Normas Texaco GEMS J-3D15 Sewers, Drains and Paving Arrangement

DEC 95 SEWERS, DRAINS, AND PAVING ARRANGEMENT GEMS J-3D15

PAGE 1 OF 23©TEXACO CENTRAL ENGINEERING & PURCHASING DEPARTMENT

TABLE OF CONTENTSPAGE

1. SCOPE .............................................................. 3

2. REFERENCES......................................................... 3

2.1 Purchaser Specifications ..................................... 32.2 Purchaser Drawings ........................................... 32.3 Industry Codes and Standards ................................. 3

3. DEFINITIONS ........................................................ 4

4. PRE-DESIGN CONSIDERATIONS .......................................... 5

5. PHILOSOPHY ......................................................... 6

6. DRAINAGE LAYOUTS FOR PAVED AREAS................................... 7

6.1 Drainage Grid Pattern ........................................ 76.2 High and Low Points of Drainage Layout ....................... 76.3 Limitations on Paving Slope .................................. 86.4 Catch Basins ................................................. 86.5 Dry Boxes .................................................... 86.6 Fired Heaters ................................................ 96.7 Heat Exchangers .............................................. 96.8 Vessels, Drums, and Towers ................................... 96.9 Building Areas and Elevated Concrete Working Decks ........... 106.10 Pipe Racks ................................................... 11

7. SEWER SYSTEMS - GENERAL............................................ 11

7.1 Materials for Sewer Pipe ..................................... 117.2 Minimum Branch, Header, and Trunk Line Sizes ................. 117.3 Drain Hubs ................................................... 117.4 Change in Direction .......................................... 127.5 Cleanouts .................................................... 127.6 Liquid Sealing and Venting ................................... 127.7 Slope and Capacity of Sewer and Drain Lines .................. 137.8 Catch Basins, Dry Boxes, and Manholes ........................ 147.9 Testing ...................................................... 14

8. CONTAMINATED WATER SEWER SYSTEM - PROCESS UNIT..................... 14

8.1 Objective .................................................... 148.2 Layout ....................................................... 148.3 Elevation .................................................... 158.4 Basis of Design .............................................. 158.5 Branch and Header Sizes ...................................... 158.6 Sewer Systems ................................................ 168.7 Connection to Plant Trunk Line ............................... 168.8 Heater Decoking .............................................. 16



8.9 Hot Water Drains ............................................. 16

9. CONTAMINATED WATER SEWER SYSTEM - NON-PROCESS UNIT AREAS (OFF-SITE) 16

9.1 Objective .................................................... 169.2 Planning and Basis of Design ................................. 16

10. OIL SEWER SYSTEM ................................................... 17

10.1 Objective .................................................... 1710.2 Basis of Design .............................................. 1710.3 Drain Hubs ................................................... 1810.4 Collecting Sump and Pump ..................................... 1810.5 High Viscosity and/or High Pour Point Hydrocarbons ........... 18

11. BENZENE SEWER SYSTEMS.............................................. 18

11.1 Objective .................................................... 1811.2 Basis of Design .............................................. 19

12. CHEMICAL SEWER SYSTEMS............................................. 19

12.1 Objective .................................................... 1912.2 Basis of Design .............................................. 19

13. SANITARY SEWER SYSTEM.............................................. 20

13.1 Objective .................................................... 2013.2 Basis of Design .............................................. 2013.3 Septic Tanks ................................................. 20

14. STORM WATER SEWER SYSTEM........................................... 20

14.1 Objective .................................................... 2014.2 Basis of Design .............................................. 2014.3 Selection of Ditches or Underground Pipe ..................... 2014.4 Open Drain Ditches ........................................... 2114.5 Piped Underground Systems .................................... 21

TABLES

1 Minimum Sizes for Branch, Header, and Trunk Lines2 Minimum Slope and Full Flow Capacity for Various Pipe Sizes



1. SCOPE

This specification defines minimum requirements for arrangement ofpaving in process areas and design of gravity type drains and sewersystems in process and non-process areas.

2. REFERENCES

2.1 Purchase r Specifications

This specification contains references to the following Purchaserspecifications:

1. GEMSGC, “General Conditions - General Equipment and MaterialSpecifications”.

2. GEMS A-1D, “Design of Foundations and Structures”.

3. GEMS B-1D, “Design of Buildings”.

4. GEMS G-3D, “Design - Climatic Design Data”.

5. GEMS J-1D, “Piping”.

6. GEMS J-2D, “Selection and Limitation of Piping Materials”.

7. GEMS J-1P, “Field Pressure Testing of Piping, Sewers, Fired HeaterTube Assemblies, and Exchangers”.

2.2 Purchase r Drawings

This specification contains references to the following Purchaserdrawings:

1. 4S-5853, “Details of Concrete Septic Tanks”.

2. 9S-8158, “Arrangement of Concrete Sewer Manholes”.

3. 9S-8159, “Details of Concrete Sewer Manholes”.

4. 9S-8160, “Details - Catch Basins, Dry Boxes, Drains and SewerLines, Sheets 1 and 2”.

5. 9S-8161, “Typical Valve Boxes for Underground Valves”.

6. 9S-8974, “Typical Paving Layout for Fired Heaters”.

7. 9S-9173, “Piping Details for Sample Connections”.

8. 9S-9224, “Oil Sewer Collecting Sump”.

9. 9S-9281, “Typical Oil Sewer Collection System”.

10. 9S-9347, “Typical Manifold and Quench Drum for Heater Decoking”.

11. 9S-9356, “Typical Distribution of Firewater to Process UnitContaminated Water Sewer Systems”.

2. 3 Industry Codes and Standards

This specification contains references to the following industry codesand standards:

2. 3 . 1 Code of Federal Regulations (CFR)

1. 40 CFR 60, “New Source Performance Standards (NSPS)”.



2. 40 CFR 61, “National Emission Standards for Hazardous AirPollutants (NESHAP)”.

3. 40 CFR 122, “National Pollutant Discharge EliminationSystem (NPDES)”.

4. 40 CFR 260, 261, “Resource Conservation and Recovery Act(RCRA)”.

2. 3 .2 National Fire Protection Association (NFPA)

30, “Flammable and Combustible Liquids Code”.

3. DEFINITIONS

1. Benzene Sewer - A collection and transmission system for benzenewaste water streams (Service Symbol - DB).

2. Benzene Waste Water - Process waste water that contains benzene.

3. Blowdown Line - A pressurized drain line for use during operationof equipment.

4. Branch Line - A secondary sewer line used to direct sewer liquidsfrom hubs, dry boxes, or catch basins to sewer header lines.

5. Catch Basin - An open concrete or masonry box designed to receivesurface drainage with its inlet lines liquid sealed.

6. Chemical Sewer System - A separate sewer system for collection andtransmission of one specific type of chemical waste water (ServiceSymbol - DC).

7. Chemical Waste Water - A process waste water that containschemicals, including acid, caustic and/or amine, which requires aseparate chemical sewer system.

8. Contaminated Water - Storm runoff, wash, fire, and other non-process waste waters drained to process unit paved areas, off-sitepump paved areas, tank car and tank truck loading and unloadingpaved areas, and other paved areas.

9. Contaminated Water Sewer System - Collection and transmissionsystem for conveying contaminated water to a waste water treatmentfacility (Service Symbol - DOW).

10. Control Device - An enclosed combustion device, vapor recoverysystem, or flare. A carbon canister is a control device.

11. Design Hourly Rainfall - Rate of rainfall in a 1 hour duration, 1in 10 year frequency storm.

12. Drain Lines - Above ground collection and transmission lines thatusually terminate above sewer line hubs.

13. Dry Box - Open concrete or masonry box designed to receive surfacedrainage and arranged such that liquid will not be trapped orretained in box.

14. Flow Indicator - Device that indicates whether gas flow is presentin a line or vent system.

15. Gas-tight - Operated with no detectable organic emissions (lessthan 500 ppmv above background levels).

16. Header Line - Main sewer line within a particular plant area intowhich branch lines connect.



17. High Point - Highest elevation of paving or surfacing.

18. Low Point - Lowest elevation of paving or surfacing.

19. Manhole - Concrete or masonry box designed to provide access tosewer lines and receive and liquid seal sewer lines as required.

20. Oil Sewer System - System for collection and transmission of wastewater streams containing oil, emulsified oil, or other hydrocarbonsthat are not benzene waste water streams (Service Symbol - DO).

21. Process Waste Water - Waste water that comes in contact with orresults from production or use of any raw material, intermediateproduct, finished product, byproduct, or waste product.

22. Sanitary Sewer System - System for collection and transmission ofsanitary sewage (Service Symbol - DS).

23. Sewer Lines - Underground collection and transmission lines thatconnect hubs, dry boxes, catch basins, and manholes and dischargeto a point of treatment or reuse.

24. Storm Water - Storm water runoff, snow melt runoff, and drainagecollected from non-paved areas, roads, and parking lots within theindustrial plant area (excludes process unit paved areas, off-sitepump paved areas, tank car and tank truck loading, and unloadingpaved areas).

25. Storm Water Sewer System - System for collection and transmissionof storm water and is completely segregated from Contaminated WaterSewer System (Service Symbol - DW).

26. Tank Water Drawoff - Any material or mixture of materialsdischarged from a tank to remove water or other contaminants fromtank.

27. Trunk Line - Main sewer line connecting various plant areas todirect sewer wastes to effluent treatment area or facilityboundary.

4. PRE-DESIGN CONSIDERATIONS

The following shall be determined prior to commencement of design:

1. Which wastewater streams should be directed to contaminated watersewer and required level of wastewater segregation (Section 5,paragraph 3.).

2. Whether or not a separate benzene sewer is required per 40 CFR 61(Section 5, paragraph 9).

3. Waste treatment requirements for contaminated water streams(Section 8.1).

4. Optimum direction of drainage to offsite areas (Section 8.2,paragraph 2.).

5. Invert elevation, if different than highest elevation, consistentwith layout of underground piping or other considerations (Section8.3).

6. Design hourly rainfall (Section 8.4, paragraph 1., and Section14.2, paragraph 2.).

7. Whether carbon canisters or other vapor control devices arerequired on sumps to reduce odors and control air emissions



(Section 10.4, paragraph 4.).

8. Location to which oil sewer wastes are to be pumped (Section 10.4,paragraph 5).

9. Waste treatment requirements for benzene wastewater streams(Section 11.1).

10. Location to which benzene wastes are to be routed (Section 11.2,paragraph 3.).

11. Requirements for special chemical sewer systems (Section 12.1).

12. Special requirements for chemical sewer sumps, such as nitrogenpurge or blanketing (Section 12.2, paragraph 3.).

13. Requirements for handling sanitary sewage (Section 13.2, paragraph1.).

14. Requirements for septic tank size and location, if required(Section 13.3, paragraph 1.)

15. Runoff coefficient from unpaved areas (Section 14.2, paragraph 4.).

16. Disposition of storm water (Section 14.2, paragraph 5.).

5. PHILOSOPHY

1. Drain and sewer systems shall be designed to:

a. Segregate various wastes and waste waters.

b. Recover liquid wastes at source in most concentrated form.

c. Control draining of water.

d. Control disposal of water contaminants.

e. Minimize air and water pollution.

f. Ensure compliance with environmental regulations.

2. Streams to be collected and managed include:

a. Contaminated water.

b. Process waste water.

c. Storm water.

d. Fire water.

e. Acid and/or caustic drainage.

f. Special chemical wastes and contaminants not permitted ineffluent water treating system.

g. Sanitary wastes.

h. Liquids that are to be recovered (to extent applicable).

3. Each process unit area shall have a contaminated water sewer systemto collect runoff, wash, and fire water from the paved areas.Separate systems shall be provided to collect process waste water,chemical waste water, and sanitary sewage in the most concentratedform and prevent entry of these streams into contaminated watersewer or storm water sewer systems. Degree of segregation shall bebased on economics, environmental regulations, and local plantpractices.

4. Units that process or produce low volatile materials with above



ambient temperature freeze points (high pour point) shall havedesign features to recover spilled material at source and prevententry into enclosed sewer systems.

5. Waste waters, such as desalter water, cooling tower blowdown,boiler blowdown, neutralized demineralizer regeneration wastewater, stripped sour water, and benzene waste water, shall bepreferentially routed to treatment units or recovery facilities inabove ground totally enclosed pressure systems.

6. Non-process unit areas, such as off-site pump stations, tank carand tank truck loading and unloading areas, truck servicing areas,and other paved areas, where inadvertent oil or chemical spillageor drainage may occur, shall have sloped paving and a contaminatedwater sewer system designed to prevent flow of contaminated waterfrom entering storm water sewer system. Separate oil, chemical, orbenzene sewer shall be provided if significant quantities ofhydrocarbons or chemicals will be drained.

7. Non-process unit areas where possibility of contamination isremote, such as roads, pipeways, non-paved areas, and industrialplant building areas, shall have a storm water sewer system.

8. Diked areas in hydrocarbon or chemical tank farms shall have astorm water sewer system. Storm water system shall have provisionsto divert drainage from diked areas alternately to contaminatedwater sewer system on a controlled basis if a hydrocarbon orchemical leak or spill occurs inside diked area. Each tank shallhave an oil, chemical, or benzene sewer hub as appropriate for tankwater drawoff.

9. A benzene sewer shall be provided if benzene is present in amountsgreat enough to require compliance with any hazardous air pollutantcontrol regulation.

6. DRAINAGE LAYOUTS FOR PAVED AREAS

6.1 Drainage Grid Pattern

1. Unit plots shall be divided into square or rectangular gridpatterns.

2. Number, size, and arrangement of grids shall be governed by:

a. Proper surface drainage around equipment and buildings.

b. Special areas to be high pointed and drained, such as firedheaters, heat exchangers, vessels, drums and towers, buildingareas and elevated concrete working decks, and pipe racks.

c. Limitations on paving slope.

d. Distance of catch basins from fired heaters.

e. Flow direction and catch basin location to permit practicallayout.

3. Maximum grid size shall be 90 feet by 90 feet. Individual segmentsof a grid perimeter shall not exceed 90 feet.

6.2 High and Low Points of Drainage Layout

6. 2 .1 General

1. Perimeter of each grid shall be high point of paving.



2. Paving shall slope from high point to a catch basin or drybox within grid.

6. 2 .2 Exceptions

1. Areas where long buildings are located close to pavinglimit and warping of paving to provide drainage betweenbuilding and paving limit would be impractical may betreated as follows:

a. High point shall be along building line.

b. Paving shall be sloped to paving limit forapproximate length of building.

c. Paving shall be warped at ends of building to avoidsharp transitions.

d. Balance of plot shall have a high point at pavinglimits.

2. Low points shall not be located near pumps and otherequipment installed at grade, where frequent access duringoperation may be required.

6.3 Limitations on Paving Slope

1. Unless specified otherwise, slopes may vary between a minimum of 2inches and a maximum of 4 inches in 10 feet.

2. Area between a dry box and edge of paving on unit limit side ofheaters may be sloped a maximum of 10 inches in 10 feet.

3. Slope within a grid shall be measured along a line perpendicular toside of catch basin or dry box and not along intersection ofsloping planes.

4. Maximum difference in elevation between high point of paving andlow point at top of catch basins or dry boxes in any one grid shallnot exceed 9 inches.

6.4 Catch Basins

1. Except in areas that require dry boxes, contaminated water surfacedrainage shall be collected in catch basins.

2. Catch basin inlet lines connecting to an upstream dry box or catchbasin shall be liquid sealed.

3. Catch basins shall not be used on upstream end of a collectionsystem where no inlet lines exist.

4. Catch basins shall be at least 50 feet from shell of fired heaters.

5. Catch basins under pipeways shall be subject to Purchaser approval.

6. Process waste water shall not be routed through downstream catchbasins.

6.5 Dry Boxes

1. Dry boxes shall be used:

a. To collect surface drainage only where catch basins areprohibited, such as fired heater areas.

b. In grids or high pointed areas at upstream end of acontaminated water collection system where no sewer lines fromother areas flow into area.



c. To collect storm water where a closed storm sewer system isused.

2. Process waste water shall not be routed through downstream dryboxes.

6.6 Fired Heaters

1. Typical paving and sewer layouts for fired heaters are shown inDrawing 9S-8974.

2. Paving around perimeter of each heater shall be high pointed.

3. Perimeter high points shall be located a minimum of 5 feet from theface of heater shell.

4. Area under long narrow heaters shall have a high pointapproximately midway and perpendicular to long heater axis.

5. Adjoining areas outside of perimeter high point shall be sloped todirect surface drainage away from heater area.

6. Paving inside of perimeter high point shall be sloped to one ormore dry boxes.

7. One dry box center line shall be located a minimum of 5 feet fromoutside of heater shell on unit limit side.

8. Additional dry boxes shall be located between heater and highpointed paving perimeter a minimum of 5 feet from heater shell.

9. Sewer lines leaving each heater area shall be sealed at theirdownstream ends in catch basins or manholes located inside unitlimits at a minimum distance of 50 feet from heater shell. Dryboxes serving one heater may be connected. If it is not possible totie into a catch basin 50 feet from heater shell, sewer linesleaving fired heater areas shall tie into a manhole connecting tounit contaminated water sewer header line.

6.7 Heat Exchangers

Area in front of tubular heat exchanger banks shall have catch basins ordry boxes.

6.8 Vessels, Drums, and Towers

1. This section applies to vessels, including those located inelevated structures, that:

a. Have a capacity of 21,000 gallons (500 barrels) or more.

b. Contain any of the following:

(1) Liquid at 500 °F and higher.

(2) Liquid whose auto-ignition temperature is less than500 °F.

(3) Liquid with operating temperature above the flash point(as defined in NFPA 30).

2. Capacity of process towers and columns shall be based only onvolume below maximum liquid level. Liquid on trays or otherinternal equipment shall not be considered.

3. Paving around perimeter of area of each applicable vertical andhorizontal vessel shall be high pointed.

4. Paving around two or three adjacent vessels, described in paragraph



1., may be high pointed around perimeter of area in which vesselsare grouped.

5. Vessels and atmospheric storage tanks other than those described inparagraph 1. shall not require separation from each other by highpointing of paving.

6. Paving on inside of high pointed perimeter of each of the aboveareas shall be sloped to drain to one or more catch basins or dryboxes.

7. Downstream end of contaminated water sewer line leaving each areashall be liquid sealed in a catch basin or manhole located outsideof the area.

6.9 Building Areas and Elevated Concrete Working Decks

6. 9 .1 Catch Basins and Dry Boxes

Catch basins and dry boxes shall be located such that theyavoid excessive slopes at building entrances.

6. 9 .2 Control Buildings and Buildings With Flammable Fluids

Paving around control buildings and buildings that containequipment which handles flammable fluids shall be sloped suchthat surface drainage will flow away from buildings.

6. 9 .3 Slopes of Building Floor Slabs and Decks

Building floor slabs and decks shall be sloped as follows:

1. 2 inches in 8 feet - maximum.

2. 1 inch in 8 feet - minimum.

3. Floors shall be sloped to floor drains.

4. Maximum difference in elevation between high point offloor or deck and any floor drain shall be 3 inches.

6. 9 .4 Floor Drains

1. Floor drains shall conform to Drawing 9S-8160.

2. Unless specified otherwise, floor drains shall beconnected into sanitary sewer.

3. Floor drains in buildings or decks where hydrocarbons/chemicals are normally handled shall be connected into thecontaminated water sewer.

6. 9 .5 House Traps

1. Except for blowdown lines, each sewer line leaving abuilding shall have a house trap of the cleanout type.

2. Cleanout plug shall be located at surface of paving orfloor.

3. Traps shall be located immediately outside of buildings,except in freezing climates, where they shall be locatedinside of totally enclosed buildings.

6. 9 .6 Blowdown Lines

1. Separate sewer lines that serve blowdown lines shall nothave house traps.



2. These sewer lines shall be liquid sealed in a manholeoutside building.

6. 9 .7 Roof Downspouts

1. Downspouts shall discharge to pavement outside of buildingonly in areas that are free of equipment and passagewaysper GEMS B-1D.

2. If equipment handling flammable fluids is located on theroof, downspouts shall be connected to contaminated watersewer lines running directly to manholes. No house trapsare required in these lines, which are liquid sealed atmanhole(s).

6. 9 .8 Sewer Lines Leaving Buildings

1. Oil, chemical, and benzene sewer lines leaving buildingsshall be routed to appropriate sewer system.

2. Contaminated water sewer lines leaving buildings shall be:

a. Routed to manholes.

b. Liquid sealed at manhole.

3. Sanitary sewer lines leaving buildings shall be:

a. Properly trapped to prevent odors from enteringbuildings.

b. Routed to sanitary sewer system.

6. 9 .9 Sewer Lines Under Buildings

Except for sewer lines originating in a building, sewer linesor lines containing hydrocarbons shall not be routed under orin the floor slab of a building.

6.10 Pipe Racks

Paving beneath process unit main pipe racks shall have a high pointalong the center line of the pipe rack.

7. SEWER SYSTEMS - GENERAL

7.1 Materials for Sewer Pipe

Pipe material shall be as specified in GEMS J-2D, Table 7.

7.2 Minimum Branch, Header, and Trunk Line Sizes

1. Branch, header, and trunk lines shall be sized to meet anticipatedflow rates.

2. Minimum branch, header, and trunk line sizes shall conform to Table1., except as specified in Section 8.5.

7.3 Drain Hubs

1. Drain hubs shall be provided to collect all process drains,including pump base plate drains for all oil, benzene, and chemicalsewer systems. Sample and sample cooler drains shall have drainhubs per Drawing 9S-9173.

2. Drain hubs shall as a minimum be 4 inches in diameter. If a numberof drain lines or a large single drain line discharge to a hub, thehub shall size shall be increased as necessary per Drawing 9S-8160.



3. Hubs shall have a removable sealed cover per Drawing 9S-8160,except where hub receives uncontrolled drainage, such as pump baseplate drains.

4. Sewer hubs shall be at least 2 inches and no more than 12 inchesabove local paving to minimize surface water entry into hubs.

5. Sewer hubs shall be positioned to avoid creating a tripping hazard.

6. Drain hubs shall be connected to a sewer line 4 inches or greaterin diameter.

7. If one or more of the drains discharging to a hub flowscontinuously, connecting sewer line shall be sized accordingly.

8. Sewer lines connected to hubs at vessels shall not be sized tohandle hydrotest water.

7.4 Change in Direction

1. Lines between manholes, catch basins, and dry boxes shall notchange direction.

2. Sewer lines between hubs and first manhole or sump shall not changehorizontal direction at any point by more than 45 °.

7.5 Cleanouts

1. If manholes are not required, sewer lines shall have capped orplugged cleanouts per Drawing 9S-8160 as follows:

a. At upstream end of headers.

b. Where sewer line makes a change in horizontal direction anddownstream length of line is more than 50 feet.

c. At 100 foot intervals in sewer header line.

2. Cleanouts shall be placed such that rodding can be performed in thedirection of flow.

3. Cleanouts shall be extended to surface of paving.

7.6 Liquid Sealing and Venting

7. 6 .1 Liquid Sealing

1. Unless specified otherwise, contaminated water sewer linerunning from one grid or high pointed area to anothershall have a liquid seal in a catch basin or manhole atdownstream end to prevent vapor and/or flame propagationbetween grids.

2. This requirement shall not apply to sewer lines betweendry boxes where dry boxes must be provided in adjacentgrids for special reasons, such as for surface drainage inindividual heater areas.

3. Additional requirements for decoking facilities and housetraps are noted in Sections 8.8 and 13.2.

4. Each sewer drain hub shall have a liquid seal (P-trap orequivalent).

5. Hubs and floor drains inside buildings shall be liquidsealed.

7. 6 .2 Vents

1. Upstream end of each sewer header line shall have a vent.



2. A vent shall be located immediately downstream of eachbuilding house trap.

3. Upstream end of each sewer branch or header line thatconnects sewer hubs to a manhole or sump shall have avent.

4. Additional vents shall be provided to prevent breakingseals by siphon action.

5. Vents shall discharge a minimum of:

a. 15 feet above grade.

b. 50 feet from shell of any heater.

6. If located beneath or adjacent to a piperack, vents shallextend 5 feet above top of piping.

7. Benzene sewer and sump vents shall have a vapor controldevice.

8. Vent pipes shall be located in sewer manholes as follows:

a. In main chamber of first manhole in any main or trunkline system.

b. In main chamber of other manholes where inlet trunkline is liquid trapped in any manner that wouldprevent venting to next upstream manhole.

c. In any manhole lateral chamber where inlet lateral isliquid trapped in any manner that would preventventing back to next upstream open catch basin or drybox. See Drawing 9S-8158.

9. Manhole vent pipes shall be 4 inch steel pipe withthreaded fittings.

7.7 Slope and Capacity of Sewer and Drain Lines

1. Sewer and drain lines shall be sloped to provide a minimum velocityof 2.5 fps for self-cleaning. If sufficient head is not available,a sump and lift station shall be provided.

2. Minimum slope and full flow capacity for various line sizes isgiven in Table 2.

3. Full flow capacity of lines that slope at greater than minimumslope may be determined using the Hazen and Williams formula:

HC

GPM

ID= ×

×2 083

100185

1 85

4 8655..

( )

( )

.

.

Where:

H = Head loss or slope, feet per 1000 feet

C = Surface roughness coefficient = 100 (cast iron,plastic, concrete, and steel pipe)

GPM = Flow rate, gallons per minute

ID = Inside pipe diameter, inches

4. Full flow line capacities may also be determined using the Manning



formula, with the Manning roughness coefficient “N” equal to 0.015for cast iron, plastic, concrete, and steel pipe.

7.8 Catch Basins, Dry Boxes, and Manholes

1. Process unit and non-process unit paved areas that require acontaminated water sewer or special chemical sewer shall have catchbasins and dry boxes designed in accordance with details shown onDrawing 9S-8160.

2. Selection of cast iron frame and grating or galvanized steel frameand grating shall be based on economic considerations and materialavailability.

a. Steel frame and grating shall be galvanized in accordance withGEMS A-1D, except as specified in paragraph b.

b. Steel frame and grating in catch basins and dry boxes inchemical sewers collecting weak acids shall not be galvanized.

3. Manholes shall be designed in accordance with details shown onDrawings 9S-8158 and 9S-8159.

4. Catch basins, dry boxes, and manholes may be cast in place,purchased precast, or be precast at project site. Changes in designshall be subject to Purchaser approval.

5. Manholes shall be designed to take surface drainage where required.

6. Manholes shall be provided in main trunk lines at points whereprocess unit or other area sewer lines discharge into main trunkline.

7. Manhole compartments shall provide a liquid seal to prevent escapeof vapors from the manhole main chamber or trunk sewer line tosurface drainage openings or to lateral sewers.

8. Manholes shall have gas-tight covers.

9. Maximum interval between manholes in sewer lines (header and trunklines) shall be:

a. 300 feet for lines 24 inches in diameter or less.

b. 500 feet for lines over 24 inches in diameter.

7.9 Testing

Sewers shall be tested in accordance with GEMS J-1P.

8. CONTAMINATED WATER SEWER SYSTEM - PROCESS UNIT

8.1 Objective

Process unit paved areas shall have a contaminated water sewer system tocollect and convey rainwater, firewater, and other contaminated water toa waste water treating facility.

8.2 Layout

1. Process unit paving and drainage layout requirements shall conformto Section 6.

2. Direction of discharge to off-site facilities shall be determinedby Purchaser.

3. Drainage layout shall minimize number of manholes.



8.3 Elevation

1. If a new sewer is to be connected to an existing sewer system,location and invert elevation shall be established.

2. Inverts shall be either:

a. Highest elevation possible consistent with economical layoutof other underground piping.

b. Otherwise determined by off-site considerations.

3. Unless approved otherwise, sewer pipe in process unit areas shallbe installed below underground electrical conduit.

8.4 Basis of Design

1. Each section of contaminated water sewer system shall be designedto carry the greater of:

a. Design hourly rainfall for locality per GEMS G-3D or asspecified in project specifications, using a runoffcoefficient of 1.00 from paved areas.

b. Design flow of fire water.

2. Design fire water flow shall be determined by assuming that firewater is distributed to catch basins and dry boxes as follows(boxes are numbered beginning from the upstream end of each sewersystem):

a. 500 GPM to each of the two most upstream boxes in each branchor header system.

b. 250 GPM to the third and each subsequent box in each branch orheader system.

c. Total quantity of fire water shall not exceed:

(1) 2000 GPM for individual branch or header lines of 6 ormore boxes.

(2) 3500 GPM after 2 or more header lines are joined.

(3) 750 GPM from any separately high pointed or vessel area.

d. Typical firewater distribution as described above is shown inDrawing 9S-9356.

3. Areas with a deluge fire water system shall have surface drainsystem sized to handle design flow.

8.5 Branch and Header Sizes

Line connecting catch basins or a catch basin and a dry box shall as aminimum be 10 inches with the following exceptions:

1. If more than one dry box is required in a single high pointedheater or hot vessel area:

a. Sewer lines connecting such boxes shall as a minimum be 8inches.

b. Sewer line leaving area shall as a minimum be 10 inches.

2. If one or more dry boxes serving a single high pointed heater orhot vessel area is separately connected to a catch basin ormanhole, line from each box shall as a minimum be 8 inches. Typicalpaving and sewer layout at fired heaters shall conform to Drawing9S-8974.



8.6 Sewer Systems

1. Catch basins and dry boxes shall be connected with sewer branchlines to form one or more header lines.

2. Several header lines may be connected inside unit such thatdischarge to off-site is from one manhole.

3. Number of off-site discharges shall be kept to a minimum. Use ofmore than one off-site discharge shall be subject to Purchaserapproval.

4. If oil, chemical, or benzene sewer is not required, drain hubsshall:

a. Connect with a liquid seal to a contaminated water sewermanhole.

b. Not be routed through a downstream catch basin.

8.7 Connection to Plant Trunk Line

1. Contaminated water sewer lines leaving paved process unit limitsshall be:

a. Connected into trunk line at a manhole located off-site.

b. Liquid sealed at that point.

2. If overloading will not occur and subject to Purchaser approval,tie-ins may be made to an existing contaminated water sewer system.

8.8 Heater Decoking

1. Each decoking quench drum shall have a separate drain line with drybox for decoking operations.

2. Drain line shall be routed directly to a downstream manhole with aliquid seal in accordance with Drawing 9S-9347.

3. Decoking sample bleeder streams from each decoking manifold shallhave separate sewer hubs with removable covers and shall be routeddirectly to a manhole with a liquid seal.

8.9 Hot Water Drains

1. Hot water above 120 °F with a flow rate less than 0.5 gpm may bedrained to the contaminated water sewer.

2. Hot water streams above 120 °F with flows greater than 0.5 gpm shalleither be:

a. Drained to another system collecting hot water.

b. Cooled to 120 °F or less before being drained to contaminatedwater sewer.

9. CONTAMINATED WATER SEWER SYSTEM - NON-PROCESS UNIT AREAS (OFF-SITE)

9.1 Objective

Non-process unit paved areas (excluding roads) and tank farms shall havea contaminated water sewer to collect and convey contaminated water to awaste water treating facility.

9.2 Planning and Basis of Design

1. Off-site areas described in Section 4, paragraphs 6. and 8., shall



have contaminated water sewers.

2. Off-site contaminated water sewer systems shall be designed inaccordance with requirements for contaminated water sewer systemson process units, except that total quantity of fire water from anyone paved area shall not exceed 2000 gpm.

3. Off-site contaminated water sewers shall connect to facilitycontaminated water sewer trunk line.

4. Contaminated water sewers serving each separate tank farm dikedarea shall have a minimum fire water capacity of 2000 gpm.

5. Hydrocarbon or chemical tank farm diked areas shall have a stormwater sewer system with provisions to divert drainage from dikedareas alternately to contaminated water sewer system on acontrolled basis should a hydrocarbon or chemical leak or spilloccur inside diked area. One oil, chemical, or benzene sewer hubshall be located as appropriate at each tank for tank waterdrawoff.

6. Grading beneath off-site process pipe racks shall be high pointedto direct drainage away from pipe rack.

7. Contaminated water drainage that must be routed under a pipe rack(e.g., swales or open ditches in tank farm diked areas) shall beenclosed with a culvert to protect piping from damage in event offire.

10. OIL SEWER SYSTEM

10.1 Objective

Process units and off-site areas (tank farm, loading racks, pumpstations, etc.) shall have oil sewer systems for collection,transmission, and reuse of waste streams with liquid hydrocarbons(generally C6 and heavier).

10.2 Basis of Design

1. Oil sewer systems shall have drain lines, sewer hubs, and sewerlines to drain concentrated hydrocarbon and hydrocarboncontaminated water to an oil sewer sump.

2. Liquid residuals shall be drained from process systems to oil sewerafter systems have been evacuated, depressured, and purged asrequired by operating procedures.

3. Typical collection system is shown in Drawing 9S-9281.

4. Process units with an oil sewer shall have an oil sewer sump inaccordance with Drawing 9S-9224.

5. Sumps shall be located within unit limits to minimize sewer piping.

6. Oil sewer sumps shall not be located under a piperack.

7. Unless approved otherwise, material above 180 °F shall not bedrained to oil sewer.

8. Above ground permanent drain piping that terminates at sewer hubsshall conform to GEMS J-1D.

9. The following hydrocarbon drains shall be drained through atemporary hose to an oil sewer hub:

a. Piping low points, including control valve station bleeders.



b. Pressure and differential pressure transmitter drain lines.

10. Oil sewer system openings, excluding vents, shall have vapor tightcovers or seals that conform to regulatory requirements.

11. Oil sewer hubs shall have a liquid seal (P-trap) per Section 7.6.1,paragraph 4.

10.3 Drain Hubs

1. If permanent drain piping is not required to hub, hubs shall belocated a maximum of 15 feet horizontally from a low point drain.

2. Each tank water draw off shall have a hub and sewer line. Sewershall be routed to an oil sewer sump, unless stored materialrequires a separate benzene sewer.

3. Hubs shall be located as follows (list is not all inclusive):

a. Adjacent to vessels.

b. At pump end of pump foundations.

c. At sample locations as specified on Drawing 9S-9173.

d. At base of structures, unit limit pipe rack, and otherlocations where drainage is piped from elevated locations.

e. As required under shell and tube exchangers to facilitatedraining from low point piping drains, TSV discharges, andshell cover drains.

f. Near control valve stations and other low point piping drainsif no other hub is within 15 feet.

g. Adjacent to analyzer buildings if no other oil sewer hub iswithin 15 feet.

10.4 Collecting Sump and Pump

1. Each process unit with an oil sewer system shall have a collectingsump and sump pump per Drawing 9S-9224.

2. Several drainage systems may be connected inside a unit such thatdischarge is to one oil sewer sump.

3. Sump cover and pump shall be sealed.

4. Unless approved otherwise, sump vent shall have a properly sizedactivated carbon canister or other vapor control device toeliminate sump odors and control air emissions.

5. Each process unit collecting sump shall be pumped out by a levelcontrolled pump out system to a location specified by Purchaser. Refer to Drawing 9S-9281.

10.5 High Viscosity and/or High Pour Point Hydrocarbons

High viscosity and/or high pour point hydrocarbons that cannot besegregated and separately collected shall be diluted with cutter stockprior to draining to oil sewer.

11. BENZENE SEWER SYSTEMS

11.1 Objective

Process units and off-site areas shall have a separate, closed, vaporcontrolled system to collect waste streams containing benzene for reuseor to convey these waste streams to a waste management unit.




1. If a separate pressurized above ground benzene waste watercollection system is not feasible, process units, tank farms, andother areas with waste waters that contain benzene shall haveseparate benzene sewers.

2. Benzene sewers shall be designed per requirements for oil sewerswith the following exceptions:

a. Benzene collecting sumps shall conform to Drawing 9S-9224,except that sump shall not have an overflow line tocontaminated water sewer system.

b. Benzene sump vent and all benzene sewer system vents shallhave a vapor control device (activated carbon canister orequal) that conforms to regulatory requirements.

3. Each sump shall be pumped out to a waste management unit by a levelcontrolled pump out system.

12. CHEMICAL SEWER SYSTEMS

12.1 Objective

Separate chemical sewer systems shall be provided for chemical wastes,including fresh acid, spent acid, caustic, and amine.


1. Except for weak acid sewer system, chemical sewer systems shall bedesigned as follows:

a. Chemical sewer systems shall be designed per requirements foroil sewer systems.

b. Consideration shall be given to appropriate piping materialsnecessary to handle such wastes.

c. Chemical sewer sumps shall be designed per same requirementsas oil sewer sumps in accordance with Drawing 9S-9224, exceptthat sump shall not have an overflow line to contaminatedwater sewer system.

2. Weak acid sewer system shall be designed as follows:

a. Sewer shall be similar to the contaminated water sewer.

b. Consideration shall be given to appropriate materials tocollect and convey acid spills and paved area drainage whichhandles acid.

c. A sump with automatic neutralizing capacity shall be providedfor dry weather flow and spills.

d. Pump base plate drains in acid areas shall drain to a weakacid sewer hub.

3. Special chemical sewer systems and disposition of materialcollected shall be designed by Purchaser.



13. SANITARY SEWER SYSTEM

13.1 Objective

A separate sewer shall be provided to collect and transport sanitarysewage to waste water treatment plant (biological treatment), septictank system, or municipal or other sanitary sewer system.


1. Sanitary sewer systems shall be designed to collect all sanitarysewage and transport the sewage to a waste treatment facility asspecified in project specifications.

2. Requirements for house traps and venting in Sections 6.9.5 and7.6.2, as well as any local building code requirements, shall benoted.

3. Sanitary sewers shall have lift stations if elevation isinsufficient for gravity flow.

4. Sanitary sewers may connect to existing plant sanitary sewers ifoverloading will not occur.

13.3 Septic Tanks

1. Septic tanks, if required or permitted, shall be specified byPurchaser.

2. If commercial prefabricated septic tanks are not suitable,economical, or available, concrete septic tanks may be designed perDrawing 4S-5853.

3. Effluent from septic tanks shall be discharged into a plantcontaminated water sewer manhole.

14. STORM WATER SEWER SYSTEM

14.1 Objective

A separate storm water sewer shall be provided to handle storm waterrunoff from roads, non-paved areas around process units, and other areaswithin industrial plant area where pollution from hydrocarbons or othercontaminates is unlikely.


1. Storm water sewers shall be designed to collect storm water fromindustrial plant areas that do not require contaminated watersewers.

2. Storm water sewers shall be designed to handle design hourlyrainfall for the particular locality. Design rainfall rate shall beas specified in GEMS G-3D or Purchaser specifications.

3. Runoff coefficient for paved areas shall be 1.00.

4. Runoff coefficient for unpaved areas shall conform to GEMS G-3D orPurchaser specifications.

5. Disposition of storm water shall be defined in Purchaserspecifications.

14.3 Selection of Ditches or Underground Pipe

1. Unless specified otherwise, storm water shall be conveyed in opendrainage ditches.



2. Areas where ditches are not practical due to space limitations,steep gradients, or access requirements shall be drained by a pipedunderground sewer system.

3. Ditches shall not be permitted beneath pipeways or within 50 feetof process units, control buildings, boilers, fired heaters, tanktruck and tank car loading and unloading areas, pump stations, orcooling towers.

4. Storm sewer ditches shall not be permitted between process unitsand adjacent roadways.

5. Storm drainage from tank farm diked areas shall be routed in pipefrom dike such that drainage may be discharged on a controlledbasis to contaminated water sewer or storm water sewer. A valve boxlocated immediately outside of diked area shall be provided todivert drainage to either sewer system.

14.4 Open Drain Ditches

1. Ditch side walls shall have a maximum slope of 2 horizontal to 1vertical where space is available.

2. Erosion shall be controlled by streamlining flow at junctions ofditches and at pipe entries into ditches.

3. Ditches shall be paved if side slopes are greater than 2 horizontalto 1 vertical or to control erosion.

14.5 Piped Underground Systems

1. Surface drains shall be dry boxes designed per details shown onDrawing 9S-8160, except that larger boxes shall be provided ifrequired.

2. Non-paved area grade slopes shall be a minimum of 1% and a maximumof 4% not to exceed 12 inches in total elevation difference betweentop of dry boxes and high point of finish grade. Area between a drybox and edge of an adjacent paved road may be sloped a maximum of10% not to exceed 12 inches in total elevation difference.

3. Valve boxes shall be designed per details shown on Drawing 9S-8161.



TABLE 1

MINIMUM SIZES FOR BRANCH, HEADER, AND TRUNK LINES

BRANCH SIZE, HEADER AND TRUNK SIZE,PIPE MATERIAL INCHES NPS INCHES NPS

PIPE LENGTH (FT) UNDER 20 20 & OVER ALL LENGTHS

Carbon Steel 4 4 6Carbon Steel-Cement Lined 4 6 6Cast Iron 4 6 6Corrugated Metal 6 8 8Reinforced Concrete 12 12 12Plastic 4 6 6



TABLE 2

MINIMUM SLOPE AND FULL FLOW CAPACITY FOR VARIOUS PIPE SIZES

Pipe I.D. Minimum Slope Capacity At Inches Ft. Per 1000 Ft. Minimum Slope (GPM)

6 and Smaller 6.0 200 - 6 Inch Only8 5.4 400

10 4.1 61012 3.5 90014 2.8 121015 2.6 139016 2.4 157018 2.1 200020 1.9 245021 1.8 272024 1.5 353027 1.3 477030 1.2 580036 1.0 833942 1.0 1249048 1.0 17760