JERES-P-315 Electrical Tracing for Piping and Equipment

JERES-P-315

Electrical Heat Tracing For Piping and Equipment

Revision 1

Responsibility JER Engineering Division

20 May 2008

Jubail Export Refinery Engineering Standard


JERES-P-315 Rev.1 Electrical Heat Tracing For Piping and Equipment 20 May 2008

This document is the property of Jubail Export Refinery and no parts of this document shall be reproduced by

any means without prior approval by the Company.

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Revision Tracking

Revision Revision Date Scope of Revision

1 20 May 2008 Updating Issued for bid package Rev. 0 to incorporate technical comments.

0 29 April 2008 Issued for bid package.

03 18 April 2008 Revised to incorporate technical audit team comments.

02 14 April 2008 Technical Audit

01 31 March 2008 Issued for bid package for review.

00 14 Dec 2007 Issued based on TPIT JSD 1600.

1 14 May 2008





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Table of Contents

Section Contents Page

1 Scope 5

2 Conflicts, Deviations and Clarifications 5

3 References 6

4 Definitions 6

5 Scope of Supply 7

6 General 7

7 Service Conditions 7

8 Hazardous Area Classification and Equipment Selection 8

9 General Design Requirements 8

10 Freeze Protection System 9

11 Process Temperature Maintenance and Heating up Systems 10

12 Main Fabrication Data 12

13 Self-Limiting Heating Cables 13

14 Constant Wattage Heater Cable 14

15 Mineral Insulated (MI) Heating Cable (High Temperature) 14

16 Flexible Series Resistance Heat Tracing 15

17 Skin Effect Heat Tracing System 15





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18 Pre-Insulated Heat Traced Tubing 16

19 Heated Instrument Enclosures 17

20 Heat Tracing Control and Monitoring Unit 18

21 Heat Tracing Control Thermostats 21

22 Heater Cable Installation 22

23 Heater Cable Connection 23

24 Heater Cable Identification 24

25 Skin Effect Heat Tracing System Installation

24

26 Field Distribution System 24

27 Local Switches 25

28 Connection Boxes

25

29 Expediting Inspections and Tests - Fabrication and quality control plan and inspections

26

30 Test Procedure

26

31 Cable Field Tests

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1 Scope 1.1 This Specification covers the design, materials, procurement, manufacture, testing

and installation of Electrical Heat Tracing (EHT) system for piping and equipment freeze protection and process fluid temperature maintenance and heat up.

1.2 The Electrical Heat Tracing shall also include the associated monitoring devices.

1.3 Electrical heat tracing systems will be provided as:

a) “Freeze protection” heat tracing system is provided to apply sufficient heat to liquid filled pipes and equipment to prevent freezing during periods of low ambient temperatures. Sensing ambient temperature controls freeze protection.

b) “Process temperature maintenance” is needed to prevent solidification in liquid lines or condensation in vapour lines.

c) “Heat up” is used where quick thaw out after freeze up is needed. More heat input is required than with other types.

1.4 Instruments, equipment and lines requiring electrical heat tracing are identified on the instrument list, on the mechanical line list and on the P & I diagram.

2 Conflicts, Deviations and Clarifications 2.1 Any conflicts between this standard and other applicable Company Engineering

Standards (JERES), Material Specifications (JERMS), Standard Drawings (JERSD), Engineering Procedures (JEREP), Company Forms or Industry standards, specifications, Codes and forms shall be brought to the attention of Company Representative by the Contractor for resolution.

Until the resolution is officially made by the Company Representative, the most stringent requirement shall govern.

2.2 Where a licensor specification is more stringent than those of this standard, the Licensor’s specific requirement shall apply.

2.3 Where applicable Codes or Standards are not called by this standard or its requirements are not clear, it shall be brought to attention of Company Representative by Contractor for resolution.

2.4 Direct all requests for deviations or clarifications in writing to the Company or its Representative who shall follow internal Company procedure and provide final resolution.





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3 References The selection of material and equipment, and the design, construction, maintenance, and repair of equipment and facilities covered by this standard shall comply with the latest edition of the references listed below as of the CUT-OFF DATE as specified in the Contract unless otherwise noted.

3.1 Company Standards

JERES-P-100 Basic Power System Design Criteria JERES-P-127 Electrical Control System

3.2 Industry Codes and Standards

International Electro-technical Commission IEC 60079 Electrical apparatus for explosive gas atmospheres. IEC 60947 Low voltage switchgears and control gear. IEC 60702 Mineral insulated cables with a rated voltage not exceeding 750 V

IEC 60800 Heating cables with a rated voltage of 300 / 500 V for comfort heating and prevention of ice formation.

4 Definitions 4.1 Definitions presented in this Standard and other JER documents have precedence

over other definitions. Conflicts between various definitions shall be brought to the attention of Company Representative by the Contractor for resolution.

Company: Jubail Export Refinery.

Company Representative: A designated person from the Company or an assigned third party representative.

Company Inspector: A designated person or an agency responsible for conducting inspection activities on behalf of the Company.

4.2 List of Definitions

5 Scope of supply





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5.1 EHT system supply shall include detailed engineering, design, and field service unless specified otherwise by Contractor.

5.2 EHT system for piping shall include all in-line equipment.

5.3 Instrument impulse lines shall be pre-insulated heat traced and excluded from the scope of heat tracing supply.

5.4 Each instrument shall be provided with a heated enclosure, excluded from the scope of heat tracing supply.

6 General 6.1 This specification requires compliance to IEC standard which shall be at the latest

applicable edition.

6.2 This specification shall take precedence over any referenced third party document.

6.3 All documentation shall be in English.

6.4 All temperatures expressed within this specification are in Celsius units.

7 Service Conditions 7.1 The EHT system shall be suitable for outdoor installation with the typical atmosphere

of chemical plant or refinery (dusty, marine and corrosive).

7.2 For ambient temperature: The temperature criteria defined in JERES-A-112 shall be used to establish equipment rating.

7.3 Power Supply Features

7.3.1 Unless otherwise specified EHT system will be suitable for continuous operation at rated voltage at the above ambient conditions with the following combined conditions of voltage and frequency variable respectively in the range defined in JERES-P-100 without exceeding the over-temperature limits specified by the applied Codes / Standards.

7.3.2 Total harmonic distortion (THD) of the supply network voltage will not exceed 5%.

7.3.3 Transient voltage drop down to 80 % of rated voltage shall not affect the EHT system performance.

8 Hazardous Area Classification and Equipment Selection 8.1 Equipment, materials, and installation shall be suitable for electrical area classification

and specified temperature class.





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8.2 In classified areas, heater cable sheath temperatures shall be in accordance with IEC standard requirements.

9 General Design Requirements 9.1 EHT system shall be used, but not be limited to, for the typical following applications:

- Freeze protection.

- Process temperature keeping,

- Heat up.

9.2 Extent of EHT system shall be indicated in area plot plans, P&I’s and piping plan, elevation, and isometric piping drawings.

9.3 Temperature information regarding temperatures of traced piping and equipment shall be specified, to include:

- Start up temperature conditions.

- Design temperatures.

- Upset temperature conditions.

- Shutdown temperature conditions (steam cleaning, etc.).

9.4 Estimated duration of temperature extremes (start up, upset, and maintenance temperatures that exceed operating temperature), in hours per occurrence and occurrence frequency shall be specified.

9.5 If EHT system is used for freeze protection, for systems other than water, freeze point shall be clearly indicated.

9.6 If EHT system is used for process temperature maintenance:

- Temperature to be maintained shall be specified.

- Minimum and maximum maintain temperatures shall be specified. (High and low temperature ranges to be maintained).

- Lines with intermittent flow or no flow shall be clearly identified (spare pumps, bypasses, etc.).

9.7 If EHT system is used for heat up, process characteristics from “frozen” state to desired condition shall be indicated.

10 Freeze Protection System





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10.1 Freeze protection system shall provide enough heat to prevent solidification of no flow liquid filled lines at specified low ambient temperature.

10.2 Freeze protection systems shall consist of, but not be limited to, the following:

- Freeze protection control panels.

- Temperature sensors (RTDs where applicable).

- Electric heat tracers with termination kits and necessary accessories to complete installation.

- Power wiring and trays or conduit to heaters.

10.3 Each freeze protection panel shall be housed in an enclosure meeting area classification, and containing the following equipment:

- Main circuit breaker.

- Master contactor.

- Power distribution panelboard.

- Ambient sensing temperature controllers.

- Selector control switches, door mounted.

- Main ammeter to indicate total load, door mounted.

- Continuity or voltage monitoring system.

- Alarm unit complete with alarms for main breaker failure (loss of power to the panel), circuit continuity, and common alarm contact output for remote information.

- Terminal blocks.

- Space heater.

10.4 Heater circuits shall be served from branch circuit breakers in power distribution panelboard located in freeze protection control panel.

10.5 Heater integrity of each circuit shall be monitored using ground leakage detection devices such as 30 mA trip circuit breakers with alarm contacts or similar devices which trip and alarm on 30 mA leakage current.

10.6 Each freeze protection control panel shall be capable of being operated in the following modes:





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- Automatic.

- Manual.

10.7 When the control system is in the “AUTOMATIC” mode the freeze protection system shall:

- Be automatic for associated piping systems.

- Cause the power circuit (and heater circuits) to be controlled by an ambient sensing thermostat, set to energize the circuit when the outside temperature falls to 1.7°C, and de-energize whenever the temperature rises to 4.4°C

10.8 The ambient sensing temperature controllers shall:

- Monitor ambient temperature outside of control panel.

- Be wired to operate the master contactor, which will energize or de-energize the power distribution panelboard.

10.9 If for freeze protection, multiple heater cables may be operated in parallel on the same electrical circuit. A maximum of five pipes or instrument lines shall be served from the same circuit breaker.

10.10 Pre-insulated, heat traced instrument lines and enclosures shall be powered and controlled from local freeze protection control panel. Power supply for these items shall be considered part of system requirements.

11 Process Temperature Maintenance and Heating up Systems 11.1 Process temperature maintenance system shall maintain temperature of process pipes,

tanks, instrumentation, and equipment within specified range during exposure to environmental conditions specified.

11.2 Process heat tracing system shall consist of, but not be limited to, the following:

- Process heat tracers control panels.

- Electric heat tracers, termination kits, and all accessories.

- 3 wire, 100 ohm, platinum RTD temperature sensors (one for each circuit unless mechanical thermostats have been approved in system).

- Power wiring and trays or conduit to heaters.

11.3 Each process heat trace panel shall be housed in a free-standing enclosure and shall contain the following equipment:





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- Main circuit breaker

- Circuit breakers for individual heating circuits

- Temperature control and monitoring equipment of individual circuits, complete with heating circuit energized indicators and alarm set point temperature calibration

- Alarm unit complete with alarms for main breaker failure (loss of power to the panel), over-temperature, under-temperature, circuit continuity, sensor failure, and common alarm contact output for remote annunciation

- Space heater to prevent condensation in control panel

- Terminal blocks for all field wiring

11.4 Heater circuits shall be served from branch circuit breakers in power distribution panelboard located in control panel.

11.5 Heater integrity of each circuit shall be monitored using ground leakage detection devices such as 30 mA trip circuit breakers with alarm contacts or similar devices which trip and alarm on 30 mA leakage current.

11.6 Process heat tracing system shall provide heat to exterior surface of specified piping, tanks, instrumentation, and other equipment.

11.7 Each process line shall be provided with an individually controlled heating circuit.

11.8 Individual flow and no-flow conditions specified shall be separately traced and controlled.

11.9 Heater circuits for process instruments shall be powered as separate electrical circuits in process heat trace control panel for each process group, up to 5 instruments.

11.10 Instrument enclosure shall be controlled separately from heat traced instrument tubing as required by process conditions.

11.11 Hoppers, bins, tanks and other such equipment requiring process heat tracing shall be considered to be a part of system requirements. Either heater cable or flexible pad type heaters shall be employed, and heaters for each piece of equipment shall be individually controlled and fed from a separate power circuit.

12 Main Fabrication Data 12.1 Heat tracing systems shall be limited to those described below. Neither impedance nor

inductance heating systems shall be used.





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12.2 Heat tracing methods not included in this specification may be used as an alternate where temperature and/or watt density dictate if approval is obtained from Company.

12.3 Heating cables shall have a metallic braid for use as a ground path.

12.4 Heating cables shall have an overjacket for applications defined below:

- Tinned or nickel plated copper braid may be used without an overjacket in non-corrosive areas.

- Tinned copper braid with a Polyolefin overjacket shall be used in moderately corrosive areas and where exposure to aqueous inorganic compounds is expected.

- Nickel plated copper braid shall be used in corrosive areas.

- Fluoropolymer overjacket shall be used over metallic braid in corrosive areas where exposure to hydrocarbon based chemical solutions or vapors are expected.

- If an overjacket is specified, a Polyolefin or fluoropolymer overjacket shall be used to reduce the possibility of mechanical damage.

12.5 Heating cables shall be furnished with suitable fluoropolymer jacketing to withstand intermittent purging of the traced piping in accordance with the temperature of saturated steam.

12.6 System design shall allow for start up current at minimum ambient temperature specified.

12.7 Thermal design rating of heaters shall be at least 120% of the required thermal output of the heaters.

12.8 Field testing of insulation resistance and continuity shall be performed using a 1000 V megger.

13 Self-Limiting Heating Cables 13.1 General

13.1.1 Cable shall be capable of being cut to any desired length (within manufacturer’s published length limitations) to suit conditions for installation and shall form a continuous heating circuit. Heat output shall respond to temperature changes on pipe or surface being heated.





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13.1.2 Heating cables shall have outer jacket markings to define lengths. Markings shall be suitable for calculating installed circuit lengths and correspond to labelling on shipping spools to establish lengths available without unreeling from spool.

13.1.3 If cable is to be installed in a corrosive environment, cables braided with tinned-copper or nickel-copper braid shall be covered with a corrosion resistant overjacket.

13.1.4 Intermittent exposure ratings for self-regulating cables shall not be considered.

13.2 Self-Regulating Heating Cable (Low Temperature)

13.2.1 Heating cables shall be self-regulating type, capable of maintaining process temperature up to 66°C and withstanding continuous exposure to temperatures of 85°C with power off.

13.3 Self-Regulating Heating Cable (Medium Temperature)

13.3.1 Heating cables shall be self-regulating type, capable of maintaining process temperature up to 121°C and withstanding continuous exposure to temperatures of 191°C with power off.

13.3.2 Tinned-copper braid shall not be used.

13.3.3 Polyethylene jacket shall not be used.

13.4 Power Limiting Heating Cables (Medium High Temperature)

13.4.1 Heaters shall be designed to limit power over entire length of each heating circuit based on pipe temperature.

13.4.2 Power limiting heating cables shall be used to maintain temperatures to 149°C and withstand exposure temperatures of 260°C with power off.

13.4.3 A high grade of fluoropolymer insulation shall be used for power limiting heating cables.

13.4.4 Carbon loaded, semi-conductive, polymer heating elements shall not be used for power limiting cable applications.

13.4.5 Tinned-copper braid shall not be used.

13.4.6 Polyethylene jacket shall not be used.

14 Constant Wattage Heater Cable 14.1 General





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Heaters shall be designed to have a constant watt density (W/m) within range of lengths recommended by manufacturer.

14.2 Constant Watt Heater Cable (Low Temperature)

14.2.1 Heating cables shall be capable of maintaining temperatures up to 32°C and withstanding continuous exposure to temperatures of 121°C when de-energized.

14.2.2 Such cables shall have solder applied at all electrical connections between Ni-Chrome heating element and bus wires and shall be rated in accordance with requirement of project specification.

14.3 Constant Watt Cable (Medium Temperature)

14.3.1 Heating cables shall be capable of maintaining temperatures of 66°C and withstand continuous exposure to temperatures of 204°C.

14.3.2 Electrical connections between bus wires and Ni-chrome heating element shall not be soldered, unless approval is obtained from Company. Insulation jacket shrinkage onto these “bus connections” along with tension on Ni-chrome wire during manufacturing shall be sufficient to ensure a sound electrical connection to copper bus wires.

14.3.3 In addition to fluoropolymer dielectric insulation, 0.25 mm of woven electrical grade fiberglass shall be layered between helically wrapped Ni-chrome heating element and outer dielectric jacket.

15 Mineral Insulated (MI) Heating Cable (High Temperature) 15.1 MI cables shall be capable of continuous exposure to temperatures of 538°C when

cable is de-energized.

15.2 Complete heater assembly shall be approved for use in hazardous areas.

15.3 Each MI heating cable shall be factory fabricated to the required lengths with cold junctions for connection to power or where splices are required.

- Cold sections shall be 0, 6/1 kV-insulated leads.

- Cold sections shall have a gland type fitting for termination in threaded hub junction boxes.

- Cables shall be factory terminated and sealed.

15.4 Each MI cable shall have a stainless steel tag connected to cold sections with stainless steel wire. Tag shall show:

- Circuit number to which it is connected.





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- Testing recognized laboratory approval.

- Heater electrical and physical characteristics such as voltage, watts/ m, heat output, resistance, and cable diameter.

16 Flexible Series Resistance Heat Tracing 16.1 Flexible series resistance heating cables shall be in one, two, or three conductor

configurations.

16.2 Electrical insulation shall be fluoropolymer, with a capability of withstanding continuous exposure to temperatures up to either 204°C or 260°C (type selected based on temperature) when circuit is de-energized.

16.3 Insulated conductors shall be connected to cold lead and end termination assemblies approved for the electrical area classification.

17 Skin Effect Heat Tracing System 17.1 Skin effect heat tracing shall only be used for piping over 1200 m and is based on skin

and proximity effects.

17.2 The skin effect is caused by the current flowing in a wire pulled inside a heat tube and the inner surface of the same tube. The insulated wire is connected to the heat tube at the end termination and the voltage source is connected between the heat tube and insulated wire at the power connection. Since the heat tube is attached to the process pipe and completely covered by the thermal isolation system, the heat is transferred to the process pipe

17.3 Skin effect heating system shall be mainly composed of specialty power transformers, special skin effect electrical conductors installed inside a heat tube, ferromagnetic heat tubes, load and control equipment, and all necessary installation accessories.

17.4 Heat tube shall be Schedule 40 mild steel pipe, either seamless or welded. ASTM A53 may be used. Heat tube size shall be specified for each design.

17.5 Design of skin effect heating system shall be by manufacturer and shall be as follows:

- Heating system shall be designed to produce even heating along entire length of pipeline to offset heat losses stated in design conditions.

- Design of ferromagnetic heat tubes and special electrical conductors that shall provide required amount of heat.

- Design shall include temperature/power control, monitoring and over-current protection devices needed for heating system.





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17.6 Pull boxes and splice boxes will be located along the line and shall allow the wire troubleshooting and replacement without removal of the pipe insulation.

17.7 The control of the skin effect heating system shall be accomplished by solid-state temperature controls with RTDs as sensor. Temperature, voltage and current values shall be monitored and overcurrent with differential current protection relays shall provide fault trips and alarms.

17.8 Detailed operating instructions shall be provided.

18 Pre-Insulated Heat Traced Tubing 18.1 Instrument impulse lines shall be heat traced to maintain tubing within temperature

limits specified.

18.2 Self-regulating parallel resistance cable supplied from the same feeder supplying instrument enclosure is the preferred tracing method for temperatures up to 121°C. Alternative forms of electric heating cables shall be used only if approval is obtained from Contractor.

18.3 Factory traced and insulated tubing bundles shall be used in conjunction with heated instrument enclosures (if required). Enclosure thermostat shall not control heat traced tubing bundle for process temperature maintenance applications.

18.4 Liquid and gas sampling lines shall also be heated to prevent freeze-ups and/or condensation formation. For temperatures within the following ranges, pre-insulated and heat traced tubing shall be used.

18.5 To maintain up to 121°C with exposure temperatures under 191°C, heat-tracing cable shall be parallel self-limiting cable.

18.6 To maintain up to 204°C with exposure temperatures under 260°C, heat-tracing cable shall be parallel power-limiting heating cable.

19 Heated Instrument Enclosures 19.1 Enclosures shall be flexible, removable, reusable type unless otherwise specified.

19.2 Vent extensions for liquid pressure sensing instruments shall be available when venting is done outside enclosure.

19.3 Drains shall be provided.

19.4 Stainless steel instrument identification tags shall be permanently mounted to an exterior surface. Tag shall display pertinent information about heating system, including model number.





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19.5 Heaters shall be removable for ease of maintenance or replacement.

19.6 Electric heating systems shall be:

- Designed, manufactured, and tested in accordance with electrical code requirements.

- Controlled by thermostat included within system.

- Approved by recognized testing laboratories for use in areas where they are to be installed.

- Installed such that instrument may be removed for maintenance without disturbing tracing installation or require disassembly of instrument to allow heat tracing installation.

19.7 Hollow steam or electric studs shall not be used.

19.8 Heat tracing for instruments and process piping may be powered from the same circuit breaker panel; however, instrument and process piping heat tracing circuits must be segregated on different circuit breakers.

19.9 Up to four heat traced instruments (and associate impulse lines) shall be powered from the same circuit breaker as long as individual instrument heat tracing cable are connected to a separate parallel circuit that can be electrically isolated for maintenance by means of a local switch.

19.10 Wetted portion sections of flow and pressure transmitters shall be provided with a heated weatherproof enclosure sufficiently insulated to minimize the heat loss. Heaters shall be provided with a thermostatically controlled temperature switch or other device to insure that the temperature cannot exceed the instrument wetted portion temperature limit.

19.11 A separate thermostatically controlled heater shall be furnished for heated secondary enclosures provided for weather protection. Total enclosures for indicating instruments shall be provided with a viewing window of safety glass or plastic.

19.12 Conduit and fittings shall be arranged so that the enclosure may be removed to permit servicing of the instrument without disconnecting wiring.

19.13 Heaters for impulse lines shall be self-limiting or thermostatically controlled to prevent boiling of process liquid. The use of self-limiting heaters shall be restricted in which the maximum temperature does not exceed the limit of the self-limiting heater.

19.14 Non-flowing connections from an external level instrument displacer chamber shall be heated using the design principles specified for impulse lines.





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20 Heat Tracing Control and Monitoring Unit 20.1 Control and monitoring unit shall be designed specifically for heat tracing

applications/service.

20.2 Heat tracing control and monitoring unit shall be provided with a simple and straightforward user interface that requires minimal documentation for effective use.

- Unit shall have an illuminated user LCD display.

- Operating control parameters shall be settable at control module without use of auxiliary hand-held programmers.

- Unit shall have RS 485 communication capability.

- Unit shall be provided with a graphical user interface (GUI) PC communication software package if system-wide heat tracing monitoring at a central location is specified.

- Each unit shall be provided with an operating guide booklet and installation/wiring drawings.

20.3 If in highly corrosive areas, external enclosure shall be IP 56. - All external latches (quick release preferred) shall be corrosion resistant and

preferably stainless steel. Viewing windows of corrosion-resistant polycarbonate shall be provided with each enclosure to permit internal viewing of display/alarm status without opening enclosure.

- Terminal strips within enclosure shall be corrosion-resistant material construction.

20.4 If in outdoor non-classified locations, module shall be housed in a IP 56 stainless steel enclosure and configured with either solid state control/power relays or mechanical control/power relays. If located indoors modules may be housed in IP 55 type enclosures.

- External latches (quick release preferred) shall be corrosion-resistant and preferably stainless steel. Viewing windows of polycarbonate shall be provided with each enclosure to permit internal viewing of display/alarm status without opening enclosure.

- Terminal strips shall be of corrosion-resistant material construction.

20.5 If in outdoor locations, a common alarm light shall be provided on exterior of cabinet.





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20.6 If in outdoor classified locations, module shall be housed in a stainless steel enclosure and configured with either solid state control and power relays or mechanical relays with enclosure purge.

20.7 If solid state heat tracing power relays are utilized, all enclosures shall be sized per manufacturer’s guidelines for total current switching capacity. Switching capacity/number of modules per enclosure shall be based on full load operating current of all heat tracing circuits.

20.8 If control and monitoring units are located outdoors, effect of solar gain shall be considered when sizing enclosure and number of control circuits.

20.9 Terminal blocks that are accessible and non-insulated wire terminations (120 VAC and up) shall be touch safe or protected by shielding and labels to ensure personnel safety.

20.10 Unit shall be:

- Factory supplied with grounding terminals for grounding path between heater cable braid, control, and monitoring unit, and facility system ground.

- Designed to allow independent power sources to be applied to instrument and heat tracing cable.

20.11 Heater power wiring in control and monitoring unit shall be 6 mm² minimum, stranded copper and approved for electrical area classification.

20.12 Power wiring to control and monitoring unit shall be sized to carry maximum heater current within voltage range specification stated by heat tracing/control and monitoring unit manufacturer.

20.13 If current monitoring transformers are included, current transformers shall be sealed and electrically isolated.

20.14 Heat tracing control and monitoring units shall be provided with Lock-Out/Tag-Out (LOTO) warning labels.

20.15 Solid state relays utilized shall be zero crossing type with single cycle surge capacity of 600 A, minimum, and a one second overcurrent capacity of 80 A, minimum.

20.16 Heat tracing control module shall be designed and constructed specifically for use in industrial environment.

20.17 Modules shall:

- Utilize components with maximum operating temperature rating of 70°C or higher.





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- Utilize three-wire resistance temperature detectors (RTD) of 100-ohm resistance (at 0°C with a nominal alpha value of 0.00385 ohms/ohms-°C. If sensor lengths are less than 2 m, modules utilizing two-wire detectors may be considered.

- Have RTD input circuitry factory-provided with transient protection as a part of printed circuit board design.

- Be provided with a field accessible tool-removable fuse to protect unit from misapplication events.

- Be designed to maintain separation of heat generating solid state heat tracing power-switching relays from control module. This feature shall also facilitate removal/repair of damaged relays.

- Have printed circuit boards correctly coated.

- Have control module electrostatically shielded from EMI/RFI by a metallic enclosure.

- Be provided with venting to assure minimal temperature rise of electronics during operation.

- Pipe-wall temperature sensing elements shall have a rating of pressure indicated for saturated steam

21 Heat Tracing Control Thermostats 21.1 Ambient sensing thermostats shall be exposed to the same weather conditions as the

electric heated pipe or equipment.

21.2 Ambient sensing thermostats may be utilized to switch on groups of heating circuits for freeze protection only if the cables under crossover, overvoltage, or thermostats runaway conditions will not damage themselves or produce sheath temperatures higher than 80% of the ignition temperature of the contained fluid.

21.3 Individual pipe sensing thermostats shall be used for each heating circuit provided for freeze protection where the sheath temperature can exceed 80% of the ignition temperature of the contained fluid.

21.4 Thermostats shall be of the capillary type. The capillary shall be no more than 5 meters long.

21.5 Individual thermostats shall be used for each heating circuit provided for maintaining a process temperature.





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21.6 All thermostats shall be factory calibrated, non-indicating type, equipped with internally adjustable set point.

21.7 Contactors shall be provided when the thermostat amperage rating is exceeded.

21.8 Thermostats used with series type heaters shall include a high temperature limit cut-off to prevent overheating.

21.9 When constant-wattage heaters are used for normally no-flow systems they shall be individually controlled.

21.10 A single thermostat may be used over flowing and non-flowing portions of pipe lines only when it is an ambient sensed or dead leg sensed system. A single pipe sensing thermostat shall not be used to simultaneously provide control over both flowing and no-flow portions of pipes where objective heat tracing temperatures are different.

21.11 Thermostat contacts shall not be loaded with more than 75% of their normal rating.

21.12 The temperature setting accuracy shall be not more than ± 5 % of the set value, with a maximum of ± 10°C. The switching hysteresis shall be between 5 and 10% of the actual setting or between 4 and 10 °C, whichever is more stringent.

21.13 Thermostats shall only be adjustable with the use of tools. Thermostats installed as temperature limiters for safety reasons shall be of the fail-safe type.

22 Heater Cable Installation 22.1 Heater cables shall be installed in accordance with manufacturer’s recommendations.

22.2 Cables shall be installed on pipes in a single pass without spiralling cable if practicable.

22.3 If heat loss of pipe exceeds output of cable, an additional pass or passes up to a 1.5:1 ratio may be used if approval is obtained from Contractor.

22.4 Self-Limiting, Power Limiting, Constant Wattage Modular and Flexible Series Resistance heater cables shall be attached to pipes with polyester fiber or glass cloth adhesive tape.

22.5 MI cable shall be attached to pipes with stainless steel tie wire or banding.

22.6 Heater cables shall be installed such that in-line devices and equipment may be easily removed and re-installed without cutting heater cable.

22.7 RTD sensors shall be installed in a location on pipe such that pipe temperature, not heater cable temperature, is sensed.





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22.8 Heater cables shall be installed on lower quadrant of horizontal pipe whenever practicable.

22.9 Heater cables shall be installed on outside radius of a 45° or 90° pipe elbow.

22.10 All flanges, pumps, valves, devices, supports, and appurtenances shall be traced with appropriate additional lengths of heater cable as indicated by manufacturer of the heat tracing.

22.11 No heater shall extend beyond the junction of two or more pipes when such junction will permit optional flow paths. In such cases, separately controlled heaters shall be used.

22.12 Separately controlled heaters shall heat piping, which in normal operation may not or does not have flow, such as dead ends or enclosed bypasses.

22.13 Extreme care shall be used in heating small taps off larger pipe to avoid over temperature of the small pipe or the heater. When practical, this shall be avoided. In each case, the expected maximum temperature for the small pipe and the insulation thickness shall be shown on the drawings. Preferably, lines with heat losses differing by 10 % or more shall be heated by separately controlled heaters.

22.14 Separately controlled heaters shall be used for each section of a pipe that are installed in various ambient temperature.

22.15 Where oversized insulation is used, heat stops shall be installed at 3 meters intervals on vertical piping to prevent chimney effect.

22.16 One heat stop shall be installed around the heater conduit at approximately the center of any dike wall penetrated by a traced pipe.

22.17 Heating circuits shall not be installed until all pipes and equipment have met all required tests.

22.18 To prevent cable damage, external thermal insulation shall be applied immediately after cables have been properly installed, inspected, and tested.

22.19 To obtain good contact between heater and heated surface, additional metal tape or foil can be used. Additional fixing straps shall be provided on both sides of the instruments, flanges, etc. to avoid loosening of the cable from the associated pipes. Special measures shall be taken to prevent damage to the cables from sharp edges or rough surfaces.

22.20 Fixing materials for cables shall ensure continuous and permanent contact between cables and heated surface. They shall be non-corrosive, suitable for the relevant operating temperature and shall not damage the cable mechanically or chemically. In





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general, for the cables with a polymer outer jacket, self-adhesive plastic or glass-fiber tape shall be used.

22.21 Extreme care shall be taken to prevent heating cables and pads absorbing water during transport as well as during and after installation. During transportation from the manufacturer factory to the site, the ends of the cables shall be suitably sealed.

23 Heater Cable Connection 23.1 All entry and exit points for power, controls, and thermostat capillaries shall be located

60 ° or more below the horizontal centerline to avoid water entry into thermal insulation. The entry and exit points shall be sealed with suitable mastic, weather proofing.

23.2 The heating cables shall be terminated in the junction boxes, switches, etc. in such a manner that any ingress of water through the cores, braiding or in between insulation layers due to the capillary effect is excluded.

23.3 Thermostat sensing bulbs installed on pipe shall be located away from the heating cable. Capillary runs outside of thermal insulation shall be enclosed in conduit or armoured tubing for mechanical protection.

23.4 Thermostat sensing bulbs shall be located at the downstream end of the pipe being controlled.

23.5 Heaters longer than 75 meters shall be fabricated in multiple sections, with cold junction splices made in an accessible junction box.

23.6 All penetrations of the thermal insulation weatherproofing for heater attachment, thermostat installation, or junction box attachment shall be made from the underside of the pipe. The penetrations shall be sealed to prevent moisture from entering the thermal insulation at the penetrations.

24 Heater Cable Identification 24.1 Signs shall be permanently attached to the outside of the finished external thermal

insulation for visibility from ground level. The sign shall read “ELECTRIC TRACED”, and shall be spaced at a maximum of every 3 meters on opposite sides of the pipe.

24.2 Traced instruments shall have individual signs. The labels shall be fixed on a non-removable part.

24.3 The elements of a circuit such as local switches, thermostats, connection boxes and heating cables shall be provided with permanent labels, which shall consistently indicate the number of the circuit to which the elements are connected.





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25 Skin Effect Heat Tracing System Installation 25.1 Skin effect heat tracing shall be installed per manufacturer recommendations and the

following:

- Each end of each pipe of heat tube shall be internally bevelled to eliminate burrs and sharp edges that could damage skin effect conductor.

- Conductor shall be insulated with a high temperature (260°C, minimum) special PFA Teflon dielectric in such a manner that minimal air space exists between conductor strands and extruded dielectric.

- System shall have 50%, maximum, fill, and highest abrasion resistant insulation shall be supplied.

26 Field Distribution System 26.1 The heater field distribution panels shall be connected to a switchgear/controlgear

installed inside the electrical substation.

26.2 The switchgear/controlgear (out of the EHT scope of supply) shall include common alarm output contacts for remote information (to ECS- JERES-P-127) of loss of power for each outgoing.

26.3 The distribution panels shall have:

- 3 Phase + Neutral + earthing incoming line

- 1Ph + Neutral + earthing outgoing lines.

26.3.1 Distribution panels shall contain sufficient terminals for all the connections to be made. Individual terminals shall be provided for each conductor. The terminals shall be of non-loosening construction and of the wedge type, obviating the use of cable lugs and constructed in such a way that direct contact between screw and conductor is avoided.

26.3.2 Terminals shall be identified in accordance with the related diagram. In addition, sufficient earth terminals or an earth bar with sufficient earth connection points shall be provided to earth the metal screens of all cables and heaters.

26.3.3 The armoured power cables (out of the EHT scope of supply) between the main switchgear/controlgear and the distribution panels and boxes shall have a cross section adequately sized for the maximum load, and restricting the voltage drop over the cable under full load conditions to maximum 5% of the nominal voltage.

26..3.4 The distribution panel incoming and outgoing entries shall be provided with threaded metal plate suitable for metallic cable glands.





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27 Local Switches 27.1 Local switches shall be installed near the associated heating equipment in an easily

accessible position and have the cable glands in the bottom.

27.2 When local switches are installed, they shall have a minimum switching capacity of 10 Amps and shall be double pole for a single phase circuit and four pole for a three phase + neutral circuit.

27.3 The switches shall not be loaded with more than 75 % of their normal rating.

27.4 The switches shall have a clear “ON-OFF” indication. The ‘OFF’ position shall be padlockable.

28 Connection Boxes 28.1 Connection boxes shall be distributed and grouped geographically in order to minimize

the number of switches and power cabling required.

28.2 Connection boxes shall be used for the connections between power supply cable and heating cable.

28.3 Connection boxes shall contain sufficient terminals for all the connections to be made.

28.4 Individual terminals shall be provided for each conductor. The terminals shall be of non-loosening construction and of the wedge type, obviating the use of cable lugs and constructed in such a way that direct contact between screw and conductor is avoided.

28.5 Terminals shall be identified in accordance with the related diagrams. In addition, earth terminals shall be provided to earth the metal screens of all cables and heaters.

29 Expediting Inspections and Tests - Fabrication and quality control plan and inspections

29.1 Inspection and testing activities shall be defined by the Manufacturer on the Fabrication and quality control plan based on the minimum requirements established on CONTRACTOR Inspection and Test Plan.

29.2 During the manufacturing period, the electrical tracing system could be subject to inspection by CONTRACTOR inspectors or by others appointed by CONTRACTOR or by the Company. Accessory material could be subject to inspection too.

29.3 The Manufacturer shall allow the free access of inspectors to the workshop, shall give all information required and shall make available all copies of internal orders to other sub-suppliers.





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30 Test Procedure 30.1 The tests shall be carried out in Manufacturer’s workshop at his care and expense.

30.2 Even in case COMPANY waives to witness the tests the Manufacturer shall draw up the certificate of the tests carried out containing a full report and all the results and the measures of the tests.

30.3 The tests shall be carried out in accordance with the requirements of IEC codes and of the Inspection and Test Plan.

31 Cable Field Tests 31.1 Heaters shall be visually inspected for damage and shall be megger tested with a 1000-

volt megger. Heaters shall have a minimum conductor-to-sheath resistance of 20 MOhm when tested at the following stages of installation:

- When received at jobsite before installation.

- After thermal insulation and weather barrier have been installed.

- After thermal insulation has been installed.

31.2 Above megger readings shall be 20 Mς, minimum, or heating cable is not acceptable and shall be repaired or replaced.

31.3 Field megger tests shall be recorded for each cable, and certified reports shall be submitted to CONTRACTOR and COMPANY.

31.4 Heater cables shall be power tested. Both the applied voltage and resulting current shall be measured and recorded. Heating cables shall be power tested at the following stages of installation.

- After the heating cable is installed on the piping and equipment, but before thermal insulation is applied.

- After thermal insulation and weather barrier have been installed.

31.5 The results of each test outlined above shall be recorded for each individual circuit, and certified reports shall be submitted to CONTRACTOR and COMPANY.

31.6 The proper operation of all control thermostats and/or control monitoring systems shall be verified and noted.

JERES-P-315 Electrical Tracing for Piping and Equipment

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Transcript of JERES-P-315 Electrical Tracing for Piping and Equipment