the plumbing drawings. Sludgeaccumulation shall be conveyed to a suitable site
or urther processing and disposal, based on ananalysis o the sludge components.
Rainwater Capture and ReuseRainwater reuse can help earn more than one credit:water use reduction, wastewater management, stormwater management, and innovation in design. Thecaptured water may be used or irrigation, fushing toilets, or cooling tower makeup, among other uses. Various ltration methods may be necessary, depend-ing on the nal use o the water. Ideally, the storagetanks should be elevated, such as on the top foor o the building, to reduce or eliminate pumping require-
ments. Remember that tanks store water, but also canstore pressure by permitting the stored water to fow bygravity. Static head increases with height. I the build-ing is high enough to require multiple water pressurezones, multiple tanks can be located at varying levels,possibly with one tank cascading down to another. Aswith all aspects o design, the approach must be cus-tomized relative to each individual project. Figure 14-1shows a typical small cistern system diagram.
Many jurisdictions require rainwater detentionto control the release rate into the sewer systems.Many municipal systems are overloaded and cannotprocess the storm water entering the system during
signicant rain events. Some cities have combinedstorm and sanitary sewer systems, which can makethe problem even worse. One o the causes o this
problem is increased impermeable surace eaturesdue to increased density, a result o urban sprawl. Thiseect can be reduced through the use o green roos,permeable paving materials, storm water detention,and other innovative approaches.
Table 14-2 outlines some types o treatment orrainwater systems. Many options are available,or dierent purposes. Most systems require somecombination o these treatment options. Table 14-3compares the cost, maintenance, and eectiveness o these ltration and disinection methods.
Storage tanks come in many shapes, sizes, andmaterials. They can be located below grade, abovegrade, near the roo, or in many other locations. Table14-4 compares the dierent storage tank options orrainwater collection.
Grawater and Black Water About 68 percent o household wastewater is gray-water. The other approximately 32 percent is blackwater. Figure 14-2 and Table 14-5 compare the two
types. Wastes rom dishwashers and kitchen sinkscan be piped to automatic grease separators. Theseseparators automatically siphon o the ats, oils, andgreases, which can be used or bio-diesel uel. Theremaining wastewater then is processed as blackwater. It’s a good idea to locate these acilities on thetruck dock or another location that provides plentyo external venting to reduce odors indoors.
Biosolids Technolog Biosolids can be a by-product o graywater, butthey primarily come rom black water processing. A biosolid is the remaining sludge and also what is
skimmed rom the surace. It consists o dierentcomponents requiring a variety o handling methodsand technologies.
Table 14-4 Storage Tank Options
Material Features Cautions Cost Weight
Plastics
Polyethylene/polypropyleneCommercially available,alterable, and moveable
UV-degradable; must bepainted
$.035–1.00/gallon 8 lbs/gallon
FiberglassCommercially available,alterable, and moveable
Must be sited on smooth,solid, level ooting
$0.50–2.00/gallon 8 lbs/gallon
Metals
Steel Commercially available,alterable, and moveable Prone to rust and corrosion $0.50–2.00/gallon 8 lbs/gallon
Welded steelCommercially available,alterable, and moveable
Possibly prone to rust andcorrosion; must be lined orpotable use
$0.80–4.00/gallon 8 lbs/gallon
Concrete and MasonryFerrocement Durable and immovable Potential to crack and ail $0.50–2.00/gallon 8 lbs/gallon
Stone, concrete block Durable and immovable Dicult to maintain $0.50–2.00/gallon 8 lbs/gallon
Monolithic/poured in place Durable and immovable Potential to crack and ai l $0.30–1.25/gallon 8 lbs/gallon
Wood
Redwood, r, cypressAttractive, durable, can bedisassembled and moved
A compostable material is one that undergoesphysical, chemical, thermal, and/or biological deg-radation in a mixed municipal solid waste (MSW)composting acility such that it is physically indis-tinguishable rom the nished compost. The nalproduct ultimately mineralizes (biodegrades to carbondioxide, water, and biomass as new microorganisms)at a rate like that o known compostable materials insolid waste such as paper and yard waste. A compost-compatible material is one that disintegrates andbecomes indistinguishable rom the nal compost andis either biodegradable or inert in the environment. A removable material is one that can be removed (notto be composted) by existing technologies in MSW composting (such as plastics, stones, or glass).
To ensure that biosolids applied to the land do notthreaten public health, the EPA created 40 CFR Part503. This rule categorizes biosolids as Class A or Bdepending on the level o pathogenic organisms in thematerial and describes specic
processes to reduce pathogensto these levels. The rule alsorequires vector attraction re-duction (VAR)—reducing thepotential o the spreading o inectious disease agents byvectors (i.e., lies, rodents,and birds)—and spells outspeciic management prac-tices, monitoring requencies,record keeping, and reporting requirements. Incineration o biosolids also is covered in the
regulation.Class A biosolids contain
minute levels o pathogens. Toachieve Class A certication,biosolids must undergo heat-ing, composting, digestion,or increased pH to reducepathogens to less than detect-able levels. Some treatmentprocesses change the composi-tion o the biosolids to a pelletor granular substance, whichcan be used as a commercial
ertilizer. Once these goals areachieved, Class A biosolids canbe applied to land without anypathogen-related restrictionsat the site. Class A biosolidscan be bagged and marketedto the public or applicationon lawns and gardens.
Class B biosolids have lessstringent standards or treat-
ment and contain small but compliant amounts o bacteria. Class B requirements ensure that pathogensin biosolids have been reduced to levels that protectpublic health and the environment and include cer-tain restrictions or crop harvesting, grazing animals,and public contact or all orms o Class B biosolids. Asis true o their Class A counterpart, Class B biosolidsare treated in a wastewater treatment acility andundergo heating, composting, digestion, or increasedpH processes beore leaving the plant. This semi-solidmaterial can receive urther treatment when exposedto the natural environment as a ertilizer, whereheat, wind, and soil microbes naturally stabilize thebiosolids.
Class A Technologies
Technologies that can meet Class A standards includethermal treatment methods such as composting, heatdrying, heat treatment, thermophilic (heat generat-ing) aerobic digestion, and pasteurization. Class A
Table 14-5 Comparison o Graywater and Black Water
Parameter Graywater Black Water Grey + BlackBOD5
1(g/p/d
2and mg/l) 25 and 150-300 20 and 2,000–3,000 71
BOD5 (% o UOD3) 90 40 –
COD4(g/p/d and mg/l) 48 and 300 72 and 2,000–6,000 –
Total P (g/p/d and mg/l) 2 and 4–35 1.6 4.6
Total N (g/p/d) 1 (0.6–5 mg/l) 11 (main source urine) 13.2
TSS (g/p/d) 18 > 50 70
Pathogens Low Very high Very high
Main Characteristic Inorganic chemicals Organics, pathogensInorganics, organics,
and pathogens1BOD5 = Oxygen required or the decomposition o the organic content in graywater during the rst ve days, determined as BOD
ater a ve-day period o incubation under standard conditions2g/p/d = grams/person/day
3UOD = Ultimate (total) oxygen demand in a sample taken
4COD = Oxygen demand or all chemical (organic and inorganic) activities; a measure o organics
Sources: Haug 1993; Droste 1997; Dixon et al. 1999b; Hammes et al. 2000; Lindstrom 2000a, 2000b
Figure 14-2 Graywater vs. Black Water
Graywater Black Water
Showers Toilets
Baths Urinals
Lavatories Kitchen Sinks
Clothes Washers Dish Washers
Graywater = Wastewaterthat has a low bacteria,
chemical, or solids loading
Black water = Wastewaterthat has a high bacteria or
high organic content
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Figure 14-3 Simple Solar Domestic Water Heater Diagram
SOLAR
RADIATION
1. SOLAR COLLECTORS
2. TEMPERATURE/PRESSURE
RELIEF VALVE
3. STORAGE TANK
4. HEAT EXCHANGER
5. WATER SUPPLY
6. AUXILLARY HEAT SOURCE
7. TO BUILDING
1
2
4 3
7
5
6
2
LEGEND
technologies are known as PFRP, or processes thatcan urther reduce pathogens. The technologies mustprocess the biosolids or a specic length o time at a specic temperature.
• Composting:Thisisanenvironmentallyfriendlyway to recycle the nutrients and organic matteround in wastewater solids. Composting systems
turn wastewater biosolids, sawdust, yard waste,and wood chips into high-quality compost. As thematerial decomposes, oxygen lters through thecompost site, releasing water, heat, and carbondioxide. This process helps dry the organic material,while the generated heat increases the rate o decomposition and kills pathogens.
• Heat drying: This process applies direct or indirectheat to reduce the moisture in biosolids. Iteliminates pathogens, reduces volume, and resultsin a product that can be used as a ertilizer or soilamendment. Because dryers produce a 90 percentdry material, additional VAR is not required.
• Digestion: In autothermal thermophilic aerobicdigestion (ATAD) systems, biosolids are heatedrom 131°F to 140°F (55°C to 60°C) and aerated orabout 10 days. This autothermal process generatesits own heat and reduces volume. The result is a high-quality Class A product acceptable or reuseas a liquid ertilizer.
• Pasteurization: Pasteurization producesa Class A material when the biosolidsare heated to at least 158°F (70°C)or 30 minutes. This extreme heatkills pathogens in the organic matter.
When ollowed by anaerobic digestion,the VAR is attained, and the biosolidscan be applied to land with minimalrestrictions. The majority o the energyused in the pasteurization processis recovered with an innovative heatexchanger system and used to maintainthe proper temperature in downstreamanaerobic digesters.
Class B Technologies
EPA regulations list technologies, which,under certain operating conditions, can
treat and reduce pathogens so the mate-rial qualies as a Class B biosolid. Theseprocesses are known as processes that cansignicantly reduce pathogens, or PSRP.Class B technologies include anaerobicdigestion, aerobic digestion, composting,air-drying, and lime stabilization.
Several EPA-approved stabilizationtechnologies are available or anaerobicand aerobic digestion, including:
• Heaters, heat exchangers, digester covers, gas, andhydraulic mixing systems, all important componentsin conventional anaerobic digestion systems
• Temperature-phased anaerobic digestion (TPAD)systems, which optimize anaerobic digestionthrough a heat-recovery system that pre-heats rawmaterial and simultaneously cools the digested
biosolids• Membrane gas storage systems, which include
an expandable membrane cover that providesvariable digester gas storage, optimizes digester gasutilization or heating and electrical generation, andincreases storage capacity
• Hydraulic mixers, which use a multi-port dischargevalve to greatly improve biosolids mixing in thedigestion process
• Air diusers and aerators, which can be incorporatedin any aerobic digester conguration
Adding lime can stabilize biosolids by raising the pH
and temperature. While adding sucient amounts o lime to wastewater solids produces Class B biosolids,adding higher amounts yields Class A biosolids. Com-bining low amounts o lime with anoxic storage alsocan yield Class A biosolids.
Energ RequirementsRainwater and condensate collection systems use mini-mal electrical power. Graywater systems or a largeproject may require up to 10,000 kilowatt-hours per year. Black water systems or the same project may beestimated to require as much as 20,000 kilowatt-hoursper year. These numbers are subject to the building
systems or the particular project and vary greatlyrom project to project. As an example, the power consumption ratios o a
typical bioremediation system may consists o 38 per-cent or membrane aeration blowers, 35 percent orother blowers, 16 percent or recirculation pumps, 5percent or process pumps, 4 percent or mixers, and 2percent or controls, monitors, and other equipment.This does not include pumping the water throughoutthe building, which may require additional power.
ENERGy EFFICIENCy AND ENERGy-SAVING STRATEGIES
Energy consumption within plumbing systems can bereduced using several methods, such as variable-re-quency drive domestic booster pump systems. However,energy savings are dicult to dene precisely and varyor every project.
Water heaters oer a potential area or energysavings, as plumbing engineers are speciying morehigh-eciency equipment these days. I required tospeciy a minimum eciency o 84 percent or gas-redboilers, speciying 98 percent ecient units can save14 percent o energy costs, theoretically. One problemin quantiying these savings lies in the act that e-ciencies vary with several actors, including incoming
water temperature and return temperature. Theseactors apply to all types o heaters, but the numberstypically are jaded. Thus, it might be reasonable to as-sume that the system is still 14 percent more ecient.Using low-fow xtures, with their related reduced hotwater consumption, saves as much as 40 percent o theenergy required to heat the domestic hot water.
The expected energy savings can be calculated us-ing gallon-per-day (gpd) gures and extrapolating an
estimated savings. These numbers, combined withenergy consumption and reduction gures or otheraspects o the building, can indicate the percentage o total energy saved. These savings may be applied toLEED energy credits.
High eciency does not always come rom high-eiciency equipment alone. The eicacy must beconsidered relative to the application. 98 percent e-cient water heaters do not necessarily save energyon every system. All designs require an integrated ap-proach and a balance o the correct elements relativeto the needs o the project and the goals o the client.
Solar Water Heating Solar water heating is an excellent way to reduce ener-gy consumption. The average solar system or a typicalhome (see Figure 14-3) can save about two-thirds o thehome’s yearly cost or providing domestic hot water.The energy savings or a commercial application aremore dicult to precisely quantiy, but they may be inthe same range, depending on a variety o actors.
One important actor in any system involving heat transer is the loading o the system. Other thanwhen they are shut down and using no energy, heatexchangers, like pumps, are most ecient when theyare running at 100 percent capacity. Oversizing equip-ment leads to reduced eciencies and maybe evenpremature ailure o the equipment.
Reer to other Plumbing Engineering Design Hand-
book chapters or additional inormation, including Volume 3, Chapter 10: “Solar Energy” and Volume 2,Chapter 6: “Domestic Water Heating Systems,” as wellas the resources listed at the end o this chapter.
Geothermal SstemsGeothermal energy can be used or homes, as well asindustrial and commercial buildings. They even areused by some utility companies to generate steam tospin turbines, creating electrical power or munici-palities. They can be used or radiant heat, as well asradiant cooling. Reer to other Plumbing Engineering
Design Handbook chapters or additional inormation,including Volume 4, Chapter 10.
A A, X#, X#A (compressed air). See compressed air A/m (amperes per meter), 2009 V1: 33 A (amperes). See amperes A (area). See area (A)a (atto) prex, 2009 V1: 34 AAMI (Association or the Advancement o Medical
air drying, 2011 V3: 178–179dened, 2009 V1: 16, 2012 V4: 199rates or soils, 2011 V3: 91trenches. See soil-absorption sewage systems
AC (air chambers). See air chambers (AC)ac, AC (alternating current), 2009 V1: 14 AC-DC rectiers, 2009 V1: 139, 140acc (accumulate or accumulators), 2009 V1: 16acceleration
acceleration limiters, 2012 V4: 125accelerators (dry-pipe systems), 2011 V3: 8–9accellerograms, 2009 V1: 150access. See also people with disabilities
aboveground tank systems, 2011 V3: 148bioremediation pretreatment systems, 2012 V4: 230clean agent gas re containers, 2011 V3: 27to equipment, piping and, 2012 V4: 25underground liquid uel tanks, 2011 V3: 139–140
access channels or pipes, 2012 V4: 125access doors, 2009 V1: 16access openings or pipes, 2012 V4: 125access to (dened), 2009 V1: 16accessibility, 2009 V1: 16. See also people with disabilities
storm drainage, 2010 V2: 48–49 Accessibility Guidelines or Buildings and Facilities, 2009
V1: 97 Accessible and Usable Buildings and Facilities, 2009 V1:
97, 115, 2012 V4: 2accessories
as source o plumbing noise, 2009 V1: 189in plumbing cost estimation, 2009 V1: 85, 88section in specications, 2009 V1: 71
accreditation o health care acilities, 2011 V3: 51accumulation, dened, 2009 V1: 16accumulators (acc, ACCUM), 2009 V1: 16, 2012 V4: 125accuracy
dened, 2009 V1: 17drinking-water coolers and, 2012 V4: 216hangers and supports or systems, 2012 V4: 119piping or ambient temperatures, 2012 V4: 118
ambulatory accessible stalls, 2009 V1: 106 American Chemical Society, 2009 V1: 142 American Concrete Institute (ACI), 2010 V2: 54 American Consulting Engineers Council (ACEC), 2009
V1: 56
American Gas Association (AGA), 2010 V2: 117abbreviation or, 2009 V1: 14, 32codes and standards, 115, 2010 V2: 114, 115relie valve standards, 2010 V2: 106water heating standards, 2010 V2: 112
American Institute o Architects (AIA)General Conditions o the Contract or Construction,
area drains (ad), 2009 V1: 14, 17areas o sprinkler operation, 2011 V3: 12areaways, 2009 V1: 17 ARI (Air Conditioning and Rerigeration Institute), 2012
V4: 215–216arm baths, 2010 V2: 99, 2011 V3: 36, 38, 40 Army Corps o Engineers, 2009 V1: 57arresters or water hammer. See water hammer arrestersarticulated-ceiling medical gas systems, 2011 V3: 56as built, dened, 2012 V4: 128as low as reasonably achievable (ALARA), 2010 V2: 238
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Index 251
ASA. See American National Standards Institute (ANSI) ASA A117.1-1961, 2009 V1: 97asbestos cement piping, 2010 V2: 75, 2011 V3: 242 ASCE. See American Society o Civil Engineers (ASCE) ASHE (American Society or Healthcare Engineering),
2010 V2: 108–109 ASHRAE. See American Society o Heating, Rerigerating
and Air-Conditioning Engineers, Inc. (ASHRAE)
ASHRAE Handbook - Fundamentals, 2010 V2: 136 ASI (architect’s supplemental instructions), 2009 V1: 57 ASJ (all-service jackets), 2012 V4: 106, 108 ASME. See American Society o Mechanical Engineers
(ASME) ASPE. See American Society o Plumbing Engineers
(ASPE) ASPERF (American Society o Plumbing Engineers
Research Foundation), 2009 V1: 32asphalt-dipped piping, 2010 V2: 78asphalt mixers, 2010 V2: 133asphalt pavement, runo, 2010 V2: 42asphyxiant gases, 2009 V1: 17aspirators, 2009 V1: 17, 2011 V3: 40, 2012 V4: 161 ASSE. See American Society o Sanitary Engineering
(ASSE)assemblies, dened, 2012 V4: 128assembly costs, 2009 V1: 210assisted creativity, 2009 V1: 227 Association or the Advancement o Medical
Instrumentation (AAMI), 2010 V2: 187, 219, 220 Association o Pool and Spa Proessionals (APSP), 2011
V3: 104 Association o State Drinking Water Administrators, 2010
V2: 155 ASTM. See American Society or Testing and Materials
(ASTM) ASTs (aboveground storage tanks). See aboveground tank
AV (acid vents), 2009 V1: 8, 16 AV (angle valves). See angle valves (AV)availability. See demandavailability o water, 2009 V1: 17available net positive suction head, 2012 V4: 100available vacuum, saety actors and, 2010 V2: 186 AVB. See atmospheric vacuum breakers (AVB)average fow rates or xtures, 2012 V4: 186average water use, 2009 V1: 117 AW (acid wastes), 2009 V1: 8, 16, 2011 V3: 42–46, 2012
V4: 51 AWS. See American Welding Society (AWS) AWWA. See American Water Works Association (AWWA)axial braces, 2012 V4: 128axial fow, 2012 V4: 100axial motions, hangers and supports and, 2012 V4: 116, 118axial pumps, 2012 V4: 91 Ayres, J.M., 2009 V1: 185
barrelsconverting to SI units, 2009 V1: 38dimensions, 2012 V4: 27–29
barrier ree, 2009 V1: 18. See also people with disabilitiesbarrier-ree water coolers, 2012 V4: 217barriers around tanks, 2011 V3: 149bars, converting to SI units, 2009 V1: 38base acquisition costs, 2009 V1: 217base materials
base dened, 2009 V1: 18compounds in water, 2010 V2: 188pH control, 2011 V3: 85–87
systemsbiological and biomedical laboratories. See laboratoriesbiological characteristics o drinking water, 2010 V2: 217biological control in pure water systems. See microbial
CCS (Certied Construction Specier), 2009 V1: 65CD. See construction contract documents (CD)cd (candelas), 2009 V1: 33CD (condensate drains), 2009 V1: 8CDA (Copper Development Association), 2009 V1: 32CDC (Centers or Disease Control and Prevention), 2009
cm (cubic eet per minute). See cubic eet per minuteCFR (Code o Federal Regulations), 2011 V3: 82cus (colony orming units), 2010 V2: 188CGA. See Compressed Gas Association, Inc.cGMP (current good manuacturing practices), 2009 V1:
14, 2010 V2: 224, 227CGPM (General Conerence o Weights and Measures),
2009 V1: 32, 33chain hangers, 2012 V4: 65chainwheel-operated valves, 2009 V1: 19chalk, 2012 V4: 173chambers (air chambers). See air chambers (AC)Chan, Wen-Yung W., 2009 V1: 39change orders, 2009 V1: 57, 254changed standpipes, 2009 V1: 13changeover gas maniolds, 2011 V3: 270–271Changes in LEED 2009 or Plumbing Fixtures and Process
Water, 2010 V2: 29channel clamps, 2012 V4: 128channels, 2009 V1: 19character in creativity checklist, 2009 V1: 227characteristic curves or pumps, 2012 V4: 95–97Characteristics and Sae Handling o Medical Gases (CGA
P-2), 2011 V3: 78Characteristics o Rural Household Waste Water, 2010
unction denitions, 2009 V1: 219–224unctional evaluation worksheets, 2009 V1: 236–247general checklists or jobs, 2009 V1: 91–92health care acility medical gas and vacuum systems,
Conerence Generale de Poids et Measures, 2009 V1: 33confuent vents, 2009 V1: 20connected loads, 2009 V1: 20, 2010 V2: 136connected standbys, 2011 V3: 27connection strainers, 2011 V3: 124connections section in specications, 2009 V1: 72connectors, fexible gas hose, 2010 V2: 124–125Connectors or Gas Appliances, 2010 V2: 124Connectors or Movable Gas Appliances, 2010 V2: 124conserving energy. See also green building and plumbing
alternate energy sources, 2009 V1: 121–126Bernoulli’s equation, 2009 V1: 5–6domestic water temperatures, 2009 V1: 117–120glossary, 2009 V1: 128hot water system improvements, 2009 V1: 118insulation thickness and, 2012 V4: 106, 107, 110
eet o head to pounds per square inch, 2009 V1: 2gas pressure to destinations, 2010 V2: 127, 130IP and SI, 2009 V1: 38–39, 2010 V2: 170, 2011 V3: 30measurements, 2009 V1: 33meters o head to pressure in kilopascals, 2009 V1: 2parts per million to grains per gallon, 2012 V4: 201vacuum acm and scm, 2010 V2: 166–167vacuum pressures, 2010 V2: 166
CV (check valves). See check valvesCVOL (specic volume). See specic volumecw (cold water). See cold water (CW)CWA. See Clean Water ActCWP (cold working pressure), 2012 V4: 83CWR (chilled water return), 2009 V1: 8CWS (chilled water supply), 2009 V1: 8cyanide, 2011 V3: 87
cycle o concentration in cooling towers, 2010 V2: 216cycles and cycle operation in water soteners, 2012 V4: 201cyclopropane, 2011 V3: 55cylinder banks, gas, 2011 V3: 267–268cylinder-maniold-supply systems, 2011 V3: 57–61, 64, 65cylinder snubbers, 2009 V1: 155cylinders
calculating volume, 2009 V1: 4carbon dioxide extinguishing systems, 2011 V3: 26clean agent gas re suppression, 2011 V3: 27laboratory gas storage, 2011 V3: 267–268regulators, 2011 V3: 271–272
cystoscopic roomsxtures, 2011 V3: 38health care acilities, 2011 V3: 36medical gas stations, 2011 V3: 52, 56
Dd (deci) prex, 2009 V1: 34D (dierence or delta), 2009 V1: 14D (drains). See drainsD (indirect drains), 2009 V1: 8da (deka) prex, 2009 V1: 34Dalton’s law, 2010 V2: 72damage. See bedding and settlement; corrosion; creep;
hazards; scale and scale ormation; seismicprotection; water damage
disposal wells in geothermal energy, 2009 V1: 123disposals, 2009 V1: 21disposers. See ood waste grindersDISS connectors, 2011 V3: 76dissociation, 2009 V1: 21dissolved air fotation, 2012 V4: 228dissolved elements and materials in water
drainage, waste, and vents (DWV). See drain, waste, andvent
drainback solar systems, 2009 V1: 122drainless water coolers, 2012 V4: 217drainline heat reclamation, 2009 V1: 123–126drains (D). See also building drains; horizontal drains;
drinking watercross connections to nonpotable water, 2012 V4: 160drinking water supply (DWS), 2009 V1: 8drinking water supply recirculating (DWR), 2009 V1: 8drinking water systems. See private water systems
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ountains vs. cup service, 2012 V4: 223health care acilities, 2011 V3: 46, 47material codes, 2009 V1: 43potable water, 2009 V1: 27, 2012 V4: 170, 174–175supply as source o plumbing noise, 2009 V1: 189system noise mitigation, 2009 V1: 190–193treatments or, 2010 V2: 218typical usage in oces, 2012 V4: 222, 223
drinking-water coolersaccess to, 2009 V1: 101–105accessories, 2012 V4: 218–219bottle llers, 2012 V4: 219centralized systems, 2012 V4: 222–224compared to water chillers, 2012 V4: 215dened, 2012 V4: 215eatures, 2012 V4: 218–219health care acilities, 2011 V3: 36heating unctions, 2012 V4: 218installing, 2012 V4: 224invention o, 2012 V4: 215options, 2012 V4: 218–219public areas in health care acilities, 2011 V3: 37ratings, 2012 V4: 215–216rerigeration systems, 2012 V4: 219–220standards, 2012 V4: 2stream regulators, 2012 V4: 219types, 2012 V4: 13, 216–218water conditioning or, 2012 V4: 220–221wheelchair space around, 2009 V1: 104
durion, 2009 V1: 22duriron pipe (high silicon), 2012 V4: 53dust, as air contaminant, 2011 V3: 265duty cycles, 2009 V1: 22, 2011 V3: 182, 183duty-cycling controls, 2011 V3: 62, 65DVC (dry vacuum cleaning), 2009 V1: 9, 2010 V2: 178, 186DW. See distilled water (DI, DW)dwellings. See buildings
DWG (drawings), 2009 V1: 14. See also plumbing drawingsDWR (drinking water supply recirculating), 2009 V1: 8DWS (drinking water supply), 2009 V1: 8DWV. See drain, waste, and vent pipes (DWV); drain,
nondepletable, 2009 V1: 128recovered, 2009 V1: 128requirements, wastewater management, 2012 V4: 241solar. See solar energyuse, 2011 V3: 188
energy code list o agencies, 2009 V1: 42energy conservation. See conserving energyenergy eciency. See conserving energyEnergy Eciency and Renewable Energy web site, 2011
F°F, F (Fahrenheit), 2009 V1: 14, 30, 37F (arads), 2009 V1: 34 (emto) prex, 2009 V1: 34F (re-protection water supply). See re-protection
systems to , F TO F (ace to ace), 2009 V1: 22-chart sizing method, solar energy, 2011 V3: 196F/m (arads per meter), 2009 V1: 34abricated steel parts, 2012 V4: 130abrication, dened, 2012 V4: 130abrication section in specications, 2009 V1: 71abricators, 2012 V4: 130
abbreviations or, 2009 V1: 14cold-water system demand, 2010 V2: 75–76conversion to gpm, 2010 V2: 85, 2011 V3: 209, 226drainage xture units (du), 2009 V1: 23orms or charting, 2010 V2: 86governing xtures, 2010 V2: 84–89maximum or vertical stacks, 2010 V2: 4minimum sizes o pipes or xtures, 2010 V2: 86pipe sizing and, 2010 V2: 83sanitary drainage system loads, 2010 V2: 3sizing bioremediation pretreatment systems, 2012
V4: 229slope o drains, 2010 V2: 6–7, 7–8steady fow in horizontal drains, 2010 V2: 8–9water xture units (wu), 2009 V1: 23water hammer and, 2010 V2: 72–73
xture vent design, 2010 V2: 38–39xture vents, types, 2010 V2: 32–34xtures and xture outlets. See also specic types o
xtures (water closets, showers, etc.)accessibility standards, 2012 V4: 2as source o plumbing noise, 2009 V1: 189batteries o xtures, 2009 V1: 18building requirement tables, 2012 V4: 20–23codes and standards, 2009 V1: 43–44cold-water system demand, 2010 V2: 75–76dened, 2012 V4: 1domestic water supply and, 2011 V3: 208xture inventories, 2012 V4: 229xture isolation, 2012 V4: 170fow rates or water soteners, 2012 V4: 186
health care acilities, 2011 V3: 35–42installation productivity rates, 2009 V1: 88laboratory acid-waste drainage systems, 2010 V2: 235LEED (Leadership in Energy and Environmental
V1: 144ungi, 2010 V2: 188, 195unnel-type drains, 2010 V2: 243, 2011 V3: 42urring-out requirements or roos, 2010 V2: 51usible link sprinklers, 2011 V3: 6usion-joint plastic piping systems, 2011 V3: 46uture expansion o compressed air systems, 2011 V3: 182
GG (giga) prex, 2009 V1: 34G (low-pressure gas), 2009 V1: 8G pipes, 2012 V4: 32, 34ga, GA (gauges). See gaugesGACs (granulated carbon lters), 2010 V2: 218, 221. See
also activated carbon ltration
gages (ga, GA, GAGE). See gaugesgal, GAL (gallons). See gallons (gal, GAL)gallons (gal, GAL)
converting to metric units, 2011 V3: 30converting to SI units, 2009 V1: 38gallons per day (gpd, GPD), 2009 V1: 14gallons per hour (gph, GPH), 2009 V1: 14, 38, 2010 V2:
government urnished, contractor installed (GFCI), 2009 V1: 64
gpd, GPD (gallons per day), 2009 V1: 14gpg (grains per gallon). See grains per gallon (gpg)gph, GPH (gallons per hour), 2009 V1: 14gpm (gallons per minute)
converting to xture units, 2010 V2: 85, 2011 V3:209, 226
green building and plumbing biosolids, 2012 V4: 238–240economic benets, 2012 V4: 234economic growth, 2012 V4: 233energy eciency, 2012 V4: 241irrigation, 2012 V4: 234LEED (Leadership in Energy and Environmental
grounding gas systems, 2010 V2: 125groundspace or wheelchairs. See clear foor spacegroundwater, 2009 V1: 24Groundwater Contamination rom Stormwater Infltration,
2010 V2: 55groundwater, 2010 V2: 188
group washups, 2012 V4: 10grouts in wells, 2010 V2: 158growth rate o res, 2011 V3: 2guaranty bonds, 2009 V1: 56guard posts or hydrants, 2011 V3: 220Guide to Federal Tax Incentives or Solar Energy, 2011
V3: 190Guidelines or Seismic Restraints o Mechanical Systems,
heat-up method, condensate drainage, 2011 V3: 163–164heated water. See hot-water systemsheaters (HTR), 2009 V1: 14. See also water heatersHEATG (heat gain). See heat gainheating engineers, 2011 V3: 29heating eed water
or microbial control, 2010 V2: 214or pure water systems, 2010 V2: 221
heating hot water return (HHWR), 2009 V1: 9heating hot water supply (HHWS), 2009 V1: 9heating systems
HVAC. See HVAC systemssolar, dened, 2011 V3: 191
heating, ventilation, and air-conditioning systems. See HVAC systems
heating water. See water heatersheavier-than-air gases, 2010 V2: 134–135heavy brackets, 2012 V4: 130heavy clay loams, 2011 V3: 91
heavy equipment earthquake recommendations, 2009 V1:153–157
heavy metals, 2011 V3: 87, 2012 V4: 198. See also nameso specic metals
heavy process gas service, 2011 V3: 251–252heavy process service gas, 2010 V2: 114hectares, 2009 V1: 34hecto prex, 2009 V1: 34heel inlets on traps, 2010 V2: 15heel-proo grates, 2010 V2: 11heel-proo strainers, 2010 V2: 52
Holtan, H.N., 2010 V2: 55homogeneity in rate o corrosion, 2009 V1: 134horizontal branch hangers and supports, 2012 V4: 65horizontal distances or graywater system elements, 2010
V2: 26horizontal drains
cross-sections o, 2010 V2: 2xture loads, 2010 V2: 6, 8–9fow in, 2010 V2: 2hydraulic jumps in, 2010 V2: 6minimum slope o piping, 2010 V2: 7–8sloping drains in sanitary drainage systems, 2010 V2:
hourly data in sizing water heaters, 2010 V2: 99hours (h, HR), 2009 V1: 34house drains. See building drainshouse pumps, 2010 V2: 66house tanks, 2010 V2: 65–66, 68house traps. See building trapshouses. See buildingshousing project sewers, 150, 2010 V2: 149housings
or gas boosters, 2010 V2: 125or gas lters, 2011 V3: 252
HOW logic path, 2009 V1: 223, 224 How to Design Spencer Central Vacuum Cleaners, 2010
incineration systems, 2009 V1: 122income, in hot water demand classications, 2010 V2: 99inconel, 2009 V1: 132, 2012 V4: 108independent unctions in FAST approach, 2009 V1: 223independent head, 2012 V4: 101indicated horsepower, dened, 2011 V3: 186indirect-circulation solar systems, 2009 V1: 122indirect discharges, 2011 V3: 83, 2012 V4: 227indirect drains (D), 2009 V1: 8indirect-red propane vaporizers, 2010 V2: 134indirect-red water heaters, 2010 V2: 104indirect waste pipes, 2009 V1: 25, 2012 V4: 12, 170indirect waste receptors, 2010 V2: 15–16, 2012 V4: 17. See
also foor sinks
indirect water heating, 2011 V3: 126–127individual aerobic waste treatment plants, 2010 V2: 150Individual Home Wastewater Characterization and
Treatment, 2010 V2: 154individual vents, 2009 V1: 25. See also revent pipesindoor gas boosters, 2010 V2: 126indoor swimming pools, 2011 V3: 108. See also swimming
poolsinduced siphonage, 2009 V1: 25industrial acid-waste drainage systems
Joukowsky’s ormula, 2010 V2: 70–71 joules, 2009 V1: 34 joules per kelvin, 2009 V1: 34 joules per kg per kelvin, 2009 V1: 34 JTUs (Jackson turbidity units), 2010 V2: 193 Judgment phase in value engineering, 2009 V1: 209 judgmentalism, 2009 V1: 227 juveniles. See children, xtures and
K k, K (conductivity), 2009 V1: 33, 2012 V4: 103K (dynamic response to ground shaking), 2009 V1: 149, 152K (Kelvin), 2009 V1: 14, 30k (kilo) prex, 2009 V1: 34
K actor (coecient o permeability), 2010 V2: 158K actor (conductivity), 2012 V4: 103K actor (sprinkler heads), 2011 V3: 13K piping. See Type K copperKalinske, A.A., 2010 V2: 19, 72Kaminsky, G., 2010 V2: 246Kauman, Jerry J., 2009 V1: 252kcal (kilocalories), 2012 V4: 103KE (kinetic energy), 2009 V1: 2, 5Kelvin (K), 2009 V1: 14, 30, 33, 2011 V3: 184kerosene, 2010 V2: 12, 2011 V3: 136keyboards, infexible thinking and, 2009 V1: 225kg (kilograms). See kilogramskg/m (kilograms per meter), 2009 V1: 34
kg/m2 (kilograms per meter squared), 2009 V1: 34kg/m3 (kilograms per meter cubed), 2009 V1: 34kg/ms (kilogram-meters per second), 2009 V1: 34kg/s (kilograms per second), 2009 V1: 34kidney dialysis. See dialysis machineskill tanks, 2010 V2: 241–242kilo prex, 2009 V1: 34kilocalories
converting to SI units, 2009 V1: 38dened, 2012 V4: 103
kilograms (kg)dened, 2009 V1: 33kilograms per cubic meter, 2009 V1: 34kilograms per meter, 2009 V1: 34
kilograms per meter squared, 2009 V1: 34kilograms per second, 2009 V1: 34kilometers (km)
converting to SI units, 2009 V1: 39kilometers per hour, 2009 V1: 34
kilopascals (kPa)converting meters o head loss to, 2009 V1: 2converting to psi, 2011 V3: 30in SI units, 2011 V3: 187vacuum pump ratings, 2010 V2: 167vacuum work orces, 2010 V2: 166
kitchens. See ood-processing areas and kitchensKlein, S.A., 2011 V3: 204km/h (kilometers per hour), 2009 V1: 34knee braces, 2012 V4: 131knee space or wheelchairs, 2009 V1: 99–101knockout pots in vacuum systems, 2010 V2: 171Konen, Thomas K., 2010 V2: 29Kortright Centre or Conservation web site, 2011 V3: 203kPa (kilopascals). See kilopascalsKreider, J.F., 2011 V3: 204Kreith, J., 2011 V3: 203KS. See kitchen sinksKullen, Howard P., 2009 V1: 144kW, KW (kilowatts), 2009 V1: 14kWh, KWH (kilowatt hours), 2009 V1: 15, 34, 2011 V3: 193KYNAR piping, 2011 V3: 49
Ll (leader). See downspouts and leadersL (length). See lengthL (liters). See litersL/min (liters per minute), 2011 V3: 187L piping. See Type L copperL/s (liters per second), 2011 V3: 187L-shaped bath seats, 2009 V1: 114
LA (laboratory compressed air), 2009 V1: 8labelslabeled, dened, 2009 V1: 25labeled re pumps, 2011 V3: 21medical gas tubing, 2011 V3: 69, 74medical gas valves, 2011 V3: 67parts o graywater systems, 2010 V2: 27
labor and materials payment bonds, 2009 V1: 56labor costs
dened, 2009 V1: 210actors in, 2009 V1: 86ongoing and one-time, 2009 V1: 217
loads. See also pipe loads; support and hanger loadscomputer analysis o loads, 2009 V1: 180connected loads, dened, 2010 V2: 136design considerations in seismic protection, 2009 V1:
180–182horizontal loads o piping, 2009 V1: 177live loads on roo, 2010 V2: 51load actors, dened, 2009 V1: 25
media rate, lter, 2011 V3: 111medical air systems. See also medical compressed air (MA)color coding, 2011 V3: 55concentrations, 2011 V3: 76dened, 2011 V3: 76–77medical compressed air (MA)
medical-gas tube, 2011 V3: 69, 74, 2012 V4: 33–34medical-grade water, 2012 V4: 52medical laboratories. See health care acilities; laboratoriesmedical schools. See health care acilitiesmedical vacuum (MV), 2009 V1: 9medical waste systems. See inectious and biological waste
microbiological ouling o water, 2010 V2: 195, 217microbiological laboratories, 2010 V2: 241. See also
laboratoriesmicrometers, vacuum units, 2010 V2: 166micromhos, 2010 V2: 193microns, converting to SI units, 2009 V1: 39microorganisms. See also bacteria; microbial growth and
n (nano) prex, 2009 V1: 34N (newtons), 2009 V1: 34n c, N C (normally closed), 2009 V1: 15n i c, N I C (not in contract), 2009 V1: 15N m (newton-meters), 2009 V1: 34n o, N O (normally open), 2009 V1: 15N2 (nitrogen). See nitrogen (N2)N2O (nitrous oxide), 2009 V1: 9NACE (National Association o Corrosion Engineers),
National Formulary (NF) USP nomographs, 2010 V2: 218 National Fuel Gas Code (NFPA 54), 117, 118, 121, 137,
2010 V2: 115natural gas system design, 2011 V3: 251pipe materials, 2011 V3: 256
National Ground Water Association (NGWA), 2010 V2: 164National Institutes o Health, 2010 V2: 172, 241National Oceanic and Atmospheric Administration (NOAA),
(NPDES), 2011 V3: 81, 82National Sanitation Foundation (NSF)
abbreviation, 2009 V1: 32domestic water piping and ttings, 2012 V4: 25drinking water standard, 2012 V4: 53 Equipment or Swimming Pools, Spas, Hot Tubs, and
Other Recreational Water Facilities (NSF/ANSI
50), 2011 V3: 111, 122hot-water system requirements, 2010 V2: 112
list o standards, 2009 V1: 53potable water standard, 2012 V4: 53
National Society o Proessional Engineers (NSPE), 2009 V1: 56, 57
National Standard Plumbing Code, 2010 V2: 115National Swimming Pool Foundation (NSPF), 2011 V3:
104, 122National Technical Inormation Service (NTIS), 2011
V3: 89National Water Research Institute, 2012 V4: 195National Weather Service (NWS), 2010 V2: 42
natural gas water heaters. See gas-red water heatersnatural osmosis, 2010 V2: 211natural period o vibration, 2009 V1: 150Natural Resources Canada, 2011 V3: 204Natural Resources Deense Council, 2011 V3: 81natural soil, building sewers and, 2010 V2: 14natural water, 2010 V2: 187, 2012 V4: 202. See also eed
water
Naturally Occurring Arsenic in Well Water in Wisconsin,2010 V2: 29naturally-vented multiple tray aerators, 2010 V2: 198naval rolled brass, 2009 V1: 132NBBPVI (National Board o Boiler and Pressure Vessel
Inspectors), 2010 V2: 106NBR (acrylonitrile butadiene rubber), 2011 V3: 150NBS (National Bureau o Standards). See National Bureau
o StandardsNC (noise criteria), 2012 V4: 137NCCLS (National Committee or Clinical Laboratory
96, 101neutralizing acid, 2012 V4: 176neutralizing acid in waste water
discharge rom laboratories, 2011 V3: 42–44health care acility systems, 2011 V3: 42–44laboratories, 2011 V3: 43–44methods o treatment, 2010 V2: 235sizing tanks, 2011 V3: 44
solids interceptors, 2011 V3: 45tank and pipe materials, 2011 V3: 85–87types o acids, 2010 V2: 230–232
neutralizing tanks, 2011 V3: 43–44neutrons, 2010 V2: 236–237New York City, ultra-low-fow toilets in, 2009 V1: 127New York City Materials and Equipment Acceptance
Division (MEA), 2012 V4: 88New York State Department o Environmental
Conservation
Technology or the Storage o Hazardous Liquids, 2011 V3: 89
non-potable hot water (NPHW), 2009 V1: 9non-potable hot water return (NPHWR), 2009 V1: 9non-potable water systems. See graywater systemsnon-pumping wells, 2010 V2: 157–158non-puncturing membrane fashing, 2010 V2: 16non-reactive silica, 2010 V2: 190non-reinorced concrete pipe, 2012 V4: 29non-rigid couplings, 2009 V1: 180
non-rising stems on valves (NRS), 2012 V4: 79non-SI units, 2009 V1: 34non-sprinklered spaces, 2009 V1: 12Non-structural Damage to Buildings, 2009 V1: 185non-tilting grates, 2010 V2: 11non-vitreous china xtures
dened, 2012 V4: 1standards, 2012 V4: 2
non-volatile substances, 2012 V4: 191normal air, dened, 2011 V3: 186normal, compared to standard, 2011 V3: 187normal cubic meters per minute (nm3/min), 2011 V3: 172normal liters per minute (nL/min), 2011 V3: 187normal pressure, 2009 V1: 26normally closed (n c, N C), 2009 V1: 15normally open (n o, N O), 2009 V1: 15North American Insulation Manuacturers Association
(NAIMA), 2009 V1: 118not in contract (n i c, N I C), 2009 V1: 15not to scale (NTS), 2009 V1: 15nouns in unction analysis, 2009 V1: 218, 219, 225nourishment stations in health care acilities, 2011 V3: 36nozzles
appliances, 2009 V1: 26appurtenances, 2009 V1: 26code agencies, 2009 V1: 42cost estimation, 2009 V1: 85–90dened, 2009 V1: 26designs, 2009 V1: 92–94ttings. See ttingsxtures. See xturesplumbing systems dened, 2009 V1: 26specications. See specicationssymbols, 2009 V1: 7–15terminology, 2009 V1: 16–21
Plumbing and Drainage Institute (PDI), 2010 V2: 96abbreviation or, 2009 V1: 32bioremediation system standards, 2012 V4: 231grease interceptor standards, 2012 V4: 228, 231hydromechanical grease interceptors, 2012 V4: 145list o standards, 2009 V1: 53PDI symbols or water hammer arresters, 2010 V2:
72–74Plumbing and Piping Industry Council (PPIC), 2009 V1: 160 Plumbing Appliance Noise Measurements, 2009 V1: 206plumbing codes, dened, 2012 V4: 170. See also codes and
standards Plumbing Design and Installation Reerence Guide, 2010
changes in technology and products, 2009 V1: 262coordinating in re protection design, 2011 V3: 29dened, 2009 V1: 26ensuring high quality in, 2009 V1: 253
Plumbing Engineering and Design Handbook o Tables,2010 V2: 130
Plumbing Engineering and Design Standard 45, 2010 V2: 55
Plumbing Engineering Design Handbook, 2012 V4: 2plumbing ttings. See ttingsplumbing xtures. See xtures and xture outletsPlumbing-Heating-Cooling Contractors-National
Association (PHCC-NA), 2009 V1: 54, 87 National Standard Plumbing Code, 2010 V2: 115
plumbing inspectors, 2009 V1: 26, 255 Plumbing Manual, 2010 V2: 96plumbing specications. See specications Plumbing Systems and Design, 2010 V2: 29pneumatic control system, resh water makeup, 2011 V3:
Preparation phase in value engineering, 2009 V1: 209preparing or jobs, checklists, 2009 V1: 91–92PRES (pressure). See pressurePresentation phase in value engineering, 2009 V1: 209, 249presets, dened, 2012 V4: 133President’s Committee on Employment o the
Handicapped, 2009 V1: 97PRESS (pressure). See pressurepress-connect joints, 2012 V4: 58press-tted ends on valves, 2012 V4: 80pressure (PRESS, PRES, P). See also pressure drops or
dened, 2012 V4: 133hangers and supports, 2012 V4: 121
protective coatings, 2009 V1: 136. See also coated metalprotective potential, dened, 2009 V1: 143protective saddles, 2012 V4: 121protein-orming oam, 2011 V3: 25protein-mixed chemical concentrates, 2011 V3: 25protocol gases, 2011 V3: 266Provent single-stack plumbing systems, 2010 V2: 17–18PRV (pressure-regulating or reducing valves). See
pressure-regulating or reducing valvesprying actions in seismic protection, 2009 V1: 182PS (polysulone), 2009 V1: 32PS (pressure switches), 2009 V1: 10PS standards. See under International Association o
Plumbing and Mechanical Ocials (IAPMO)pseudo-dynamic elastic analysis, 2009 V1: 151Pseudo Value Engineers, 2009 V1: 249Pseudomonas aeruginosa, 2010 V2: 43ps, PSF (pounds per square oot), 2009 V1: 15psi, PSI (pounds per square inch)
laboratory grade water, 2012 V4: 198pure water systems and, 2011 V3: 47
pyrophoric gases, 2011 V3: 267
Qqt, QT (quarts), 2009 V1: 39quads, converting to SI units, 2009 V1: 39quality
appearance o installations, 2009 V1: 262–263building noise and perceptions o, 2009 V1: 187building occupants and, 2009 V1: 263
building owners and, 2009 V1: 262contractors and, 2009 V1: 262in cost estimation, 2009 V1: 89costs vs. benets, 2009 V1: 253equipment supports, 2009 V1: 258low cost vs. high quality, 2009 V1: 263–264makeshit or eld-devised methods, 2009 V1: 254–257mock-ups, 2009 V1: 264
quality assurance in specications, 2009 V1: 63, 70quality control section in specications, 2009 V1: 64, 72regional and climate considerations, 2009 V1: 262researching readily-available products and
technologies, 2009 V1: 262saety and, 2009 V1: 258–262specication clarity and, 2009 V1: 253–254, 264o water, 2010 V2: 27–28, 159–160. See also water
analysis; water puricationquantities. See also demand
Sansone, John T., 2010 V2: 55SARA Title III Act (Superund Amendment and
Reauthorization Act o 1986), 2011 V3: 137sasol, 2010 V2: 114sat., SAT (saturation). See saturationsaturated air and vapor mixtures, 2011 V3: 187, 265saturated steam
shutdown pump eatures, 2010 V2: 63shutdown relays, 2011 V3: 28shuto NPSH, 2012 V4: 101Shweitzer, Philip A., 2011 V3: 89SI units. See International System o Unitssiamese re-department connections, 2009 V1: 12, 28. See
solar absorptance, dened, 2011 V3: 191Solar and Sustainable Energy Society o Canada web site,
2011 V3: 203solar constants, 2011 V3: 192The Solar Decision Book, 2011 V3: 203solar degradation, 2011 V3: 192Solar Design Workbook, 2011 V3: 204solar energy. See also green building and plumbing
solids-handling pumps, 2012 V4: 98soluble silica, 2010 V2: 190solute. See treated watersolution sinks, 2011 V3: 38Solution Source or Steam, Air, and Hot Water Systems,
2011 V3: 169solutions to puzzles, 2009 V1: 252solvents
sonic cleaners, 2011 V3: 40sound isolation in building code requirements, 2009 V1: 188Sound Transmission Class (STC), 2009 V1: 187sounds. See acoustics in plumbing systemssour gas, 2011 V3: 252source shut-o valves, 2011 V3: 66source water
standard ch (sch), 2010 V2: 126standard cubic eet per minute (scm). See scm, SCFM(standard cubic eet per minute)
standard dimension ratio (SDR), 2009 V1: 15, 29, 2012 V4: 42
standard re-protection symbols, 2009 V1: 12–13standard re tests, 2011 V3: 2Standard or Bulk Oxygen Systems at Consumer Sites
(NFPA 50), 2011 V3: 57, 78Standard or Color-marking o Compressed Gas Cylinders
Intended or Medical Use (CGA C-9), 2011 V3: 78Standard or Combustible Metals (NFPA 484), 2011 V3: 30Standard or Disinecting Water Mains, 2010 V2: 95Standard or Disinection o Water Storage Facilities, 2010
V2: 95Standard or Dry Chemical Extinguishing Systems (NFPA
17), 2011 V3: 24, 30Standard or Energy Conservation in New Building
Design (ASHRAE 90A), 2011 V3: 203Standard or Fire Prevention During Welding, Cutting,
and Other Hot Work, 2010 V2: 136Standard or Health-care Facilities, 2010 V2: 172, 2011
V3: 78, 263Standard or Health-care Facilities (NFPA 99), 2011 V3:
51, 76Standard or Hypochlorites, 2010 V2: 95Standard or Liquid Chlorine, 2010 V2: 95Standard or Low-, Medium-, and High-Expansion Foam
(NFPA 11), 2011 V3: 25, 30Standard or Parking Structures, 2010 V2: 115Standard or Portable Fire Extinguishers (NFPA 10), 2011
V3: 28, 30Standard or Tank Vehicles or Flammable and
Combustible Liquids (NFPA 385), 2011 V3: 137Standard or the Design and Installation o Oxygen-uel
Gas Systems or Welding, Cutting, and Allied
Processes, 2010 V2: 137Standard or the Installation o Foam-Water Sprinkler
Systems and Foam-Water Spray Systems (NFPA16), 2011 V3: 25, 30
Standard or the Installation o Nitrous Oxide Systems at
Consumer Sites (CGA G-8.1), 2011 V3: 78Standard or the Installation o Private Fire Service Mains
and their Appurtenances, 2011 V3: 30Standard or the Installation o Sprinkler Systems (NFPA
13), 2009 V1: 185, 2011 V3: 30Standard or the Installation o Sprinkler Systems in One-
and Two-Family Dwellings and Manuactured
Homes, 2011 V3: 18Standard or the Installation o Sprinkler Systems in
Residential Occupancies up to and Including FourStories in Height, 2011 V3: 18
Standard or the Installation o Standpipe and Hose
Systems (NFPA 14), 2011 V3: 30
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Index 351
Standard or the Installation o Stationary Pumps or Fire Protection (NFPA 20), 2011 V3: 30
Standard or Water Spray Fixed Systems or Fire Protection (NFPA 15), 2011 V3: 24
Standard or Wet Chemical Extinguishing Agents, 2011 V3: 24? 30
standard ree airat atmospheric pressure (scm). See scm, SCFM
(standard cubic eet per minute)in vacuum sizing calculations, 2010 V2: 175Standard Handbook or Mechanical Engineers, 2009 V1: 1Standard Method o Test o Surace Burning
Characteristics o Building Materials (NFPA 255),2011 V3: 69
Standard o Testing to Determine the Perormance o Solar
Collections (ASHRAE 93), 2011 V3: 203Standard on Carbon Dioxide Extinguishing Systems
(NFPA 12), 2011 V3: 30Standard on Clean Agent Extinguishing Systems (NFPA
2001), 2011 V3: 30Standard on Halon 1301 Fire Extinguishing Systems
(NFPA 12A), 2011 V3: 27, 30Standard on Water Mist Fire Protection Systems (NFPA
B75), 2011 V3: 276Standard Specifcation or Seamless Copper Tube or Air
Conditioning and Rerigeration Field Service
(ASTM B280), 2011 V3: 276Standard Specifcation or Seamless Copper Tube or
Medical Gas Systems (ASTM B819), 2011 V3: 276
Standard Specifcation or Seamless Copper Water Tube(ASTM B88), 2010 V2: 122, 2011 V3: 276
Standard Specifcation or Thermoplastic Gas Pressure Pipe, 2010 V2: 123–124
standard temperature and pressure, 2009 V1: 29Standard Text Method or Surace Burning Characteristics
o Building Materials, 2010 V2: 122, 224standard water closets, 2012 V4: 4standard-weight steel pipe, 2012 V4: 37standards. See codes and standardsstandby losses in circulating systems, 2009 V1: 119
surace ponds, 2010 V2: 47surace runo. See runo surace skimmers. See skimmerssurace temperature o insulation, 2012 V4: 111surace-type sprinkler spray heads, 2011 V3: 92–93surace water
as eed water or pure water systems, 2010 V2: 220carbon dioxide in, 2012 V4: 176dened, 2010 V2: 188discharge permits or, 2011 V3: 83need or treatment, 2012 V4: 173–174
tannin in water, 2012 V4: 202tape thread sealants, 2012 V4: 60tapping illegally into water lines, 2010 V2: 59
tapping valves, 2012 V4: 67taps
large wet tap excavations, 2011 V3: 213pressure loss and, 2011 V3: 210–214
target areas in water closets, 2012 V4: 3taste o drinking water, 2010 V2: 160, 217tax credits, solar energy, 2011 V3: 190Tax Incentives Assistance Project (TIAP) web site, 2011
V3: 203taxes
in labor costs, 2009 V1: 86
in plumbing cost estimation, 2009 V1: 86Taylor, Halsey Willard, 2012 V4: 215TD (temperature dierences), 2009 V1: 128TD (turndown ratio), 2010 V2: 127TDS (total dissolved solids). See total dissolved solids
(TDS)TE (top elevation), 2009 V1: 15teaspoons, converting to SI units, 2009 V1: 39
technetium 99, 2010 V2: 238Techniques o Value Analysis and Engineering, 2009 V1: 252technology advances, value engineering and, 2009 V1: 208Technology or the Storage o Hazardous Liquids, 2011
UU bolts, 2012 V4: 120U , U (heat transer coecients) (U actor), 2012 V4: 104U-bolts, 2012 V4: 64, 120, 136UF. See ultralters and ultraltrationUF membranes, 2010 V2: 191UFAS (Uniorm Federal Accessibility Standard), 2009 V1:
97–98
Uhlig, Herbert H., 2009 V1: 144UHP (utility horsepower), 2012 V4: 102UL listings. See Underwriters Laboratories, Inc. (UL)ULC (Underwriters Laboratories o Canada), 2009 V1:
41–42ULF. See ultra-low-fow water closetsultra-clean tanks, gas cylinders, 2011 V3: 268ultra-high purity gas grade, 2011 V3: 267, 276ultra-high purity plus gas grade, 2011 V3: 267ultra-high vacuum, 2010 V2: 165ultra-low-fow water closets
U.S. Public Health Service (USPHS), 2010 V2: 154U.S. Veterans Administration, 2009 V1: 185U.S. War Department, 2010 V2: 55USACOE. See U.S. Army Corps o Engineersusage. See demandusages in swimming pools, 2011 V3: 107use actors
air compressors, 2011 V3: 183compressed air systems, 2011 V3: 183
USEPA. See U.S. Environmental Protection Agencyusers in cost equation, 2009 V1: 217USGBC. See U.S. Green Building Council (USGBC)USP. See U.S. Pharmacopoeia (USP)USP gas grade, 2011 V3: 267USPHS (U.S. Public Health Service), 2010 V2: 154USTs. See underground storage tanks (USTs)utilities. See site utilitiesutility controllers (gas systems), 2010 V2: 121utility costs, lowering, 2009 V1: 119utility gas. See uel-gas piping systemsutility horsepower (UHP), 2012 V4: 102Utility LP-Gas Plant Code, 2010 V2: 137utility sinks, 2011 V3: 36utility water treatment, 2010 V2: 214–215UV (ultraviolet rays), 2009 V1: 15
V v, V (valves). See valves V (specic volume). See specic volume V (velocity o uniorm fow), 2009 V1: 1 V (velocity). See velocity
V (vents). See vents and venting systems V (volts). See voltsv/v (volume to volume), 2010 V2: 191vac, VAC (vacuum). See vacuum (vac, VAC)vacation pay, in labor costs, 2009 V1: 86vacuum (vac, VAC)
value changes, 2009 V1: 208value dened, 2009 V1: 209
Value Engineering, A Plan or Invention, 2009 V1: 252Value Engineering, A Systematic Approach, 2009 V1: 252Value Engineering Change Proposals (VECP), 2009 V1: 251Value Engineering or the Practitioner, 2009 V1: 252Value Engineering in the Construction Industry, 2009 V1: 252Value Engineering Job Plan (VEJP), 2009 V1: 209
Value Engineering: Practical Applications, 2009 V1: 252Value Engineering, Theory and Practice in Industry, 2009 V1: 252
valve-per-sprinkler irrigation, 2011 V3: 92valved zones in irrigation systems, 2010 V2: 25valves (v, V, VLV). See also specic types o valves
W W (walls), 2009 V1: 202 W (waste sewers), 2009 V1: 8, 15 W (watts). See watts W/m K (watts per meter per kelvin), 2009 V1: 34w/w (weight to weight), 2010 V2: 191wading areas, 2011 V3: 107wading pools, 2011 V3: 109, 111
water deposits, 2010 V2: 195, 196–197 Water Distributing Systems or Buildings, 2010 V2: 96water distribution, dened, 2010 V2: 95water-distribution pipes and systems. See also cold-water
water metersdomestic water meters, 2010 V2: 59–60fow-pressure loss averages, 2010 V2: 61irrigation, 2011 V3: 95–96loss o pressure, 2010 V2: 84pressure losses, 2011 V3: 216readings in consumption estimates, 2012 V4: 186
water mist extinguishing systems, 2011 V3: 24–25Water Mist Fire Protection Systems (NFPA 750), 2011 V3: 30water motor gongs, 2011 V3: 6water, oil, and gas (WOG) pressure rating, 2009 V1: 15,
2012 V4: 78, 84water pipes. See cold-water systems; hot-water systems;
water-distribution pipes and systemswater polishing, 2012 V4: 198water pressure