SECTION-II GENERAL INSTRUMENTS SPECIFICAITONS 6.3-(INSTRU)-PRO6... · SECTION-II . GENERAL INSTRUMENTS SPECIFICAITONS . ... Owner’s approved vendor list shall be followed strictly

PAC PROJECT INSTRUMENTATION SPECIFICATIONS

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SECTION-II

GENERAL INSTRUMENTS SPECIFICAITONS


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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 15 9 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 23 13.6 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 in general. The specific design requirements for each type of instrument or instrument system are covered by the individual specification of that particular item/category. Any conflict between the requirements of this specification and related codes, standards, data sheets, drawings, requisition, etc., shall be referred to the OWNER for clarification. Owner’s approved vendor list shall be followed strictly for procurement of various instruments. 2.0 CODES AND STANDARDS The various applicable codes and standards are as mentioned below. In case of any conflicts / discrepancies in general instrument specifications and individual items’ specifications, the most stringent conditions shall apply based on the following standards. However, in all such cases, before taking any decision, BIDDER shall get formal approved of data/specification sheets from OWNER. The following standards shall be followed as a minimum during basic and detail engineering 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 Fittings 4. ANSI/ISA S18.1 Annunciator Sequences and Specifications 5. ANSI/ASME PTC 19.3 Pt 3: Power Test Code. Thermowell strength

Calculations 6. 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: Installation 9. 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 European

Community. 16. 97/23/EC Pressure Equipment Directive 17. 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 for Distance Sensor and Signal Converter.

20. DIN V19250 Measurement and Control Fundamental Safety Aspects for Measuring 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 Gas Atmospheres.

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

Sensor/converters 25. 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 cables 29. 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 Fluid

Flow under Installed Conditions. Part 2: Flow Capacity: Section 2: Sizing Equations for Compressible Fluid

Flow under Installed Conditions. Part 8: Noise Considerations: Section 1: Laboratory Measurement of Noise Generated by Aerodynamic

Flow 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 and

Control 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/programmable

electronic safety related systems. 43. ISO 5167 Measurement of Fluid Flow by Means of Pressure Differential

Devices. 44. NACE MR0175 (95) Standard Material Requirements - Sulfide Stress

Cracking-resistant Metallic Materials for Oil field Equipment. 45. CCOE = Chief Controller of Explosions, India for

intrinsic 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/h Volumetric Flow = m³/h Steam Flow = kg/h or T/h Gas/Vapor Flow = Nm3/h Level Absolute = Absolute Meter or mm Level Relative = 0-100% in Direct range Pressure Gauge = Kg/cm2 –g / mmwc Pressure Absolute = Kg/cm2 -a Temperature = °C Analysis = % or PPM Viscosity = cP Conductivity = µ s/cm Density = Kg/m³ Velocity = m/s Impulse tube size = ½” or ¼” 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 display 4.1.2 All Switch function shall be snap acting, Single-pole Double Throw (SPDT),

hermetically sealed and potential-free gold plated contacts with 230 V AC/5 amp or 24 V DC/2 amp contact ratings.

4.1.3 The use of Foundation Field Bus/ PROFIBUS or any other cluster/Multiplexer type I/O philosophy shall not be allowed in project and any part thereof as an alternate to conventional 4-20 ma dc signal transmission 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 same service shall be equal.

4.1.7 Ranges used for measurement and control instrumentation shall overlap alarm 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” size Flange with diaphragm as process connection with calibration ring. However in case of measurement of vary low range pressure ( in the range of vacuum to mmwc pressure measurement), the diaphragm flange size shall be 3”

4.1.11 All displacer type level transmitters, externally mounted float/displacer type level 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 ½” flanged thermowells with min. flange rating of ANSI 300#.

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 and be with ½” NPT (F), SS 316 valves. From the nearby air manifold, instrument air shall be supplied to the control valves. For the purpose, all tubing shall be used shall be of SS316, ½” or ¼” OD, seamless tubes, laid in perforated FRP trays. All intermediate fittings shall be double compression, SS316 MOC, Swagelok make, double compression type only.


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4.1.14 Standardization features shall be taken care of during design and packages 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 control room 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 for commissioning and 2 years operation.

4.2 Signal Types & Transmission 4.2.1 Electric Signals

Electric signal transmission shall be applied in conjunction with electronic/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-wire

system) shall be applied as measuring inputs and controller outputs. - Where 2 wire system is not suitable, 4 wire transmitter with isolated 4-20 mA 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 a

current of 4 to 20 mA. DC, superimposed with digital communication protocol (HART). All interlock shall also be realized from 4-20 ma analog input transmitters in the DCS. No field switches shall be used for interlock purpose, except NAMUR type proximity sensors for valve positions switches for ON-OFF valves.

4.2.3 All signal exchange between field and central cabinet room shall be via individual hardwire pair of cable as specified in detailed cable specifications. From the field, all field transmitters shall be routed to field mounted junction boxes, from where these shall be taken to central cabinet room 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 multi pair cables shall be either 24 core or 12 pair only. Multi pair power cable shall also be 12 pair only.

4.2.4 To the extent possible, direct run cable from field instrument to central cabinet room shall not be employed. All the signals to the central cabinet room shall be routed through multi pair cables via field mounted junction boxes only.

4.2.5 Usage of Foundation Field bus / Profibus type clustered I/O wiring philosophy is not allowed at any location in the whole plant as an alternate to conventional 4-20 ma dc signal transmission.

4.2.6 Few dedicated, special type of cables from special control system may be directly 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 junction boxes/local panels to the central cabinet room shall be thru’ overhead perforated cable trays / MS cable duct with min. 3 mm thickness on the pipe racks. 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 power cables (e.g. 110 V AC for Solenoid valves, 110 V A.C. power supply cables to field instruments, etc.). On the trunk and branch route from main cable duct to field junction boxes and local panels, 300 mm(w) x 60mm (H)x3mm thick FRP perforated cable trays will be used. For other branch cables various sizes of perforated FRP cable trays shall be used with the following general specifications.

300 mm (W) x 60 mm(H) x 3 mm thick perforated FRP cable trays 200 mm (W) x 50 mm (H) x 3 mm thick perforated FRP cable trays 100 mm (W) x 50 mm (H) x 3 mm thick perforated FRP cable trays 50 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 GI

conduit preferable in overhead trays/duct only. 4.2.10 All type of single and multi pair power, control and signal cables in the field

shall be with GI armored only for mechanical protection, including fiber optic cables.

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

4.2.12 All fiber optic cables shall also be with armored only 4.2.13 All the cable exchange between the central cabinet room and field

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

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


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4.3 FIELD INSTRUMENTATION 4.3.1 Field instrument connections shall be as follows. Instrument Type

Piping/Vessel Connection

Instrumentation Connections

DP Flow Instruments

½” NPT

½” NPT

External Displacer (as per pipe class)

2" Flanged

2" Flanged

Internal Displacer (as per pipe class)

4" Flanged

4" Flanged

External Ball Float (as per pipe class)

2" Flanged

2" Flanged

Internal Ball Float (as per pipe class)

4” Flanged

4” flanged

Level Gauge (as per pipe class)

2” Flanged

2" Flanged

D/P Level

½” NPT

½” NPT

D/P Level with Remote Diaphragm Seal (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

½” NPT ½” NPT

Press. Gauge

½” NPT ½” NPT

Pressure with diaphragm seal (as per pipe class)

2" Flanged

2" Flanged

Thermowell (as per pipe class)

1 ½” Flanged on pipe and 2” flanged on equipment

1 ½” 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 accordance with EN 60423.

4.3.6 Standard instrument connection shall be ½” NPT female, except that pressure gauges and pressure switches shall have ½” NPT male connections. 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 ½” OD SS tubes. The thickness of impulse tube shall be 1.6 mm for ½” OD SS304 tubes and 1.0 mm for ¼” OD SS tubes, unless otherwise specified. These thickness shall be followed as standard minimum, except special case requirements for vary high pressure and temperature services. For steam services, it shall be ½” CS/IBR pipes (Min. SCH160).

4.3.8 For very low pressure measurement, the remote seal size PT/DPT size shall 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 ½” NPT (F) cable entry and either ½” 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 ½” 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 meter in length and it shall be either armored or shall be laid in PVC 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 standard

type. The instruments / equipment shall be purchased only from manufacturers with long-standing experience. The vendor list approved by OWNER shall be followed for the purpose. For items not covered in the vendor list, OWNER’s prior approval shall be taken.

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

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


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/ or chemicals may be present. All external surfaces shall be suitably treated to provide protection against corrosive plant atmosphere with epoxy painting / powder coating.

4.4.20 The design of electronic instruments shall be in compliance with the electromagnetic 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 the mating flanges on piping / equipment are of different materials (e.g. SS-316 thermowell on CS pipes). The contractor shall in such cases, ensure that the rating of flange is chosen for the instrument and the corresponding flange on piping / equipment.

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

4.4.23 Piping/Instrument scope change for instrumentation shall always be after first isolation/drain valve for all types of instruments, including local Pressure gauges.

4.4.24 Instrument impulse tube size shall be either ¼” or ½’ 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 with either 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 all open 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 thermowell along with nipple-union-nipple assly along with dual entry thermocouple head, certified to weatherproof to IP65 as a minimum. Thermowell shall be manufactured from drilled bar stock, tapered. MOC of thermo well shall be suitable to process fluid and pressure/temperature conditions. The cable entry shall be ½” NPT(F) and complete assembly shall be provided with SS MOC, double compression cable glands certified for weatherproof to IP65 with PVC hood.

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

4.4.32 All instruments / devices shall be immune to interference due to normal walkie-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 instrument and/or system, its required accuracy and repeatability, the maximum obtainable industrial accuracy and its repeatability.

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

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

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

b. ± 0.5% for all Vortex and Magnetic Flow meters c. ± 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 services f. ± 0.5% for Displacer type level transmitters. g. ±1.5 ‘C between −40 °C and 375 °C Max. for TC with Class-1 accuracy h. ±0.004×T ‘C between 375 °C and 1000 °C Max. for TC with Class-1 accuracy i. ±(0.15 + 0.002*t)°C or 100.00 ±0.06 at 0°C 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 transfer l. ± 5 mm for General Purpose RADAR type level transmitters m. ±5% for all Gas Detectors n. ±0.75% for Annubar/Averaging Pitot tube flow meters o. ±1.5% for Critical flow measurement by Orifice Plate p. ± 2% for General purpose flow measurement by Orifice Plate q. For mass flow meters:

± 0.1% for liquid flow. ± 0.1 kg/m³ on liquid/gas density.

r. ± 0.5% for Belt weighers and Bagging machines s. ± 5 kg for Weigh Bridges of a capacity up to 60 Ton and ± 10 kg for 100 ton t. ± 20 gms for Bagging machine of 25/50 Kg bag Note:-1 Hysteresis shall be maximum 0.1% of the range Note:- 2 All dp transmitters shall have minimum static pressure rating of 250 kg/cm². Note:- 3 Ambient temperature variation of 40 °C shall not change output signals by more 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 heavy rains/storms. Cable glands shall also be IP-65 to avoid ingress. All field instruments shall be damp-proof and dust-proof, minimum protection class as per IEC 529 shall be as follows: Electrical / Electronic instruments : IP 67 Sensors; RTD, T/C, etc. : IP 65 Local Gauges; PG, etc. : IP 55


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Pneumatic instruments : IP 54 Solenoid valves : IP 67 Local Panel / Skid Mounted Panels : IP 55 6.2 Electromagnetic Compatibility (EMC) The design of electronic instruments should be in compliance with the European Community (EC) harmonized codes and standards, which includes Radio Frequency Immunity (RFI) and EC 61000 electromagnetic Compatibility 6.3 Electrical Safety Generally, PAC plant process is classified as general purpose, safe area. Hence flameproof/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 for

transmission 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 of

instrument enclosures and breathing (safety) masks. 7.4 All control valve actuators shall be sized at max. 4.0 bar g instrument air

available at control valve. 7.5 All the air to instrument control valves and individual consumer shall be

routed thru’ 10 way instrument air headers form the field. Air manifold, instrument fittings, tubing and needle/ball valves shall be of SS316 MOC as a minimum.

7.6 There shall be instrument air buffer vessel to cater to requirement of whole plant 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 instrumentation

purposes only. 8.2 Field instruments which are loop powered shall be used. Field instruments

requiring a separate power supply shall be avoided. The loop powered transmitters shall be always 24 V DC, 2 wire, 4-20 mA DC signal type and HART 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 fed from central cabinet room located UPS PDB only.

8.4 All central cabinet room located instrument systems including DCS shall be 110 V AC UPS Power only.

8.5 All of above systems shall be capable of accepting dual redundant 110 V AC UPS feeders, which will be fed power form two diff. UPS feeders The feeders shall be connected to the UPS distribution boards in such a way that 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 each system vendor with dual redundant 24 V DC bulk power supply installed in separate 24 V DC PDB. The same shall be used for 24 V DC Solenoid Valves also.

9.0 Instrument Earthing 9.1 General 9.1.1 All equipment for electric transmission, including the enclosures as well as

the armoring, lead sheathing and screening of cables, shall be properly earthed for personnel safety reasons and to obtain the maximum possible rejection of interference.

9.1.2 Instruments and associated equipment requiring electricity with a potential to 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 protection against electric shock.)

9.1.3 Unintentional interconnections between the two systems are not allowed to occur.

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

9.2 General Earthing System

All metal enclosures housing instrument and/or instrument systems and all armoring of field cables shall be connected to the general earthing system. 9.3 Instrument Earthing System 9.3.1 The instrument earthing system consists of one or more earthing electrodes

close 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 array of parallel electrodes may be used.

9.3.3 The instrument earthing shall terminate in a copper bus, mounted centrally to all instrument equipment, but electrically isolated from any other equipment 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 wire conductor of at least 4 mm².

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 connected to the instrument earth system only at one side (in the control room/satellite building). The shielding shall be kept isolated from cable armoring and instrument enclosures.

10.0 Package Unit Instrumentation


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10.1 There shall not be any local control panels with proprietary or 3rd party 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 various machine 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 Owner’s 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, instrument list, Tag list, datasheets, sizing calculation sheets, etc.

11.0 Broad Specifications for Various type of Instruments power/signal and

control 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 OWNER’s 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 primary insulation 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, 1

sq. mm, white/black color, screened / armored/ FRLS cable, Outer Jacket color code: Grey for non-IS, Blue for IS. This shall be used for all 4-20 m amp. analog inputs/outputs signals.

b. Multi pair signal cable: ATC, Multi strand (Max 7 strands), 12 Pair, twisted pair 1 sq. mm, white/black color, individual and overall screened / armored/ FRLS cable, 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 shall not 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 AC power supply to field instruments, solenoid valves, etc. 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, 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 PDB from central cabinet room only).

d. 110 V AC Power cable – Multi Pair: - ATC, Multi strand (Max 7 strands), min. 1.5 sq. 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, via power 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 to maintain 110 V AC -2% & +1% at 50 Hz -3/+1 Hz at field devices (wired from centrally 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 supply to field Solenoid Valves, Field Lamps/Alarms, etc. as a minimum size. BIDDER to ensure correct size (cross section area) for various requirements to maintain minimum 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/FRLS cable, Outer Jacket Color code: Black for non-IS, Blue for IS. This shall be used for 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) for various requirements to maintain minimum 24 V DC at field device. Use of 6 pair/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 Color code: Black for non-IS, Blue for IS. This shall be used for all 24 V DC Digital input signals.

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 Color code: 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 to be wired up to Control room DCS/ESD, the specifications of 8 triad RTD cable is not 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 are required to be wired up to Control room DCS/ESD, the specifications for 12 pair T/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 output b. 24 V DC Digital Input / NAMUR sensors c. 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 way

that from the tag number of the particular junction box, it shall be evident to decide type of signal and destination

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

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

g. All junction boxes shall be weather proof to IP65 as a minimum. Generally 12 branch entries of ½” 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 code shall be based on type of signals. The qty. shall be as required.

i. Each junction box shall have engraved/embossed SS tag plate with tag number. 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 for following 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 flow

meters 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 neck flanges 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 used for line sizes 14" and above. For line sizes 1 ½” and below and for conical


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entrance orifices, corner taps shall be used. (In case of fouling of tapping points 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 Piping specifications.

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

13.1.5 Conical entrance type of orifice plates shall preferably be used for highly viscous fluid up to throat Reynolds number of 250. These shall be fabricated as per BS1042 part I. The Beta Ratio for these plates shall not exceed 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 the bottom I.D. of the pipe. Eccentric or segmental orifice plates shall be used in horizontal run only.

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

13.1.8 Plate dimensions and machining tolerances shall be as per BS 1042 and Sizing 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 orifice type transmitter shall be used in lines with 1 ½” (40 mm) nominal diameter.

13.1.10 Integral flow assembly shall be supplied as an integral assembly consisting of upstream and downstream straight pipes, integral orifice of 316L SS (as a minimum) installed along with manifold and SMART , 2 wire 24 V DC , DP transmitters. End flanges shall be as per piping specifications. Upstream and downstream pipes shall be honed from inside to achieve smooth surface. Integral orifice meters, when used, shall be installed with block and bypass valves.

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

13.1.12 Orifice plates shall be installed on horizontal lines when practical. Vertical meter 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, which boils at maximum design ambient temperature at operating pressure.

13.1.14 Where piping clearance are a factor, taps may be located up to 45” below the 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 for gas and non condensable vapor.

13.1.15 Each orifice plate shall be provided with a tab that is clearly visible in position. The tab will be stamped, or deep engraved, on the upstream with the 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 Vent hole 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 ANSI 300#.

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

13.1.18 Orifice flanges used at pressure ratings up to 600 Ib. shall be tapped ½” NPT(F) tap for 900 # above ¾” NPT(F). Orifice connections for Vena contracta taps or pipe taps ½” socket with schedule/MOC as per piping specs.

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

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

Static Pressure Diff. Range (in Kg/Cm2g) (in mmwc) 0.35 to 2.5 500-1200 2.6 to 6 1250-2500 Above 6 2500-5000 13.1.21 Where compressible fluids are measured using differential pressure

producing devices, the selected differential in mm of water shall be preferably not numerically exceed 5.5 times the upstream static absolute pressure in kg/cm2 x 100.

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

Type Beta Ratio Corner Tap 0.23 to 0.8 Flange 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 Venturi Meters and Flow Nozzles:

Venturi meter & flow nozzles may be considered for gas/air flow measurement in large size pipes / ducts, where high accuracy is required with less permanent pressure loss For high velocity steam or similar fluid, flow nozzles may be used in place of orifice plates to avoid problems due to erosion.

13.3 Averaging Pitot Tubes:

Averaging pilot tubes shall be considered for low pressure loss, high velocity, large diameter lines and air ducts. This shall be installed on 1 ½” 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 be retractable with ball valve arrangement and shall be provided with end supports.

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 services or 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 indicating or 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 be as per piping specifications. \Rota transmitter shall be 24 V DC, 2 wire, 4-20 ma, 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 rotameters shall not be used if an outlet line is connected to a line or vessel containing hazardous or toxic fluid unless a check valve is installed at the downstream side of rotameter.

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

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

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

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

13.5 Ultrasonic Flow Meters, Thermal Mass Flow meters, Turbine &

Positive Displacement type Flow meters:

Multi Path (min 5 path) ultrasonic flow meter for gas flow measurement shall be used for high accuracy custody transfer application or for GTR parameter measurements.

13.6 Coriolis Mass Flow Meters: 13.6.1 Coriolis mass flow meter shall be used for high-rangeabilty, high-accuracy

application requiring mass flow measurement or where plant’s input/output fluid quantity is used for mass balance or custody transfer purpose. If mass flow meter is not proven for the service, The Coriolis mass flow meters shall 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 high accuracy Magnetic flow meter with GNFC approval.

13.6.2 The Coriolis mass flow meters shall be used for all density measurement 13.6.3 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 be

selected in such a way that pressure drop at max. flow / velocity shall be minimum.

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

13.6.6 All mass flow meters shall have accuracy of +/- 0.1% for both analog and pulse output. It shall be possible to freely configure density or flow output over 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/transmitter cable shall be min. 15 meter long, laid in protective conduit. All mass flow meters shall be suitable for 2” pipe mounting and shall be supplied with Local LCD type display. All mounting bracket MOC shall be SS304.

13.6.9 While selecting mass flow meters, consideration shall be given to fluid velocity 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 size bypass, with block and cleaning valves, at the lowest point in piping to ensure that meter run is always liquid filled.

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

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

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

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/transmitter cable shall be min. 15 meter long, laid in protective conduit. All magnetic flow 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 be SS316L

13.7.9 The end connections shall be flanged type and min. pressure rating for flanges 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 as

possible 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/transmitter cable shall be min. 15 meter long, laid in protective conduit. All vortex flow meters shall be suitable for 2” pipe mounting and shall be supplied with Local 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 level

transmitter / controller range and the alarm/ trip level switches. In the case of diff. pressure level transmitters where large spans are involved, a gauge located at the top, centre and bottom of the installation with overlap in visible area shall be acceptable.

14.1.2 All gauges glasses shall be steel armored reflex or transparent type with body & cover material of forged carbon steel as a minimum and shall have mechanical & 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 class specified. Illuminator shall be of the plastic solid wedge type designed to give an even diffusion of light over the entire length of the gauge glass. All gauge glasses must have a rating equal to or more than the vessel design pressure 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 or viscous liquids, coloured liquids and liquids interface level. Transparent type 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 for non-hazardous services at ambient temperature and low .pressures.

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

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

Depth of Block Design Temperature 38 mm above-19 °C 75 mm -20°C to -49°C 150 mm -50°C to -99°C 200 mm below-100°C 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 gauge

with top and bottom connections and when both the nozzles are from the side shall be 300 mm with/without standpipe.

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

following. Visible length (mm) Centre to Centre Length (mm) 220 470 470 720 720 970 980 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 a given section, the visible length shall not be less than 90% of the total length of section.

14.1.11 Float operated magnetically coupled gauges with 2" (50 mm) flanged end connections shall be used, for level gauging in very viscous liquids, liquids with crystals, sour services, toxic services and shall be of Bi-Color rolling cylinders/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 and the top gauge valve shall be used. Level gauges on steam / boiler drums shall 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 from

350 mm to 1500 mm. for interface level measurement. In general, remote seal type DP transmitters shall be used for level measuring application. For condensable services, simple DP transmitter shall not be used with lag filling. It shall be remote seal type DP transmitters only.

14.2.2 External displacer type instruments with side-side connections and rotatable head shall be normally used for level measurement up to 1500 mm. 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 case of excess heat in the surrounding area.

14.2.7 Transmitters shall have ½” 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 fluid better options shall be selected.

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

14.2.10 Differential pressure transmitter shall be used for level measurement above 1500 mm for services requiring purge or where liquid might boil in external portion. DP transmitters with lag filling mechanism shall not be acceptable.

14.2.11 Differential pressure transmitters for use on corrosive, condensable or fouling 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 diaphragm type Level Transmitters. All remote seal type instruments shall be supplied with calibration ring with two blind plug/needle valves.

14.2.13 Flush or extended diaphragm type differential pressure transmitter shall be considered for special applications only. Transmitters for closed vessel shall 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 to obtain 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 viscous services and in underground tanks / vessels.

14.3.3 The low-level switch shall be mounted directly on the column when the set point is not less than 630mm. When level gauge and level switch are on the same 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 based on application.

14.3.5 For all type of level switches, the micro-switches shall be hermetically sealed, snap acting, with 24 V DC/2 Amps contact ratings with gold plated contacts. 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/NC contacts with adjustable differential.

14.3.7 For all type of level switches as specified above, the process connection shall 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 level

gauges or Ultra Sonic type level transmitters/switches for any of the level measurement/trip/alarm application. For all type of tank level instruments, a 2 wire RADAR instrument shall be used. Measurement accuracy shall be +/- 5mm or better for these RADAR type level instruments. Also, where more than 2 level instruments are used on same location, one of them shall be RADAR type.

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

14.4.3 Irrespective of pressure rating, the minimum pressure rating for RADAR flange shall be min. 3” ANSI. Flange MOC shall be same as that of wetted parts.

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 ROD type 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, the RADAR transmitter shall be SMART with all other specifications same as above.

14.4.7 All RADAR type level transmitters shall be weatherproof to IP67 as per IEC529.

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 displacer instrument 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” as a minimum.

14.4.11 Trip level switches should be directly mounted on vessel/column and not with 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 for

boot interface level measurement in addition to standpipe used for horizontal vessel.

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

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

15 Pressure/Diff. pressure measurement: 15.1 Pressure & Differential Pressure Transmitters: In addition to the general field transmitters specified in Section 4.0, the following minimum guide lines shall be followed for all the temperature transmitters used through out in the project, including the package unit instruments. 15.1.1 All the field transmitters for flow, pressure, differential pressure and level

applications shall be yoke mounted, 2 wire, 24 V DC, 4-20 ma dc, SMART with 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 with 600 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 Epoxy paint as a minimum.

15.1.5 Pressure/ Differential Pressure Transmitter shall have electronic capacitance, silicon resonant wire, piezo crystal or any other type of proven sensor technology meeting all functional specifications. Inductive type measuring principle is not acceptable.

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

15.1.7 All remote seal diaphragm type pressure/diff. pressure transmitters shall have 2” Flanged diaphragm as process connection. For very low range pressure/diff. pressure measurement application, diaphragm size shall be 3” ANSI.

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

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


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

15.1.11 The transmitter shall be microprocessor based and it shall incorporate a non-volatile memory, which shall store complete configuration data of transmitter. All necessary signal conversions, including conversion to produce output with the required protocol shall be carried out in the transmitter electronics. The design of electronic parts shall be in compliance with the electromagnetic compatibility requirements as per IEC 801

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

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

15.1.14 Transmitter rangeability shall be 100:1. The transmitter shall be able to assure an accuracy of +/- 0.1% of span for a rangeability of 1:30. The accuracy shall include the combined effect of linearity, hysterisis and repeatability. Effect of static pressure on the transmitter in either direction shall be negligible.

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

15.1.16 Transmitter shall be selected so as to have calibrated range within turndown ratio of 1:10. The normal pressure shall be read at no greater than 75 percent of the calibrated range for transmitter reading steady pressures. For fluctuating services the normal pressure shall be read at 60 percent of the range.

15.1.17 In case of differential pressure transmitter with remote seals, adequate care shall be taken to consider head pressure effect of capillary fill fluid while selecting 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 critical loops for process requirement like anti surge controllers. In any case, this shall not be less than 30 updates per second.

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

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

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

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

15.1.20 Unless recommended otherwise by compressor manufacturer, field

transmitters used in anti-surge control loop shall be non-smart and weatherproof 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 field for 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 SS316L only.

15.1.24 Process connection for standard pressure & differentia! pressure transmitter shall be ½” 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. Filled fluid shall be capable of withstanding the process temperature/pressure/fluid.

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

15.1.27 For all the diaphragm type pressure and diff. pressure transmitters, a Flushing rings with MOC suitable to process conditions, shall be provided with 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 manifolds shall be same as those of wetted parts.

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

15.1.30 Design materials, connections and accessories not specified herein shall be in accordance with the vendor's standards, suitable for the specified service conditions.

15.2 Pressure Gauges & Diff. Pressure Indicators:

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

15.2.2 All the Pressure gauges’ dial shall be white, non-glaring and non-rusting plastic with black figures. Dial size shall be 150 mm. Dial cover shall be of shatterproof glass. The dial face shall be marked with pressure element material. Pointers shall have micrometer adjustment. Pressure gauges shall have feature like screwed bezels, externally adjustable zero, over range protection and blowout disc.

15.2.3 Pressure gauge sensing element shall be of SS 316 and movement of SS 304, 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. The movement mounting shall be integral with the bourdon tube socket.

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

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


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

- For ranges above 60 kg/cm2 g, AISI-316 bored stainless steel otherwise as above.

15.2.6 All pressure gauges and diff. pressure gauges’ Cases shall normally be of

304SS 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 located

in the back or side of the case. For pressure gauges with maximum operating pressure below 60 Kg/cm2g, the minimum size of blow out disc shall be 1" and for maximum operating pressure of 60 Kg/Cm2 and above, pressure gauge shall be safety type with solid front where pointer and gauges 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 a minimum. Differential pressure gauges may have an accuracy of 2 % of full scale.

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

15.2.10 Over-range protection such as gauge savers shall be provided where the process pressures may exceed 1.3 x full scale deflection. Gauge savers if provided 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 the middle 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 for diaphragm seal where 2” flanged connection shall be used in general.

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

15.2.14 Socket stem shall extend a minimum of 1 ¼” beyond gauge case and shall be provided with wrench flats.

15.2.15 Diaphragm seals, filled type shall be furnished where plugging of the element may occur or where suitable material is not available in highly corrosive services. When chemical seals are required, they shall be provided with fabricated vent and drain arrangement. Diaphragm seal device shall be furnished completely assembled with the pressure gauge.

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

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

15.2.18 Liquid filled gauge shall be used where extreme vibration of the gauge is expected. Glycerin or other suitable case filling liquid with non coloring property shall be used.

15.2.19 An inert liquid shall fill the entire system between the diaphragm of the diaphragm seal device and the elastic element. Unless otherwise specified, filling liquid shall be suitable for an ambient temperature range of -18°C to 204°C.


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15.2.20 Oxygen service pressure/diff. pressure gauges shall be supplied with special inert fluids and shall be free from grease/oil. These shall be clearly marked 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 parts of this specification except as follows:

- Elastic elements shall be SS designed for a 0.2 to 1 kg/cm2 g (3 to 15psig) pressure range, but shall be able to withstand 1.4 kg/cm2 g (22 psig).

- Dials shall be graduated for the range specified on the data sheet, with an additional 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 range specified is 0-100, the "0" marking on the dial shall correspond to 0.2 kg/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 of

SS 316 as a minimum. Pulsation dampener shall be used for all pulsating services. It shall be floating pin type, externally mounted and externally adjustable.

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 the specified service conditions.

15.3 Pressure & Differential Pressure Switches: Generally pressure and diff. pressure switches shall be used only for alarm purpose and shall 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 machine

safety, for few critical applications, use of pressure and diff. pressure switches shall be allowed with due justifications.

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

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

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

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 element with ¼” 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 protection against process fluids entering the electrical housing in the event of element failure.

15.3.10 Pressure switches shall be blind type with ½” NPT (F) process connection and shall be operative in full specified range. The switch differential shall be selected as per operating conditions; it shall be less than 60% of difference between set value and operating value.

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

15.3.12 All diaphragm type pressure / diff. pressure switches with flushing connection. Diaphragm seal device shall be furnished completely assembled with the pressure switch.

15.3.13 Pressure switches shall have repeatability of ± 0.5% of full scale as a minimum.

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

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

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

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

16 Temperature Measurement:

16.1 General 16.1.1 All temperature measurement in the plant shall be carried out using only

Thermocouple or RTD elements. No local temperature gauges shall be used throughout the project or any part thereof, including package unit instruments.

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

Thermocouple/RTD elements and field mountable 2 wire SMART temperature transmitters. Hence in DCS, there shall not be any RTD or T/C input cards.

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


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16.1.4 All temperature interlocks/logic related measurement shall be carried out with the help of Thermocouple / RTD elements along with field mounted ,2 wire, 24 V DC, 4-20 ma, SMART temperature transmitters. No head mounted transmitters shall be used throughout the project or any part thereof, including package unit instruments.

16.1.5 By default all temperature elements shall be duplex, unless otherwise specified.

16.1.6 Irrespective of design pressure rating, the minimum pressure rating of Thermowell flange shall be ANSI type as per piping class rating.

16.2 THERMOWELLS 16.2.1 All temperature elements shall be provided with thermowells. The flange

MOC shall be SS316 as a minimum. In case of corrosive and erosive services Titanium/ Hastalloy ‘C’ bar-stock thermowell shall be provided. The thermowell design shall ensure no air gap between the tip of the element and thermowell to minimize measurement lag. The internal diameter of thermowell shall be suitable for sensing element /bulk OD of mm or 8 mm.

16.2.2 Thermowells shall be assessed for resonance effects. Where Thermowells in lines subjected to high fluid velocities (exceeding 6 m/s for liquid and 120 m/s for vapors, gases), combined stress and frequency calculation shall be carried out by a proven method. In case the thermowell design fails vibration analysis , alternate design may be used by the contractor. All such design along with calculations shall be submitted for purchaser's review.

16.2.3 Immersion length U of the thermowell shall be as follows. Line Size Immersion length From 4' to 6" 280 mm From 8" onwards 320 mm Vessels / columns 400 mm 16.2.4 Immersion length is based on 200 mm length between flange face and

inner wall of pipe. In special applications, where thermowell nozzle sizes are larger or where temperature is to be measured at any specific location, contractor shall decide the immersion length based on actual requirements.

16.2.5 All skin temperature elements and flue/fuel gas path elements shall be with Inconel capillary with proper wedge element for proper sensing of exact location temperature.

16.2.6 Any pipe line less than 4" nominal bore shall be blown to 4" size to installing the thermowells.

16.3 Temperature Gauges:

No local temperature gauges/thermometers or any type of local temperature gauges shall be used in main plant as well as any of the package unit instruments.


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All temperature measurement points shall be through either T/C or RTD type element only with field mounted 2 wire, SMART with HART protocol Temperature Transmitters.

16.4 Temperature Elements: 16.4.1 For all type of temperature measurement, either thermocouple or RTD

elements shall be used depending on the requirements. 16.4.2 All the temperature Elements shall be spring-loaded, duplex, mineral

insulated and sheath MOC as SS316 as a minimum. 16.4.3 Bulb OD of all the elements shall be 8 mm and the overall diameter of the

sheathed element shall not deviate by more than 2%. 16.4.4 RTD and Thermocouple metallic head assemblies shall be furnished with

screwed in type heads / enclosure certified as Weatherproof to IP65 as a minimum, irrespective of plant’s hazardous area classifications. All head assembly shall have two ½” NPT (F) cable entries. All assemblies shall be supplied with either 1 no. of two nos. of double compression type SS MOC cable glands certified for weatherproof to IP65. Wherever second element is not in use, the spare cable entry shall be provided with ½” NPT SS304 blind plug.

16.4.5 MOC for head assembly shall be die cast aluminum. 16.4.6 The terminals shall be color coded as per element’s color code. 16.4.7 Thermocouples shall comply with ANSI MC 96.1 and IEC 584, Eidtion-2,

IS7358. They shall have wire size of 18 AWG for single and 20AWG for duplex elements.

16.4.8 In general, the following guidelines shall be used for selecting thermocouple elements/wire size, as a minimum.

Type 8 AWG 14 AWG 18 AWG T - >37’ C For all other E >871’ C >649’ C -do- K >1260’ C >1093’ C -do- S - - <1500’ C 16.4.9 Thermocouples shall be compact Magnesium Oxide (MgO) filled and

ungrounded, unless specified. Grounded junctions are to be used where fast response is required, if secondary system allows the use of grounded T/C elements. The insulation resistance shall be >100 Mega Ohm. The thermocouple wires shall be joined together by welding to form a hot junction. Bulb / Sheath diameter shall be 8 mm and the overall diameter of the sheathed element shall not deviate by more than 2%.

16.4.10 The type of thermocouple shall be selected based on the following guidelines as minimum


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Copper-Constantan (ISA-Type-T) (-) 200 to 200°C Chromel-Constantan (ISA-Type-E) 200 to 600°C Iron-Constantan (ISA-Type-J) 0 to 600°C Chromel-Alumel (ISA-Type-K) 600 to 1200°C Platinum Rhodium-Platinum (ISA-Type-S or B) 600 to 1600°C 16.4.11 The design of thermocouple assemblies shall be such that replacement of

elements shall be possible on-line. It shall be equipped with SS304 MOC Nipple-Union-Nipple Joints. Assembly shall include nipple-union-nipple (1/2" NPT threaded) to allow approximately 150 mm between top of well and bottom of head, when made up.

16.4.12 Thermocouple sheathing material shall be 316 stainless steel as a minimum and are constructed from a seamless tube with a wall thickness of at least 1 mm. Inconel 600 sheath shall be used for all application, where the temperature is above 600’C.

16.4.13 RTD (Resistance Temperature Detector) shall be 3 wire type platinum elements with 100 ohms resistance at 0°C. RTD shall be calibrated as per IEC 751 / DIN 43760.

16.4.14 RTD shall be used for a temperature range of -200 to 650°C. Three-wire system shall be the element.

16.4.15 RTD shall generally be selected for applications requiring low temp with comparatively shorter temperature span requiring accuracies of better than +/-0.25%.

16.4.16 All RTD elements shall be duplex by default. It shall be compact Magnesium Oxide (MgO) filled. The insulation resistance shall be >100 Mega Ohm.

16.4.17 The design of RTD assemblies shall be such that replacement of elements shall be possible on-line. It shall be equipped with SS304 MOC Nipple-Union-Nipple Joints. Assembly shall include nipple-union-nipple (1/2" NPT threaded) to allow approximately 150 mm between top of well and bottom of head, when made up.

16.4.18 RTD bulb sheathing material shall be 316 stainless steel as a minimum and are constructed from a seamless tube with a wall thickness of at least 1 mm. Bulb / Sheath diameter shall be 8 mm and the overall diameter of the sheathed element shall not deviate by more than 2%.

16.4.19 The special thermocouples such as reactor thermocouples, etc. shall be designed by BIDDER and needs purchaser’s approval.

16.4.20 For Reactor / heater tube skin thermocouple, wherever applicable, assembly shall meet the equipment design requirements and shall be provided with expansion loops. The sheath MOC shall be selected based temperature.

16.4.21 Flare application or Reactor thermocouples shall be Pad / Knife-edge type with Inconel sheath.


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16.4.22 Class 'A' / Class '1’ tolerance as per IEC 751 / 584-2 shall be specified for all RTD and thermocouple sensors in complete temperature measurements for all open/closed loops and interlocks.

16.5 Temperature Transmitters: 16.5.1 In addition to the general field transmitters specified in Section 4.0, the

following minimum guide lines shall be followed for all the temperature transmitters used through out in the project, including the package unit instruments.

16.5.2 Head mounted temperature transmitters are not allowed at any location, through out the project or part thereof. Field mounted transmitters shall be used for all temperature transmitters.

16.5.3 All Field mounted temperature transmitters shall be specified for all closed and open loops in DCS, for all interlock inputs to DCS, which are taking part in Flow correction or any other calculations. Remaining all other T/C & RTD for open loops, which are only for monitoring purpose shall be directly connected to DCS without temperature transmitters.

16.5.4 All the Temperature transmitters shall be 24 V DC, 2 Wire, 4-20 m amp dc output with SMART with HART protocol.

16.5.5 Temperature transmitters shall be suitable for 2” pipe mounting and shall be supplied with all SS304 mounting brackets/nut/bolts, etc.

16.5.6 All temperature transmitters shall be equipped with local, LCD type digital indication which shall be configurable in engineering unit.

16.5.7 Temperature transmitters shall have a built-in linearising function. 16.5.8 The minimum accuracy of all the temperature transmitters shall be 0.1% of

FSD 16.5.9 All transmitters shall be of universal input type, so that it can accept all type

of Thermocouples or all type of RTD inputs with 2/3/4 wire options. This feature is a must to reduce inventory and have interchangeability of various transmitters.

16.5.10 All the transmitters shall be provided with min. two cable entries with ½” NPT(F) size. One entry shall be used for sensor cable input and other shall be for 24 V DC/2 wire output cable.

16.5.11 All temperature transmitters shall weatherproof to IP67 as per IEC529. 16.5.12 Transmitter housing MOC shall be die-cast aluminum with epoxy paint as a

minimum. 16.5.13 Each temperature transmitters shall be supplied with min. of two nos. of

double compression type, SS304 MOC, cable glands with PVC hood. Cable glands shall be Weatherproof to IP65 as per IEC529.

17 Limit switches / Position Switches:

17.1 All type of limit switches shall be 2 wire, proximity type, and NAMUR sensors only.

17.2 The make shall be P+F only. The sensor shall be generally cylindrical NAMUR sensor type proximity switch. The diameter and sensing range shall be selected based on application.


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17.3 The MOC of sensor shall be SS316. Krastin type probes shall not be used, unless surrounding atmosphere heat permits the use of the same under worst condition.

17.4 All limit switches sensor shall be adjustable with the threaded length and check nut arrangement.

17.5 Flying lead type loose connections for NAMUR sensors are not acceptable. All these NAMUR sensors installed on any instruments to sense the position shall be housed in a closed box certified for weatherproof to IP67. The gland size shall be ½” NPT(F).

17.6 All ON-OFF type application valves taking in part in interlock/shutdown shall be provided with Open and Close type NAMUR sensor as limit switches. The sensors along with enclosure shall be installed in control valve in such a way that it can be removed with ease for maintenance.

17.7 Limit switches shall not be used for Control Valves. All controls valves shall be equipped with SMART positioner, from where the analog output for continuous position is available, which shall be used for interlock/control purpose.

17.8 NAMUR type Proximity switches shall not be directly wired to DCS Digital input cards. These shall be connected with Isolation Amplifier of P+F make, located in auxiliary cabinet/panels in central cabinet room. The isolation amplifier shall provide potential free contact for further use in DCS. The isolation amplifier shall be suitable for 110 V AC power supply , mountable on DIN rail.

18 Control Valves

18.1 The control valves shall be designed based on following guide lines, as a minimum.

18.1.1 Control valve type / design selection shall be made with considering the following conditions

1. Pressure drops, which exceed 10 bars. 2. Flashing or cavitating liquids. 3. Steam service where pressure drop exceeds 5 bar. 4. Corrosive fluids. 5. Control valves on erosive services (slurries). 18.1.2 Control valves shall normally be globe type, top guided (up to 10 Kg/Cm2

Delta P) or cage guided (more than 10 Kg/Cm2 Delta P), single seated, non-pressure balanced type only. Other valves like butterfly, ball, rotary, angle or 3 way valves shall be selected based on application. All control valves shall be flanged end type only the control valve Body material and Body rating shall be as per piping specifications. Valve bodies and other pressure parts, except diaphragm and housing shall be of forged or cast type conforming to ASTM standards, unless otherwise specified.


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18.1.3 The Minimum control valve body size shall be 1" in general. Body size shall be limited to 1", 1-1/2". 2", 3", 4", 6", 8'”, and 12”. Higher size may be used if required. The flanged connection dimensions and pressure temperature ratings shall be as per ANSI B16.5.

18.1.4 The accessories like Air Filter Regulator, Solenoid Valve, Limit switches, Positioners, etc. shall be pre-tubed with actuator so that they can be removed easily for maintenance purpose.

18.1.5 The max. allowable noise shall be 85 DB SPL (Sound Pressure Level). Control valves at a 1 meter distance, exceeding this limit will be provided with special precautions.

18.1.6 Leakage class VI shall be considered, where tight shutoff is specified. If no leakage class is specified, min. leakage class V is to be considered.

18.1.7 For all interlock/shutdown valves, the minimum leakage class shall be Class VI as per ANSI B16.104.

18.1.8 Control valve sizing shall be carried out as per ISA S75.01. The selected CV shall permit up to 150% of normal flow or 110 % of maximum flow, whichever is higher. In general, control valves shall be sized so that the valve opening is as mentioned below.

At Max. Flow :- 80% Open At Normal Flow :- 70% open At Min. Flow :- 20% open 18.1.9 Equal % control valve shall be sized for 60% to 80% opening for normal

flow. For two phase flow, both phase CV is to be considered with relevant process condition while sizing the valve.

18.1.10 Flanged bolted type gland packing boxes shall be used, unless other specified. Gland packing shall normally be self-lubricating type. Packing shall be PTFE type up to 200”C. For temperature above 200 “ C, grafoil is to be used. Usage of asbestos is not allowed in any part.

18.1.11 Bellows seals shall be used wherever gland leakage is not permissible like toxic / hazardous product like carbon monoxide gas, etc.

18.1.12 As a minimum, trim MOC shall be SS316. By default, all Guide MOC shall be hardened stainless steel like 440 C, 17.4 PH. For corrosive services PTFE lined globe / ball valves shall be used.

18.1.13 Where tight shutoff is required, fire safe type soft seat trims shall be used, provided pressure/temperature of service permits the use of this.

18.1.14 Trim characteristics shall be equal percentage, unless otherwise specified. For high erosion service or in steam service where, the delta P is higher than 5 Kg/Cm2, hardened trim with stelliting shall be used. When this is not sufficient, in such cases, special Anti-cavitating trim or shall be selected

18.1.15 The allowed stroking time shall be governed by process requirement. Generally, for control valves, equipped with positioner, max. stroke time shall be 10 seconds up to control valve size 4” or smaller. And shall be max. 15 second for control valve with size 6” and above. For critical control valves, like anti surge control valve, stroke time may be in the range of 2-5 seconds. For interlock valves, this could be in the range of 1 to 2 seconds.

18.1.16 PCV shall be used only when load is constant and precise control is not required like nitrogen blanketing system for storage tanks, etc.


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18.1.17 All shutdown valves shall be floating ball design with full bore design, unless otherwise specified.

18.1.18 All valves with flow tends to open design, shall be used. 18.1.19 Oxygen service valves shall be de-greased completely and certified for

oxygen service use. MOC for body shall be Monel and trim shall be Inconel 600 only.

18.1.20 For all steam service valve, BIDDER to ensure submission of IBR FORM IIIC certificate in original.

18.1.21 For all shutdown valves on fire safe applications, air volume tank shall be supplied for the storage of air volume for minimum 3 stroke operation.

18.1.22 For steam de-superheating, single valve is not acceptable. Both valve for water injection and pressure reduction shall be separate.

18.2 ACTUATORS 18.2.1 Generally all actuators shall be single acting, spring return, diaphragm or

piston type only. Use of double acting piston actuator is not allowed. If thrust requirement is more, a spring return piston actuator shall be used. Also the usage of Hydraulic or Motorized actuators is not acceptable.

18.2.2 All actuators shall be designed with max. 4 kg/cm2g air pressure availability only. The actuator shall be sized in such a way that it should be able to open the valve when full static upstream pressure is acting on upstream in valve full closed condition and down stream pressure is atmospheric pressure. Actuator shall be oversized to 125% of the thrust required for DP Shut off, as specified above. In short, actuator shall be able to with stand max. shut off static pressure with down stream atmospheric pressure, when available instrument air pressure to actuator diaphragm is minimum specified. Spring shall be painted with corrosion resistant paint. All actuator open/vent port shall be provided with breathers. Paint shall be min. epoxy type.

18.2.3 Actuator case MOC shall be Steel and Yoke MOC shall be high tensile ductile iron as a minimum. Diaphragm shall be of nylon reinforced neoprene or Buna N rubber. Extended bonnet shall be selected based on high temperature or cryogenic services.

18.3 POSITIONERS 18.3.1 By default, all the control valves’ positioners shall be SMART with HART

protocol, Electro-pneumatic type, accepting 2 wire, 4-20 m amp input signals from central DCS system.

18.3.2 All the positioners shall be weatherproof to IP65. 18.3.3 There shall be min. two ½” NPT (F) cable entries in each SMART

positioner, from where input signal and position output feedback signal wires can be terminated separately.

18.3.4 Air consumption of the SMART positioner shall not be more than 0.3 NM3/Hr. Positioner shall be having AUTO STROKE functionality, Self Diagnostic, etc. features in built with local push button and LCD display.

18.3.5 Positioner shall be mounted on control valve so that it can be removed with ease during the maintenance.

18.3.6 Positioner feedback link with control valve shall be fixed with 100% secure


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mechanism so that there is no backlash in motions, resulting hysteresis or chance of dis-engagement of the link while the control valve is installed with severs pipe vibrations.

18.4 OTHER ACCESSORIES 18.4.1 Hand wheels shall be provided as per requirement indicated the data sheet. 18.4.2 Valve stem position indicators shall be fitted as standard, showing

incremental stroke positions. 18.4.3 Direction of flow indication shall be engraved or embossed on the body. 18.4.4 Limit switches, if specified in datasheets, shall be 2 wire, NAMUR sensor,

proximity type and P+F make only. This shall be installed in weatherproof IP65 box. No flying lead type connections are acceptable.

18.4.5 All Solenoid Valves used in the whole plant (including those being supplied by package unit vendors) shall be of either ASCO or HERION make only.

18.4.6 It shall be 110 V AC/50 Hz, 3/2 way, ½” NPT(F) or ¼” NPT(F) process connections based on Kv/Flow requirement of control valve actuator and stroke speed requirement, SS 316 MOC body, weatherproof to IP67, ½” NPT(F) cable entry. The make of all the solenoid valves shall be Herion Only.

18.4.7 The max. working pressure for all Solenoid valve shall be 10 kg/cm2g. There shall be only two types of common models of Solenoid valves shall be used (½” and ¼” Process connections) through out the complete plant design to maintain fewer inventories and have interchangeability at any time.

18.4.8 This philosophy shall be extended for all the package unit instruments too. BIDDER to ensure the same type/model of solenoid valves along with each package unit instrumentation also.

18.4.9 All solenoid valves shall be supplied with ½” NPT, SS MOC, double compression Cables glands, weather proof to IP65 with PVC hood.

18.5 INSPECTION & TESTING Test Procedure shall cover the following test as minimum, but not limited to - Dimensional /Physical Test - Hydrostatic Body Test. - Duration 3 min. ( including all parts in assembled condition like body, gland, all joints) - Seat leakage as per ANSI B16.104/FCI 70.2 - Diaphragm head test - Complete actuator leak test - Helium leak test for control valve with below seals - Stroke calibration - Stroke speed test 18.6 Documents/Test Certificates BIDDER to ensure the delivery of the following documents as a minimum along with the valves

- MOC certificate for control valve, all accessories and other bought out items - GA Drawings, including all accessories


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- Dimensional Cross sectional drawings of complete control valve/accessories - All type of tests certificate like Hydro test / seal leakage test certificates - Radiography test - IGC test as per ASTM A262, Practice A, Fig. 1 - DP Test - Stroke calibration and stroke time test certificates - Operation and Maintenance manual of control valve and all accessories - Product catalog of control valve and all accessories - Functional test certificates for all accessories

18.7 Each valve shall be provided with SS MOC tag plate indicating the following details as a minimum

- Instrument Tag Number - Vendor's Name - Valve Model Number - Order/Requisition Number - Body & Trim Material - Stem Packing - Material Body Size and Rating - Design CV (For Control valve and Regulator) - Trim Characteristic or Cam Code/type as necessary - Air-Fail Action - Hazardous Area Class - Actuator size - spring range - air supply pressure

18.8 The following standards/documents shall be used as design/test criteria. - ANSIB16.10 - Control valve dimension - ANSI / ISA S75.C1 - Flow equation for sizing of control valves - ANSI / ISA S75.02 - Control valve capacity test procedure - ANSI / ISA S75.03 - Face to Face dimension for flanged type control valve - ANSI / ISA S75.04 - Face to Face dimension for flange less control valve - ANSI / ISA S75.05 - Control Valve Terminology - ANSI / ISA S75.11 - Flow Characteristic and rangeability - API Std. 598 ISA - Test procedure. 19 pH / Conductivity Analysers:

All pH and conductivity analysers shall be 2 wire, 24 V DC, SMART with HART protocol and with local display. The pH transmitter electrode shall not have inbuilt preamplifier. This will be a part of pH transmitters. Adequate sample handling system shall be designed with pH /Conductivity meters.

20 Material Handling Systems Bidder to include min. 1 running + 1 stand-by fully automatic bagging machine with integrated PLC control and interface the same to DCS over OPC interface. The capacity of one machine shall be equal to 150 tons of


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complete product in 25 kg bags with max. 18 working hours a day. The accuracy of bagging machine shall be +/-20 gms per bag. The baging machine shall be fully automatic with empty bag placement, automatic filling of required qty with min. 3 nos. of gates, i.e. coarse, fine and dribble and cross check of weight at regular interval and auto correction of timings and movement of bags along with automatic stitching and stacking. The complete operation shall be unmanned with one person supervising complete bagging, stacking activities without any human intervention. There shall be a full-fledged terminal automation system (TAS) for 1 no. of road tanker filling product gantry along with all required mass flow meter, digital set-stop valves, batch controller and remote interface unit with local push button stations, terminal server, load rack server and related hardware software required for its interconnectivity with new PAC project DCS via OPC and existing Terminal Automation System/ SAP interconnectivity. This will be an augmentation of existing main TDI project TAS. The detail specifications of existing TAS shall be made available to all prospective bidders. Additionally, there shall be 1 no. of carboy/drum filling station with electronic check weigh machine facility for PAC liquid product. The carboy filling station is envisaged with mass flow meter, batch controller, RIT with local push button station and on-off valves.

21 Other instrumentation Items

Any other instrumentation items, which are not covered in these general minimum specifications, shall be as per GNFC requirement and technical specifications shall be approved by GNFC along with vendor list approval.