General Instruments Specifications

8/12/2019 General Instruments Specifications

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INSTRUMENTATION SPECIFICATIONSSECTION-II

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SECTION-II

GENERAL INSTRUMENTSSPECIFICAITONS


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INDEX

Sr. no. INDEX Page No.

1 SCOPE 4

2 CODES AND STANDARDS 4

MEASUREMENT UNITS 6

4 BASIC DESIGN CRITERIA 7

4.1 MEASUREMENT & CONTROL 7

4.2 SIGNAL TYPE AND TRANSMISSION 8

4.3 FIELD INSTRUMENATION 10

4.4 FIELD TRANSMITTERS 11

5 ACCURACY & REPEATABILITY 13

6 PROTECTION 14

7 INSTRUMENT AIR SUPPLY 15

8 INSTRUMENT POWER SUPPLY 159 INSTRUMENT EARTHING 16

10 PACKAGE UNIT INSTRUMENTATION 17

11 BROAD SPECS FOR VARIOUS INST CABLES 18

12 BROAD SPECS FOR INST JUNCTION BOXES 19

13 FLOW MEASUREMENT 20

13.1 ORIFICE FLOW MEASUREMENT 20

13.2 VENTURI FLOW NOZZLE MEASUREMENT 22

13.3 AVERAGING PITOT TUBE FLOW MEASUREMENT 22

13.4 VARIABLE AREA FLOW MEASUREMENT 23

13.5 ULTRASONIC FLOW MEASUREMENT 2313.6 CORIOLIS MASS FLOW METER 23

13.7 MAGNETIC FLOW METERS 24

13.8 VORTEX FLOW METERS 24

14 LEVEL MEASUREMENT 25

14.1 LEVEL GAUGE 25

14.2 LEVEL TRANSMITTERS 27

14.3 LEVEL SWTICH 27

14.4 TANK LEVEL MEASUREMENT 28

15 PRESSURE / DIFF. PRESSURE MEASUREMENT 29

15.1 PRESS/DIFF. PRESS TRANSMITTERS 29

15.2 PRESSURE GAUGE AND DIFF. PRESSURE INDICATORS 31

15.3 PRESSURE AND DIFF. PRESSURE SWITCHES 33

16 TEMPERATURE MEASUREMENT 34

16.1 GENERAL TEMPERATURE MEASUREMENT 34

16.2 THERMOWELL 35

16.3 TEMPERATURE GAGUES 35

16.4 TEMPERATURE ELEMENT 36


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16.5 TEMPERATURE TRANSMITTERS 38

17 LIMIT SWITCH/POSITION SWITCH 38

18 CONTROL VALVES 39

19 pH/CONDUCTIVITY ANALYSERS 43

20 MATERIAL HANDLING SYSTEMS 43

21 OTHER INSTRUMENT ITEMS 44


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1. SCOPE

This specification gives directives for the basic design criteria for instrumentation ingeneral. The specific design requirements for each type of instrument or instrument

system are covered by the individual specification of that particular item/category. Anyconflict between the requirements of this specification and related codes, standards,data sheets, drawings, requisition, etc., shall be referred to the OWNER for clarification.Owners approved vendor list shall be followed strictly for procurement of variousinstruments.

2.0 CODES AND STANDARDS

The various applicable codes and standards are as mentioned below. In case of anyconflicts / discrepancies in general instrument specifications and individual itemsspecifications, the most stringent conditions shall apply based on the followingstandards. However, in all such cases, before taking any decision, BIDDER shall getformal approved of data/specification sheets from OWNER.

The following standards shall be followed as a minimum during basic and detailengineering of plant by consultant/vendors.

1. ASME B1.20.1 Pipe Threads, General Purpose (inch)2. ASME B46.1 Surface Texture (Surface Roughness, Waviness and Lay)3. ANSI/ASME B16.5 Pipe Flanges and Flanged Fittings4. ANSI/ISA S18.1 Annunciator Sequences and Specifications5. ANSI/ASME PTC 19.3 Pt 3: Power Test Code. Thermowell strength

Calculations6. ANSI/FCI-70.2 Control Valve Seat Leakage.7. ANSI/ISA 75.01 Flow Equations for Sizing Control Valves.8. API RP 520 Sizing, Selection and Installation of Pressure Relieving Devices

in Refineries: Part 1: Sizing and Selection Part 2: Installation9. API RP 551 Process Measurement Instrumentation.10. API RP 550 Manual on Installation of Refinery Instruments and Control

Systems - Part I - Process Control and Instrumentation.11. API RP 556 Instrumentation and Control Systems for Fired Heaters and

Steam Generators.12. API 607 Fire Test for Soft-seated Quarter-turn Valves.13. API 670 Vibration, axial position and bearing temperature monitoring

systems.14. BS 3643 ISO Metric Screw Threads: Part 1: Principles and Basic Data. Part

2: Specification for Selected Limits of size.

15. CE Conformite Europeenne, Harmonized Codes directed by the EuropeanCommunity.

16. 97/23/EC Pressure Equipment Directive17. DIN ISO 228, Pt. 1 Pipe Threads where Pressure-tight Joints are not made

on the Threads. Pt. 1: Designation, Dimensions and Tolerances.18. DIN 16128 Nominal Ranges, Scale Spacing and Scale Numbering of

Accuracy Classes 1.0, 1.6, 2.5 and 4.0 Pressure Gauges.


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19. DIN 19234 (NAMUR) Electrical Distance Sensors; DC Interface forDistance Sensor and Signal Converter.

20. DIN V19250 Measurement and Control Fundamental Safety Aspects forMeasuring and Control Protective Equipment.

21. DIN 43729 Electrical Temperature Sensors; Connection Heads for

Thermocouple Thermometers and Resistance Thermometers.22. EN Standards (CENELEC) Electrical Apparatus for Explosive GasAtmospheres.

23. EN 10204: Inspection Documents for the Delivery of Metallic Products.24. EN 60947 : Electrical Distance Sensors; DC Interface for Distance

Sensor/converters25. IEC 60079:Electrical Apparatus for Explosive Gas Atmospheres.26. IEC 60085 : Thermal Evaluation and Classification of Electrical Insulation.27. IEC 60227 : Polyvinyl chloride insulated cables of rated voltages up to and

including 450/750V.28. IEC 60228 : Conductors of insulated cables29. IEC 60331 : Test for electric cables under fire conditions. (Fire resistant)30. IEC 60332: Test for electric cables under fire conditions. (Flame retardant)31. IEC 60364: Electrical Installation of Buildings.32. IEC 60391: Marking of Insulated Conductors.33. IEC 60423 : Conduits for Electrical Purposes: Outside Diameters of

Conduits for Electrical Installations and Threads for Conduits and Fittings.34. IEC 60529 : Degrees of Protection Provided by Enclosures (IP Code).35. EC 60534 Industrial Process Control Valves:

Part 1: Control Valve Terminology and General Considerations.Part 2: Flow Capacity: Section 1: Sizing Equations for Incompressible FluidFlow under Installed Conditions.Part 2: Flow Capacity: Section 2: Sizing Equations for Compressible FluidFlow under Installed Conditions.Part 8: Noise Considerations:Section 1: Laboratory Measurement of Noise Generated by AerodynamicFlow through Control Valves.

36. IEC 60584 Thermocouples - Part 2: Tolerances. Thermocouples - Part 3:Extension and Compensating Cables Tolerances and Identification System.

37. IEC 60654 Operating Conditions for Industrial Process Measurement andControl Equipment.

38. IEC 60751 Industrial Platinum Resistance Thermometer Sensors.39. IEC 60757 Code for Designation of Colors.40. IEC 60902 Industrial Process Measurement and Control Terms and

Definitions.41. IEC 61000 Electromagnetic Compatibility for Industrial Process

Measurement and Control Equipment.

42. IEC 61508 Functional safety of electrical/electronic/programmableelectronic safety related systems.

43. ISO 5167 Measurement of Fluid Flow by Means of Pressure DifferentialDevices.

44. NACE MR0175 (95) Standard Material Requirements - Sulfide StressCracking-resistant Metallic Materials for Oil field Equipment.

45. CCOE = Chief Controller of Explosions, India forintrinsic safe and Explosion proof apparatus.


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3.0 Measurement Units

Unless otherwise, specified, the following unit shall be used for complete project,including package unit instrumentation, wherever the units are not specified, these will

be based the internationally accepted SI units.

Mass Flow = kg/hVolumetric Flow = m/hSteam Flow = kg/h or T/hGas/Vapor Flow = Nm3/hLevel Absolute = Absolute Meter or mmLevel Relative = 0-100% in Direct rangePressure Gauge = Kg/cm2 g / mmwcPressure Absolute = Kg/cm2 -aTemperature = C

Analysis = % or PPMViscosity = cPConductivity = s/cmDensity = Kg/mVelocity = m/sImpulse tube size = or OD


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4.0 Basic Design Criteria

4.1 Measurement and Control

4.1.1 All field transmitter shall of 2 wire, 24 V DC, SMART with HART protocol

and with local LCD type display4.1.2 All Switch function shall be snap acting, Single-pole Double Throw (SPDT),hermetically sealed and potential-free gold plated contacts with 230 V AC/5amp or 24 V DC/2 amp contact ratings.

4.1.3 The use of Foundation Field Bus/ PROFIBUS or any othercluster/Multiplexer type I/O philosophy shall not be allowed in project andany part thereof as an alternate to conventional 4-20 ma dc signaltransmission by individual pair of wires.

4.1.4 Minimum contact rating for disconnecting inductive loads shall be:

- 1.0A for 24-48 V DC- 0.4A for 110-125 V DC- 5.0A for 60-260 V AC

4.1.5 Transmitters shall be utilized for indication, control/trip/calculation functions.In principle no switches to be used in process related areas, except ON-OFF valves limit/position switches.

4.1.6 Instrument ranges for trip functions and control functions in the sameservice shall be equal.

4.1.7 Ranges used for measurement and control instrumentation shall overlapalarm and trip settings by minimum 5% of the span.

4.1.8 Mercury, Asbestos and asbestos compounds are not allowed.4.1.9 All field instruments, junction boxes, cabinets, panels etc. shall be provided

screwed SS tag plate with tag no. engraved or embossed on it.4.1.10 All remote seal diaphragm type Pressure and Diff. pressure transmitters for

pressure, diff. pressure, and flow and level application shall have 2 sizeFlange with diaphragm as process connection with calibration ring.However in case of measurement of vary low range pressure ( in the rangeof vacuum to mmwc pressure measurement), the diaphragm flange sizeshall be 3

4.1.11 All displacer type level transmitters, externally mounted float/displacer typelevel switches, the process connection size shall be 2 on vessel.

4.1.12 All temperature measurement points on vessel, pipe line, towers, columns,etc. shall with 1 flanged thermowells with min. flange rating of ANSI300#.

4.1.13 Instrument air headers, pipes and distributors shall be of SS316.Instrument air manifold shall be used for supplying instrument air to control

valves and other instruments. These shall be with 10 nos. of tapings andbe with NPT (F), SS 316 valves. From the nearby air manifold,instrument air shall be supplied to the control valves. For the purpose, alltubing shall be used shall be of SS316, or OD, seamless tubes, laidin perforated FRP trays. All intermediate fittings shall be doublecompression, SS316 MOC, Swagelok make, double compression typeonly.


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4.1.14 Standardization features shall be taken care of during design andpackages for junction boxes, instrument air headers, instrument fittings,and other erection hardware like cable duct, cable trays, etc.

4.1.15 Air conditioning capacity shall meet the total requirement of the controlroom and cabinet room all instrument system hardware in addition to man

power movement/losses, etc.4.1.16 All equipment/materials supply should include spares required forcommissioning and 2 years operation.

4.2 Signal Types & Transmission

4.2.1 Electric Signals

Electric signal transmission shall be applied in conjunction withelectronic/digital control systems.

In general the loop power will be supplied by the systems.

- Analog Signals with standard 4 20 mA DC signals (24 V DC, two-wiresystem) shall be applied as measuring inputs and controller outputs.

- Where 2 wire system is not suitable, 4 wire transmitter with isolated 4-20mA DC output signal and 110 V AC UPS supply shall be used.- Proximiter signals shall be 2 wire NAMUR sensors as per EN 60947(NAMUR) with control room aux. panel mounted Isolation amplifiers.- Digital signals may be applied as potential-free inputs

4.2.2 The standard signals for transmitting measuring and control shall be acurrent of 4 to 20 mA. DC, superimposed with digital communicationprotocol (HART). All interlock shall also be realized from 4-20 ma analoginput transmitters in the DCS. No field switches shall be used for interlockpurpose, except NAMUR type proximity sensors for valve positionsswitches for ON-OFF valves.

4.2.3 All signal exchange between field and central cabinet room shall be viaindividual hardwire pair of cable as specified in detailed cablespecifications. From the field, all field transmitters shall be routed to fieldmounted junction boxes, from where these shall be taken to central cabinetroom via multi pair cables. Use of 6 pair or 12 core cable is not allowed.

All analog multi pair cable shall be 12 pair only. All Digital input/output multipair cables shall be either 24 core or 12 pair only. Multi pair power cableshall also be 12 pair only.

4.2.4 To the extent possible, direct run cable from field instrument to centralcabinet room shall not be employed. All the signals to the central cabinet

room shall be routed through multi pair cables via field mounted junctionboxes only.

4.2.5 Usage of Foundation Field bus / Profibus type clustered I/O wiringphilosophy is not allowedat any location in the whole plant as an alternateto conventional 4-20 ma dc signal transmission.

4.2.6 Few dedicated, special type of cables from special control system may bedirectly routed to cabinet room in place of multi pair cables.

4.2.7 All the power/control and signal cables in a single or multi pair cables


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between field instruments to field junction boxes and between field junctionboxes/local panels to the central cabinet room shall be thru overheadperforated cable trays / MS cable duct with min. 3 mm thickness on the piperacks. No underground cabling for any type of instrument cables is allowed.

4.2.8 On the main cable route, FRP ladder tray of min. 3 mm thickness shall be

used with separate ladder trays of various low voltage signal cables(AI/AO/DI/DO with 24 V DC and lower voltage) and high voltage powercables (e.g. 110 V AC for Solenoid valves, 110 V A.C. power supply cablesto field instruments, etc.). On the trunk and branch route from main cableduct to field junction boxes and local panels, 300 mm(w) x 60mm (H)x3mmthick FRP perforated cable trays will be used. For other branch cablesvarious sizes of perforated FRP cable trays shall be used with the followinggeneral specifications.

300 mm (W) x 60 mm(H) x 3 mm thick perforated FRP cable trays200 mm (W) x 50 mm (H) x 3 mm thick perforated FRP cable trays100 mm (W) x 50 mm (H) x 3 mm thick perforated FRP cable trays50 mm (W) x 40 mm (H) x 3 mm thick perforated FRP cable trays

4.2.9 All the fiber optic cables / system cables, special cables shall be laid in GIconduit preferable in overhead trays/duct only.

4.2.10 All type of single and multi pair power, control and signal cables in the fieldshall be with GI armored only for mechanical protection, including fiber opticcables.

4.2.11 In the whole plant area, where there are chances of fluid leakages/spillagein normal operating conditions, all cable trays/cable ducts shall be providedwith closed covers made of 2 mm thick SS304 sheets.

4.2.12 All fiber optic cables shall also be with armored only4.2.13 All the cable exchange between the central cabinet room and field

instrumentations shall be from any one side of the cabinet room throughMCT blocks.

4.2.14 All the above mentioned philosophy shall be followed for various type ofcable exchange between electrical and instruments signals. Signal andpower/high voltage cables shall be laid in separate cable duct betweencabinet room and MCC. The central cabinet room and MCC room designshall be such that there shall be a minimum distance between these twobuildings.


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4.3 FIELD INSTRUMENTATION

4.3.1 Field instrument connections shall be as follows.

Instrument Type Piping/VesselConnection

InstrumentationConnections

DP Flow Instruments NPT NPT

External Displacer(as per pipe class)

2" Flanged 2" Flanged

Internal Displacer(as per pipe class)


External Ball Float

(as per pipe class)


Internal Ball Float(as per pipe class)

4 Flanged 4 flanged

Level Gauge(as per pipe class)

2 Flanged 2" Flanged

D/P Level NPT NPT

D/P Level with Remote DiaphragmSeal(as per pipe class)

2 Flanged 2 Flanged

D/P Level Direct Vessel Mounted(as per pipe class) 2 Flanged 2 Flanged

RADAR(as per pipe class)

4" flanged 4" flanged

Pressure Instruments NPT NPT

Press. Gauge NPT NPT

Pressure with diaphragm seal(as per pipe class)


Thermowell

(as per pipe class)

1 Flanged on

pipe and 2 flangedon equipment

1 Flanged on pipe and 2

flanged on equipment

4.3.2 Flanged instrument connections shall be in accordance with ASME B16.5.4.3.3 Flange surface finish shall be as per relevant piping specification and in

accordance with ASME B46.1.4.3.4 Screwed connections shall be in accordance with ASME B1.20.1 (NPT)


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4.3.5 Cable gland connections to be M20 x 1.5mm as a minimum in accordancewith EN 60423.

4.3.6 Standard instrument connection shall be NPT female, except thatpressure gauges and pressure switches shall have NPT maleconnections. A parallel thread should be used in cases of a hazardous

process fluid.4.3.7 Except for steam service instrument impulse lines, all other location shall be OD SS tubes. The thickness of impulse tube shall be 1.6 mm for ODSS304 tubes and 1.0 mm for OD SS tubes, unless otherwise specified.These thickness shall be followed as standard minimum, except specialcase requirements for vary high pressure and temperature services. Forsteam services, it shall be CS/IBR pipes (Min. SCH160).

4.3.8 For very low pressure measurement, the remote seal size PT/DPT sizeshall be 3 ANSI in place of 2 ANSI.

4.4 Field Transmitters:

4.4.1 All field transmitters shall be 2 wire type, 24 Volt DC, loop powered, SMART

with HART protocol, and shall be equipped with Local LCD type digital

indicator.

4.4.2 The transmitters shall be suitable for 2 pipe mounting and shall be supplied

with SS304 MOC mounting brackets, hardware, nut/bolts, etc.

4.4.3 The basic accuracy of all transmitters shall be 0.075% of span or better with

1:30 rangeability to reduce the inventory. The accuracy shall remain constant

throughout the above range. However the overall rangeability shall be 1:100.

4.4.4 All transmitters shall be supplied with local digital display configured in

engineering unit.

4.4.5 All transmitters shall be supplied with NPT (F) cable entry and either

NPT (F) process connection.

4.4.6 All transmitters shall be supplied with SS304 MOC, double compression cable

glands, certified for weatherproof to IP67 as per IEC529 with PVC hood.

4.4.7 Wherever the above requirement of 2 wire, 24 V DC transmitters can not be

fulfilled, the 4 wire transmitter (SMART with HART protocol) option shall be

used such as RADAR type level transmitters, Magnetic Flow meters, Mass

Flow meters, etc. All theses device shall be powered with 110 V AC UPS

supply only. The power shall be fed from PDB located at central cabinet room.

4.4.8 All the field instruments shall be weatherproof to IP65 as per IEC529 as a

minimum.

4.4.9 The wetted parts MOC of all transmitters/devices/instruments shall be suitable

for process fluid, pressure and temperature, but SS316 as a minimum unless

otherwise specified.


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4.4.10 All DP transmitters used for flow/level and PDI measurement application shall

be supplied with 3 way valve, SS316L Manifold or better MOC to suite process

fluid. All Pressure transmitters used for Pressure measurement application

shall be supplied with 2 way valve manifold with SS316L MOC or better MOC

to suite process fluid. The process connections for manifold shall be

NPT(F).

4.4.11 All the transmitters housing MOC shall be die cast aluminum and it shall be

supplied with EPOXY paint, suitable for protection against harsh environment

4.4.12 While designing, a care shall be taken to choose transmitters ranges/

rangeability, etc. for various applications in such a way that there shall be min.

type of diff. models of the same category of transmitters are required to be

maintained as spares.

4.4.13 For all remote mount transmitters, the sensor and transmitter cable shall be

with min. 15 meterin length and it shall be either armored or shall be laid inPVC protective conduit only.

4.4.14 Head mounted Temperature transmitters are not acceptable. All temperature

transmitters, wherever applicable shall be remote mount (mounted in the field)

type only.

4.4.15 All remote seal diaphragm type PT/DPT shall be supplied with min. 5 mtr. of

capillary with SS armored in PVC sheath for protection

4.4.16 The following types of reports/certificates should at least be considered:

- EC declaration of conformity;- Calibration report;- Functional test report;- Welding procedure/report;- NDE report;- Material certificates;- Electrical certificates;- IBR certificates for IBR service control valves, PSV, orifice assemblies,

level gauges, thermowells, annubars.

4.4.17 All instruments/equipments to be supplied shall be manufacture's standardtype. The instruments / equipment shall be purchased only from

manufacturers with long-standing experience. The vendor list approved byOWNER shall be followed for the purpose. For items not covered in thevendor list, OWNERs prior approval shall be taken.

4.4.18 The material components, which come into contact with the fluids to bemeasured, shall be resistant to corrosion caused by said fluids. It shall becompatible with the piping material when being clamped, welded orconnected by other methods.

4.4.19 All instruments and equipments shall be suitable for use in specified siteclimatic conditions and industrial environment in which corrosive gases and


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/ or chemicals may be present. All external surfaces shall be suitablytreated to provide protection against corrosive plant atmosphere with epoxypainting / powder coating.

4.4.20 The design of electronic instruments shall be in compliance with theelectromagnetic compatibility requirements as per IEC 801 'Electromagnetic

Compatibility for Industrial Process Measurement and control Equipment.'4.4.21 Flange ratings for instruments may differ when instrument flanges and themating flanges on piping / equipment are of different materials (e.g. SS-316thermowell on CS pipes). The contractor shall in such cases, ensure thatthe rating of flange is chosen for the instrument and the correspondingflange on piping / equipment.

4.4.22 Instruments like control valves, orifice flanges, level instruments,thermowells, etc. coming on pipes and vessels under Indian BoilerRegulation (IBR) shall be certified by IBR. (or authorized representative ifprocured outside India).

4.4.23 Piping/Instrument scope change for instrumentation shall always be afterfirst isolation/drain valve for all types of instruments, including localPressure gauges.

4.4.24 Instrument impulse tube size shall be either or OD, SS316 MOC only.4.4.25 Transmitters shall be mounted on nearest platform / grade level keeping in

view requirements of readability and accessibility.4.4.26 All instruments shall have an integrally mounted terminal box to terminate

armored cables. Instruments with loose flying leads shall not be used.4.4.27 Canopy made of bolted FRP sheets of min. 2 mm thickness shall be

provided for all transmitters, electronic instruments and local panels.4.4.28 All remote seal diaphragm type Flow, Pressure and Level transmitters shall be

designed with 2 flange size.4.4.29 The local temperature gauges shall not be used in the whole project (including

any of the package unit also). All temperature points shall be provided witheither direct thermocouple (generally K type) or RTD (generally 3 wires,PT100) sensors with flanged thermowell assemblies and field mounted 2 wire,24 V DC, SMART with HART protocol Temperature transmitter with LCD for allopen and closed loops. No RTD and T/C signal will be interfaced with DCS.

4.4.30 All thermocouple/RTD sensors shall be duplex type with Flanged thermowellalong with nipple-union-nipple assly along with dual entry thermocouple head,certified to weatherproof to IP65 as a minimum. Thermowell shall bemanufactured from drilled bar stock, tapered. MOC of thermo well shall besuitable to process fluid and pressure/temperature conditions. The cable entryshall be NPT(F) and complete assembly shall be provided with SS MOC,double compression cable glands certified for weatherproof to IP65 with PVChood.

4.4.31 Displacer type level transmitters and float type level switches with external / sidemounted chambers shall have 2 flanged tapping size. Irrespective of pressurerating, the minimum flange rating shall be ANSI 300#.

4.4.32 All instruments / devices shall be immune to interference due to normalwalkie-talkies with output of 1W at UHF.

5.0 Accuracy and Repeatability


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5.1 Consideration shall be given to the relevant function of the instrumentand/or system, its required accuracy and repeatability, the maximumobtainable industrial accuracy and its repeatability.

5.1 The characteristics of sensing devices shall be specified to meet thefollowing requirements:

Measurement error (accuracy) percent value of span, unless stated otherwise, not worsethan:

a. 0.075 % for all types of pressure transmitters, diff. pressure transmitters usedfor Pressure, DP, Flow or Level measurement.

b. 0.5% for all Vortex and Magnetic Flow metersc. 1.0% of calibrated range (acc.class 1) for pressure gauges.d. 1.5% for (differential) pressure gauges.e. 0.2% for multipath ultrasonic flow measurement for Gas servicesf. 0.5% for Displacer type level transmitters.g. 1.5 C between 40 C and 375 C Max. for TC with Class-1 accuracyh. 0.004T C between 375 C and 1000 C Max. for TC with Class-1 accuracyi. (0.15 + 0.002*t)C or 100.00 0.06 at 0C for RTD, i.e. Class-A accuracy

j. 0.12 C for all temperature transmitters.k. 1 mm for RADAR type tank Gauging systems for Custody transferl. 5 mm for General Purpose RADAR type level transmittersm. 5% for all Gas Detectorsn. 0.75% for Annubar/Averaging Pitot tube flow meterso. 1.5% for Critical flow measurement by Orifice Platep. 2% for General purpose flow measurement by Orifice Plateq. For mass flow meters:

0.1% for liquid flow. 0.1 kg/m on liquid/gas density.

r. 0.5% for Belt weighers and Bagging machiness. 5 kg for Weigh Bridges of a capacity up to 60 Ton and 10 kg for 100 tont. 20 gms for Bagging machine of 25/50 Kg bag

Note:-1 Hysteresis shall be maximum 0.1% of the rangeNote:- 2 All dp transmitters shall have minimum static pressure rating of 250 kg/cm.Note:- 3 Ambient temperature variation of 40 C shall not change output signals bymore than 1% of the range.

6.0 PROTECTION

6.1 Climate

Systems enclosures shall have a degree of protection in accordance with IEC 60529,

protection code IP 65 as a minimum. Preference is given to IP-65 due to heavyrains/storms. Cable glands shall also be IP-65 to avoid ingress.

All field instruments shall be damp-proof and dust-proof, minimum protection class asper IEC 529 shall be as follows:

Electrical / Electronic instruments : IP 67Sensors; RTD, T/C, etc. : IP 65Local Gauges; PG, etc. : IP 55


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Pneumatic instruments : IP 54Solenoid valves : IP 67Local Panel / Skid Mounted Panels : IP 55

6.2 Electromagnetic Compatibi lity (EMC)

The design of electronic instruments should be in compliance with the EuropeanCommunity (EC) harmonized codes and standards, which includes Radio FrequencyImmunity (RFI) and EC 61000 electromagnetic Compatibility

6.3 Electrical Safety

Generally, PAC plant process is classified as general purpose, safe area. Henceflameproof/explosion protection is not required at individual instrument level.

7.0 Instrument Air Supply

7.1 The quality of the instrument air and the air supply pressure range fortransmission devices shall be in accordance with IEC 60654.

7.2 Instrument air shall be used for the pneumatic operated actuators (e.g.control, on/off valves).

7.3 Instrument air may be used for purging purposes, for pressurizing ofinstrument enclosures and breathing (safety) masks.

7.4 All control valve actuators shall be sized at max. 4.0 bar g instrument airavailable at control valve.

7.5 All the air to instrument control valves and individual consumer shall berouted thru 10 way instrument air headers form the field. Air manifold,instrument fittings, tubing and needle/ball valves shall be of SS316 MOC asa minimum.

7.6 There shall be instrument air buffer vessel to cater to requirement of wholeplant during safe shutdown for a minimum of half an hour.

8.0 Instrument Power Supply:

8.1 The instrument power supply systems shall be used for instrumentationpurposes only.

8.2 Field instruments which are loop powered shall be used. Field instrumentsrequiring a separate power supply shall be avoided. The loop poweredtransmitters shall be always 24 V DC, 2 wire, 4-20 mA DC signal type andHART with SMART protocol.

8.3 Where two wire transmitters are not possible, 4 wire transmitters with 110 V

AC supply shall be selected. The supply to these instruments shall be fedfrom central cabinet room located UPS PDB only.

8.4 All central cabinet room located instrument systems including DCS shall be110 V AC UPS Power only.

8.5 All of above systems shall be capable of accepting dual redundant 110 VAC UPS feeders, which will be fed power form two diff. UPS feeders Thefeeders shall be connected to the UPS distribution boards in such a waythat at all times power will be available on at least one (1) feeder.


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8.6 The conversion to the required voltage level(s) shall be carried out by eachsystem vendor with dual redundant 24 V DC bulk power supply installed inseparate 24 V DC PDB. The same shall be used for 24 V DC SolenoidValves also.

9.0 Instrument Earth ing

9.1 General

9.1.1 All equipment for electric transmission, including the enclosures as well asthe armoring, lead sheathing and screening of cables, shall be properlyearthed for personnel safety reasons and to obtain the maximum possiblerejection of interference.

9.1.2 Instruments and associated equipment requiring electricity with a potentialto earth greater than 50 V AC or 120 V DC shall be adequately earthed(refer to IEC 60364 part 4, protection of safety, section 41, and protectionagainst electric shock.)

9.1.3 Unintentional interconnections between the two systems are not allowed tooccur.

9.1.4 All earth connections shall be protected against corrosion, which mightadversely effect the earth resistance.

9.2 General Earth ing System

All metal enclosures housing instrument and/or instrument systems and allarmoring of field cables shall be connected to the general earthing system.

9.3 Instrument Earth ing System

9.3.1 The instrument earthing system consists of one or more earthing electrodesclose to the control satellite building at a safe distance from any plant-earthing electrode.

9.3.2 The resistance to earth is to be less than 1 ohm. To achieve this, an arrayof parallel electrodes may be used.

9.3.3 The instrument earthing shall terminate in a copper bus, mounted centrallyto all instrument equipment, but electrically isolated from any otherequipment or structure.

9.3.4 The cable connections shall be easily accessible for testing facilities.9.3.5 All connections between the copper bus bars and to the central earth bar

shall be individually connected via a separate, insulated, stranded wireconductor of at least 4 mm.

9.3.6 To avoid undesired ground loops due to differences in earth potential or

influence of surface currents, the shield of signal wires shall be connectedto the instrument earth system only at one side (in the control room/satellitebuilding). The shielding shall be kept isolated from cable armoring andinstrument enclosures.

10.0 Package Unit Instrumentation


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10.1 There shall not be any local control panels with proprietary or 3rdparty control

system like field mounted small PLC, etc. for any of the package unit or part

thereof, in the whole plant. All the controls and interlocks shall be realized in

PAC plant DCS system. No separate, small, skid mounted PLC systems,

dedicated controllers, or any other third party proprietary control systems are

acceptable, except the system as specified below. This includes variousmachine safety interlocks and anti-surge controls also. There shall be no field

mounted control panels. Local panels at machine/package unit shall be used

only for Local Push Buttons and a few clustered LED type Lamps for start/stop

and health/running status indications of machine/peripherals and initial start up

procedure only. The field mounted Local Panel shall be weather proof to IP55

as a minimum. The panel make shall be RITTAL only and color shed shall be

RAL7032.

10.2 A common field alarm hooter at each package unit / local control panel shall be

generated from central control room DCS to alert the machine trip condition.

Complete control should be possible from central DCS for all the machines.Also emergency shutdown of this entire machine/package unit shall be

governed by PAC plant DCS only.

10.3 Apart from field instrumentation philosophy, specified in these documents for

various field instrument specifications, for all package units field instruments,

the following minimum guide lines shall be followed, additionally.

10.7.1 All the instruments within package units shall be supplied as per Owners

specifications as per this ITB guide line applicable for main plant.

10.7.2 Approved vendor list for instruments shall be provided by OWNER. If a

package unit vendor wants to deviate from the approved vendor list, they have

to obtain prior approval from Owner.

10.7.3 The type of instruments shall be weatherproof to IP65 as per IEC529 and all

field panels shall be weatherproof to IP55 as a minimum.

10.7.4 Package unit vendor to lay branch cables from individual instrument to skid

mounted Junction box in closed FRP perforated cable trays. Junction box

segregation shall be maintained for various type of I/O signals like AI/AO can

be combined in common junction boxes, Digital inputs shall be wired in

separate junction boxes, Digital Output for lamps and Digital Output for

Solenoid valves shall be wired in separate junction boxes.

10.7.5 All branch cables shall be PVC sheathed and armored only. The broad specs,

mentioned in the field instrumentation specifications shall be strictly followed as

minimum. Other specs shall be as per IS1554 and shall be approved by

Owner.


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10.7.6 All cable glands shall be of double compression type with SS MOC and

weatherproof to IP65 as per IEC529, with PVC hood.

10.7.7 Package unit vendor shall maintain segregation of Electrical (all MCC related

I/O) and Instrument signals in diff. junction boxes. Electrical and instrument

interface junction boxes shall be a separate junction box in the package unit.

10.7.8 Power supply to individual shall be provided from UPS grade 110 V AC / 50 Hz

power supply at one location only per package unit from PDB panel located in

central cabinet room. Further distribution / voltage level conversions, Fuse co-

ordinations, etc. shall be performed by package unit vendors.

10.7.9 Package unit vendor to supply all drawings/documents in 4 sets of hard copy

and 2 sets in editable software like Microsoft Excel / AUTOCAD only. The

drawing and documents includes, various panel drawings, panel GA/IA

drawings, dimensional drawings, loop sheets, interlock and logic diagrams,

wiring diagram, cable schedule, PDB SLDs, Junction box schedule, instrumentlist, Tag list, datasheets, sizing calculation sheets, etc.

11.0 Broad Specifications for Various type of Instruments power/signal andcontrol cables:

In addition to various cable manufacturing standards like IS1554 part-I,

BS/ IS5831, BS5308 and IS694-Part-I standards, the following basic

design criteria as per OWNERs standard shall be followed as a

minimum. All cables, color codes shall be strictly as follows. This

philosophy applies to package unit instruments also. The primaryinsulation material shall be XLPE (cross linked polyethylene) for all types

of cables. The voltage grade shall be min. 600 V for all signal and control

cables and 1100 V for all 110 V AC/24 V DC power cable.

a. Single pair signal cable: ATC, Multi strand (Max 7 strands), 1 Pair, twisted pair, 1sq. mm, white/black color, screened / armored/ FRLS cable, Outer Jacket colorcode: Grey for non-IS, Blue for IS. This shall be used for all 4-20 m amp. analoginputs/outputs signals.

b. Multi pair signal cable: ATC, Multi strand (Max 7 strands), 12 Pair, twisted pair 1sq. mm, white/black color, individual and overall screened / armored/ FRLScable, Outer Jacket color code: Grey for non-IS, Blue for IS. This shall be used

for all 4-20 m amps. analog inputs/outputs signals. 6 pair multi pair cable shallnot be used.

c. 110 V AC Power cable Single Pair: - ATC, Multi strand (Max 7 strands), min.1.5 sq. mm for 110 v ac, (2 core- Red / black, 3 core- Red / Black / Green,)armored/FRLS, Outer jacket color code: Black. This shall be used for 110 V ACpower supply to field instruments, solenoid valves, etc. This shall be used for 110V AC power supply as a minimum size. BIDDER to ensure correct size (crosssection area) for various requirements, to maintain 110 V AC -2% & +1% at 50


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Hz -3/+1 Hz at field devices (wired from centrally located non-system UPS PDBfrom central cabinet room only).

d. 110 V AC Power cable Multi Pair: - ATC, Multi strand (Max 7 strands), min. 1.5sq. mm for 110 v ac, 2 C x 12 pair, (2 core- Red / black, 3 core- Red / Black /Green,) armored/FRLS, Outer jacket color code: Black. This shall be used for

110 V AC power supply distribution to field instruments, solenoid valves, etc, viapower JB. This shall be used for 110 V AC power supply as a minimum size.BIDDER to ensure correct size (cross section area) for various requirements tomaintain 110 V AC -2% & +1% at 50 Hz -3/+1 Hz at field devices (wired fromcentrally located non-system UPS PDB from central cabinet room only).

e. 24 V DC Power cable, Single Pair: - ATC, Multi strand (Max 7 strands), 2.5 sq.mm for 24 V DC, (2 core- Red/black) armored/FRLS, Outer jacket color code:Black for non-IS and Blue for IS. This shall be used for all 24 V DC power supplyto field Solenoid Valves, Field Lamps/Alarms, etc. as a minimum size. BIDDER toensure correct size (cross section area) for various requirements to maintainminimum 24 V DC at field device.

f. 24V DC Power Cable, Multi pair :- Single Pair:- ATC, Multi strand(Max 7 strands),2.5 sq. mm, 2Cx12 Pair, overall screened, 2 core- Red/Black, armored/FRLScable, Outer Jacket Color code: Black for non-IS, Blue for IS. This shall be usedfor all 24 V DC Digital output signals for Solenoid valves, Field lamps/Alarms, etc,as a minimum size. BIDDER to ensure correct size (cross section area) forvarious requirements to maintain minimum 24 V DC at field device. Use of 6pair/12 core cable is not allowed.

g. Control Cable for DI - Single Pair:- ATC, Multi strand(Max 7 strands), 1.5 sq. mm,2Cx1Pair, overall screened, Red/Blue, armored/FRLS cable, Outer Jacket Colorcode: Black for non-IS, Blue for IS. This shall be used for all 24 V DC Digital inputsignals.

h. Control Cable for DI - Multi pair:- ATC, Multi strand(Max 7 strands), 1.5 sq. mm,2Cx12Pair, overall screened, Red/Blue, armored/FRLS cable, Outer Jacket Colorcode: Black for non-IS, Blue for IS. 6 pair multi pair cable shall not be used.These shall be used for all 24 V DC Digital inputs.

i. Single Triad RTD cable ATC, Multi strand (Max 7 strands), 1 Triad, 1.3 sq. mm,red/white/black color, screened / armored/ FRLS cable, Outer Jacket color code:Blue. This shall be used for all RTD input signals. Since no RTDs are required tobe wired up to Control room DCS/ESD, the specifications of 8 triad RTD cable isnot envisaged and not provided.

j. T/C single pair: 1 P x 18 AWG (Single) or 20 AWG (Duplex) as per IEC 60584-3,Special compensating cable for particular type of thermocouple. Since no T/C arerequired to be wired up to Control room DCS/ESD, the specifications for 12 pairT/C cable is not envisaged and not provided.

k. The fiber optic cables shall be single mode, 6 core, jelly filled, armored type only,

as a minimum. This shall be laid in overhead cable trays.

12.0 Broad Specifications for various Field Junction boxes:

The following basic design criteria is to be followed for all type of junction boxes,

through out the specifications, including those being supplied by package unit vendors.


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a. All the field junction boxes shall be weatherproof to IP65, as per IEC529,as a minimum.

b. All the field junction box shall be made of FRP Material.c. There shall be diff. junction box for diff. type of I/O signals. As a minimum

the following segregation shall be maintained

Signal Category wise segregation

a. Analog Input and Analog outputb. 24 V DC Digital Input / NAMUR sensorsc. 24 V DC Digital Output used for lamps, etc.d. 110 V AC power cables for field instrument power, SOV, etc.

d. The naming philosophy for junction box shall be adopted in such a waythat from the tag number of the particular junction box, it shall be evidentto decide type of signal and destination

e. All junction box MOC shall be of GRP / Polycarbonate material. Based onrequirement, there shall be diff. insulated shield and earth bus bars are tobe provided in the junction box. The individual branch cable shall bebrought to central cabinet room panel instrument shield bus bar viainsulated shield bus bars and multi pair shields from junction boxes.

f. All junction boxes shall have branch and multi pair cable entries frombottom only.

g. All junction boxes shall be weather proof to IP65 as a minimum. Generally12 branch entries of NPT and 1 no. of main multi pair cable entry type

junction boxes shall be used in the total project.h. Each Junction box shall have 0.5 to 4.0 sqmm, screw less, WAGO make

terminals inside them. These shall be DIN rail mounted. The color codeshall be based on type of signals. The qty. shall be as required.

i. Each junction box shall have engraved/embossed SS tag plate with tagnumber. This tag plate shall be screwed on the junction box.

13.0 Flow Measurement:

13.1 Orifice Plates:

Orifice plate shall be the standard flow measurement device except forfollowing conditions

- where required accuracy is not obtained- where flow rate varies in wide range- where allowable pressure drop is limited

- where other type of more accurate devices are required. Like mass flowmeters for custody transfers, etc.

13.1.1 Flow measurement shall be normally carried out using thin,square edge, concentric orifice plate mounted between a pair of weld neckflanges of minimum 300# rating, for line size 2" and above.

13.1.2 Flange taps shall be used for line sizes up to 12. D-D/2 taps shall be usedfor line sizes 14" and above. For line sizes 1 and below and for conical


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entrance orifices, corner taps shall be used. (In case of fouling of tappingpoints w.r.t. to welding of flanges, flange tapings are to be used)

13.1.3 The material of the orifice plates shall be normally SS 316, as a min.Flange, gaskets, bolts & nuts material shall be as per the relevant Pipingspecifications.

13.1.4 Quadrant edge or quarter circle orifice plates shall be used for highlyviscous fluids for pipe Reynolds number below 10,000. The Beta Ratio forthese plates shall not exceed 0.6.

13.1.5 Conical entrance type of orifice plates shall preferably be used for highlyviscous fluid up to throat Reynolds number of 250. These shall befabricated as per BS1042 part I. The Beta Ratio for these plates shall notexceed 0.3.

13.1.6 Eccentric orifice plates shall be used for fluids containing two phases.Eccentric orifice plates shall have bottom of the orifice bore flush with thebottom I.D. of the pipe. Eccentric or segmental orifice plates shall be usedin horizontal run only.

13.1.7 Vent and drain hole shall be provided for orifices where bore diameter ismore than 25 mm

13.1.8 Plate dimensions and machining tolerances shall be as per BS 1042 andSizing of orifice plates shall be carried out in accordance with ISO 5167.

13.1.9 Honed metering runs in accordance with AGA tolerances or integral orificetype transmitter shall be used in lines with 1 (40 mm) nominal diameter.

13.1.10 Integral flow assembly shall be supplied as an integral assembly consistingof upstream and downstream straight pipes, integral orifice of 316L SS (asa minimum) installed along with manifold and SMART , 2 wire 24 V DC , DPtransmitters. End flanges shall be as per piping specifications. Upstreamand downstream pipes shall be honed from inside to achieve smoothsurface. Integral orifice meters, when used, shall be installed with block andbypass valves.

13.1.11 Upstream and downstream straight length shall be provided based onmaximum d/D ratio of 0.75, in general. Where it is difficult to meet thisrequirement, the actual d/D can be considered for reducing the straightlength as permitted by ' recommended practice shall be as per API-MPMSRecommended Practices and AGA Report No.3. The piping layout, wherepossible, shall be arranged such that straightening vanes are not required.

13.1.12 Orifice plates shall be installed on horizontal lines when practical. Verticalmeter runs may be used for down flow of vapor and up flow of liquids.

13.1.13 Meter taps shall be horizontal for liquids, condensable vapors and steam.The tap shall be on top for gas, non-condensable vapor, or liquids, whichboils at maximum design ambient temperature at operating pressure.

13.1.14 Where piping clearance are a factor, taps may be located up to 45 belowthe horizontal centre line for liquid and up to 45 above the horizontal centre

line for condensable vapor and may be located up to 60 from vertical forgas and non condensable vapor.

13.1.15 Each orifice plate shall be provided with a tab that is clearly visible inposition. The tab will be stamped, or deep engraved, on the upstream withthe tag number, orifice plate material, measured bore, I.D. of the pipe,flange size and rating. The tab shall also be in line with the Drain or Venthole and shall indicate the direction of flow

13.1.16 Flanges shall be as per ANSI B16.36 and shall generally be of weld-neck


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type only. Irrespective of pressure, the minimum flange rating shall be ANSI300#.

13.1.17 Flanges larger than 3" shall have a pair of jack-screws. The mating flangedshall be aligned in such a way that jack-screws will be diametricallyopposite.

13.1.18 Orifice flanges used at pressure ratings up to 600 Ib. shall be tapped NPT(F) tap for 900 # above NPT(F). Orifice connections for Venacontracta taps or pipe taps socket with schedule/MOC as per pipingspecs.

13.1.19 The Meter Range flow shall be equal to the 1.5 times of normal flow or 1.3times of the maximum flow.

13.1.20 Differential ranges for all liquid flow meters shall not exceed 5000 mmwater. Typical ranges for gas, steam or vapor meters are as follows:

Static Pressure Diff. Range(in Kg/Cm2g) (in mmwc)

0.35 to 2.5 500-12002.6 to 6 1250-2500

Above 6 2500-5000

13.1.21 Where compressible fluids are measured using differential pressureproducing devices, the selected differential in mm of water shall bepreferably not numerically exceed 5.5 times the upstream static absolutepressure in kg/cm2 x 100.

13.1.22 Though it is preferable to select diameter ratio between 0.3 to 0.65, Thediameter ratio of orifice plates shall be as follows:

Type Beta Ratio

Corner Tap 0.23 to 0.8Flange Tap 0.2 to 0.75

13.1.23 Orifice bore with diameter less than 0.125 shall be avoided.13.1.24 Orifice plates with RTJ flange connections above 2 shall be supplied with

Carrier rings.

13.2 Ventur i Meters and Flow Nozzles:

Venturi meter & flow nozzles may be considered for gas/air flowmeasurement in large size pipes / ducts, where high accuracy is requiredwith less permanent pressure loss

For high velocity steam or similar fluid, flow nozzles may be used in placeof orifice plates to avoid problems due to erosion.

13.3 Averaging Pitot Tubes:

Averaging pilot tubes shall be considered for low pressure loss, highvelocity, large diameter lines and air ducts. This shall be installed on 1 size nozzle for small lines and 3 for large lines or lines with large velocity.


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The averaging pitot tube shall be of SS316 MOC as a minimum. It shall beretractable with ball valve arrangement and shall be provided with endsupports.

13.4 Variable Area Flow meters:

13.4.1 Variable Area Flow meters or Rota meters shall be as per ISA-RP 16.1.16.2, 16.3 16.5 and 16.6 and shall be used for viscous or corrosive servicesor where rangeability of required flow precludes the use of an orifice.

13.4.2 Metal tube rota meters shall be used for all fluids. The devices for indicatingor transmitting shall be magnetically coupled with float or extension.Magnetic coupling shall be glandless type.

13.4.3 The tube and flange be SS316 as a minimum. Flange connections shall beas per piping specifications. \Rota transmitter shall be 24 V DC, 2 wire, 4-20ma, SMART with local display type.

13.4.4 All the Rota transmitter shall be Weather proof to IP65.13.4.5 Glass tube rota meters shall be used for low pressure utility services for

local and where line size is 1-1/2" (40 mm) or less. Glass tube rotametersshall not be used if an outlet line is connected to a line or vessel containinghazardous or toxic fluid unless a check valve is installed at the downstreamside of rotameter.

13.4.6 Glass tube meters mechanically protected and (may only be used on non-hazardous fluid service up to temperatures of 130C, and on fluids alwaysabove freezing.

13.4.7 Linearity should be better than 5% for indication-only rotameters and betterthen 1% for rotameter transmitter. Accuracy shall be 2% (or better) of fullscale for general and metal tube rotameters.

13.4.8 Variable Area Flow meters (purge rotameters) fitted with a constant flowregulators shall only be used for fixed rate flows such as flushing orpurging.

13.4.9 For low cost measurement of high flow rates generally 2" and larger size, aby-pass rotameters shall be used.

13.5 Ultrasonic Flow Meters, Thermal Mass Flow meters, Turbine &Positive Displacement t ype Flow meters:

Multi Path (min 5 path) ultrasonic flow meter for gas flow measurementshall be used for high accuracy custody transfer application or for GTRparameter measurements.

13.6 Corio lis Mass Flow Meters:

13.6.1 Coriolis mass flow meter shall be used for high-rangeabilty, high-accuracyapplication requiring mass flow measurement or where plants input/outputfluid quantity is used for mass balance or custody transfer purpose. If massflow meter is not proven for the service, The Coriolis mass flow metersshall be used at all those locations, where fluid physical property will vary. If


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Mass flow meter is not proven for the service, Bidder may use highaccuracy Magnetic flow meter with GNFC approval.

13.6.2 The Coriolis mass flow meters shall be used for all density measurement13.6.3 As a standard, sensor tube material to be SS 316L (a minimum). Better

MOC shall be provided based on process fluid/service conditions.

13.6.4 Mass flow meters end connections shall be flanged and meter size shall beselected in such a way that pressure drop at max. flow / velocity shall beminimum.

13.6.5 Mass flow meters shall be 4 wire transmitters and supply shall be 110 V AConly.

13.6.6 All mass flow meters shall have accuracy of +/- 0.1% for both analog andpulse output. It shall be possible to freely configure density or flow outputover any of these two available output options.

13.6.7 All mass flow meters shall be weather proof to IP67 as per IEC529.13.6.8 Mass flow meters shall be supplied with Remote mount, SMART transmitter

with 4-20 ma output and pulse+RS485 outputs. The sensor/transmittercable shall be min. 15 meter long, laid in protective conduit. All mass flowmeters shall be suitable for 2 pipe mounting and shall be supplied withLocal LCD type display. All mounting bracket MOC shall be SS304.

13.6.9 While selecting mass flow meters, consideration shall be given to fluidvelocity max. limit ( 2 meter /second for liquids), pressure loss, etc.

13.7 Magnetic Flow Meters:

13.7.1 Magnetic type flow meters shall be used for electrically conductive slurry,cooling water or corrosive services and shall be installed with line sizebypass, with block and cleaning valves, at the lowest point in piping toensure that meter run is always liquid filled.

13.7.2 Grounding ring or ground electrode shall be used in all the magnetic flowmeters.

13.7.3 If the electrical conductivity is equal to or more than 20 micro siemens/cmmost of the conventional magnetic flow meter can be used. While selectingmeter, effect of temperature on conductivity shall be considered.

13.7.4 Magnetic flow meter size shall be selected so that the measurement isaccurate.

13.7.5 Magnetic flow meters shall be installed with required straight lengths.13.7.6 All magnetic flow meters shall be 4 wire transmitters. The power supply

shall be 110 V AC.13.7.7 All Magnetic flow meters shall be supplied with Remote mount, SMART

transmitter with 4-20 ma output and pulse output. The sensor/transmittercable shall be min. 15 meter long, laid in protective conduit. All magneticflow meters shall be suitable for 2 pipe mounting and shall be supplied with

Local LCD type display.13.7.8 All the magnetic flow meters assembly shall be weather proof to IP67. All

mounting bracket MOC shall be SS304. Flow tube and flange MOC shall beSS316L

13.7.9 The end connections shall be flanged type and min. pressure rating forflanges shall be as per pipe class.

13.8 Vortex Flow Meters:


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13.8.1 Vortex flow meters shall be considered for following applications

- Where higher rangeability is required- Where high accuracy is required

- Where no maintenance spare is expected- Where process is a clean service- Where mechanical vibrations are not existent in pipe and sufficient straight length

can be provided.

13.8.2 Size the meter so that its maximum permitted flow rate is as close aspossible application maximum flow rate.

13.8.3 Vortex flow meter shall not be used for the following services:

- High viscous and slurry service- Liquids having large concentration of solids and two phase flow service.

13.8.4 Vortex flow meters shall be installed with required straight lengths.13.8.5 All Vortex flow meters shall be 4 wire transmitters. The power supply shall

be 110 V AC.13.8.6 Vortex flow meters shall be supplied with Remote mount, SMART

transmitter with 4-20 ma output and pulse output. The sensor/transmittercable shall be min. 15 meter long, laid in protective conduit. All vortex flowmeters shall be suitable for 2 pipe mounting and shall be supplied withLocal LCD type display.

13.8.7 Wetted part MOC shall be suitable for process fluid / temperature.13.8.8 All the Vortex flow meters assembly shall be weather proof to IP67. All

mounting bracket MOC shall be SS304.

14. Level Measurement:

14.1 Level Gauge:

14.1.1 The Level gauge shall provide visible coverage of complete leveltransmitter / controller range and the alarm/ trip level switches. In the caseof diff. pressure level transmitters where large spans are involved, a gaugelocated at the top, centre and bottom of the installation with overlap invisible area shall be acceptable.

14.1.2 All gauges glasses shall be steel armored reflex or transparent type withbody & cover material of forged carbon steel as a minimum and shall havemechanical & thermal shock resistant type toughened borosilicate glass

with suitable gaskets. Bolting shall be of SAE 4140 steel.14.1.3 Transparent type of gauges shall be provided with internal illuminators

operating at 240 V 50 Hz supply and suitable for electrical area classspecified. Illuminator shall be of the plastic solid wedge type designed togive an even diffusion of light over the entire length of the gauge glass. Allgauge glasses must have a rating equal to or more than the vessel designpressure and temperature and shall be provided with suitable metal guard.Reflex type shall be used for clean and colorless liquids like water and


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hydrocarbon service, except liquids interlace level.14.1.4 For low temperature, low boiling point services, large chamber type will be

used. Transparent type will be used for light fluids, acids, caustic, dirty orviscous liquids, coloured liquids and liquids interface level. Transparenttype with Mica or Kel-F shields shall be used for treated water, boiler and

condensate services and for corrosive liquids which will attack glass.Tubular gauge glasses shall, in general, not be used. They may be used fornon-hazardous services at ambient temperature and low .pressures.

14.1.5 AlI gauges shall have top and bottom chamber connections, unlessotherwise specified. Vent and Drain valves shall be fitted, as applicable.Vent and drain valve shall be provided with nipple and end caps. Drain andvent shall be of welded construction. Level gauges with side-sideconnections shall be avoided. Each gauge shall be provided with ball checkvalves & pipe union.

14.1.6 Large chamber gauges with frost shields shall be provided for coldservices, below 0C. Frost shield shall be transparent plastic type coveringfull width of vision slot and suitably sealed to the glass.

Depth of Block Design Temperature

38 mm above-19 C75 mm -20C to -49C150 mm -50C to -99C200 mm below-100C

14.1.7 Heating jacket shall be provided for viscous liquids.

14.1.8 The minimum readable liquid level from bottom tangent line for level gaugewith top and bottom connections and when both the nozzles are from theside shall be 300 mm with/without standpipe.

14.1.9 In general, the visible length of the level gauges shall be selected from thefollowing.

Visible length (mm) Centre to Centre Length (mm)

220 470470 720720 970980 1230

14.1.10 The maximum visibility length shall not exceed 1500 mm for a single gauge.Multiple gauges with overlapping range shall be used for such cases. For agiven section, the visible length shall not be less than 90% of the totallength of section.

14.1.11 Float operated magnetically coupled gauges with 2" (50 mm) flanged endconnections shall be used, for level gauging in very viscous liquids, liquidswith crystals, sour services, toxic services and shall be of Bi-Color rollingcylinders/Balls.

14.1.12 Bi-color type level gauges shall be used on steam drums. Larger chamber


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gauge glasses and an expansion loop between the top of the gauge andthe top gauge valve shall be used. Level gauges on steam / boiler drumsshall be in accordance with the latest requirements of the IBR code.

14.2 Level Transmitters:

14.2.1 Displacer type instruments shall be used with displacer length varying from350 mm to 1500 mm. for interface level measurement. In general, remoteseal type DP transmitters shall be used for level measuring application. Forcondensable services, simple DP transmitter shall not be used with lagfilling. It shall be remote seal type DP transmitters only.

14.2.2 External displacer type instruments with side-side connections androtatable head shall be normally used for level measurement up to 1500mm. Side-bottom are preferred when RTJ connections are required.Internal displacer type of level transmitter shall not be used.

14.2.3 The process connection shall be 2 size.14.2.4 Displacer type level transmitter shall be 2-wire, 24 VDC, 4-20 mA output

with LCD type local display.14.2.5 The displacer type level transmitters shall be of LVDT / RVDT or strain

gauge type and the torque tube material of inconel, as a minimum.14.2.6 All displacer type level transmitters shall be weatherproof to IP67 to

IEC529. Transmitter shall have remote mount facilities as an option, in caseof excess heat in the surrounding area.

14.2.7 Transmitters shall have NPT(F) electrical cable entry.14.2.8 The standard materials for Displacer and displacer chamber shall be SS316

and Torque tube shall be Inconel, as a minimum. Based on process fluidbetter options shall be selected.

14.2.9 Finned torque tube extensions shall be provided as necessary fortemperature service conditions.

14.2.10 Differential pressure transmitter shall be used for level measurement above1500 mm for services requiring purge or where liquid might boil in externalportion. DP transmitters with lag filling mechanism shall not be acceptable.

14.2.11 Differential pressure transmitters for use on corrosive, condensable orfouling service shall be diaphragm wafer with extended filled capillary type.The length of capillary shall be 5 mtr. with SS armored in PVC sheath.

14.2.12 The process connection size shall be 2 Flanged for remote seal diaphragmtype Level Transmitters. All remote seal type instruments shall be suppliedwith calibration ring with two blind plug/needle valves.

14.2.13 Flush or extended diaphragm type differential pressure transmitter shall beconsidered for special applications only. Transmitters for closed vesselshall have correction for suppression or elevation.

14.2.14 Dip Tube type level transmitters may be used on corrosive, congealing,slurry services, where suitable diaphragm seal type transmitter is difficult toobtain or where accuracy is not of prime importance.

14.3 Level Switch:

14.3.1 Level switches shall generally be external ball float type with flanged head.14.3.2 External displacer type level switches can be considered for lighter fluids

where specific gravity is less than 0.5. Internal float / displacer type level


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switches shall only be used if external type is not possible, like in viscousservices and in underground tanks / vessels.

14.3.3 The low-level switch shall be mounted directly on the column when the setpoint is not less than 630mm. When level gauge and level switch are on thesame stand pipe, minimum allowable low level set point shall be 480mm on

the column.14.3.4 Tuning fork, capacitance, or displacer type level switch may be used basedon application.

14.3.5 For all type of level switches, the micro-switches shall be hermeticallysealed, snap acting, with 24 V DC/2 Amps contact ratings with gold platedcontacts. Level switches with reed switch shall not be used.

14.3.6 For all type of Level switches, there shall be a SPDT with 2 NO/NCcontacts with adjustable differential.

14.3.7 For all type of level switches as specified above, the process connectionshall be flanged type and the flange size shall be 2 .

14.4 Tank Level Instruments:

14.4.1 There shall be NO Mechanical float type gauges, Servo controlled levelgauges or Ultra Sonic type level transmitters/switches for any of the levelmeasurement/trip/alarm application. For all type of tank level instruments, a2 wire RADAR instrument shall be used. Measurement accuracy shall be+/- 5mm or better for these RADAR type level instruments. Also, wheremore than 2 level instruments are used on same location, one of them shallbe RADAR type.

14.4.2 All RADAR type instruments shall have Flanged process connections andmin. nozzle height for process connection shall be 150mm.

14.4.3 Irrespective of pressure rating, the minimum pressure rating for RADARflange shall be min. 3 ANSI. Flange MOC shall be same as that of wettedparts.

14.4.4 RADAR type transmitter shall be standard 2 wire, 24 V DC, 4-20 ma,SMART with HART protocol type with Local LCD display and with RODtype antenna only.

14.4.5 Flange and wetted part MOC for RADAR and flange shall be min.SS316/PTFE coated or better to suite process fluid/temperature.

14.4.6 Wherever, the range can not be covered with 2 wire, 24 V DC type RADAR,a 4 wire transmitter with 110 V AC supply may be used. However, theRADAR transmitter shall be SMART with all other specifications same asabove.

14.4.7 All RADAR type level transmitters shall be weatherproof to IP67 as perIEC529.

14.4.8 RADAR shall be with various software features like empty tank spectrum,dynamic error corrections, false echo filtering, Programmable range from 0-100%, throughout out the tank height, SPAN/ZERO elevation/suppression,programmable blocking window distance, etc.

14.4.9 For solid level measurement, type of instrument shall be RADAR only.14.4.10 Standpipe shall be used for clean, non-viscous and non-crystallizing service

if more than 4 nozzles are required for level instruments, e.g. one displacerinstrument and one level gauge can be mounted directly on the equipment.The size of Standpipe shall be 3" NB minimum and shall have valves at the


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instrument connections. Taping size on vessel for stand pipe shall be 2 asa minimum.

14.4.11 Trip level switches should be directly mounted on vessel/column and notwith the standpipes.

14.4.12 Connection of standpipe from the bottom of vessel must be avoided.

14.4.13 On horizontal vessels with boot, a separate standpipe shall be used forboot interface level measurement in addition to standpipe used forhorizontal vessel.

14.4.14 Level co-ordination sketches shall be produced showing all pertinent detailsincluding nozzle locations, alarm levels, controlled level zones, shutdownlevel, interface line, etc.

14.4.15 All displacer and float type instruments shall have provisions for on-sitecalibration simulation check.

15 Pressure/Diff. pressure measurement:

15.1 Pressure & Differential Pressure Transmit ters:

In addition to the general field transmitters specified in Section 4.0, the followingminimum guide lines shall be followed for all the temperature transmitters used throughout in the project, including the package unit instruments.

15.1.1 All the field transmitters for flow, pressure, differential pressure and levelapplications shall be yoke mounted, 2 wire, 24 V DC, 4-20 ma dc, SMARTwith HART protocol.

15.1.2 All these transmitters shall be weatherproof to IP67 as per IEC529.15.1.3 The min. loop load shall be 600 ohm for 4-20 ma output circuit of

transmitters. Transmitters shall be able to work between 12 to 35 V DC with600 ohm loop impedance.

15.1.4 Transmitter lower housing shall be of SS316 unless otherwise specified.The upper housing of transmitter shall be of die cast aluminum with Epoxypaint as a minimum.

15.1.5 Pressure/ Differential Pressure Transmitter shall have electroniccapacitance, silicon resonant wire, piezo crystal or any other type of provensensor technology meeting all functional specifications. Inductive typemeasuring principle is not acceptable.

15.1.6 Diaphragm, Element material for transmitter shall be SS316L as a minimumfor and shall be able to withstand over pressure of at least 1.5 times themaximum working pressure. Other wetted part MOC shall be selectedbased on process requirement.

15.1.7 All remote seal diaphragm type pressure/diff. pressure transmitters shallhave 2 Flanged diaphragm as process connection. For very low rangepressure/diff. pressure measurement application, diaphragm size shall be3 ANSI.

15.1.8 The transmitter shall be so constructed that in case of a pressure sensingdiaphragm /element failure, the process material will not enter the electronicportion of transmitter or wiring conduits

15.1.9 Transmitters shall be provided with external zero adjustment and shall haveintegral vent/drain.


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15.1.10 All the transmitters shall be quipped with Local LCD type digital indicatorcapable of indicating engineering unit display.

15.1.11 The transmitter shall be microprocessor based and it shall incorporate anon-volatile memory, which shall store complete configuration data oftransmitter. All necessary signal conversions, including conversion to

produce output with the required protocol shall be carried out in thetransmitter electronics. The design of electronic parts shall be incompliance with the electromagnetic compatibility requirements as per IEC801

15.1.12 Transmitter shall also run complete diagnostic routine. In the event ofdetection of failure, the output shall be driven to predefined value, whichcould be either minimum (4 ma) , maximum(20 ma) or last good value. Thisfeature shall be programmable.

15.1.13 Built in temperature sensors shall be provided to compensate for processtemperature and ambient temperature variations.

15.1.14 Transmitter rangeability shall be 100:1. The transmitter shall be able toassure an accuracy of +/- 0.1% of span for a rangeability of 1:30. Theaccuracy shall include the combined effect of linearity, hysterisis andrepeatability. Effect ofstatic pressure on the transmitter in either directionshall be negligible.

15.1.15 Care shall be taken while selecting the transmitter models that there shallbe minimum type of diff. models of the same category of transmitters toreduce spare/inventory.

15.1.16 Transmitter shall be selected so as to have calibrated range withinturndown ratio of 1:10. The normal pressure shall be read at no greaterthan 75 percent of the calibrated range for transmitter reading steadypressures. For fluctuating services the normal pressure shall be read at 60percent of the range.

15.1.17 In case of differential pressure transmitter with remote seals, adequate careshall be taken to consider head pressure effect of capillary fill fluid whileselecting the transmitter.

15.1.18 The response time of smart transmitters shall commensurate with process.It shall be equal or better than the half of the total scan time of any criticalloops for process requirement like anti surge controllers. In any case, thisshall not be less than 30 updates per second.

15.1.19 HART protocol of latest version shall be used and shall be suitable forHART maintenance system with corner stone or AMS like software with thefollowing features as minimum:

o It shall allow multi masters (two for example, primary and secondary) forconfiguration, calibration, diagnosis and maintenance.

o The primary could be control system or host computer and the secondarycould be the hand held communicator or a maintenance computer.

o It shall be capable of implementing universal commands. It must bepossible to communicate all the commands of HART maintenance systemto field transmitter and smart transmitters shall be selected accordingly.

15.1.20 Unless recommended otherwise by compressor manufacturer, fieldtransmitters used in anti-surge control loop shall be non-smart andweatherproof types with IP67 protection.

15.1.21 The transmitters shall have their calibration adjustment from out side


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without any need to remove the cover of electronic enclosure.15.1.22 Retrofit type SMART transmitters are not acceptable. The model selected

shall be the latest from the vendors product range and proven in the fieldfor minimum of 1 year of operation.

15.1.23 For hydrogen gas service transmitters, Hastelloy wetted parts shall not

used to avoid damage due to hydrogen ion permeability. It shall be SS316Lonly.15.1.24 Process connection for standard pressure & differentia! pressure

transmitter shall be NPT(F) and 2 " flanged for diaphragm seal type.15.1.25 Diaphragm seal element with capillary shall be used for congealing,

corrosive and highly viscous services at high operating temperatures. Filledfluid shall be capable of withstanding the processtemperature/pressure/fluid.

15.1.26 Capillary shall be SS armored with PVC cover and 5 meter in length. Its IDshall be selected to have minimum lag.

15.1.27 For all the diaphragm type pressure and diff. pressure transmitters, aFlushing rings with MOC suitable to process conditions, shall be providedwith screwed vent & drain connections duly plugged.

15.1.28 All transmitters shall be provided with integral two valves / three valves /five valves manifold as per the specific requirements. MOC of manifoldsshall be same as those of wetted parts.

15.1.29 Oxygen service pressure/diff. pressure transmitters shall be supplied withspecial inert fluids (including diaphragm type with remote seal and capillary)and shall be free from grease/oil. These shall be clearly marked with Foruse in Oxygen services.

15.1.30 Design materials, connections and accessories not specified herein shall bein accordance with the vendor's standards, suitable for the specified serviceconditions.

15.2 Pressure Gauges & Diff. Pressure Indicators:

15.2.1 Gauges shall conform to the requirements of BS 1780 gauges of the elasticelement type, unless-otherwise specified.

15.2.2 All the Pressure gauges dial shall be white, non-glaring and non-rustingplastic with black figures. Dial size shall be 150 mm. Dial cover shall be ofshatterproof glass. The dial face shall be marked with pressure elementmaterial. Pointers shall have micrometer adjustment. Pressure gauges shallhave feature like screwed bezels, externally adjustable zero, over rangeprotection and blowout disc.

15.2.3 Pressure gauge sensing element shall be of SS 316 and movement of SS304, as a minimum except where the process requires a special material.For general use gauges shall use a bourdon tube as measuring element.The movement shall be either rotary geared or cam and roller type. Themovement mounting shall be integral with the bourdon tube socket.

15.2.4 For low pressure and vacuum services pressure gauges with capsulesensing element to be used.

15.2.5 The elastic element material, unless specified otherwise, shall be asfollows:


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- For ranges 60 kg/cm2 g and less, AISI-316 seamless drawn stainlesssteel tube, argon arc welded at AISI-316 forged or wrought stain less steeltube anchorage and tube end piece.- For ranges above 60 kg/cm2 g, AISI-316 bored stainless steel otherwiseas above.

15.2.6 All pressure gauges and diff. pressure gauges Cases shall normally be of304SS and weatherproof to IP-65 as per IEC-529 / IS-2147.

15.2.7 Safety blow out discs shall be provided for all gauges and shall be locatedin the back or side of the case. For pressure gauges with maximumoperating pressure below 60 Kg/cm2g, the minimum size of blow out discshall be 1" and for maximum operating pressure of 60 Kg/Cm2 and above,pressure gauge shall be safety type with solid front where pointer andgauges are partitioned from the sensor by a solid disc of 316SS material.

15.2.8 Pressure gauges shall have an accuracy of 1% of full scale as aminimum. Differential pressure gauges may have an accuracy of 2 % of fullscale.

15.2.9 Gauges shall be able to withstand, over-range pressure of 1.3 times thecalibrated range for at least 30 minutes as standard without zero orcalibration shift.

15.2.10 Over-range protection such as gauge savers shall be provided where theprocess pressures may exceed 1.3 x full scale deflection. Gauge savers ifprovided shall be of non bleed type with internal pressure release/block.

15.2.11 Ranges shall be so specified that the gauge normally operates in themiddle third of the scale and shall conform to IS-3624 standard dials,wherever possible.

15.2.12 Process connection shall normally be 1/2" NPT(M) bottom, except fordiaphragm seal where 2flanged connection shall be used in general.

15.2.13 Connection ( including flange MOC) shall normally be 316SS unlessotherwise the special material is required.

15.2.14 Socket stem shall extend a minimum of 1 beyond gauge case and shallbe provided with wrench flats.

15.2.15 Diaphragm seals, filled type shall be furnished where plugging of theelement may occur or where suitable material is not available in highlycorrosive services. When chemical seals are required, they shall beprovided with fabricated vent and drain arrangement. Diaphragm sealdevice shall be furnished completely assembled with the pressure gauge.

15.2.16 Remote seal Diaphragm type pressure gauges with capillary shall be usedwherever required for access and visibility. Use of Schaffer diaphragm typegauges will be avoided as far as possible.

15.2.17 The diaphragm seal devices shall be stainless steel SS316. The MOC forthe flanges, rings and top housings shall be of SS304, unless a specialmaterial is required.

15.2.18 Liquid filled gauge shall be used where extreme vibration of the gauge isexpected. Glycerin or other suitable case filling liquid with non coloringproperty shall be used.

15.2.19 An inert liquid shall fill the entire system between the diaphragm of thediaphragm seal device and the elastic element. Unless otherwise specified,filling liquid shall be suitable for an ambient temperature range of -18C to204C.


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15.2.20 Oxygen service pressure/diff. pressure gauges shall be supplied withspecial inert fluids and shall be free from grease/oil. These shall be clearlymarked with For use in Oxygen services.

15.2.21 Receiver pressure gauges for local/ local panel or those of electro-pneumatic positioners input/output indication shall have 100 mm dial with

stainless steel element and 1/4" NPTM back side connection.15.2.22 Pneumatic indicating receiver gauges shall conform to the applicable partsof this specification except as follows:- Elastic elements shall be SS designed for a 0.2 to 1 kg/cm2 g (3 to15psig) pressure range, but shall be able to withstand 1.4 kg/cm2 g (22psig).- Dials shall be graduated for the range specified on the data sheet, with anadditional scale graduated 0.2 to 1 kg/cm2 g (3 to 15 psig) linear.- The dial range shall correspond to the 0.2 to 1 kg/cm2g (3 to 15 psig)element range in the data sheet specified. (For example, when the rangespecified is 0-100, the "0" marking on the dial shall correspond to 0.2kg/cm2 g (3 psig) and the "100" marking to 1 kq/cm2 g (15 psig).

15.2.23 Over range protector and pulsation dampener, whenever used, shall be ofSS 316 as a minimum. Pulsation dampener shall be used for all pulsatingservices. It shall be floating pin type, externally mounted and externallyadjustable.

15.2.24 Gauge savers shall be used in all pump service applications.15.2.25 Pig tail siphons with SS304 MOC shall be provided for steam applications

unless liquid filled impulse line is used.15.2.26 All type of Gauges shall be supplied with engraved labels stating tag no.15.2.27 Design materials, connections and accessories not specified herein

shall be in accordance with the Vendor's standards, suitable for thespecified service conditions.

15.3 Pressure & Differential Pressure Switches:

Generally pressure and diff. pressure switches shall be used only for alarm purpose andshall be connected with DCS. Generally, all interlocks/logic shall be realized via 2 wire,24 V DC, SMART pressure/diff. pressure transmitters connected to DCS for pressure,diff. pressure and level application.

15.3.1 However, in special case, when required by machine vendors for machinesafety, for few critical applications, use of pressure and diff. pressureswitches shall be allowed with due justifications.

15.3.2 All the Pressure/Diff. pressure switches shall have either diaphragm orbellow type of primary element with SS316 material of construction as aminimum. Switch shall be hermetically sealed, snap acting micro switchwith SPDT contacts.

15.3.3 The contact rating shall be 230 V AC/ 2 amp or 24 V DC/2 Amp as aminimum.

15.3.4 The switch mechanism shall be designed to prevent spurious operation byvibration.

15.3.5 Pressure/DP switch design with Reed type switches shall not be selected.


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15.3.6 The primary element and the diaphragm shall be made of 18 Cr/8 Ni.Stainless steel, unless otherwise specified.

15.3.7 Receiver pressure switches shall have SS316 bellows as primary elementwith NPT (F) connection.

15.3.8 The primary element shall be designed to withstand an over-range pressure

of 25% greater than the full scale.15.3.9 Pressure switches shall be provided with a positive means of protectionagainst process fluids entering the electrical housing in the event ofelement failure.

15.3.10 Pressure switches shall be blind type with NPT (F) process connectionand shall be operative in full specified range. The switch differential shall beselected as per operating conditions; it shall be less than 60% of differencebetween set value and operating value.

15.3.11 Diaphragm seal type pressure switches with flanged end connections shallbe specified for applications on corrosive / congealing services. In all thesecase, the diaphragm flange size shall be min. 2 x 300 # ANSI ratings andMOC shall be SS316 for flange and MOC. Better MOC shall be optedbased on process requirement.

15.3.12 All diaphragm type pressure / diff. pressure switches with flushingconnection. Diaphragm seal device shall be furnished completelyassembled with the pressure switch.

15.3.13 Pressure switches shall have repeatability of 0.5% of full scale as aminimum.

15.3.14 The switching set point shall be adjustable over the whole range, with aninternally calibrated scale.

15.3.15 Switches shall be specified such that the on/off differential does not preventthe switch resetting inside normal operating pressure ranges.

15.3.16 Over range protection and pulsation dampener requirements and designshall be as per as specified above.

15.3.17 Design materials, connections and accessories not specifiedherein shall be in accordance with the vendor's standards, suitable forthe specified service conditions.

16 Temperature Measurement:

16.1 General16.1.1 All temperature measurement in the plant shall be carried out using only

Thermocouple or RTD elements. No local temperature gauges shall beused throughout the project or any part thereof, including package unitinstruments.

16.1.2 All open loop/closed loop temperature shall be carried with

Thermocouple/RTD elements and field mountable 2 wire SMARTtemperature transmitters. Hence in DCS, there shall not be any RTD or T/Cinput cards.

16.1.3 All open/closed loop temperature measurement shall be carried out with thehelp of Thermocouple / RTD elements along with field mounted ,2 wire, 24V DC, 4-20 ma, SMART temperature transmitters. No head mountedtransmitters shall be used throughout the project or any part thereof,including package unit inst ruments.


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