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Bechtel Confidential Bechtel Corporation 1993, 2002. Contains
confidential and/or proprietary information to Bechtel and its
affiliated companies which shall not
be used, disclosed or reproduced in any format by any
non-Bechtel party without Bechtels prior written permission. All
rights reserved.3DG-P23-00001-001 PAGE 1 OF 35
BECHTEL CORPORATIONENGINEERING PLANT DESIGN
DESIGN GUIDEHEAT TRACING
3DG-P23-00001, Revision 001, 2002 Sept 30Reason for Issue:
Issued for Use supersedes 3SS-PY25-E0100Prepared by:
P.R.WoodChecked by: A.W.HarphamApproved by: R. Fox
INTRODUCTION
This design guide addresses the design of heat tracing systems
that are most commonly usedin industrial complexes.
The Plant Design group is responsible for developing a
comprehensive, safe and well thought-out design that includes
meeting codes, manufacturer and/or client requirements to
includelength of tracers, length of leads and tails, design and
location of distribution and collectionmanifolds, Manifold Schedule
and completion of the Steam Tracing Schedule.
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 2 of 35
TABLE OF CONTENTS PAGE
INTRODUCTION
.......................................................................................................................
1
1.0
PURPOSE.......................................................................................................................
6
2.0
SCOPE............................................................................................................................
6
3.0
EXCLUSIONS...................................................................................................................
6
4.0 DEFINITIONS
.................................................................................................................
7
5.0 SYSTEMS OR COMPONENTS REQUIRING HEAT
TRACING....................................... 7
6.0 HEAT TRACING
METHODS...........................................................................................
8
6.1 STEAM TRACING
...........................................................................................................
8
6.1 HOT OIL TRACING
........................................................................................................
9
6.3 ELECTRIC
TRACING...................................................................................................10
7.0 STEAM TRACING DESIGN
.........................................................................................
11
7.1 GENERAL
....................................................................................................................
11
7.2 STEAM DISTRIBUTION AND COND. COLLECTION MANIFOLDS (GENERAL)
....... 11
7.3 TRACER MATERIAL SELECTION
..............................................................................
12
7.4 TUBING FITTINGS
.......................................................................................................
13
7.5 TRACER LEAD AND TRACER TAIL
MATERIAL........................................................
13
7.6 TRACER ATTACHMENT
.............................................................................................
13
7.7 STEAM
TRAPS.............................................................................................................
14
7.8 TRACER LENGTH AND SELECTION
.........................................................................14
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 3 of 35
7.9 STEAM TRACING SCHEDULE
......................................................................................
15
7.10 HEAT SENSITIVE LINES
.............................................................................................
15
8.0 STEAM AND CONDENSATE MANIFOLD DESIGN
..................................................... 17
8.1 FABRICATED DISTRIBUTION & COLLECTION
MANIFOLDS................................... 17
8.2 VENDOR SUPPLIED DISTRIBUTION & COLLECTION MANIFOLDS
(FORGED)...... 20
8.3 NUMBER OF MANIFOLD CONNECTIONS
.................................................................
22
8.4 MANIFOLD LINE SIZE
.................................................................................................22
8.5 MANIFOLD BLOCK VALVES
......................................................................................
22
9.0 HEAT TRANSFER
CEMENT.........................................................................................
22
9.1
PURPOSE.....................................................................................................................
22
9.2
OBJECTIVE....................................................................................................................
23
9.3 USAGE
.........................................................................................................................
23
9.4 APPROVAL
..................................................................................................................
23
9.5 PRESSURE TEST
........................................................................................................
23
9.6 APPLICATION AND
PROTECTION.............................................................................
23
10.0 STEAM TRACING LAYOUT AND
INSTALLATION.....................................................
23
10.1
GENERAL.....................................................................................................................
23
10.2 MANIFOLD
LOCATION................................................................................................
27
10.3 FLEXIBILITY &
SUPPORT...........................................................................................
28
10.4 TRACER ROUTING AND
INSTALLATION..................................................................
28
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 4 of 35
10.5 TRACER
FITTINGS.........................................................................................................
29
10.6 NEW FEEDER REQUIREMENTS
...................................................................................
29
11.0 IDENTIFICATION OF MANIFOLDS AND TRACERS
..................................................29
11.1 IDENTIFICATION OF MANIFOLDS
.............................................................................
29
11.2 IDENTIFICATION OF TRACERS
.................................................................................
29
12.0 STEAM TRACING DRAWINGS FOR CONSTRUCTION PURPOSES
........................30
13.0 HOT OIL TRACING
......................................................................................................
33
13.1
GENERAL.....................................................................................................................
33
13.2 HEAT TRANSFER
FLUIDS..........................................................................................
33
13.3 HOT OIL
SYSTEM........................................................................................................
33
13.4 MATERIALS
.................................................................................................................
33
13.4 TRACER LENGTH AND SELECTION
.........................................................................33
14.0
REFERENCES..............................................................................................................
33
APPENDIX A - STEAM TRACING SCHEDULE AND MANIFOLD SCHEDULE
....................34
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 5 of 35
LIST OF FIGURES PAGEFigure 1 Banding Details
..................................................................................................
14Figure 2 Tracer Location Detail
........................................................................................
17Figure 3 Fabricated Manifolds (Vertical
Design)...............................................................
18Figure 4 Fabricated Manifolds (Horizontal
Design)...........................................................
19Figure 5 Prefabricated
Manifolds......................................................................................
21Figure 6 Tracer
Penetration..............................................................................................
24Figure 7 Tracer Expansion Loop
......................................................................................
24Figure 8 Tracing
Valves....................................................................................................25Figure
9 Tracing Relief
Valves..........................................................................................
25Figure 10 Tracing Control Valve
Assemblies......................................................................26Figure
11 Detail at Flanged
Joint........................................................................................
26Figure 12 Tracer with
Pockets............................................................................................
27Figure 13 Typical Steam Tracing Arrangement
..................................................................
32
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 6 of 35
1.0 PURPOSE
To provide piping designers with guidelines for the development
of heat tracing systems.
2.0 SCOPE
This guide covers the requirements for external heat tracing of
piping, instruments andequipment for the purpose of heat
conservation dictated by process reasons and forwinterization.
3.0 EXCLUSIONS
All or part of this guide may be superseded by client mandatory
standards or by the codes andregulations imposed by governmental
jurisdictions covering the location of the heat tracing
installation.
The following are excluded from the scope of this document:
a) Jacketed piping.
b) Electrical engineering detailed requirements for electric
tracing.
c) Guidelines for determining the requirements for heat tracing.
(This is a Process / ProjectEngineering / Mechanical group
function).
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 7 of 35
4.0 DEFINITIONS
The following definitions are used throughout this Design
Guide:
T
STEAM SUPPLYHEADER
DISTRIBUTION MANIFOLDSTEAM SUPPLY
DISTRIBUTIONMANIFOLD
TRACER LEAD
CONTACT TRACER
TRACED PIPE ORINSTRUMENT
TRACER TAIL
COLLECTIONMANIFOLD
COLLECTION MANIFOLDCONDENSATE RETURN
CONDENSAHEADER
5.0 SYSTEMS OR COMPONENTS REQUIRING HEAT TRACING
The extent of piping, instrumentation and equipment that
requires heat tracing for processreasons, or for winterization (due
to climatic conditions) shall be defined on the P & IDs
(Pipingand Instrumentation Diagrams) and Line Data sheets.
Equipment tracing may alternatively bedefined in the Equipment
List.The following items are listed to give the piping designer
insight into what may be heat traced,and the reason for the
tracing. The final extent of tracing however, is the responsibility
ofProcess / Project Engineering / Mechanical.
Process, utility and auxiliary piping will normally require heat
tracing when continuously orintermittently conveying fluids or
gases having the following characteristics:
a) Liquids with a pour point or freezing point at a temperature
higher than the ambienttemperature.
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 8 of 35
b) Liquids with high viscosity at ambient temperature.
c) Gases having a moisture content such that the formation of
condensation would beharmful to the process or cause mechanical
damage either through corrosion or impact
(e.g. gas compressor inlet piping).
d) Fluids with the possibility of undesirable separation
occurring at ambient temperature.
e) Systems conveying water and subject to freezing, are required
to be heat traced. Thistracing may be limited to dead end sections
of piping, instruments, and piping in standbyor intermittent
service. For plants in cold climates, this would include systems
locatedinside buildings, but in close proximity to intake louvers
or other openings that permit theingress of cold outside air. This
requirement may only be applicable during the winterperiod.
f) Gases that must maintain a minimum temperature for proper
system operation (e.g.ammonia vapor injected into the Selective
Catalytic Reduction (SCR) reactor(s) for Noxcontrol.
Instruments and instrument piping may require winterizing as
follows:
a) Pressure leads, flow meter leads, lines connecting external
float cages and gaugeglasses to vessels, instrument pots, externals
float cages and gauge glasses, inservices in which water may be
present. However, when such equipment is sealed, heatingshall be
limited to exclude the sealed portion.
b) Equipment listed in (a) above and in services in which the
contained or conveyed fluidhas a freezing point above the ambient
temperature or a viscosity or pour point whichmay make an
instrument inoperable.
Pumps may require winterizing when handling fluids having a pour
point or freezingpoint above the ambient temperature.
Vessels may have winterization applied to the liquid space only
when containing liquids having apour-point or freezing point above
the ambient temperature. Vessels containing water as a resultof
separation shall have trace heat tracing limited to the water
draw-off only.
6.0 HEAT TRACING METHODS
6.1 STEAM TRACING
6.1.1 General
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 9 of 35
As steam is usually readily available in most facilities, it is
one of the most common forms ofheat tracing in process and chemical
facilities. The steam tracing system consists of steamtracers
generally run in direct contact with the pipe to be heated, a steam
supply line to eachtracer and condensate collection line from each
tracer. Variations in detail of these items arecovered within this
guide.
6.1.2 Steam Tracing Advantages
a) Steam is usually available at low cost.
b) Can be used in hazardous areas.
c) Nearly constant temperature for full length of system.
6.1.3 Steam Tracing Disadvantages
a) Prone to freezing.
b) Prone to leaks.
c) Requires costly steam traps, strainers and isolation valves
for each steam tracer.
d) Is difficult to control temperature resulting in the
possibility of over heating especially in non-flowing lines.
e) Personnel safety in the event of leakage.
f) Need uninterupted source of steam at all times.
6.1 HOT OIL TRACING
6.2.1 General
Hot oil tracing is generally used in situations where steam at
the requiredpressure/temperature is not available or where
economics dictate in favor of installing a hot oilsystem. The hot
oil system consists of hot oil tracers (similar to steam tracers)
in direct contactwith the pipe to be heated, hot oil supply piping
to each tracer and a hot oil return andcollection system.
Hot oil tracing systems shall be shown on the P&IDs with
sufficient detail to enable PD (PlantDesign) to run all associated
supply and return headers, manifolds and tracers.
6.2.2 Hot Oil Advantages
a) Ability to control temperature.
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 10 of 35
b) Will not freeze if heating medium fails.
c) Can be used in hazardous areas.
d) Non-corrosive if used with inhibitors.
e) Can also be used for cooling.
f) Higher temperatures can be achieved with relatively low
pressures.
6.2.3 Hot Oil Tracing Disadvantages
a) Requires tanks, pumps, heating system controls, etc.
b) Flow balancing required on each loop.
c) Temperature varies from inlet to outlet of branches and
tracers.
d) Environmental and safety issues in the event of leakage.
e) Need heating source in the event the plant shuts down.
6.3 ELECTRIC TRACING
6.3.1 General
Electric tracing is generally used for power generating
facilities, offshore applications, onshoreapplications where an
economic study yields an overall cost advantage, or where
stricttemperature control is required. A typical heat tracing
system consists of heating elementsattached to the pipe or
equipment to be heated, together with appropriate
cabling,transformers, switchgear and controls to supply each
heating element. Although space mustbe allowed for location of any
transformers, switchgear and control panels required for
electrictracing, the detailed design of the system remains the
responsibility of the electricaldepartment. It is Plant Designs
responsibility to provide Electrical with the estimated footagesof
heat traced piping and all isometrics accurately reflecting the
boundaries, thicknesses andtypes of insulation. In the event
Mineral Insulated (MI) heat tracing is used as a means ofheating or
maintaining temperaturein a system, it is Plant Designs
responsibility that all
revisions in piping design be conveyed to the vendor since this
heat tracing is pre-fabricatedand cannot be reworked in the
field.
6.3.2 Electrical Tracing Advantages
a) Ability to control temperature.
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 11 of 35
b) Low maintenance cost.
c) Freedom from leaks
d) Should a power failure occur, heat can be restored readily,
without repairs to tracers being necessary.
6.3.3 Electrical tracing disadvantages
a) Cannot be used in hazardous areas.
b) Difficulty in removing equipment for repair.
c) Cost of power usually higher than cost of steam.
7.0 STEAM TRACING DESIGN
7.1 GENERAL
7.1.1 Design Codes
The design of piping for protective heating systems shall
conform to the latest edition of ASMEB31.3 for refinery and
petrochemical projects or ASME B31.1 for power projects.
7.1.2 Steam Supply Source
Client specifications may dictate that the steam for tracing be
supplied from a source, whichwill remain continuous even during
shut down periods. Also, the steam supply for line tracingand the
steam supply for off-line instrumentation may be required to be two
separate systems.Steam tracing winterizing systems will be
manifolded independently from non-winterizingsystems.
7.2 STEAM DISTRIBUTION AND COND. COLLECTION MANIFOLDS
(GENERAL)
Steam distribution manifolds shall be provided to supply steam
to a number of tracers from asingle connection off of the main
steam supply header. Steam is then fed to each tracer via a
tracer lead from a valved connection on the manifold. Each
tracer shall have a tracer tailfitted with a steam trap discharging
to drain or to a condensate collection manifold. Generallymultiple
traps will discharge into a manifold whether the condensate runs to
drain or acollection system in order to minimize steam discharges
to the atmosphere.
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 12 of 35
7.3 TRACER MATERIAL SELECTION
7.3.1 Temperature and Pressure Limitations
Copper or stainless steel tubing shall be used for steam tracers
subject to pressure and
temperature limitations. For situations where lines are normally
operating at temperatures abovethe tracer temperature then
selection of the tracer material shall take into consideration the
fullrange of conditions. Carbon steel tubing shall not be used
unless specific circumstances existwhere its use would provide an
overall installed cost saving. The relatively lower capital cost
ofcarbon steel tubing is usually offset by higher installation
costs, and consideration must also begiven to the susceptibility of
the material to corrosion, particularly in cyclic operation.
7.3.2 Copper Tubing Material Chart
Copper tubing shall be used up to a maximum temperature of 260C
/ 500F. Tubing shall beseamless soft annealed in accordance with
ASTM B75/75M.
C O P P E R T U B I N G M A T E R I A L C H A R T
ASTM B75 ASTM B75M
1/4" OD Min WT 0.028 7mm OD Min WT 0.71mm
3/8" OD Min WT 0.035 10mm OD Min WT 0.89mm
1/2" OD Min WT 0.035" 15mm OD Min WT 0.89mm
3/4" OD Min WT 0.049" 20mm OD Min WT 1.24mm
7.3.3 Stainless Steel Tubing Material Chart
Stainless steel tubing shall be seamless in accordance with ASTM
A269.
1/4" OD Min WT 0.028 7mm OD Min WT 0.71mm3/8" OD Min WT 0.035
10mm OD Min WT 0.89mm1/2" OD Min WT 0.035" 15mm OD Min WT
0.89mm
3/4" OD Min WT 0.049" 20mm OD Min WT 1.24mm
STAINLESS STEEL TUBING MATERIAL CHARTASTM A269 ASTM A269M
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 13 of 35
While 3/4"/20mm SS tubing maybe allowed in the specifications,
its use should be reviewedcarefully. 3/4"/20mm SS tubing is
difficult to bend and Bechtel standard craft rates do not
recognize the increased difficulty.
7.4 TUBING FITTINGS
Fittings for connecting copper to copper and copper to steel
shall be brass compression typefittings and compression/threaded
adaptors.
Fittings for connecting stainless steel to stainless steel and
stainless steel to copper shall bedouble ferrule type compression
fittings. Brass ferrules shall be used on copper tubing.
Forconnecting stainless steel to carbon steel, compression/threaded
adaptors shall be used.
7.5 TRACER LEAD AND TRACER TAIL MATERIAL
Tracer leads and tracer tails to and from the item being traced,
shall be of carbon steel,stainless steel or copper pre-insulated
tubing supplied in coils. The relatively high material costis
usually offset by reduced installation costs compared to carbon
steel piping with insulation,due to the ease of installation and
supporting with resultant reduced construction
man-hours.Consideration shall be given to the use of pipe when the
tracer size is /20mm and larger.
7.6 TRACER ATTACHMENT
Steam tracers shall be attached to the main pipe using / 12mm
wide x 24 gauge stainlesssteel banding (Figure 1).
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 14 of 35
PROVIDE FLEXIBILITY IN FEEDER & OUTLET
PIPING TO PERMIT LONGITUDINAL TRACER
EXPANSION AND MOVEMENT. DO NOT USE
"U" BOLT TYPE SUPPORTS WITHIN 6ft / 2m
NOTEDOUBLE STRAP TRACERS AT
ELBOWS & ANCHOR POINTS
TRACER BANDING ON 2ft / 600mm CENTERSFOR 3/8" AND 1/2"
TRACERS
FIGURE 1BANDING DETAILS
Figure 1 Banding Details
7.7 STEAM TRAPS
Steam traps shall have 1/2 screwed connections and shall be
thermodynamic (controlled disc)type with integral strainer.
7.8 TRACER LENGTH AND SELECTION
The size, length and number of steam tracers is dependent on the
heat input required to themain line and the temperature and
pressure of the tracing steam. The optimum size and lengthof tracer
is such that there is a balance between heat transfer and
condensation of the tracingsteam. Refer to project Steam Tracing
Schedule for size & number of tracers.
7.8.1 Tracer Distance Chart
Preferably steam tracers should be standardized at /15mm OD
tubing, and multiple tracersused where greater heat input is
required. A single tracer with heat transfer cement may
beconsidered as an alternative to multiple tracers. The maximum
length of a tracer in contact withthe main line shall be as
follows:
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 15 of 35
The length of steam supply or condensate return leads shall not
exceed 50 ft/15 m. Individualleads with length greater than
50ft/15m shall have the tracer length reduced accordingly.In
offsite areas where long pipe lengths are traced, consideration
should be given tocalculating tracer lengths on an individual basis
to minimize the number of distribution and
collection manifolds required.
7.9 STEAM TRACING SCHEDULE
The requirements for steam tracing shall be shown on the Steam
Tracing Schedule. Refer toAppendix A.
7.9.1 Steam Tracing Schedule Input
Project Engineering shall create a MS Access database and
identify all items requiring tracing,the size of the tracers, use
of heat transfer cement, the number of tracer circuits required,
and
any heat sensitive lines that may need spacers. The partially
completed schedule shall then bepassed on to Plant Design, who
shall take ownership and complete the tracer schedule.
As a minimum, Plant Design shall be responsible for:-
Numbering each tracer circuit Developing the Manifold Schedule
(MS Access database)
Ensuring that there are sufficient manifolds to feed all of the
tracer circuits. Theallocation of manifolds shall be reviewed by
Project Systems to ensure that anysystems requirements (e.g.
uninterruptible steam supply) are met.
While the Project Engineering group remain responsible for
identifying any new tracer circuitsrequired due to development of
the P&IDs, Plant Design is responsible for combining
andsplitting circuits according to the constraints of the maximum
tracer length criteria.
7.10 HEAT SENSITIVE LINES
S T E A M T R A C E R L E N G T H S
STEAM PRESSURE TUBINGSIZETRACER LENGTH(Without cement)
TRACER LENGTH(With cement)
Up to 49 psig/3.4 bar3/8" / 12mm &1/2" / 15mm 200 ft /60 m
120 ft / 40 m
Up to 49 psig/3.4 bar3/4" / 20mm &
1" / 25mm 300 ft./90 m 200 ft / 60 m50 psig/3.5 bar to200
psig/13.8 bar
3/8" / 12mm &1/2" / 15mm 200 ft./60 m 120 ft / 40 m
50 psig/3.5 bar to200 psig/13.8 bar
3/4" / 20mm &1" / 25mm 400 ft./120 m 240 ft / 75 m
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 16 of 35
Heat sensitive lines are those where excess heat input is
detrimental for one of the followingreasons:
a) The fluid to be heated will undergo undesirable changes at
elevated temperature.
b) Hot Spots in the pipework combined with the fluid will cause
undesirable reaction inthe pipe material.
c) Excessive temperature will be dangerous to personnel (for
example, excessivewinterization of safety shower supply
piping).
7.10.1 Avoiding Excessive Heat Input
Depending on specific applications, excessive heat input shall
be avoided by one of thefollowing methods:
a) Install insulating spacers between the tracer and the line to
be heated (see Figure 2).
b) Add temperature control.
c) Consider an alternate method of tracing.
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 17 of 35
SINGLE TRACER SINGLE TRACERWITH INSULATING SPACER
INSULATION
TYPE 43 OR MORE TRACERS
EQUALLY SPACED
INSULATINGBLOCK
1/2" x 1" / 13mm x 25mmWIDE SPACER30
BOTTOM OFHORIZONTAL LINES
TRACER
TYPE 1 TYPE 2
INSULATION
60APPROX.
TYPE 3DOUBLE TRACERS
FIGURE 2TRACER LOCATION DETAILS
Figure 2 Tracer Location Detail
8.0 STEAM AND CONDENSATE MANIFOLD DESIGN
8.1 FABRICATED DISTRIBUTION & COLLECTION MANIFOLDS
These manifolds are fabricated from project standard piping line
classes. The units arefabricated by either the project spool
fabricator or by a separate fabricator. Manifolds can behorizontal
or vertical design. A vertical design is shown in Figure 3 and a
horizontal design inFigure 4.
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 18 of 35
MATERIALS PER
PIPING MATERIALCLASS
GATEVALVE
PIPE / TUBINGTRACER LEADS
SPARECONNECTION
CONDENSATECOLLECTION
HEADER
BRANCH CONNECTION TO
PIPING MATERIAL CLASS
2" / 50mm (PREFERRED)MINIMUM HEADER SIZE
FABRICATED CONDENSATE COLLECTION MANIFOLD(VERTICAL DESIGN)
UNION OR PIPE /
TUBING ADAPTOR
UNION
T
T
T
T
T
MATERIALS PERPIPING MATERIAL
CLASS
GATEVALVE
PIPE / TUBINGTRACER LEADS
T
TO DRAIN ORCONDENSATECOLLECTION
STEAMTRAP
SPARECONNECTION
UNION OR PIPE /
TUBING ADAPTORSTEAMSUPPLYHEADER
BRANCH CONNECTION TOPIPING MATERIAL CLASS
2" / 50mm (PREFERRED)
MINIMUM HEADER SIZE
FABRICATED STEAM DISTRIBUTION MANIFOLD
(VERTICAL DESIGN)
FIGURE 3
Figure 3 Fabricated Manifolds (Vertical Design)
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 19 of 35
MATERIALS PERPIPING MATERIAL
CLASSGATE VALVE
PIPE / TUBINGTRACER LEADS
SPARECONNECTION
CONDENSATECOLLECTION
HEADER
BRANCH CONNECTION TOPIPING MATERIAL CLASS
2" / 50mm (PREFERRED)
MINIMUM HEADER SIZE
FABRICATED CONDENSATE COLLECTION MANIFOLD(HORIZONTAL DESIGN)
UNION OR PIPE /TUBING ADAPTOR
UNION
FIGURE 4
MATERIALS PER PIPINGMATERIAL CLASS
GATE VALVE
PIPE / TUBINGTRACER LEADS
TO DRAIN ORCONDENSATECOLLECTIONSTEAM
TRAP
SPARE CONNECTION
UNION OR PIPE / TUBINGADAPTOR
STEAMSUPPLY
HEADER
BRANCH CONNECTION TOPIPING MATERIAL CLASS
2" / 50mm (PREFERRED)MINIMUM HEADER SIZE T
FABRICATED STEAM DISTRIBUTION MANIFOLD(HORIZONTAL DESIGN)
TTTTT
Figure 4 Fabricated Manifolds (Horizontal Design)
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 20 of 35
8.2 VENDOR SUPPLIED DISTRIBUTION & COLLECTION MANIFOLDS
(FORGED)
These manifolds are usually of the forged type and are supplied
by a specialist company(Figure 4). They offer significant savings
on installed cost over fabricated manifolds. Use of thistype of
manifold is to be evaluated on a case-by-case basis to ensure that
all components
meet project codes and specifications. Client approval should be
obtained for the use of thistype of manifold. Care should be taken
to ensure that all applicable weld procedures areincluded with the
Material Requisition.
Manifolds should be purchased from a Material Requisition raised
either specifically for thetracing manifolds, or as part of a
piping specials requisition. They should not be obtainedthrough the
project piping spool fabricator.
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CONDENSATE
COLLECTIONHEADER
PRE-INSULATEDTUBING LEADS
PIPE / TUBINGADAPTOR
C.S.PIPE
SPARECONNECTION
PROPRIETARY
PREFABRICATEDMANIFOLD
PREFABRICATED CONDENSATE COLLECTION MANIFOLD
T
TT
TT
UNION
FIGURE 5
T
TO DRAIN ORCONDENSATECOLLECTION
STEAM
TRAP
STEAM
SUPPLYHEADER
PRE-INSULATEDTUBING LEADS
PIPE / TUBINGADAPTOR
C.S. PIPE
SPARECONNECTION
PROPRIETARYPREFABRICATED
MANIFOLD
PREFABRICATED STEAM DISTRIBUTION MANIFOLD
Figure 5 Prefabricated Manifolds
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8.3 NUMBER OF MANIFOLD CONNECTIONS
A maximum of 12 connections shall be supplied from one manifold.
One tracer connection shallbe left spare for manifolds supplying up
to six tracers and two left spare for manifolds supplyingmore than
six tracers.
8.4 MANIFOLD LINE SIZE
The steam supply and condensate return manifold line size shall
be based on the following, andincludes spare connections:
MANIFOLD LINE SIZE
NUMBER OF CONNECTIONS LINE SIZE
1 or 2 See Note 1 below
3 or 4 1
5 to 7 1
8 to 12 2
Note 1Where only one or two tracers are to be supplied with
steam, a manifold should not be provided,
and the steam supply lead should be connected by a 3/4" pipe
(increase for span) and gatevalve from the steam supply header to
the tracer lead. This arrangement applies particularly tothe steam
tracing of lines that are off-plot, or non-process plant
installation, such as supply linesto and from product storage
tanks.
8.5 MANIFOLD BLOCK VALVES
A block valve shall be provided for isolation of the steam
distribution manifold from the steamsupply header. A block and
check valve shall be provided for isolation of the
condensatecollection manifold from the condensate collection
header.
9.0 HEAT TRANSFER CEMENT
9.1 PURPOSE
The purpose of heat transfer cement is to increase heat transfer
between the tracing elementand the piping or equipment through
conductive heating. Heat transfer cement decreases heat-up times,
while allowing closer temperature control and higher process
temperatures.
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9.2 OBJECTIVE
The objective for using heat transfer cement is to provide an
economic advantage for theinstalled cost of steam tracing by
reducing the size and number of tracers required for largebore
piping or for high temperatures.
9.3 USAGE
Heat tracing cement shall only be used where there is a definite
economic advantage overinstalling multiple or larger tracers.
Considerations must be given to the time and cost ofapplication of
the cement and any curing process required.
9.4 APPROVAL
The use of heat tracing cement must have client approval.
9.5 PRESSURE TEST
Prior to beginning the installation of heat transfer cement, all
tracing should be subjected to apressure or service test as
required by the project specifications. All leaks detected should
berepaired and all tracers should be clean of dirt, grease and oil
before application of heattransfer cements.
9.6 APPLICATION AND PROTECTION
Tracers embedded in heat transfer cement shall be installed
parallel on the process line andshall be located on the most
accessible surface of the process line, if more than one tracer
is
required, they shall be spaced approximately 30 apart, where it
is most convenient, andpreferably not closer than 6in / 150mm.
Tracers shall be in contact with the process line over their
entire length.
After application of the cement, steps shall be taken to protect
the cement from weather and ormechanical damage prior to installing
insulation.
Heat tracing cement shall be handled and stored in accordance
with the manufacturersinstructions.
10.0 STEAM TRACING LAYOUT AND INSTALLATION
10.1 GENERAL
Steam tracing systems shall be laid out in an orderly manner
with provision for thermalexpansion of pipes and tracers (see
Figures 5 & 6), and access to all equipment, flanges,
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 24 of 35
unions, valves, instruments etc. Tracers shall be arranged such
that in-line valves etc can beremoved without removing the tracer
(see Figures 7 & 8).
3"/75
mm
1"/25
mm
1"/25mm
TRACER
COUPLING
PRE-INSULATED TUBING
SLOT INSULATION (& INSULATION JACKET)TO PROVIDE FOR TRACER
EXPANSION.
SEAL OPENING WITH SUITABLE MASTICCOMPOUND.
FIGURE 6
TRACER PENETRATION
Figure 6 Tracer Penetration
TRACER
BAND TRACER SNUG TOPIPE BUT ALLOW MOVEMENT
TRACER LOOP TOBE HORIZONTAL
SECTION
FIGURE 7TRACER EXPANSION LOOP
Figure 7 Tracer Expansion Loop
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 25 of 35
2" AND SMALLER VALVES
WITH BONNETS
2 1/2" AND LARGER VALVES
WITH BONNETS
ALL SIZE CHECKS AND
OTHER VALVES WITH NO
BONNETS
TRACE ONE SIDE
OF VALVE ONLY
TRACING IS SIMILAR FOR ALL
VALVE POSITIONS
FIGURE 8TRACING VALVES
Figure 8 Tracing Valves
FIGURE 9TRACING RELIEF VALVES
TO TRAPS
TRACERSUPPLY
ARRANGEMENT O
TRACER SHALL NO
OBSTRUCT VALVEREMOVAL
DETAIL AT RELIEF
VALVE BODY
SEE DETAIL RIGHT
TRACE AND INSULATE
12" / 300mm ABOVE
CENTER LINE OF
VALVE OUTLET
TRACER
SUPPLY
TO ATMOSPHERE
Figure 9 Tracing Relief Valves
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 26 of 35
ALTERNATIVE:
TO TRAP OR
CONTINUE TRACING
CONTROL
VALVE
CONTROL
VALVE
TOTR
AP
TOTR
APS
COUPLINGS FOR REMOVAL
OF CONTROL VALVE
FIGURE 10TRACING CONTROL VALVE ASSEMBLIES
Figure 10 Tracing Control Valve Assemblies
FIGURE 11DETAIL AT FLANGED JOINT
TRACER
UNION
Figure 11 Detail at Flanged Joint
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10.2 MANIFOLD LOCATION
Steam distribution and condensate collection manifolds shall be
located at grade or on (oraccessible from) a platform. Wherever
possible the manifolds should be sited such that the
supply leads and tracers are not pocketed. Where pockets are
unavoidable they shall notexceed the limits specified Figure
11.
"A"
"B
" "C"
STEA
M
TRAP
TRAP
DISC
HARG
E
THE SUM OF THE RISERS ("A"+"B"+"C")EXPRESSED IN METERS SHALL NOT
EXCEED
THE MINIMUM SUPPLY PRESSUREEXPRESSED IN BARS.
STEA
MSU
PPLY
FIGURE 12TRACER WITH POCKETS
THE SUM OF THE RISERS ("A"+"B"+"C")EXPRESSED IN FEET SHALL NOT
EXCEED0.23 OF THE MINIMUM SUPPLY PRESSUREEXPRESSED IN PSIG.
Figure 12 Tracer with Pockets
Manifold arrangements and/or individual tracer steam traps shall
be located as indicated onPiping Plans and/or isometrics. They
shall be easily accessible for operation and maintenance,shall not
block or obstruct maintenance access to any equipment, and shall
not block or
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 28 of 35
interfere with any passageways, walkways, stairways, or ladders.
The location of steam tracingmanifolds shall be considered during
the early phases of plant layout to ensure that adequatespace is
allowed in the plant for these items.
10.3 FLEXIBILITY & SUPPORT
Manifold steam supply and condensate return lines, individual
tracer supplies and discharges,leads to tracers and tails from
tracers shall be routed and supported to avoid blocking
orinterfering with passageways, walkways, maintenance accessways,
stairways or ladders.Generally tracing leads and tails will follow
the main pipe routes.Tracer leads and tails shall be routed and
supported with built-in flexibility to allow for thermalexpansion
of the traced pipe.
10.4 TRACER ROUTING AND INSTALLATION
Contact tracers shall follow the contour of the item being
traced and should start at the highpoint of the system where
possible. A slight waviness in the contact tracer is satisfactory
andserves to accommodate expansion.
10.4.1 Vents & Drains
Tracing of the run pipe shall extend to the first block valve of
any branch connection. Vents anddrains shall be traced up to the
first block valve in the same manner as the lines or equipment
towhich they are connected. Vents and drains shall be traced
downstream of the first block valveonly if specifically shown on
the P&ID. Double block and bleed configurations on traced
linesshall be traced up to the downstream block valve.
10.4.2 Instruments
Steam supply for line tracing and steam supply for off-line
instrumentation could be two separatesystems if dictated by the
Project Specifications.
Line mounted instruments (PIs, FIs etc) that require tracing,
shall be traced with the sametracer as the parent line.
For off-line instruments (transmitters, recorders etc.) tracer
supply and return points shallterminate adjacent to any instruments
that require tracing. The details for tracing off-line
instruments shall be shown on instrument detail sheets.Off-line
Instruments shall each be traced seperately, except that multiple
gauge glasses maybe traced together.
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10.4.3 Tracer Damage
No deformed sections at any bend in tubing shall be allowed to
enter any fitting. Tube must bestraight at each fitting.
If pre-insulated tubing is used, it shall be bent and supported
in accordance with themanufacturers instructions. All open ends of
insulation shall be sealed against ingress ofmoisture.
10.5 TRACER FITTINGS
Use of fittings shall be minimized to prevent leaks. However,
when unions are used at in-lineitems, which may need to be removed
for maintenance, the unions shall be located outside ofthe pipe
insulation.
10.6 NEW FEEDER REQUIREMENTS
A contact tracer shall be terminated and discharged to a trap,
and a new tracer lead installedto serve the next length of contact
tracer, where the following occurs:-a) The maximum allowable length
of tracer would be exceeded.b) The maximum allowable pocket, where
condensate may collect in a tracer would beexceeded (Figure 9).
11.0 IDENTIFICATION OF MANIFOLDS AND TRACERS
11.1 IDENTIFICATION OF MANIFOLDS
Each manifold shall be identified in the field with a unique
number, in accordance with specificproject requirements.
Typical examples are as follows:
DM-01 WWhere DM = Distribution Manifold, 01 is the manifold
number, W = for winterizing
CM-07 PWhere CM = Collection Manifold, 07 is the manifold
number, P = for process heating
11.2 IDENTIFICATION OF TRACERS
Each tracer shall be identified with a tag at each end. These
tags shall be positioned at thesupply manifold valve and at the
return steam trap. Marking shall be in accordance with
projectrequirements, but shall usually indicate the start and
finish of the tracer (manifold number), andmay also include the
lines or items traced.
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DESIGN GUIDE HEAT TRACING3DG-P23-00001-001 Page 30 of 35
Each steam supply lead should be tagged with a stainless steel
tag plate at the supply valveon the manifold identifying the tracer
number, the destination collection manifold number andplant number,
as shown below:
CM-2-05-07
Collection Manifold
Plant Number (if applicable)
Manifold number
Tracer number(series number for manifold)
Each condensate lead should be similarly tagged at the steam
trap identifying the distributionmanifold and tracer number, as
shown below:
DM-4-07-03
Distribution Manifold
Plant Number (if applicable)
Manifold number
Tracer number(series number for manifold)
The tag plates should have a punched hole and use stainless
steel wire to fix tag plate tovalve.
This method of identification and tagging enables the plant
operator to know the source ofsteam supply to the respective trap,
without the need for reference lists of tracer and line data.
12.0 STEAM TRACING DRAWINGS FOR CONSTRUCTION PURPOSES
The following describes the type of design drawings that may be
produced for the installationof steam tracing.
1) Manifold location plans: Prepared from current revision of
plot plan or equipmentarrangement drawings and shows location and
elevation of steam distribution andcondensate collection
manifolds.
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2) Steam Tracing Isometrics: Prepared from current revision of
isometrics and shows bymeans of a bold line, the contact tracer
routing and termination location points (includingmultiple
tracers). As a minimum the steam tracing isometric shall contain
the following:
a) Where the contact tracer terminates & connects to the
pre-insulated tracer lead, a
connector will be shown and identified.
b) A short tail for the pre-insulated tubing will be shown and
the length, size, materialand manifold that the tubing connects to
will be identified. (Example:- 40 ft/15 m
1/2/15 mm pre-insulated copper tubing from DM-01 W).
c) Provide a Bill of Material identifying all tubing
fittings.
d) On the body of the isometric, indicate the total length, size
and material of thetracer. (Example, 150 ft- 1/2 copper tubing / 50
m 15 mm copper tubing).
The steam tracing isometric shall retain the same isometric
number with the prefix ST.The revision number shall be zero for the
first issue of all steam tracing isometrics. Allsteam tracing data
and materials are required to be shown on the steam
tracingisometric.The steam supply piping and condensate return
piping between the manifolds and theutility headers shall be
designed in the 3D CADD model. Isometrics will be extracted
andissued for construction.
3) Equipment tracing: On a blank isometric sheet show the
equipment in a simple singleline presentation and prepare drawing
in the same manner as indicated for lineisometrics.
4) General arrangements: Where lines to be traced are shown on
general arrangementdrawing (G.A.), but not on isometrics, a
transparency of the G.A. should be made andthe tracer indicated
together with termination location points. The information may
beincorporated on the same G.A. as that which is prepared for the
manifold location plan.
5) Manifold drawings: If distribution and collection manifolds
are not part of the 3D CADDpiping model, then standard drawings of
1and 2" steam and condensate manifoldsfor vertical and
alternatively horizontal installation and the various numbers of
tracertrappings should be prepared to cover all possible
requirements for the project.Condensate manifold drawings shall
show steam trap assembly fittings and valves. The
particular standard drawing may be specified for each
application.
Tracer 'leads' and 'tails' should be field run. Therefore
drawings are not required.
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confidential and/or proprietary information to Bechtel and its
affiliated companies which shall not be
used, disclosed or reproduced in any format by any non-Bechtel
party without Bechtels prior written permission. All rights
reserved.3DG-p23-00001-001 Page 32 of 35
Figure 13 Typical Steam Tracing Arrangement
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confidential and/or proprietary information to Bechtel and its
affiliated companies which shall not be
used, disclosed or reproduced in any format by any non-Bechtel
party without Bechtels prior written permission. All rights
reserved.3DG-p23-00001-001 Page 33 of 35
13.0 HOT OIL TRACING
13.1 GENERAL
Hot oil tracing systems generally follow the same principles for
materials, design and
installation as steam tracing. To avoid duplication, this
section gives guidelines specific to hotoil tracing, highlighting
differences between the systems.
13.2 HEAT TRANSFER FLUIDS
Manufacturers offer a range of heat transfer fluids for use in
hot oil tracing systems. The heattransfer fluids available offer a
variety of type and heat transfer properties which can operate
ineither liquid or liquid/vapor phase.
13.3 HOT OIL SYSTEM
The hot oil tracing system consists of storage, heating and a
pumped circulation system.Distribution manifolds shall be provided
to supply a number of tracers from a single conectionon the main
hot oil header. Hot oil is fed to each contact tracer from a valved
connection on themanifold. Each contact tracer shall have a tracer
tail running to a collection manifold, which inturn is piped to the
hot oil return header.
13.4 MATERIALS
The heat transfer fluids manufacturers recommendations shall be
followed for piping materials.
13.4 TRACER LENGTH AND SELECTION
Due to the variety of heat transfer fluids available, the
optimum length of tracer will vary. TheSystems or Mechanical group
shall be responsible for determining the length, number and sizeof
tracers. This information can be transmitted to PD in a similar
format to steam tracing (see7.9.1)
14.0 REFERENCES
3DG-P23F-00001 Steam Tracing3DG-P23F-A0001 Steam Tracing
Estimate Checklist
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3DG-P23-00001-001 Page 34 of 35
APPENDIX A - STEAM TRACING SCHEDULE AND MANIFOLD SCHEDULE
INSTRUCTIONS
Data should be entered directly into the tables.
Step one is for a Project/Systems engineer to enter a list of
the traced lines. This can be donemanually by entering the data
directly into the tracing schedule table into the field Traced
item:Line No/tag No. Alternately a list of traced lines can be
copied from a PPS query directly intothe tracer summary table. For
the first pass, assume that each line has its own tracer. Todefine
all traced items, this field shall also include a list of the
traced instruments (developedfrom the P&IDs) and all traced
equipment items.
Step two is to add additional rows into the tracer table to
allow for lines and items that will havemore than one tracer
circuit. The number of tracers required per line shall be read from
the
clients project specifications, calculated, or estimated from
other data (see 7.9.1).
Should the project require a material take off at this point,
then the following default propertiesand lengths can be
assumed:
Tracer Lead 30 ft/10m x /15mm Preinsulated tubing Contact Tracer
60 ft/20m x /15mm Bare tubing Tracer Tail 30 ft/10m x /15mm
Preinsulated tubing
Care should be taken to ensure that the right material is
chosen. Copper is the usual choice
for duties up to 400-500F / 200-260Cpiping design temperature.
Be aware that some
clients mandate the use of stainless steel tubing for all
applications. While the majority oftracer tubing will be bare
tubing, note that some applications require a limited heat input
andtherefore special pre-insulated tubing may also be used for the
tracer tubing. (Typicalapplications are caustic, sour water and
some acid lines).
At this point the Project Systems Engineers should have
identified all items requiring tracing,and the number of tracer
circuits required. The partially completed schedule should then
bepassed on to Plant Design, who will complete and take ownership
of the tracer schedule andthe manifold schedule.
As a minimum Plant Design shall:
Replace the default lengths with estimated lengths based on the
actual pipe lengthsand proposed manifold locations
Complete the material and diameter selection for each tracer
circuit (Diameter byProject Engineering, see 7.9.1).
Number each tracer circuit Develop the Manifold Schedule
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3DG-P23-00001-001 Page 35 of 35
Ensure that there are sufficient manifolds to feed all of the
tracer circuits. (Theallocation of manifolds shall be reviewed by
Project Systems to ensure that anysystems requirements, e.g.
uninterruptible steam supply, are met.
While the Project Systems group remain responsible for
identifying any new tracer circuits
required due to development of the P&IDs, Plant Design are
responsible for combining andsplitting circuits according to the
constraints of the maximum tracer length criteria.
The tracer schedule and the manifold schedule should be printed
from the report view of thedatabase.
Steam Tracing Schedule and Manifold Schedule: