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PETRONAS TECHNICAL STANDARDS

DESIGN AND ENGINEERING PRACTICE

INSTRUMENT SIGNAL LINES

PTS 32.37.20.10SEPTEMBER 2008

2010 PETROLIAM NASIONAL BERHAD (PETRONAS)All rights reserved. No part of this document may be reproduced, stored in a retrieval system or transmitted in any form or by any means (electronic,

mechanical, photocopying, recording or otherwise) without the permission of the copyright owner


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PTS Circular

2009 - 001

This revision of PTS 32.37.20.10 - Instrument Signal Lines has been updated incorporatingPETRONAS Lessons Learnt, Best Practice and new information issued by relevant industry codeand standards. All updates in the document are highlighted in italicfont.

The previous version of this PTS will be removed from PTS binder/ e-repository from hereinonwards.

Document Approval

Revision History

Date Version Descript ion of Updates Author

PTS No: 32.37.20.10

Publication Title: Instrument Signal Lines

Base PTS Version:


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Summary of Changes

Section Descript ion of Changes

Standards MESC standards remove and replaced with other International Standardsand/or PTS standard whichever deemed relevant

2.1 Additional clause added as follows:The selection of instrument signal cables shall be governed by the specific

electrical application and by the areas through which the cable is to run.

The physical construction of the cable shall be dependent upon the electrical

application, the intended service and the type of signals.

The locality in which the cable is installed determines whether armouring is

necessary and what resistance to environmental elements is required.

Locality can also dictate the fire performance of materials used for insulation and

sheathing since the acceptability of smoke and toxic gas emission during fire

depends on ventilation and accessibility of areas concerned and on the normal

manning levels in these areas.

However, it is important to note that in all locations, resistance to fire propagation

by cable material is of paramount importance. Hence, the minimum requirement

for all cables for normal service shall be of reduced flame propagation type

conforming to IEC-332 part 3 cat. A.

Cables for vital services (where service must be maintained during or afterexposure to fire condition) shall be of fire-resistant type conforming to IEC-331.

2.2 -Fundamental

Requirements

New clauses and written as follows:All cables used shall be minimum flame retardant. Fire resistant

cables shall be used whenever required.

All cable insulation, filler and sheathing material must add a minimum offuel to any fire.

Mud resistant cables shall be used where cables are routed into orthrough areas exposed to mud/oil.

Material used in cables for manned or confined areas e.g.

accommodation should produce minimum levels of smoke and acid gas

under fire conditions.

Installation of cables in hazardous areas must conform to BS 5345 and

BS 5501.

All field cables shall be armoured. Braidedarmour is preferred to single

wirearmour where there is an option since it is lighter, more flexible and

easier to install. However for trench and underground cables, single wire

armour shall be used. (Note: Braided and single wire armoured cables

require different types of cable glands)

The capacitance, inductance and L/R ratio must not exceed certain

values for intrinsically safe circuits depending on the hazardous area

classification and equipment parameters. Reference should be made to

the equipment hazardous area certification.

Cables for switched signals (e.g. alarm and indication) should be twisted

multi-core type whereas cable for analogue signals should be twisted

multi-pair withoverall screen and drain wire.


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Multicore cables with collective screen shall be standard, individualscreens shall be used only when required.

Cable without armour may be used in indoor installation

2.2.1 Cable Specifications - Normal Service

Selection of electrical signal cables for control and monitoring shall take

account of service, environment and circuit conditions.

Mineral Insulated (Ml) cables shall only be used on those applications

where cables are permanently exposed to intense heat e.g. flare tip

thermocouples (Exception to PTS 33.64.10.10 Electrical Engineering

Guidelines).

In all locations, resistance to fire propagation by cable material is of

paramount importance. Hence the minimum requirement for all cables

for normal service shall be of reduced flame propagation-type

conforming to IEC-332 part 3 cat. A.

2.2.2 Cable Specifications - Emergency Service

On all applications where an instrument connection or signal must be

maintained for a limited period during or after exposure to a condition,

the design shall specify fire-resistant cables (other than MI cables) which

conform to IEC 331.

2.3 Additional clause as follows:The following systems shall have separate multicore cables:

- General instrumentation.- Fire and Gas.- ESD.- Telecommunication.- DCS.- Foundation Fieldbus.- General Electrical (control)- Powered Outputs

Table 1, 2, 3, 4,

5, 6, 7

New table - Incorporate and revised from 20.078.

3.1 Added new clause as follows

Multi-core cables between junction boxes and control rooms shall be laid

without splices.

Cables entering junction boxes, consoles, cross panels or the like, shall be

fastened by means of a cable gland, suitably sized and classified for the area of

operation.

The design shall incorporate right of way and cable channeling for instrument

and electrical signal cables. Instrument signal cables, shall be separated at a

distance of at least 0.3 m from electric power cables when laid underground in

cable trenches, or be on separate channels with metal separation when laidabove ground.


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Routing of cables shall take account of any risk of damage or deterioration due

to high temperature lines, corrosive fluids, hydrocarbons or radiation (including

UV radiation from direct sunlight).

In any process-connected instrument where rupture of the sensing element may

subject the instrument case to process pressure and where the cable used has

interstices which would permit the migration of gas or liquid to a control room, a

"Barrier Type" gland with sealing compound shall be specified.

All cables for intrinsically-safe circuits must consist of groups of conductors

twisted for each independent circuit with screen and drain wires over the cable

as a whole. The capacitance, inductance and L/R ratio must not exceed values

for intrinsically-safe circuits, depending on the hazardous area classification and

equipment parameters. Reference should be made to the equipment hazardous

area certification.

3.2 Added new clause as follows:

The preferred method of cable protection is single-wire armouring for onshore

and braided for offshore, in accordance with the relevant. Conduit will not

normally be approved, except for use inside buildings in non-hazardous areas.

All conduits shall be rigid steel, heavy wall, minimum 20 mm diameter, electro -

galvanised, and shall be supported with appropriate straps, saddles or hangers.

See BS 31, BS 4568 and BS 4607 for conduit requirements. Unarmoured

single-pair thermocouple cable shall be protected by U-channel conduits or 1/2"

galvanised pipe.

Where cables require support or protection from mechanical damage, they shall

be run on purpose-made proprietary ladder-rack, U-channel or cable tray,

ladder-rack being specified for widths of 300 mm or greater.

All components and accessories used with such proprietary systems should be

of 316L SS materials.

The appropriate proprietary fittings shall be specified for branch connections

from tray or channel to individual field instruments.

Cable support systems shall not be attached to process lines.

Design of the cable support system shall specify minimum clearance from any

lines or equipment where close proximity due to heat, chemicals or vibration may

adversely affect the cables.

Supports for cable trays or cable ladders shall be suitable painted as per PTS

30.48.00.31 and firmly fastened or welded.

For underground or trench cables where there is extensive oil contamination in

the soil or sand, only then lead sheathed cables shall be used.

Horizontal cable trays shall be situated above air supply lines. Vertical cable

trays shall be situated behind or by the side of air supply lines unless space is

limited by major equipment layout or piping arrangements.

Cable trays shall be mounted in such a way as to allow access for maintenance

or removal of equipment without undue disturbance to the installation.


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Cable trays and conduits shall be designed to be supported by steel structures

or have their own supports at every 2 meters lengths. Pipes for other services

e.g. gas, steam, water etc. shall not be used to support cable trays.

When a cable tray is designed for branching out, a flanged section shall be

provided on the cable tray leading to at each instrument. The tray shall be

extended to the furthest instruments.

For cables lying in the cable channel, tray or underground trench, a marking strip

(with tag no.) of nylon-covered stainless steel or lead shall be fitted around the

cable at every 5 meters length, at both the starting and terminating points of the

cable and at where the cable is fed into the control room or auxiliary room. All

marking strips for cables in cable channels shall be fastened by stainless steel

cable ties.

Cables entering junction boxes, consoles, cross panels or the like shall bedesigned to be fastened by means of a cable clamp,

Instrument signal cables shall be designed to be situated at least 300 mm from

electric power cables shall be entirely clear of hot process lines.

Separate trays shall be used for l.S. and non I.S. cables as far as possible as

per BS 5345. Whenever this is a constraint, a barrier shall be provided for cable

segregation.

Cable trays, conduits and cable ladders shall be galvanized iron or stainless

steel.

3.3 Added clause as follows:The Cable Network shall be separated into:

System 1: High voltage systems (above 1000V).System 2: Low voltage power supply and control cables for electrical systems(1000V and below)System 3: Instrumentation and Telecommunication systems.

Where the cable support systems are installed horizontally one above the other,the cable network shall be arranged from top to bottom, system 1, system 2 andsystem 3.

Cable ladders installed horizontally shall have sufficient space to facilitate cablepulling and cleating/strapping.

Instrument and telecommunication cables shall be separated from low voltagepower cables and high voltage cables by minimum 300 mm.

Instrumentation and telecommunication cables may be routed on system 2 cablesupport systems when the defined distance between the individual systems canbe kept.

When separation of the cable systems specified above is not possible orpractical, a metal segregation barrier shall be installed to avoid induceddisturbances on the instrument/telecommunication cables.

However, crossing at right angles is acceptable without further segregation.


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Non IS, IS instrument cables and Foundation Fieldbus can be routed on thesame cable ladders/trays provided segregation/separation is done.

3.4 Added new clause as follows:All above ground cables shall be routed on cable ladders and trays.

Underground cables shall be routed through dedicated cable trenches.

Trunking or conduits may be used for special mechanical protection of singlefield routed cables for shorter distances (approximately 5 m). Where conduitsare used, they shall be installed with open ends.

A computer based cable routing system reflecting the layout of the main cablesupport system (i.e. cable ladders with width 300 mm and above) represented byladder segment references, transit numbers, etc. and necessary describinginformation related to the individual cable including its route, shall be used in the

design.

Field cables may utilise the main cable support system provided the route of theindividual cable is being registered in the routing system and the filing andloading of the main cable support system is acceptable.

The cable ladders shall not be filled so the height of the cable ladder side rail isexceeded.

Redundant cable systems shall be routed separately.

3.4.1 Cable Bending Radius

The minimum permissible bending radius specified by Supplier shall beadhered to.

3.4.2 Cable Strapping

PVC coated stainless steel AISI 316L straps shall be used for verticalruns and for horizontal runs in the vertical plane.

For strapping of fibre-optical and coaxial cables, Supplier guidelinesshall be adhered to.

The distance between cable straps shall not exceed the distancebetween the horizontal and vertical runs on the cable tray. Thereforeeach cable shall be strapped on each horizontal and vertical run on thecable tray.

3.4.3 Cable Splic ing

Cable splicing is not allowed. In the event of damage, temporary cablesplicing is allowed (non standard repair) provided the necessary riskassessment has been carried out. Temporary cable splicing shall have atime limit before permanent cable repair takes place.

Temporary cable splicing shall be reported to Plant Management andtracking for permanent repair shall be in place.


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3.5 Added new clause as follows:

All junction boxes shall be ingress-protected to IP-65(IEC-529/BS 5490) as aminimum. The dimensions of the boxes should be as close as possible to

PETRONAS standard drawing S37.603.

Junction boxes for terminating fire-resistant cables (IEC 331) shall be of 316 SS

material and also suitably certified for use in the classified area.

Separate multi-element cables as well as separate junction boxes, shall be

provided for I.S. and non l.S. signals.

Signal segregation shall be observed for digital and analogue transmissions with

due regard being given to the above mentioned l.S. and non l.S. circuitry

segregation.

All junction boxes shall be complete with sufficient number of insulated earthingrails to terminate all cable armour (SWA or SWB).

All junction boxes shall be sized to terminate all cores of cables and screens with

a minimum of 20% spare terminals and cable entries. Spare cable entries shall

be plugged with certified plugs.

All spare cores shall be terminated at both ends.

3.6 Added clause as follows:3.6.1 Cable Glands and Mult i Cable Transi ts (MCT)

Cables shall be terminated into enclosures using mechanical typecompression glands

Glands shall be suitable for the reception of all strands of the wirearmouring which shall be securely clamped in a permanent manner.Glands shall be provided with clamping rings for cables with wire braids

When MCT are used on panels, cables have to be earthed with thebraided earth wire under the armour to the earthing bar.

MCT shall be installed such that the integrity of the bulkhead or wall ismaintained. Contractor shall locate and install MCT. MCT shall beprovided with 20% spare entries.

When preparing cables prior to fitting glands, the gland manufacturer's

instructions shall be followed. In all cases, care shall be taken to ensurethat the lay of the armour is maintained after the gland is completelyfitted.

All spare multicore cable ends which are not terminated, immediatelyafter cutting, shall be sealed effectively to prevent ingress of moistureand shall be protected from damage until termination is complete.

Spare and unused glands or MCT frame openings shall be properlyblinded (certified plug where applicable) or sealed.

3.6.2 Cable Glands Selection

Cable glands/blanking and drain plugs shall be selected as follows:

Metal enclosures (except aluminium) - stainless steel (AISI 316L)

Aluminium enclosures - stainless steel/nickel plated brass


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The certification of the cable glands, blanking and drain plugs shallcomply with the certification of the equipment in which the glands/plugsare connected.

Ex d gland shall have clamping of braid armour and sealing of inner andouter sheath. Only to be used on Ex d direct entry equipment.

Dual certified glands, Ex d and Ex e (flameproof and increased safety) tobe used and installed according to Supplier specifications.

3.7 New clause3.7 CABLE TERMINATIONS

All cable conductors shall be terminated by use of compression lugs orferrules dependent upon the type of termination. The compressionferrule shall be the type where the conductor strands are insertedthrough the whole ferrule and reach the bottom of the terminal.

Support for cleating of cables when entering panels shall be provided.

All cables shall enter field junction boxes via suitably sized and certified

cable glands Cable entries shall be from bottom and side of the box

only.

Terminations in field junction boxes shall NOT be of quick disconnect

(e.g. knife-edge) type.

Terminals shall be industry proven. The number of terminals in a

junction box shall be sufficient to terminate all wires of the cables andscreens including a minimum of 20% spare terminals. Signal wiresshall be terminated with crimped insulated bootlace ferrules andidentified by using colour-coded core markers.

Terminal blocks shall be non-hygroscopic vibration-proof and shall use

captive screws for terminals. Hinged knife-blade switches/terminals may

be used in control room or FAR for isolation and testing purposes.

Consideration should be given to the use of ceramic high temperature

terminals for the terminations of fire-resistant cables.

Where the screens shall be left disconnected (applicable for field

instruments), it shall be sealed and isolated with an isolating cap whichallows for insulation testing without any disconnecting.

Only one conductor is allowed in each terminal of a terminal block/rowfor external connections. This is not related to terminals as an integratedpart of internal components (e.g. relays, contactors) of the equipment.

3.11 Added following Para:

3.11.1 MARSHALLING CABINETS

Marshalling cabinets in the control room and equipment room (non-

hazardous area) for signal distribution should be fitted with quick

disconnecting type terminals and ELCO interconnecting boards for

interconnection to system cabinets via system cables.


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However, special care and attention must be given to the requirementsof signal separation of l.S. and non-l.S. type of signal in the selectionand application of ELCO interconnecting boards. ELCO interconnecting

boards shall not be required for applications where system cables arenot used.

Cable glands are, however, not required for cables or wires usually of

small diameter, entering via rubber grommets in the enclosures of

equipment installed in the control rooms and cables entering in the

bottom of system cabinets or marshalling cabinets via false floors in the

control room. In cases like this, it would be appropriate to install

arrangements for cable clamping of the bottom of cabinets to avoid

possible strain on terminations.

The cabinet shall be executed as a complete enclosure and shall beprovided with internal iron angle or channel frame work of sufficientstrength to support the internal system.

The cabinet shall be constructed as follows:

3.11.1.1 Outdoor installation

The panels shall be made of 316L stainless steel plate,thickness minimum 3 mm.

The carbon steel framing, supports and other constructionparts shall be anti-corrosion treated and painted inaccordance with Buyers Painting and Coating Specification

The enclosure classification shall be minimum IP-65.Generally, all material shall be selected suitable for theenvironment conditions as described in section 4 of thisspecification

3.11.1.2 Indoor installation:

The panels shall be made of mild steel plate, thicknessminimum 3 mm for the front plate to receive panel mountedinstruments. The panels shall be reinforced againstbuckling.

The enclosure classification shall be IP-44 as a minimum.

The cabinet(s) shall be provided with front and/or backaccess door(s) mounted on hinges. The door(s) shall have"T" type door handles without locks.

The cabinet(s) shall be furnished with proper mountingassembly suitable for mounting in the specifiedarea/location. A plinth, minimum 100 mm, shall be providedfor free-standing type cabinet(s). For wall mounting type, thecabinet(s) shall be provided with the suitable mountingbrackets assembly.

The cabinet(s) shall also be provided with lifting eyes on thetop of the cabinet for lifting purposes.

Cable entries, such as MCT's (multi cable transit), Ex'd'cable glands and bulkhead connectors, etc. for interfaceswith other systems, shall also be part of this system cabinet.


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Buyer will advise the size and numbers of the entries whichhave interfaces with Buyer's systems.

Before shipment all cable entries shall be covered, providing

IP-44 degree of protection.

3.11.1.3 Power Supply

For electrical services, the cabinet shall be provided withterminals to receive the required power supplies. This powerdistribution system shall be furnished with a lockable mainswitch. If required, sub-distribution by means of circuitbreakers shall be incorporated.

The cabinet shall also be provided with a service lightingfixture and socket outlet connected to 110 VAC powersupply. Furthermore a drawing pocket shall be installed.

Details of the power consumption of the cabinet shall beprovided to enable Buyer to calculate the required size ofthe power supply cables and fuses.

3.11.1.4 Cooling

Cooling shall be adequate for the installed environment. It isSupplier's responsibility to provide heat dissipationcalculations showing that the temperature inside the cabinetdoes not exceed 40C under the maximum load conditionsat maximum ambient temperature. When applicable,Supplier shall supply a forced redundant cooling ventilationfan system to be installed in the system.

Any cooling fan installed in the cabinet shall be maintainableand replaceable online. Critical cabinets shall be providedwith fan failure alarm.

3.11.1.5 Sparage

Wire and cable trunking and/or supporting shall have aminimum of 20% spare capacity on completion, includingknown future installations

3.11.1.6 Painti ng and Nameplates

The cabinet shall have standard finish and painted 'grey'(RAL 3032).

Painting shall be in accordance with Manufacturer'sStandard.

Stainless steel cabinet for outdoor use shall be painted incompliance with Buyers Painting ad Coating specification

Supplier shall furnish one white nameplate, fixed to thecabinet, in black letters, stating the tag number of thecabinet, description, manufacturer, year, power supply,order number, name Supplier.

Instrument nameplates shall be made of corrosion resistantweatherproof material with black letters with a minimumheight of 5 mm on a white background. Inscription shall bein the English language.


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Permanent nameplates shall also be provided identifyingeach instrument, instrument switch, meter, relays, controlswitch, indication lights, etc. in accordance with IEC

regulations.

3.11.1.7 Wiring and Terminations

Input/output terminals shall be of proven industrial madeand shall be fitted to terminal rails located on a mountingplate in the cabinet. I.S. terminals shall be colored blue.

There shall be a physical segregation between the I.S.circuits and the non-I.S. circuits in the cabinet in accordancewith the applicable standards.

All terminals shall be elevated at least 30 mm from the

terminal rails.

Terminals for voltage levels >50V AC or 120V AC shall bephysically segregated from all other terminals and shall befitted with a personnel protection cover clearly labeled.

Terminals shall be of the non-self loosening type, shall benickel plated and only accept one wire.

Terminals to accommodate wiring by others shall be sizedto accept 1.5 mm wires for signal cables and wires of aminimum 4 mm for power cables. The terminals shall be ofa separation type whereby the input circuit can be separated

from the other circuit without shutdown the system.

Sockets and terminals for input/output connections shall bearranged and labeled according to the documents anddrawings provided by Buyer with Purchase Order. Eachshall be identified by a securely fixed label which is clearlyvisible after site cabling is complete.

Cable screens of instrument cables are to be connected tothe instrument earth bar which shall be supplied andinstalled by the cabinet Supplier. All earth connectionswithin Supplier's scope of responsibility shall be made andshall be suitable and in accordance with the system

requirements. Note that earth bars for I.S. and non-I.S. earthconnections shall be separately installed within the cabinet

All powered outputs to solenoid valves, indicating lamps andthe like shall be fused on the positive side of the powersupply.

For AC solenoid, only live conductor shall be fused (neutralshall not be fused).


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All wires within the panel that are connected to terminalstrips used for convenience in internal wiring, or wiresterminating on device terminals not otherwise marked, and

wires terminating on terminal strips for external connectionsshall be marked with permanent type wire markers bearingthe number of the terminal row and/or the device terminal towhich it is connected. Wire markers shall be of theinterlockable type.

All control wiring within the panel shall be of stranded wire0.5 mm with an insulation rating of 500V and a minimum of2.5 mm for power busses.

Bootlace ferrules shall be used.

Systems operating at different voltage levels are to be fully

segregated.

Wiring to the swing-out rack(s) and door(s) shall be properlysecured in wire looms by using spiral lacing or equal.

All intrinsically safe equipment and wiring shall besegregated. Overall insulating sheath of intrinsically safewiring shall be blue. Trunking shall also be segregated andcolored blue.

Internal wiring shall be by single core, insulated wires, withthe following colors:

- black colour - AC/DC wiring, power supplies- grey colour - electronic signal, incoming and outgoingcontacts- Blue colour - intrinsically safe wiring.

Wiring shall be housed in a system of plastic wire ducts. Aseparate duct is required for the following:

- AC wiring, power supply, incoming and outgoing contacts(grey colour)- Electronics signal wiring (grey colour)- Intrinsically safe wiring (blue colour).

A 50 mm distance is required between the intrinsically safewiring and the other wiring types.

4.1 Additional clause added:

All equipment for electric signal transmission, including the enclosures, as well

as the armouring, lead sheathing and screening of cables, shall be properly

earthed for personnel safety reasons and for obtaining the maximum possible

rejection of interference.

The instrument 'clean' earth shall be physically separated from the electrical or

plant earth. On offshore structures, the instrument 'clean' earth shall be taken to

a leg separate from this electrical earth and this earth connection shall be

thermic welded. For onshore locations, in addition to the instrument 'clean' earth,a separate 'clean' earth shall be provided for intrinsically-safe system if shunt

diode barriers are specified (total loop impedance shall not exceed 1 ohm). The

normal instrument earth may be used to ground l.S. systems if opto- or

transformer-isolation is used.


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For EMC plants, single ground is applicable.

The cable armouring at each junction box shall be connected to earth via cable

gland. Armour shall not be connected to the screen earth at any point in thesystems. All screen earthing shall be earthed at the control room end only.

All cable screens including spares shall be earthed at one point only (usually in

the marshalling cabinet at the control centre except for tip grounded

thermocouples) and shall be kept isolated from cable armouring, instrument

enclosures, steel structures and any other electric conductors.

Instrument equipment installed in control rooms shall be provided with insulated

earth busbars, which are interconnected with 6 sq. mm. single core green

insulated wire. To form a ring circuit, both ends shall be connected to a suitable

earth point below the support frame by using 70 sq. mm. single core

green/yellow insulated cables. To facilitate maintenance, two connection bolts

shall be provided on the earth point.

To ensure high integrity earthing of cabinets and panels, all moving metallic

parts including hinged doors, swing frames, slide out racks, etc. shall be

permanently bonded or earthed on an individual basis to the main body of the

enclosure using flexible earth bonding straps.

Ex 'i' or Ex 'd' solenoid valve, switches, etc., which do not have integral junction

boxes shall be connected to the signal cable by means of an appropriate

connecting box. The thread of the Ex 'd' enclosure cover shall be applied with a

thin smear of approved grease before it is installed.

To ensure a good earthing via the frame structure (plant or platform earth),instruments having electric connections shall be fixed by means of Mb, 316L SS

bolts having a lock washer each under the nut and under the bolt.

In field junction boxes, the individual shields of single pairs and those of multi-

core cables shall be through connected on insulated terminals. To avoid

accidental shorting or grounding of this shield within a terminal box, the shield

end and shield drain wire between the end of the cable jacket and the terminal

strips shall be insulated. The shield of the ungrounded end of a cable shall be

insulated by green/yellow colored PVC sleeve to avoid accidental grounding of

any exposed shield or the shield drain wire. The maximum length of an

unshielded core at the terminal strips shall be 25 mm.

The ring is completed by connecting both ends to a suitable earth point below

the support frame by using a 70 mm square single core green/yellow insulated

cable.

Two M10 316L SS connection bolts shall be provided on this earth point so that

each end of the ring, can be connected to an individual bolt, thus allowing

maintenance checks that resistance of the ring is less than 1 ohm while the other

ring end is still connected and ensures continuous earthing.

Where insulated glands are used in metal boxes, the armour shall be through-

connected to other cables and connected to plant (or platform) earth in another

junction box. Where insulated boxes are used, the armour shall be through

connected to a separate earth source.

A separate earth bar should be specified for this purpose in all junction boxes.


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6.0 This is new clause: 6. PNEUMATIC TUBING

All instrument tubing shall be seamless, soft annealed 316 stainless

steel. Recommended tubing hardness shall not exceed ROCKWELL No.Rb 80. .

All compression fittings shall be 316 Stainless steel of Swagelok make

or equal in order to ensure compatibility with existing facilities and

minimise stock holding.

It is stressed that metric size tubing and fittings are not compatiblewith

their imperial size counterpart.

The Company makes extensive use of hydrocarbon gas as an

alternative to instrument air on offshore platforms, particularly unmanned

platforms. The design shall ensure that the instrument system iscompatible with the expected gas composition.

Where the length of pneumatic signal-transmission tubing exceeds 60

m, signal booster relays shall be used. Where the tubing length exceeds

90 m, design consideration shall be given to the use of electronic

instrumentation.

316 SS tubing is considered to be self-supporting up to a length of 1 m.

For longer lengths, the tubing shall be supported over its full length at

every 1 m.

Air header layout after the primary block valve shall be in accordance

with Company practice as shown in the PTS standard drawings.

The branch lines shall be connected to the main header with a shut-off

valve. All branch line connections shall be made on the top of the line.

(Instrument scope commences at the downstream flange of the shut-off

valve).

Instrument air mains shall be provided with a 316 SS valved branch

connection (of one size smaller than the main) at least every 5 m,

complete with union coupling, and a 10% spare capacity provision shall

be made for future extensions. All future tie-in points shall be valved and

plugged.

From the main branch lines, all further connections to manifolds and

individual air filter/regulators shall be made via 12 mm or " O.D. 316L

SS tubing. Areas where the carbon steel pipe meets stainless steel

piping/fittings, a sacrificial carbon steel nipple shall be installed to cater

for galvanic corrosion.

The rating of instrument air mains and branch air lines shall be in

accordance with Table 4 below unless otherwise specified.


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Table 4: Instrument Air Mains and Branch Air Lines

Nominal Pipe

Size (OD)

Pipe/tubing &

fitting Material

Maximum

Number of

UsersDN 15 ( inch) 316L SS 5

DN 25 (1 inch) 316L SS 25

DN 50 (2 inch) 316L SS 100

Air supply lines shall be sloped towards drain points.

A sufficient number of filters, regulators, drain and bleeders shall be

provided in the instrument air system. A filter regulator shall be provided

for each individual air user and shall be complete with an output gauge.

Filter regulators shall be stainless steel to minimise life cycle costs.

Instrument air supply lines from the nearest block valve to the air userand the pneumatic signal line shall consist of 12 mm O.D. x 1.0 mm WTor 1/2" OD x 0.035" WT 316 SS tubing and compression fittings.

Instrument air receivers/headers capacity primarily depends on a

summed tabulation of all the known users, instruments and instrument

system, and their respective consumption rates, which can be obtained

from the manufacturers. It also depends on the availability of alternative

air sources and has to match other back-up requirements such as UPS,

batteries etc.

Tubing shall be joined by compression type fittings only.

Tubing shall be selected for the applicable pressure ratings specified and sizedadequately for the required capacity and duty.

Tubing material shall be 316 SS as per ASTM A269, with the exception of

Molybdenum (Mo) content which shall be 2.5% minimum. Mill certificates of

tubing shall be required for every batch of tubing ordered or supplied by

fabricators and suppliers.

For offshore installation, tubing material shall be either Tungum, 254 SMO,

Super duplex Stainless Steel and Alloy 625 to avoid crevice and pitting

corrosion caused by chloride attack.

For reasons of variety control, fast delivery and to minimise life cycle costs, 317

SS tubing (Mo content of between 3% and 4%) shall not be used unless the

process conditions and field conditions warrants their use.

With the exception of hydraulic lines, all SS 316 instrument tubing shall have

the following dimensions:


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Table 5: SS316 Instrument Tubing Dimensions

OD Thickness Applications

0.035 Signal Lines3/8 0.065 Fusible Loops, Impulse Lines,

Supply Lines

0.035 Supply Lines, Drain Lines

6mm

1.0 mm Signal Lines

10mm

1.5 mm Fusible Loops, Impulse Lines,Supply Lines

12mm

1.0 mm Supply Lines, Drain Lines

316L Stainless steel compression type fittings shall be selected for theapplicable pressure ratings specified and sized for the tubing described aboveand shall be installed in strict accordance with the manufacturer'srecommendations. Fittings shall be manufactured by Swagelok.

Only NPT type threads shall be used for screwed connections. The threadcutting shall be in accordance with API Code for threading.

The number of joints in piping and tubing shall be kept to a minimum, consistentwith good practice. All shall be made with the aid of approved tubing benders,correct for the size of tube being worked, to ensure neat serviceable bends.

Pipes and tubes shall be run in vertical and horizontal planes as far as possibleand shall be run with the minimum number of changes of direction consistentwith the good practice and neat appearance. Horizontal runs shall have thepipes or tubes mounted one above the other.

Where pipes or tubes run parallel to each other, joints shall be systematicallystaggered and neatly off-set.

Isolation valves shall be located as close to the source as practical.

No piping or tubing shall be installed in such a way that it is subject to vibrationor any other mechanical stress.

All piping and tubing shall be de-burred properly after cutting (preferably with ade-burring drill on a drilling machine). After de-burring process, all piping andtubing shall be cleaned by blowing through with filtered dry and oil-freecompressed air before connection to instrument.

The installed, but not connected, pipes and tubes shall have their ends cappedto prevent the entry of foreign material.

All instrument piping connected to process piping shall be run with a slope ofnot less than 1 to 12, except where otherwise specified. The slope shall bedown from the tapping points for liquids and up from the tapping points for gasservice.

The Contractor must pay special attention to the correct location of vents anddrains to ensure that they are respectively at the highest and lowest point of

piping runs. All drains shall be connected to the closed drain systems orplugged by an isolation valve.


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Handling and storage of Tubing

Tubing shall be stored and transported in dedicated plastic boxed/tubes, to

prevent tubing corrosion before installation. The transport and storage indedicated plastic boxed/tubes applies for offshore locations and any onshorelocation, including construction sites.

Multi-core Tubing

Where indicated on the hook-up drawings, multi-core tubing shall be used.

Multi-core tubing shall be routed, supported and secured in a similar manner tothat of the electrical cable.

All entries to junction boxes shall be made weatherproof, using suitable cableglands and/or bulkhead fittings.

Piping and Tubing Support

All piping and tubing shall be adequately supported and/or braced so as toprovide maximum protection against mechanical damage and vibration.

The distance between supports shall not exceed those in the following table:

Table 6: Distance Requirement for Tubing Support

Line Size Maximum Distance

inch 1.0 m

1 inch 1.5 m

1 - 2 inch 2.0 m

Multi-core tube shall be supported each 0.25 m. Single tube size 1/2 inch or lessshall be supported continuously.

For continuously supporting five or more single tubes, one 316L SS cable trayshall be used. For continuously supporting four or less single tubes, 316L SSangle bar (50 x 50), or 316L SS Unistrut channel shall be used.

The tubing shall be secured to the tray with fastening blocks at (maximum) 0.6meters intervals. Blocks with stainless steel cover plates, bolts and nuts shall bedelivered and supplied by the Contractor.

The supports shall be fabricated by the Contractor (or supports to be made of

SS 316L), including coating in accordance with the Painting and CoatingSpecification 525. Coating shall be finished before installation supportingmaterials. The required small mounting materials and consumable items shall bedelivered and supplied by the Contractor.

Capillaries of filled systems shall run independently of all other lines and shall becontinuously supported using 316L SS angle bar 316L SS Unistrut channel withadequate fastening clamps or tie-wraps at 0.25mintervals. Adequate means ofprotecting capillaries from damage shall be employed. Special care shall betaken against kinks in the capillaries on bends or changes of direction.

Cable trays shall be run with the width of the tray in a horizontal plane. A shortsection may be run with the width in a vertical plane after Company's approval.In this case, additional support shall be provided to prevent sagging.


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Under certain circumstances and with Company's approval, trunking or conduitsmay be used instead of cable trays. The required materials shall be deliveredand supplied by the Contractor.

Unless otherwise specified, the process pipelines and handrails shall not beused to support instrument pressure and air piping and tubing.

Process equipment, rotating equipment and electric motors which are liable tovibration shall not be used to support instrument pressure and air piping andtubing.

Multi-core transit, insert frames and blocks, supplied by the Contractor, shall beprovided after piping or tubing installation, in accordance with the drawings orwhen required by Company.

7.1 7.1 CABLE IDENTIFICATIONS

Quads or pairs shall be identified by black numbers on each individual

core of the quads or pairs, no greater than 50 mm apart. If the

dimension of a core does not permit this, other means of identifying the

cores shall be used.

A purpose-made identification method shall be specified for cables in the

cable channel, at every 5 meters. In addition, similar identification

markings/bands shall be specified for the starting and terminating points

of the cable, and on both sides of any wall or bulkhead penetration. The

identification markings/bands shall be blue for I.S. cables, green for non

I.S. cables and red for F&G cables.

Cable identification numbers shall be permanent, character size being

10 mm.

Cable numbers shall be as per PTS 32.37.20.31.

All cables, whether I.S. or non l.S., shall have black outer sheath

regardless of type of cable and conform to BS 5308.


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PREFACE

PETRONAS Technical Standards (PTS) publications reflect the views, at the time of publication, ofPETRONAS OPUs/Divisions.

They are based on the experience acquired during the involvement with the design, construction,

operation and maintenance of processing units and facilities. Where appropriate they are based on,or reference is made to, national and international standards and codes of practice.

The objective is to set the recommended standard for good technical practice to be applied byPETRONAS' OPUs in oil and gas production facilities, refineries, gas processing plants, chemicalplants, marketing facilities or any other such facility, and thereby to achieve maximum technical andeconomic benefit from standardisation.

The information set forth in these publications is provided to users for their consideration anddecision to implement. This is of particular importance where PTS may not cover every requirementor diversity of condition at each locality. The system of PTS is expected to be sufficiently flexible toallow individual operating units to adapt the information set forth in PTS to their own environmentand requirements.

When Contractors or Manufacturers/Suppliers use PTS they shall be solely responsible for thequality of work and the attainment of the required design and engineering standards. In particular,for those requirements not specifically covered, it is expected of them to follow those design andengineering practices which will achieve the same level of integrity as reflected in the PTS. If indoubt, the Contractor or Manufacturer/Supplier shall, without detracting from his own responsibility,consult the owner.

The right to use PTS rests with three categories of users:

1) PETRONAS and its affiliates.2) Other parties who are authorised to use PTS subject to appropriate contractual

arrangements.

3) Contractors/subcontractors and Manufacturers/Suppliers under a contract withusers referred to under 1) and 2) which requires that tenders for projects, materialssupplied or - generally - work performed on behalf of the said users comply with therelevant standards.

Subject to any particular terms and conditions as may be set forth in specific agreements with users,PETRONAS disclaims any liability of whatsoever nature for any damage (including injury or death)suffered by any company or person whomsoever as a result of or in connection with the use,application or implementation of any PTS, combination of PTS or any part thereof. The benefit of thisdisclaimer shall inure in all respects to PETRONAS and/or any company affiliated to PETRONASthat may issue PTS or require the use of PTS.

Without prejudice to any specific terms in respect of confidentiality under relevant contractualarrangements, PTS shall not, without the prior written consent of PETRONAS, be disclosed by usersto any company or person whomsoever and the PTS shall be used exclusively for the purpose theyhave been provided to the user. They shall be returned after use, including any copies which shallonly be made by users with the express prior written consent of PETRONAS.

The copyright of PTS vests in PETRONAS. Users shall arrange for PTS to be held in safe custodyand PETRONAS may at any time require information satisfactory to PETRONAS in order toascertain how users implement this requirement.


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TABLE OF CONTENTS

1. INTRODUCTION...............................................................................................................................1

1.1 SCOPE..............................................................................................................................................1

1.2 DISTRIBUTION, APPLICABILITY AND REGULATORY CONSIDERATIONS ................................1

1.3 DEFINITIONS AND ABBREVIATIONS.............................................................................................11.4 CROSS REFERENCES....................................................................................................................2

2. ELECTRICAL CABLING ...................................................................................................................3

2.1 GENERAL .........................................................................................................................................3

2.2 FUNDAMENTAL REQUIREMENTS .................................................................................................3

2.3 SIGNAL SEGREGATION IN MULTICORE CABLES .......................................................................4

2.4 SELECTION AND SPECIFICATION OF INSTRUMENT CABLES...................................................5

2.5 CABLES FOR DIGITAL AND VIDEO SIGNALS...............................................................................7

2.6 CABLES FOR SPECIAL APPLICATIONS........................................................................................7

2.7 PROTECTION OF CABLES AGAINST FIRE DAMAGE...................................................................8

3. CABLE SEGREGATION, ROUTING AND INSTALLATION.............................................................93.1 INSTALLATION ASPECTS...............................................................................................................9

3.2 MOUNTING AND PROTECTION OF CABLES ................................................................................9

3.3 CABLE SEGREGATION .................................................................................................................10

3.4 ROUTING........................................................................................................................................11

3.5 JUNCTION BOXES FOR MULTICORE CABLES ..........................................................................13

3.6 CABLE GLANDS.............................................................................................................................14

3.7 CABLE TERMINATIONS ................................................................................................................15

3.8 TRUNKING AND TRAYS................................................................................................................16

3.9 TRENCHES.....................................................................................................................................17

3.10 CABLE PULLING AND INSTALLATION ASPECTS.......................................................................18

3.11 CONTROL ROOM/AUXILIARY AREAS .........................................................................................18

4. EARTHING AND BONDING ...........................................................................................................23

4.1 GENERAL .......................................................................................................................................23

4.2 CONNECTIONS TO THE EARTHING SYSTEMS .........................................................................24

4.3 EARTHING OF INTRINSICALLY SAFE CIRCUITRY.....................................................................25

4.4 EARTHING OF CAVITY FLOORS..................................................................................................25

5. LIGHTNING PROTECTION OF INSTRUMENTATION ..................................................................26

5.1 GENERAL .......................................................................................................................................26

5.2 INSTRUMENTATION AND CABLING IN THE FIELD ....................................................................26

6. PNEUMATIC TUBING.....................................................................................................................27

6.1 GENERAL .......................................................................................................................................28

6.2 SELECTION AND SPECIFICATION OF TUBING..........................................................................31

6.3 JUNCTION BOXES FOR MULTICORE TUBING ...........................................................................31

6.4 INSTALLATION...............................................................................................................................31

7. IDENTIFICATION AND MARKING .................................................................................................32

7.1 CABLE IDENTIFICATIONS.............................................................................................................32

7.2 IDENTIFICATION OF SYSTEM CABLES.......................................................................................32

7.3 IDENTIFICATION OF SINGLE CABLES/TUBING .........................................................................32

7.4 IDENTIFICATION OF MULTICORES AND JUNCTION BOXES....................................................32

7.5 MARKING........................................................................................................................................33

8. REFERENCES................................................................................................................................34


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APPENDICES

APPENDIX 1 DISTANCE BETWEEN CABLE TRENCHESAPPENDIX 2 ARRANGEMENT OF CABLE TRENCHES

APPENDIX 3 TYPICAL EARTHING AT FAR/CCRAPPENDIX 4 TYPICAL EARTHING OF INSTRUMENT SIGNAL CABLES IN THE FIELDAPPENDIX 5 TYPICAL EARTHING OF INSTRUMENT SIGNAL CABLES IN THE MDF


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1. INTRODUCTION

1.1 SCOPE

This PTS specifies requirements and gives recommendations for the design and engineering of

instrument signal lines, with immunity from electromagnetic interference as appropriate. It coversdesign, material selection and installation methods for cabling the signal lines of the differentsystems. Cabling for transmitting digital and video signals is also covered in this PTS.

In the context of this PTS, instrument signal lines include:

a) Electric signal lines (paths), including thermo-electric voltage lines from thermocouples; linesfrom transmitters to their receiving instruments, auxiliaries, logic systems, controllers etc. andthe lines from these to the relevant actuating elements such as solenoid valves, converters,transducers or control valves.

b) Pneumatic signal lines (paths) from pneumatic transmitters to their receiving instruments,auxiliaries, controllers and the lines from these to the relevant final control elements.

Signal lines for similar applications such as fire and gas detection and protection systems, plantcommunication systems, CCTV systems, plant information systems, maintenance managementsystems and plant security systems are also within the scope of this PTS.

This PTS is a revision of the PTS of the same number dated October 1990.

1.2 DISTRIBUTION, APPLICABILITY AND REGULATORY CONSIDERATIONS

Unless otherwise authorised by PE TRONAS, the distribution of this PTS is confined to companiesforming part of PETRONAS Group, and to contractors nominated by them.

This PTS is intended for use in oil refineries, chemical plants, gas plants, exploration andproduction facilities and supply/marketing installations.

If national and/or local regulations exist in which some of the requirements are more stringent thanin this PTS, the contractor shall determine by careful scrutiny which of the requirements are themore stringent and which combination of requirements will be acceptable as regards safety,economic and legal aspects. In all cases the contractor shall inform the Principal of any deviationfrom the requirements of this document which is considered to be necessary in order to complywith national and/or local regulations. The Principal may then negotiate with the authoritiesconcerned with the object of obtaining agreement to follow this document as closely as possible.

1.3 DEFINITIONS AND ABBREVIATIONS

1.3.1 General defini tions

The Contractor is the party which carries out all or part of the design, engineering, procurement,construction, commissioning or management of a project or operation of a facility. The Principalmay undertake all or part of the duties of the Contractor.

The Manufacturer/Supplier is the party which manufactures or supplies equipment and servicesto perform the duties specified by the Contractor.

The Principal is the party which initiates the project and ultimately pays for its design andconstruction. The Principal will generally specify the technical requirements. The Principal may

also include an agent or consultant authorised to act for, and on behalf of, the Principal.


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The word shall indicate a requirement.

The word should indicate a recommendation.

1.3.2 Specific defini tions

Bonding The act of connecting together exposed conductive parts and extraneousconductive parts of apparatus, systems or installations that are atessentially the same potential (IEC TR 61000-5-2).

Cable ladder Above-ground, ladder-type cable tray without cover.

Cavity floor Computer floor or false floor.

Instrument earth Dedicated earth for instrument systems.

Safety earth Plant safety earth.

Sealing fitt ing Conduit fitting which, when filled with a suitable sealing compound,

prevents transportation of flammable substances through the conduit.

System cabling A wiring concept, consisting of cables, plugs and sockets, as detailed inPTS 32.37.20.31.

Tray Above-ground, open cable support system, such as U-shaped flat-bottomed or ladder type.

Trench Underground cable routing system provided with a mechanical protectionon top of the cables.

Trunking Above-ground, U-shaped cable support system with cover. It is flat-bottomed and has a top cover secured by cover clips/fasteners.

1.3.3 Abbreviations

AL/HDPE/PA Aluminium/High Density Polyethylene/Polyamide (nylon)CCR Central Control RoomCCTV Closed Circuit TelevisionDCS Distributed Control SystemEM Electro magneticEMC Electro magnetic compatibilityEMI Electro magnetic interferenceFAR Field Auxiliary RoomIPF Instrumented protective functionMDF Main Distribution Frame

ROV Remote operated valveSWA Steel wire armouringSWB Steel wire braiding

1.4 CROSS REFERENCES

Where cross references to other parts of this PTS are made, the referenced section number isshown in brackets. Other documents referenced in this PTS are listed in (8).


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2. ELECTRICAL CABLING

2.1 GENERAL

Single pair cables are used for signal transmission from field instruments to field mounted junctionboxes. Multicore cabling will subsequently transmit the signals from the junction box to an MDF in

the CCR or FAR.

Wherever possible and consistent with the design of other plant facilities, multicore cabling shouldbe routed underground because it then has inherent protection against fi re and mechanicaldamage. However, above-ground cabling is acceptable, subject to the Principal's approval,provided a definite cost advantage can be demonstrated, or where it is the standard local practice.

Outdoor, above-ground and underground cabling shall be provided with steel wire braiding (SWB)or steel wire armouring (SWA) to protect them against mechanical damage and for EMC reasons,even if these cables are installed in trenches / trunking or on cable trays. Underground cablingshall additionally be provided with a chemical/moisture barrier.

The selection of instrument signal cables shall be governed by the specific electrical application

and by the areas through which the cable is to run.

The physical construction of the cable shall be dependent upon the electrical application, the

intended service and the type of signals.

The locality in which the cable is installed determines whether armouring is necessary and what

resistance to environmental elements is required.

Locality can also dictate the fire performance of materials used for insulation and sheathing since

the acceptability of smoke and toxic gas emission during fire depends on ventilation and

accessibility of areas concerned and on the normal manning levels in these areas.

However, it is important to note that in all locations, resistance to fire propagation by cablematerial is of paramount importance. Hence, the minimum requirement for all cables for normal

service shall be of reduced flame propagation type conforming to IEC-332 part 3 cat. A.

Cables for vital services (where service must be maintained during or after exposure to firecondition) shall be of fire-resistant type conforming to IEC-331.

2.2 FUNDAMENTAL REQUIREMENTS

All cables used shall be minimum flame retardant. Fire resistant cables shall be used wheneverrequired.

All cable insulation, filler and sheathing material must add a minimum of fuel to any fire.

Mud resistant cables shall be used where cables are routed into or through areas exposed tomud/oil.

Material used in cables for manned or confined areas e.g. accommodation should produce

minimum levels of smoke and acid gas under fire conditions.

Installation of cables in hazardous areas must conform to BS 5345 and BS 5501.

All field cables shall be armoured. Braidedarmour is preferred to single wirearmour where there

is an option since it is lighter, more flexible and easier to install. However for trench and

underground cables, single wire armour shall be used. (Note: Braided and single wire armoured

cables require different types of cable glands)


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The capacitance, inductance and L/R ratio must not exceed certain values for intrinsically safe

circuits depending on the hazardous area classification and equipment parameters. Reference

should be made to the equipment hazardous area certification.

Cables for switched signals (e.g. alarm and indication) should be twisted multi-coretype whereas

cable for analogue signals should be twisted multi-pair withoverall screen and drain wire.

Multicore cables with collective screen shall be standard, individual screens shall be used onlywhen required.

Cable without armour may be used in indoor installation

2.2.1 Cable Specifications - Normal Service

Selection of electrical signal cables for control and monitoring shall take account of service,

environment and circuit conditions.

Mineral Insulated (Ml) cables shall only be used on those applications where cables are

permanently exposed to intense heat e.g. flare tip thermocouples (Exception to PTS 33.64.10.10

Electrical Engineering Guidelines).

In all locations, resistance to fire propagation by cable material is of paramount importance. Hence

the minimum requirement for all cables for normal service shall be of reduced flame propagation-

type conforming to IEC-332 part 3 cat. A.

2.2.2 Cable Specifications - Emergency Service

On all applications where an instrument connection or signal must be maintained for a limited

period during or after exposure to a condition, the design shall specify fire-resistant cables (other

than MI cables) which conform to IEC 331.

2.3 SIGNAL SEGREGATION IN MULTICORE CABLES

When electrical signals are assigned to multicore cables, the following signal segregation rulesshall be followed:

Intrinsically safe and non-intrinsically safe signals shall be segregated as required by IEC60079-14.

Segregation on the basis of cabling requirements may be required.

Example: Thermocouple signals require extension cabling and thus can only be combined in one cable with signals

from thermocouples of the same type.

For practical reasons, segregation between disciplines is recommended (e.g. no signalcabling for Instrumentation and Electrical in one multicore cable).

The following systems shall have separate multicore cables:

- General instrumentation.- Fire and Gas.- ESD.- Telecommunication.- DCS.- Foundation Fieldbus.

- General Electrical (control)

- Powered Outputs


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The supply and return conductor of a signal shall be contained in the same cable pair.

Segregation on the basis of signal level classes shall be applied as shown in Table 1 toachieve EMC.

Table 1: Classif ication of Instrument Signal LevelsSIGNALLEVELCLASS

SIGNAL TYPE EXAMPLES

Low energy digital systems Computer bus signals

Analogue low level (mV signals) Thermocouples

1

Analogue medium level (approx, 1V) Resistance temperaturemeasurements, analysers

Analogue high level (e.g. 1-10 VDC, 4-20 mA

Electronic instrumentation loops

Digital and analogue IS

Binary low level (below 24 VDC andbelow 0.5 VA)

Actuating logic systems, annunciators

2

Digital low level (pulse train) Turbine meter, proximity sensors

Digital high level (pulse train) Tank gauging system3

Proximitors for machine monitoring Vibration sensors4 On-Off medium level (< 50 V or > 0.5

VA, > 40 VA) 24 VDC solenoids (note 2)

5 High level signals > 50 VAC and DCpower signals higher than Class 4

110 VDC solenoids (note 2)

Power supply cables Power supply cables to instrumentcabinets and field instruments

NOTES: 1. The classification is based on the use of cables with metal screen for signal level classes 1, 2 and 3.2. The classification is based on de-coupled solenoids to limit induction. DC solenoids shall be de-

coupled with shunt diodes and AC solenoids with RC networks, connected directly across the solenoidterminals.

In addition to the above segregation rules for multicore cabling, functional segregation may bedesirable for operability and maintainability reasons (e.g. segregation between process units orsegregated cabling for fire and gas systems).

The design shall cater for spare capacity in multicore cabling. When the design is finalised, 10-15% of the installed cabling capacity shall be available in each signal level class and plant area toaccommodate unforeseen future plant modifications.

2.4 SELECTION AND SPECIFICATION OF INSTRUMENT CABLES

2.4.1 Conductors

Solid insulated conductors should be used for instrument field cables. The minimum conductordiameter shall be 1.13 mm for single signal cables and 0.8 mm for multicore signal cables. Themaximum permissible current rating and allowable voltage drop criteria shall be observed inselecting signal cables and larger conductor diameters may be required to reduce the voltagedrop. Stranded wires are permitted for internal wiring inside cabinets; for connections in screwtype terminals, wire crimp pins/lugs shall be applied

NOTES: 1. Cables having conductors of 0.8 mm diameter (cross section approx. 0.5 mm2) have a maximum continuouscurrent rating of 1 A per core. The fuse rating for these cables shall not exceed 4 A. The voltage drop in signal cabling shallbe calculated and the available voltage at the terminals of field instruments shall be checked against the minimumrequirements. If the allowable voltage drop is exceeded, a larger conductor diameter and/or a higher supply voltage shallbe selected.2. Crimped-on wire pins/lugs shall provide a gas-tight (corrosion free) connection between the crimp pin/lug and conductorin the signal cable.3. Solid conductors should not be provided with crimp-on wire pins/lugs.


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For thermocouple signals, the conductors shall consist of pairs of dissimilar materials with thecorrect thermo-electric voltage as a function of temperature, based on IEC 60584-3.

For all other signals, the conductor material shall be copper.

For resistance thermometer elements, the conductor resistance shall be compatible with the

requirements as specified by the Manufacturer of the resistance thermometer elements and/or theinstrument.

Signal wires shall be twisted in pairs. The use of quad cables requires approval by the Principal.

2.4.2 Cable Construct ion

2.4.2.1 Cable construction for signal level classes 1/2/3

Instrument signal cabling for signal level classes 1, 2 and 3 of Table 1 (2.2) shall be specified witha metal screen and drain wire. Multicore cabling shall be provided with a collective screen;individual pair screening should only be applied if specifically needed for the application.

Where possible, underground cabling shall be provided with an AL/HDPE/PA inner sheathing as amoisture/chemical barrier in preference to lead sheathing.

Cable capacitance and inductance shall not invalidate the requirements for intrinsically safe ornon-incendive (switched) circuits.

Unless special cabling construction requirements apply, the following cables types arerecommended:

Table 2: Recommended Cable Types for Signals Level Classes 1/2/3 (Note 1)Type-1 Type-2 Type-3

Type ID

(Note 1)

PE-MS-PVC PE-MS-PE-SWB-PVC PE-AL/HDPE/PA-SWA-

HDPEApplication Indoor use in a

protected EMAbove ground cabling in

a plantUnderground cabling

Conductor PE (note 2) PE (note 2) PE (note 2)

Screen MS MS

InnerSheath

- PE

AL/HDPE/PA

MechanicalProtection

- SWB SWA

Oversheath PVC PVC HDPE

NOTES:

1. Identification of cable construction is from the centre to the outside.2. Cross linked polyethylene (XLPE) may be used as alternative insulation material.3. Cables of table 2 are not suitable for direct connection to a low impedance source, e.g. the public mains electricity

supply.4. For multicore cellular PE-insulated telecommunication cables, based on BS 3573.


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Background to and abbreviations used, in Table 2:

AL/HDPE/PA Aluminium / high density polyethylene / polyamide (nylon), that combinesoverall, metal screening with inner sheathing. The aluminium acts asmetal screen and moisture barrier. HDPE and PA act as chemicalbarriers, while PA provides also protection against termite attacks.

AL/HDPE/PA is a low cost and light weight alternative for lead sheathing.HDPE High density polyethylene used as outer sheathing.HDPE as outer sheathing has a good chemical resistance and water tightness,

but is inflammable (acts as torch) and stiff. Furthermore, HDPE is onlyUV-resistant, if it is of black colour and containing carbon black.

MS Metal screen with drain wire.PE Polyethylene, used as conductor insulation or inner sheathing.PVC Polyvinyl chloride used as outer sheathing.PVC as outer sheathing is UV-resistant, flame retardant and commercially

attractive.SWA Steel wire armouring by a single layer of round galvanised steel wire.SWB Steel wire braiding.

2.4.2.2 Cable construction for signal level classes 4 and 5.

Cables for signal level classes 4 and 5 of Table 1 (2.2) shall follow the requirements for lowvoltage cables, as defined in PTS 33.64.10.10. The conductor cross section for signal levelclasses 4 and 5 shall be at least 2.5 mm2.

2.5 CABLES FOR DIGITAL AND VIDEO SIGNALS

Microprocessor-based digital instrumentation and CCTV systems may require special cables totransmit the associated digital and video signal paths.

Digital signals can be carried by screened twisted pair cables, coaxial cables or fibre optic cables,

depending on the system requirements. The choice is usually dictated by bandwidth and layoutrequirements.

Wherever relevant (e.g. long cable runs via lightning-unprotected areas), fibre optic cabling shallbe considered for digital and video signal paths (e.g. between a CCR and FAR) to take advantageof the large bandwidth capability, inherent EM immunity and inherent intrinsic safety offered bysuch cabling.

2.6 CABLES FOR SPECIAL APPLICATIONS

Special cabling and/or earthing requirements may apply for signal transmission outside thestandard 4-20 mA range. This may be the case with inline flow meters with remote electronics,

machine monitoring devices, analyzer systems, systems for fire and gas detection & protectionand other devices with non-standard output signals.

Manufacturers instructions with regard to cable selection, routing, termination and earthing shallbe followed.

The routing of special cabling in one unbroken length from the transmitting to the receivinginstrument, i.e. bypassing the junction box and MDF, should be considered.


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2.7 PROTECTION OF CABLES AGAINST FIRE DAMAGE

In general, above-ground cabling shall be routed via low fire risk areas. However, some cablingmay be exposed to fires. The cabling for certain critical duties, such as cabling in fire protection,process isolation (ROVs) and depressuring duty, shall maintain circuit integrity for a limited periodof time after commencement of a fire to reduce or limit the consequences of the fire.

For cabling associated with fire safety and fire protection, see PTS 80.47.10.12., PTS 80.47.10.30.and PTS 80.47.10.31.

For cabling associated with hydraulic systems for remote operation of shut-off valves, see PTS31.36.10.30.

For cabling associated with depressuring systems, see PTS 32.45.10.10.

Protection against fire damage may be achieved by special cabling or by fire resistant covering.For the selection of cabling requiring protection against fire damage, reference is made to PTS33.64.10.10.

If chemical spillage is likely to occur during fire conditions, fire resistant cabling shall also beresistant to chemical attack.


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3. CABLE SEGREGATION, ROUTING AND INSTALLATION

3.1 INSTALLATION ASPECTS

Multi-core cables between junction boxes and control rooms shall be laid without splices.

Cables entering junction boxes, consoles, cross panels or the like, shall be fastened by means of

a cable gland, suitably sized and classified for the area of operation.

The design shall incorporate right of way and cable channeling for instrument and electrical signal

cables. Instrument signal cables, shall be separated at a distance of at least 0.3 m from electric

power cables when laid underground in cable trenches, or be on separate channels with metal

separation when laid above ground.

Routing of cables shall take account of any risk of damage or deterioration due to high

temperature lines, corrosive fluids, hydrocarbons or radiation (including UV radiation from direct

sunlight).

In any process-connected instrument where rupture of the sensing element may subject theinstrument case to process pressure and where the cable used has interstices which would permit

the migration of gas or liquid to a control room, a "Barrier Type" gland with sealing compound shall

be specified.

All cables for intrinsically-safe circuits must consist of groups of conductors twisted for each

independent circuit with screen and drain wires over the cable as a whole. The capacitance,

inductance and L/R ratio must not exceed values for intrinsically-safe circuits, depending on the

hazardous area classification and equipment parameters. Reference should be made to the

equipment hazardous area certification.

3.2 MOUNTING AND PROTECTION OF CABLES

The preferred method of cable protection is single-wire armouring for onshore and braided for

offshore, in accordance with the relevant. Conduit will not normally be approved, except for use

inside buildings in non-hazardous areas. All conduits shall be rigid steel, heavy wall, minimum 20

mm diameter, electro - galvanised, and shall be supported with appropriate straps, saddles or

hangers. See BS 31, BS 4568 and BS 4607 for conduit requirements. Unarmoured single-pair

thermocouple cable shall be protected by U-channel conduits or 1/2" galvanised pipe.

Where cables require support or protection from mechanical damage, they shall be run on

purpose-made proprietary ladder-rack, U-channel or cable tray, ladder-rack being specified for

widths of 300 mm or greater.

All components and accessories used with such proprietary systems should be of 316L SSmaterials.

The appropriate proprietary fittings shall be specified for branch connections from tray or channel

to individual field instruments.

Cable support systems shall not be attached to process lines.

Design of the cable support system shall specify minimum clearance from any lines or equipment

where close proximity due to heat, chemicals or vibration may adversely affect the cables.

Supports for cable trays or cable ladders shall be suitable painted as per PTS 30.48.00.31 and

firmly fastened or welded.


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For underground or trench cables where there is extensive oil contamination in the soil or sand,

only then lead sheathed cables shall be used.

Horizontal cable trays shall be situated above air supply lines. Vertical cable trays shall be situated

behind or by the side of air supply lines unless space is limited by major equipment layout or

piping arrangements.

Cable trays shall be mounted in such a way as to allow access for maintenance or removal of

equipment without undue disturbance to the installation.

Cable trays and conduits shall be designed to be supported by steel structures or have their own

supports at every 2 meters lengths. Pipes for other services e.g. gas, steam, water etc. shall not

be used to support cable trays.

When a cable tray is designed for branching out, a flanged section shall be provided on the cable

tray leading to at each instrument. The tray shall be extended to the furthest instruments.

For cables lying in the cable channel, tray or underground trench, a marking strip (with tag no.) of

nylon-covered stainless steel or lead shall be fitted around the cable at every 5 meters length, atboth the starting and terminating points of the cable and at where the cable is fed into the control

room or auxiliary room. All marking strips for cables in cable channels shall be fastened by

stainless steel cable ties.

Cables entering junction boxes, consoles, cross panels or the like shall be designed to be

fastened by means of a cable clamp,

Instrument signal cables shall be designed to be situated at least 300 mm from electric power

cables shall be entirely clear of hot process lines.

Separate trays shall be used for l.S. and non I.S. cables as far as possible as per BS 5345.

Whenever this is a constraint, a barrier shall be provided for cable segregation.

Cable trays, conduits and cable ladders shall be galvanized iron or stainless steel.

3.3 CABLE SEGREGATION

The Cable Network shall be separated into:

System 1: High voltage systems (above 1000V).System 2: Low voltage power supply and control cables for electrical systems (1000V and below)System 3: Instrumentation and Telecommunication systems.

Where the cable support systems are installed horizontally one above the other, the cable networkshall be arranged from top to bottom, system 1, system 2 and system 3.

Cable ladders installed horizontally shall have sufficient space to facilitate cable pulling andcleating/strapping.

Instrument and telecommunication cables shall be separated from low voltage power cables andhigh voltage cables by minimum 300 mm.

Instrumentation and telecommunication cables may be routed on system 2 cable support systemswhen the defined distance between the individual systems can be kept.


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When separation of the cable systems specified above is not possible or practical, a metalsegregation barrier shall be installed to avoid induced disturbances on theinstrument/telecommunication cables.

However, crossing at right angles is acceptable without further segregation.

Non IS, IS instrument cables and Foundation Fieldbus can be routed on the same cableladders/trays provided segregation/separation is done.

When combining instrument cables for electrical signals in trenches/trunking and on cable trays,the following cable segregation rules shall apply:

Redundant cabling for critical services shall be physically segregated and follow separatecable routes in the field and in the CCR/FAR (e.g. redundant highways for the DCS andredundant signal cabling for normally de-energised IPF functions, such as depressuringsystems).

Intrinsically safe and non-intrinsically safe cabling shall only be segregated if so dictated byIEC 60079-14.

Cables of signal level class 5 (Table 1) shall be segregated from cables for signal levelclasses 1 through 4. Cables for signal level classes 1 through 4 inclusive may be combined inthe same trench/trunking and on the same cable tray without physical separation.

NOTE: Cables of signal level class 5 are to be considered as electrical cables.

Pneumatic tubing and fibre optic cables may be combined with any type of instrument signalcable.

3.4 ROUTING

All above ground cables shall be routed on cable ladders and trays.

Underground cables shall be routed through dedicated cable trenches.

Trunking or conduits may be used for special mechanical protection of single field routed cablesfor shorter distances (approximately 5 m). Where conduits are used, they shall be installed withopen ends.

A computer based cable routing system reflecting the layout of the main cable support system (i.e.cable ladders with width 300 mm and above) represented by ladder segment references, transitnumbers, etc. and necessary describing information related to the individual cable including itsroute, shall be used in the design.

Field cables may utilise the main cable support system provided the route of the individual cable isbeing registered in the routing system and the filing and loading of the main cable support systemis acceptable.

The cable ladders shall not be filled so the height of the cable ladder side rail is exceeded.

Redundant cable systems shall be routed separately.

3.4.1 Cable Bending Radius

The minimum permissible bending radius specified by Supplier shall be adhered to.


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3.4.2 Cable Strapping

PVC coated stainless steel AISI 316L straps shall be used for vertical runs and for horizontal runsin the vertical plane.

For strapping of fibre-optical and coaxial cables, Supplier guidelines shall be adhered to.

The distance between cable straps shall not exceed the distance between the horizontal andvertical runs on the cable tray. Therefore each cable shall be strapped on each horizontal andvertical run on the cable tray.

3.4.3 Cable Splic ing

Cable splicing is not allowed. In the event of damage, temporary cable splicing is allowed (nonstandard repair) provided the necessary risk assessment has been carried out. Temporary cablesplicing shall have a time limit before permanent cable repair takes place.

Temporary cable splicing shall be reported to Plant Management and tracking for permanent

repair shall be in place.

The optimum cable routing and junction box locations are related to plant layout and can only bedetermined after equipment and piping layouts have been finalised.

Single cables connect field instruments to junction boxes and shall be supported and protectedagainst mechanical damage by cable trunking, cable trays, steel angles, beams etc. asappropriate. Use of conduits is not favored. Cables shall not be supported from processequipment or piping.

When selecting the above-ground routing for cables, the following aspects shall be considered:

Constructability and cost: make optimum use of structures for process equipment, pipe racks

etc. The need for special passages/ducts and crossings will also affect the route selection. Required cable length and associated cost.

EMC aspects: apply cable segregation (3.1) and do not route cabling through areas classifiedas severe EM environments; if feasible, route cabling through areas that are protected againstdirect lightning strikes. Cable routing along and in the direct vicinity of earthed steel structuresand piping will reduce electromagnetic interference.

Avoid obstructing other users: layout shall not obstruct traffic or interfere with the accessibilityof process equipment (pumps, compressors, motors, heat exchanger bundles, etc.).

Accessibility: layout shall guarantee sufficient access for cable pulling and maintenance.

Prevent cable damage: the layout shall be selected so that the cables are not prone todamage.

This involves at least the following:

- Cabling shall be routed through low fire risk areas.

- Cabling shall not be routed in the vicinity of sample points, drains, vents, hot pipes and hotsurfaces.

- Where riser points are liable to damage by traffic, they shall be protected by free standing,sturdy mechanical structures.


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For multicore cabling, underground routing is preferred as it provides excellent protection againstmechanical and fire damage. The route selection for underground cable trenches shall take thefollowing rules into consideration:

- Maintain a safe distance from power and lighting cables. For separation distances, seeAppendix 1. When power cables intersect instrument signal cables, the crossing shall be at

right angles, with a minimum separation distance of 0.3 m.

- Trenches shall be kept away from buried hot surfaces (e.g. pipes) so that the properties of thecable shall not be adversely affected. The minimum separation distance shall be 0.2 m plus0.1 m for every 100 C temperature of the non-insulated surface.

The conceptual design for the cable routing shall be submitted to the Principal for approval.

3.5 JUNCTION BOXES FOR MULTICORE CABLES

Junction boxes shall be located in low fire risk locations th

32372010_instrument signal line

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