Heat Tracing

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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

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BECHTEL CORPORATIONENGINEERING – PLANT DESIGN

DESIGN GUIDEHEAT TRACING3DG-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.

Electronic documents, once printed, are uncontrolled and may become outdated.Refer to the electronic documents in BecWeb for current revisions.

Bechtel Confidential © Bechtel Corporation 1993, 2002. All rights reserved.

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




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




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




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




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 tracinginstallation.

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).




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

CONDENSATEHEADER

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.




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




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.




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 Design’s 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 Design’s responsibility that allrevisions 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.




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 tail”fitted 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.




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 andtemperature 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 260°C / 500°F. 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 TASTM B75 ASTM B75M 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 0.89mm3/4" 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 0.89mm3/4" OD Min WT 0.049" 20mm OD Min WT 1.24mm

STAINLESS STEEL TUBING MATERIAL CHARTASTM A269 ASTM A269M




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 notrecognize 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 ¾”/20mm and larger.

7.6 TRACER ATTACHMENT

Steam tracers shall be attached to the main pipe using ½” / 12mm wide x 24 gauge stainlesssteel banding (Figure 1).




PROVIDE FLEXIBILITY IN FEEDER & OUTLETPIPING TO PERMIT LONGITUDINAL TRACEREXPANSION AND MOVEMENT. DO NOT USE"U" BOLT TYPE SUPPORTS WITHIN 6ft / 2m

NOTEDOUBLE STRAP TRACERS ATELBOWS & 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 ½”/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:




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 andcollection 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, andany 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. The

allocation 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 TUBING SIZETRACER 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




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.




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.




MATERIALS PERPIPING MATERIAL

CLASS

GATEVALVE

PIPE / TUBINGTRACER LEADS

SPARECONNECTION

CONDENSATECOLLECTION

HEADER

BRANCH CONNECTION TOPIPING 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


CLASS

GATEVALVE


T

TO DRAIN ORCONDENSATECOLLECTION

STEAMTRAP

SPARECONNECTION

UNION OR PIPE /TUBING ADAPTORSTEAM

SUPPLYHEADER



FABRICATED STEAM DISTRIBUTION MANIFOLD(VERTICAL DESIGN)

FIGURE 3

Figure 3 Fabricated Manifolds (Vertical Design)





CLASSGATE VALVE


SPARECONNECTION


HEADER



FABRICATED CONDENSATE COLLECTION MANIFOLD(HORIZONTAL DESIGN)

UNION OR PIPE /TUBING ADAPTOR

UNION

FIGURE 4

MATERIALS PER PIPINGMATERIAL CLASS

GATE VALVE


TO DRAIN ORCONDENSATECOLLECTIONSTEAM

TRAP

SPARE CONNECTION

UNION OR PIPE / TUBINGADAPTOR

STEAMSUPPLYHEADER


2" / 50mm (PREFERRED)MINIMUM HEADER SIZE T

FABRICATED STEAM DISTRIBUTION MANIFOLD(HORIZONTAL DESIGN)

TTTTT

Figure 4 Fabricated Manifolds (Horizontal Design)




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 componentsmeet 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.





HEADER

PRE-INSULATEDTUBING LEADS

PIPE / TUBINGADAPTOR

C.S.PIPE

SPARECONNECTION

PROPRIETARYPREFABRICATED

MANIFOLD

PREFABRICATED CONDENSATE COLLECTION MANIFOLD

T

TT

TT

UNION

FIGURE 5

T

TO DRAIN ORCONDENSATECOLLECTION

STEAMTRAP

STEAMSUPPLYHEADER

PRE-INSULATEDTUBING LEADS

PIPE / TUBINGADAPTOR

C.S. PIPE

SPARECONNECTION

PROPRIETARYPREFABRICATED

MANIFOLD

PREFABRICATED STEAM DISTRIBUTION MANIFOLD

Figure 5 Prefabricated Manifolds




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 ½”

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.




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 isrequired, 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,




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"/ 75mm

1"/ 25mm

1" /

25m

m

TRACER

COUPLING

PRE-INSULATED TUBING

SLOT INSULATION (& INSULATION JACKET)TO PROVIDE FOR TRACER EXPANSION.SEAL OPENING WITH SUITABLE MASTICCOMPOUND.

FIGURE 6TRACER 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




2" AND SMALLER VALVESWITH BONNETS

2 1/2" AND LARGER VALVESWITH BONNETS

ALL SIZE CHECKS ANDOTHER VALVES WITH NO

BONNETS

TRACE ONE SIDEOF VALVE ONLY

TRACING IS SIMILAR FOR ALLVALVE POSITIONS

FIGURE 8TRACING VALVES

Figure 8 Tracing Valves

FIGURE 9TRACING RELIEF VALVES

TO TRAPS

TRACERSUPPLY

ARRANGEMENT OFTRACER SHALL NOTOBSTRUCT VALVE

REMOVAL

DETAIL AT RELIEFVALVE BODY

SEE DETAIL RIGHT

TRACE AND INSULATE12" / 300mm ABOVE

CENTER LINE OFVALVE OUTLET

TRACERSUPPLY

TO ATMOSPHERE

Figure 9 Tracing Relief Valves




ALTERNATIVE:TO TRAP ORCONTINUE TRACING

CONTROLVALVE

CONTROLVALVE

TO TRAP

TO TRAPS

COUPLINGS FOR REMOVALOF 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




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 thesupply leads and tracers are not pocketed. Where pockets are unavoidable they shall notexceed the limits specified Figure 11.

"A"

"B" "C

"

STEAM

TRAP

TRAP DISCHARGE

THE SUM OF THE RISERS ("A"+"B"+"C")EXPRESSED IN METERS SHALL NOT EXCEEDTHE MINIMUM SUPPLY PRESSUREEXPRESSED IN BARS.

STEAM SUPPLY

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




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 (PI’s, FI’s 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-lineinstruments shall be shown on instrument detail sheets.Off-line Instruments shall each be traced seperately, except that multiple gauge glasses maybe traced together.




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.




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.




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, aconnector 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 1½” and 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. Theparticular 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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Figure 13 Typical Steam Tracing Arrangement


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used, disclosed or reproduced in any format by any non-Bechtel party without Bechtel’s 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 andinstallation 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 theclients 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 ½”/15mm Preinsulated tubing• Contact Tracer 60 ft/20m x ½”/15mm Bare tubing• Tracer Tail 30 ft/10m x ½”/15mm Preinsulated tubing

Care should be taken to ensure that the right material is chosen. Copper is the usual choicefor duties up to 400°-500° F / 200°-260°C piping design temperature. Be aware that someclients 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 circuitsrequired 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:

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Heat Tracing