instrument design basis_akpg

SPECIFICATION NUMBER

INSTRUMENT DESIGN BASIS

CLIENT: -- SHEET NO 1 OF 34

INSTRUMENT DESIGN BASIS

REVISION NO.

ISSUED FOR

PREPD. BY/DATE

CHKD. BY/DATE

APPD. BY/DATE

C930034 R3 Comp. Ref. document.doc


Aker Kvaerner Powergas

REVISION RECORD SHEET XXXX/515/01

DESCRIPTION: INSTRUMENT DESIGN BASIS SHEET NO 2 OF 34

PROJECT: -- CLIENT: -- JOB NUMBER: --

DATE DETAILS OF REVISION REV NO

REVISION NO.

PREPD. BY/DATE

CHKD. BY/DATE

C930033 R3


INSTRUMENT DESIGN BASISREV : 02





CONTENTS PAGE NO.

1 General 51.1 Scope 51.2 Units of Measurement 51.3 Codes and Standards 51.4 Environment Data 51.5 P & ID Diagrams 5

2 Design Philosophy 52.1 Materials of Construction 52.2 Pressure and Temperature rating 62.3 Hazardous Area Requirement 62.4 Accessibility 62.5 Analogue Signals 62.6 Digital Signals 72.7 Motor Control Signals 72.8 Frequency Signals 82.9 Pneumatic Control Signals 8

3 Flow Instruments 83.1 Mass Flow Meters 83.2 Vortex Meters 83.3 Variable – Area Meters 83.4 Magnetic Type Flow Meters 93.5 Orifice Plates 93.6 Positive Displacement Meters 103.7 Inferential Meter 103.8 Venture Tubes and Flow Nozzle 10

4 Temperature Instruments 104.1 Temperature Elements 104.2 Transmitters 104.3 Protecting Thermowells 114.4 Local Temperature Indicators 11

5 Pressure Instrument 115.1 Pressure Transmitters 115.2 Pressure Switches 125.3 Pressure Gauges 125.4 Chemical Seals 135.5 Instrument Manifolds 13

6 Level Instruments 136.1 Level Transmitters 136.2 Level Switches 136.3 Level Gauges 14

7 Analysis Instruments 147.1 Gas Detection 147.2 Fire Detection 147.3 PH and Conductivity 15




8 Weighing System 159 Valves 15

9.1 Control Valves 159.2 On – Off Actuated Valves 179.3 Actuators 179.4 Solenoid Valves 179.5 Valve Switch Boxes 179.6 Self-Operated Regulating Valves 17

10 Safety and Relief Systems 1810.1 General 1810.2 Safety Relief Valves 1810.3 Rupture Disc 18

11 Desuperheater 1912 Control System 1913 Emergency Shutdown System wherever required 22

13.1 Hardwired Relay Logic 2213.2 Programmable Logic Controllers for ESD 22

14 Control Room 2315 Utility Supplies 24

15.1 Instrument Power Supplies 2415.2 Instrument Air Supplies 24

16 Instrument Connection 2516.1 Standard Connections 2516.2 Instrument Process Piping 2516.3 Instrument Air Tubing 25

17 Instrument Cable and Wiring 2517.1 Cable 2517.2 Junction Boxes (Field) 26

18 Segregation and Installation 2619 Earthing 2720 Package Equipment 2821 Documentation 2822 Testing and Inspection 2823 Installation 28

APPENDIX – A 29APPENDIX – B 30APPENDIX – C 31APPENDIX – D 32




1. GENERAL

1.1. Scope

This document defines the basic requirements for the engineering and design of the instrumentation. The purpose of this specification is to ensure a standard approach is maintained to the engineering and design of instrumentation and equipment and that it complies with all relevant national and international standards.

1.2. Units of Measurement

Units shall be in accordance with the list given in Appendix - A.

1.3. Code and Standards

All instrumentation shall comply with the latest version of codes and standards as given in Appendix - D.

1.4. Environmental Data

1.4.1. Environmental Conditions - Refer Appendix - C

Instruments and equipment shall be consistent with the environmental impact statement, with particular emphasis to the following:

Noise within 20 meters of the battery limit must not exceed 45dBA.

Fugitive process emissions must be minimized e.g.) from control valve glands and analyser vents.

1.4.2. Field instrumentation shall have a minimum ingress protection of IP65 in accordance with IS 2147/IEC 529. In case of instruments in hazardous area, the intrinsically safe, explosion proof/flameproof instruments shall be certified to specific hazardous area class by statutory body such as ATEX, PTB etc. Purging shall not be used unless specifically called for.

1.5. Instrument Connections on Vessel – Refer Appendix - B

1.6. P&I Diagrams

P&I Diagrams shall identify all instrumentation in accordance with symbols shown on the P&I Legend Sheets.

2. DESIGN PHILOSOPHY

2.1. Materials of Construction




Materials of construction for instrument equipment shall be consistent with corrosion resistance and the pressure and temperature conditions of the process fluids involved. Generally the parts in contact with the process fluid shall be of a material equal to or better than that used for the related vessel or line. Where instrument design prohibits the use of these materials, or where a suitable material cannot be reasonably procured, the instruments shall be isolated from the process by means of a chemical seal which shall be identified on P&ID.

The following materials shall not be used in contact with the product:

Aluminum

Zinc

Asbestos

Brass, Bronze, Copper

Heavy metals including Mercury, Antimony and Cadmium.

Plastics containing free Phenol, formaldehyde or plasticizers.

2.2. Pressure & temperature rating

Pressure and temperature rating of instruments and components shall conform to the design rating of the process system to which they are connected. Instruments which can be exposed to vacuum shall have under-range protection to full vacuum.

2.3. Hazardous area requirement

2.3.1. Classification of Hazardous Areas shall be as indicated elsewhere.

2.3.2. All instrumentation located or partially located in the hazardous area shall be suitable for classified hazardous area.

2.3.3. The preferred method of protection is by Intrinsically safe (EExia) circuits using galvanic isolated safety barriers. Alternate methods of protection, are subject to approval by client/consultant.

Flameproof (EExd)

Pressurised enclosures (EExp)

Increased safety (EExe)

2.3.4. ATEX/PTB approved certification shall be supplied for all electrical / electronic equipment in the hazardous area. The use of other recognised approval authorities shall be subject to approval by the Engineer.

2.4. Accessibility

All instruments shall be accessible from grade or platform for measurement .In case of gas service where instruments are mounted above the taps, the installation of platform shall be considered, if accessibility is not available. Ladder shall be provided for all such platform. This should be properly co-ordinated with the piping group.




2.5. Analogue signals

2.5.1. Transmitters shall be two-wire conventional/smart 4-20 mA dc powered, from the control system.

2.5.2. In case of Smart transmitters, the minimum requirement shall be as follows.

2.5.2.1. Communication Protocol shall be HART(Latest Version) and shall be suitable for HART Maintenance System.

2.5.2.2. Accuracy of transmitters shall be +0.1% or range or better for a rangeability of 1:15. The accuracy includes the combined effect of linearity, hysterisis and repeatability.

2.5.2.3. Hand held configuration shall be provided for remote calibration, remote configuration and diagnostics. It shall be possible to connect the configurator in the main control room or junction box located in field.

2.5.2.4. Smart transmitters shall be microprocessor based and shall incorporate non-volatile RAM, which shall store configurational data of transmittal.

2.5.3. Retrofit type Smart Model shall not be accepted.

2.5.4. Where two wire transmitters can not be sourced transmitters shall be powered externally by 24Vdc (preferred) or 230/100 VAC.

2.5.5. Transmitters shall be supplied with integral output meter (LCD type).

2.5.6. The range of a transmitter shall be specified such that its normal operating point is within the middle third of the calibrated range.

2.5.7. Transmitter accuracy, repeatability and rangeability shall be suitable for their intended use.

2.5.8. Control valve positioners shall be either with integral E/P converters or pneumatic positioner with I/P converter powered from the control system.

2.6. Digital signals

2.6.1. Process switches shall be SPDT with noble metal contacts, wired normally closed for the safe condition, with contacts opening in the Alarm State.

2.6.2. Digital signals shall be powered from the control system.

2.6.3. Position switches shall be inductive two-wire proximity type or mechanical contacts as defined elsewhere.

2.6.4. Outputs to solenoid valves shall be 24Vdc or 110V AC from the control system. In case of 24V DC Voltage level the solenoid valve shall be necessarily I.S. type.

2.7. Motor control signals




2.7.1. Remote control of motors shall typically comprise of the following:

START / STOP control output

Drive RUNNING control input

Drive REMOTE/LOCAL SELECTOR SWITCH control input

SPEED SET POINT control output to VFD (where appropriate)

The interface between Motor Control Centre located in substation and the control system shall be indicated in Motor Control Philosophy document which shall be separately issued to Electrical department.

2.8. Frequency signals

2.8.1. Frequency signals may be utilized for flow totalisation, or rotating equipment shaft speed monitoring by proximity sensor.

2.9. Pneumatic control signals

2.9.1. Pneumatic control and transmission signals shall be 0.2 to 1 KG/CM2 G.

3. FLOW INSTRUMENTS

3.1. Mass flow meters

3.1.1. Coriolis flow meters shall be used for product critical flow measurement, as they measure accurately the mass flow of fluids with varying density over a wide rangeability and with minimum pressure loss.

3.1.2. In case of line size less than 2” and the accuracy is not main criterion straight tube meters may be used. However in case of food / pharmaciteucal applications straight tube may be preferred considering the contamination and cleaning requirement.

3.1.3. In case of bent Coriolis U tubes, it shall be supported in accordance with the manufacturers instructions to prevent piping vibration affecting the instrument. The meter must be orientated in the pipe work to allow for self-draining. The preferred method of installation is, vertical with flow upwards.

3.2. Vortex meters

3.2.1. Vortex shedding flow meters shall be used for general process / utility service, and are preferred to differential pressure devices such as orifice plate.

3.2.2. This meter type may be installed either horizontally or vertically. The straight run requirement shall be in accordance with the piping geometry.

3.3. Variable – Area meters

3.3.1. Variable – area meters may also be considered for clean process / utility service and are particularly suited for Nitrogen purging applications.




3.3.2. The Meter design shall be preferably of metal tube type. The flow regulation wherever required shall be provided by means of an integral throttle valve.

3.3.3. Installation shall be vertical with flow upwards.

3.3.4. Meters may be supplied for local indication, remote transmission of measured variable, or a flow switch output as appropriate.




3.3.5. The use of glass VA meters shall be for non critical application

3.4. Magnetic type flow meters

3.4.1. Magnetic flow meters may be used for general process / utility service and have the advantage of an unobtrusive crevice free installation. This meter type can only be used on conductive liquids and is therefore not suitable for high purity water and solvent applications. Typical applications include metering of water, caustic and acid.

3.4.2. The meter liner material shall be suitable for the process media and design conditions including full vacuum rating where appropriate.

3.4.3. Installation shall be at the lowest point in the pipe work to ensure the meter is always liquid filled.

3.5. Orifice Plates

3.5.1. Orifice plates may be considered for general process and utility service where the above methods are commercially prohibitive.

3.5.2. Orifice plates shall be sharp edged concentric type designed in accordance with ISO5167. The orifice flanges shall be designed in accordance with ANSI B 16.36.

3.5.3. Flange taps shall be used for line sizes 50mm through to and including 200mm. For line sizes above 250mm D and D/2 tapping will be used.

3.5.4. For line sizes less than 50mm specially calibrated orifice metering section or Integral orifice assembly shall be used.

3.5.5. Plate material shall be stainless steel or superior material as required by process conditions. Plate thickness shall be relative to pipe diameter and line pressure but not less than 3 mm.

3.5.6. In general, orifice plates shall be sized using 2500mm WG differential pressure for full scale transmitted range. Other permitted differential pressure ranges are 5000, 3750, 1250, 750 and 500 mm WG.

3.5.7. The ratio of the orifice bore to inside pipe diameter (d/D) shall be between the limits 0.25 to 0.7.

3.5.8. Segmental orifice plates shall be used for liquids containing solids. Quarter circle or conical entrance plates shall be used for viscous liquids.

3.5.9. Flow straightening vanes may be considered upstream of an orifice plate for flow meter installations in large size pipes when it would be both inconvenient and expensive to provide the "required straight run".

3.5.10. Annubar, pitot tubes may be used for flow measurement on large diameter pipe / duct work, or where only a small pressure drop is allowed.




3.6. Positive displacement meters

3.6.1. For simple local batching application, positive displacement flow meters may be used.

3.6.2. This meter is suitable for clean liquids free from entrained vapours and provides a high accuracy output, including low flow and viscous applications.

3.6.3. Installation shall be arranged to ensure continuous flooding of the meter. A strainer and drain shall be provided upstream of the meter.

3.7. Inferential Meter

3.7.1. The use of inferential meters such as turbine meters and semi-positive displacement meters may be used as alternative to positive displacement meter.

3.8. Venturi Tubes and flow nozzle

Venturi tube and flow nozzle shall be sized as per ISO 5167. Flow nozzle material shall be minimum SS-316. Spool piece shall be provided at the flow nozzle outlet for maintenance purpose.

4. TEMPERATURE INSTRUMENTS

4.1. Temperature elements

4.1.1. The preferred method of temperature measurement for temperature up to 6000C is by Resistance Thermometer Detectors (RTD’s) Resistance thermometers shall be duplex 3-wire type, Platinum 100 ohm at 0 C complying with IEC-751.

4.1.2. Temperature measurement greater than 600 C shall be made using Nickel-Chrome / Nickel-Aluminum, type K thermocouples. Cryogenic temperature measurements shall be made using Copper-Copper / Nickel / Aluminum, type T thermocouples.

4.1.3. Thermocouple shall be supplied in accordance with IEC-584. Appropriate extension and compensating cable shall be used.

4.1.4. Thermistor elements are not permitted except for motor winding thermal protection.

4.1.5. Temperature elements shall be supplied complete with thermowell, extension, head and integrally mounted transmitter as a complete assembly.

4.2. Transmitters

4.2.1. Transmitters should be conventional/smart, range configurable type transmitting a linearised 4 to 20 mA .




4.2.2. Where it is not practical to mount the transmitter within the sensor head due to layout or environmental constraints, the transmitter shall be mounted within a local enclosure and wired to the element with compensating cable, where appropriate.

4.2.3. In the event of temperature element failure, transmitters shall be arranged to drive towards the alarm condition or safe control condition where one exists, or otherwise upscale.

4.3. Protecting Thermowells

4.3.1. All temperature sensing devices shall be installed in protecting thermowells. The thermowell material shall be minimum 316SS for temperature up to 6000C and Inconel above it.

4.3.2. Thermowells shall be flanged according to equipment and pipe specifications. The flange size shall be 40 mm (1.1/2 inch) with rating and facing according to the line classification.

4.3.3. Thermowells in high velocity service mounted on pipeline shall be assessed for vibration resonance effect as per ASME PTC 19.3

4.3.4. For line sizes less than 80 mm (3 inch), the line size shall be increased to 80 mm for the insertion of thermowells. For line sizes 150 and above the thermowell length shall be selected to ensure the measurement element is within the middle third of the pipe. Standard lengths of thermowell shall be used where possible, these are 225 mm, 275 mm, 325 mm, 350 mm, 375 mm, 400mm, 450 mm &500 mm.

4.3.5. Temperature elements on HVAC ductwork may be installed without thermowells. Connection shall be by proprietary ductwork mounting brackets.

4.4. Local temperature indicators

4.4.1. Local temperature indicators shall be rigid stem bimetallic dial thermometer type supplied complete with protective thermowells.

4.4.2. Dial size shall be 100 mm nominal and instruments shall be heavy duty `every angle' head type. Temperature scales shall be direct reading and comply with manufacturer's standard ranges. The case and stem shall be in stainless steel.

4.4.3. Scales shall be selected to cover the range requirements for both normal and design conditions of plant operation. Filled system temperature indicators with capillary connected bulb may be used where reading remote from measurement points is required. Mercury filled systems must not be used.

5. PRESSURE INSTRUMENTS

5.1. Pressure transmitters

5.1.1. Pressure transmitters shall be referenced to atmospheric pressure.




5.1.2. Transmitters should be smart type, with independent adjustment of zero and span at the instrument and from a remote location. Accuracy shall be +/-0.1% of the calibrated span.

5.1.3. Materials of construction shall be suitable for the process media and based upon the piping specification. In general pressure transmitters should have carbon steel bodies and 316L stainless steel diaphragms as a minimum. For corrosive service suitable materials and chemical seals shall be selected.

5.1.4. Scales shall be selected to cover the range requirements for both start-up, normal and design conditions of plant operation.

5.2. Pressure switches

5.2.1. Generally analogue devices are preferred as the measurement loop is continuously monitored for fault conditions. Where a pressure switch is selected its set point and associated switch differential shall be clearly specified.

5.2.2. Pressure switches connected to the process shall have as a minimum, stainless steel measuring elements.

5.2.3. Diaphragm elements are preferred for low-pressure applications but must provide adequate containment of process media.

5.3. Pressure gauges

5.3.1. Pressure gauge accuracy shall be + 1.0% of full range.

5.3.2. Dial size shall be 100 mm and cases shall be stainless steel screw on or bayonet bezel type. Blowout disc protection shall be provided and gauges shall be orientated such that they vent safely.

5.3.3. Gauge windows shall be constructed from safety pattern / toughened glass.

5.3.4. Gauges shall be normally Bourdon tube type. Bellows or diaphragm-actuated gauges shall be used for lower pressure ranges.

5.3.5. Bourdon tube material shall be type 316 stainless steel, as a minimum, with stainless steel movement, except where process conditions require more stringent materials.

5.3.6. Over-range protection shall be 1.3 times the maximum scale range. Where a gauge is subject a greater pressure, a gauge protector shall be used.

5.3.7. On pulsating service a damper shall be fitted in the input connection.

5.3.8. For vibrating service gauge dials shall be glycerin filled.

5.3.9. Siphons shall be fitted to pressure gauges on steam or hot condensable gas services.




5.3.10. A gauge valve shall be provided for isolation and calibration purposes. A primary isolation valve shall be provided where appropriate.(To be debated)

5.3.11. To facilitate pressure gauge removal and alignment, gauges shall be connected to the piping by means of a gauge adapter and not directly into valves.

5.3.12. Connections shall be 1/2" NPTM/BSPT (to be debated)

5.4. Chemical seals

5.4.1. Chemical seals shall be provided as required for highly viscous, corrosive, slurry, and toxic applications. Gauges fitted with chemical seals shall be flanged in accordance with the piping specification.

5.4.2. Fill fluids shall be suitable for the maximum process operating temperature.

5.4.3. Capillary tubes shall be armoured stainless steel and installed such that they are continuously supported. Tube length shall be minimised to suit each installation.

5.5. Instrument Manifolds

5.5.1. 2-valve manifolds shall be used for secondary isolation, venting and calibration of pressure instruments.

5.5.2. 3-valve manifolds shall be used for secondary isolation, venting and calibration of differential pressure instruments.

6. LEVEL INSTRUMENTS

6.1. Level Transmitters

6.1.1. Generally Chemical seal flush diaphragm type Differential pressure instrument shall be used for the process Equipment.

6.1.2. Float and Tape/Board type or Ultrasonic type Instrument shall be used for large liquid storage tanks

6.1.3. Displacer type level instruments, where used, shall be external type with side / side connections and rotatable transmitter head. Vent and drain valves shall be provided.

6.1.4. Nucleonic level, density or interface detection is not envisaged.

6.2. Level Switches

6.2.1. For Liquid application, Float/Displacer type level switches shall be used, either external cage / internal.

6.2.2. For Solids application the Level switches vibrating turning fork or capacitance type or paddle type. Switch material shall be suitable for the fluid under use.




6.2.3. Level switch connections shall be flanged in accordance with the piping / vessel trim specification. Nozzle connections for lined vessels and pipe work shall be suitably sized for switch insertion

6.3. Level gauges

6.3.1. Reflex type gauge glass shall be used on all services except the following, where transparent type shall be used

i) Interface between two liquid

ii) Liquids containing sediments or solids

iii) Liquids requiring protective shields.

6.3.2. Transparent type

Transparent type gauge glass shall be with integral illuminators.

6.3.3. The visible portion of gauge glass shall cover the range of any associated level instrument. When two or more columns are required to cover a large range, the visible portion of glass shall overlap atleast 50mm.

7. ANALYSIS INSTRUMENTS

These items are considered to be of specialised design and may differ widely in type depending on the sample to be analysed. The vendor’s standard analysers shall be selected. Special attention shall be given to the analyser sample conditioning systems. Detailed equipment specifications shall be produced for all process analysers.

7.1. Gas detection

7.1.1. Flammable gas detectors shall be provided within the process plant. Sensor calibration shall be in %LEL.

7.1.2. Toxic gas detectors shall be provided in high containment areas. Sensor calibration shall be in ppm.

7.1.3. Sensor locations shall be determined by process, but typical locations are:

At room high / low points.

At agitator / pump seals and points of potential escape.

Within HVAC extract ductwork.

7.1.4. A local means of visual and audible alarm shall be provided.

7.2. Fire Detection

7.2.1. The plant areas should be divided into fire zone. The fire system shall be microprocessor based addressable type.

7.2.2. The fire detection shall be carried out using fire detectors, smoke detectors, manual call points.




7.2.3. The detector location shall be as per fire and gas system location plan.

7.2.4. The fire panel shall comprise components for the reception, indication, control and relay signals originating from various fire detector or call points connected to it, for activation of fire alarm sounders and Visual alarms.

7.2.5. In event of fire and gas incident with in the process area or building, the fire panel shall initiate audible and visual alarms. Audible alarms through fire sounders and visual alarms through beacons and all control action as per cause and effect chart.

7.3. pH and Conductivity

7.3.1. Sensors shall be insertion in line or flow through chamber type. A by-pass loop shall be provided to allow isolation, de-pressurisation, and calibration of the electrode system.

7.3.2. Electrodes and sealing assemblies must be designed to withstand the process conditions, including pressure, temperature and dynamic forces as well as being resistant to chemical attack.

7.3.3. Electrodes shall be temperature compensated and supplied complete with buffer reference solution.

8. WEIGHING SYSTEM

8.1. Weighing systems shall be designed in conjunction with process, vessel, piping and civil Engineers and in accordance with the manufacturer recommendations. Erroneous effects from the following shall be minimised:

Side loads Temperature effects Pressure loads Inadequate support / rigidity of civil structure. Thermal expansion Piping resilience Vibration, liquid inflow / outflow effects

8.2. Load cells shall be generally shear beam type of stainless steel construction. Installation should be of three or four load cell configuration, depending on the application.

8.3. The weigh equipment manufacturer shall supply as a minimum requirement load cells, dummy cells, supports, tie rods, cable, summation box, zenner barriers, (if required) signal conditioning electronics and all equipment for system calibration.

9. VALVES

9.1. Control valves

9.1.1. Control valves shall normally be pneumatic diaphragms or piston actuated eccentric disc type with valve characteristics to suit the control application requirements. Eccentric disc valves shall be wafer type for mounting between process flanges.




9.1.2. Butterfly valves shall normally be used for larger line sizes, or where a small pressure drop is available. Butterfly valves shall operate over 60 angular opening unless the valve design provides a full 90 characteristic capability. Rotary valves shall be wafer type suitable for mounting between pipeline flanges.

9.1.3. Control valves shall be supplied equipped and piped with air filter regulator, electro pneumatic positioner, solenoid valve, proximity sensor, volume booster, etc., as required.

9.1.4. Lined control valves shall generally be used for corrosive applications, however where flashing or cavitation is likely to occur exotic materials shall be considered.

9.1.5. Plug type valves may be used in crystalline and slurry services.

9.1.6. The minimum size control valve shall be 25mm. Where the pipe size is less than 25mm the pipe size shall be increased locally to accommodate the valve.

9.1.7. Control valves glands on lethal toxic or hydrogen service shall be specified with special consideration given to gland sealing such as providing bellow seals.

9.1.8. Trim material shall be stainless steel minimum for normal applications. Hardened trim material or facing will be furnished on steam, high pressure, high temperature, or erosive service as the application prescribes.

9.1.9. Leakage rate of the valves shall normally be Class IV Where tight shut-off is required, Class VI shall be specified.

9.1.10. Control valves shall be specified to provide an acceptable noise level when continuously operating to meet local area requirements but shall generally be less than 80 dBA at 1 metre from control valve body and less than 45dBA 20 metres within the site battery limit. Standard valves shall be used and solutions to noise generation problems shall be in the following order:

Low noise trim

Inclusion of in-line diffusers and/or silencers.

Acoustic insulation.

9.1.11. Control valves operated during emergency shutdown conditions will not be provided with either bypasses or hand wheels unless specifically shown on the P&I Diagrams. Where bypasses are provided the CV of the bypass valve shall not exceed the CV value of the control valve.

9.1.12. Control valves should preferably be installed in horizontal lines with the stem vertical and the actuator uppermost. Rotary valves shall be installed with the vane-shaft horizontal.




9.2. On – off actuated valves

9.2.1. Actuated valve type, materials and connections shall be in accordance with the pipe specification.

9.2.2. The on-off valve body size shall be same as line size.

9.3. Actuators

9.3.1. Pneumatic spring return actuators shall be generally diaphragm type for control valves and piston actuated for on-off service. The use of motor or hydraulic actuators shall be restricted to special applications and shall be subject to approval by the Engineer.

9.3.2. To protect personnel and equipment actuators shall on air or control signal failure drive the valve to the fail-safe state as indicated on the P&I diagram.

9.3.3. Double acting actuators shall be normally specified for fail last position applications.

9.3.4. Where spring return actuation can not be provided capacity chambers may be specified to ensure the valve fails safe on motive power failure.

9.3.5. Actuators are to be sized to drive the valve to its fail position against the maximum line differential pressure.

9.3.6. Actuators for all valves are to be sized for the site minimum operating instrument air pressure of 3.5 Kg/cm2g.

9.4. Solenoid valves

9.4.1. Solenoid valves and must have sufficiently sized CV so as not to impede the valve stroking time.

9.4.2. Solenoid coils shall be mounted integral to the valve switch box

9.4.3. Where solenoid valves are fitted remote to the valve, quick exhaust valves may be utilised to improve valve response time.

9.5. Valve switch boxes

9.5.1. A standard switch box design is preferred for all ¼ turn on –off actuated valves. The switch box shall comprise of NAMUR proximity sensors and integrally mounted solenoid valve. Flying leads are not acceptable.

9.6. Self-Operated Regulating Valves

9.6.1. Self-operated regulating valves shall be used for pressure regulation of utility supplies / equipment purging applications and are not recommended where precise control is required.




9.6.2. Regulating valves shall where possible be integral type to minimise process tapping. Pilot-operated regulation valves should be restricted to high capacity applications.

9.6.3. Where appropriate, relief valves shall be used to protect down stream equipment from pressure regulator failure.

9.6.4. A local means of pressure indication shall be provided to facilitate regulator adjustment.

10. SAFETY AND RELIEF SYSTEMS

10.1. General

10.1.1. Safety and relief valves shall meet the requirements of the ASME unfired pressure vessel code, API RP 520, and API RP 521.

10.1.2. In addition, where local codes are also applicable, the stringent requirements shall govern.

10.2. Safety Relief valves

10.2.1. Safety relief valve orifice sizes shall be calculated on a pure ‘area’ requirement basis, capacity adjustments required by code revisions or other applicable regulations shall be covered within valve selection procedure.

10.2.2. Safety valves for general process service shall be direct spring loaded with high lift characteristics and be flanged with minimum carbon-steel body and stainless steel nozzle, disc. and guides.

10.2.3. Lifting levers shall be provided as required by the applicable code for air, hot water and steam service, to allow the disc to be lifted from the seat when the operating pressure is 75% of the seat pressure.

10.2.4. Safety valves will be set to open at the pressure stated on the P&ID. Where variable back pressure exceeds 10% of the set pressure balanced bellows seal type valves shall be used.

10.3. Rupture Discs

10.3.1. Rupture discs will be scored, reverse buckling narrow face capsule type complete with holders to fit inside the ID of the bolt circle of standard flanges. Jacking bolts shall be supplied for disc sizes 2” and larger.

10.3.2. Where a rupture disc is installed upstream of a safety valve an excess flow valve must be installed downstream of the disc to prevent any back pressure on the disc in the event of disc seepage insufficient to burst the disc, and a 50mm (2”) dia pressure gauge provided to detect leakage or rupture.




11. DESUPERHEATER

The desuperheater can be either of the following types based on application.

11.1. Combined Pressure/Temperature Reducing Desuperheater.

11.1.1. This type is a combination unit, which provides steam pressure reduction and temperature control within one unit.

11.1.2. The unit will consist of an in line or angle body type pressure reducing valve, an at temperature section, Spray water valve and nozzle to spray cooling water and a fixed area exit baffle (if required).

11.1.3. This unit shall be capable of providing high flow rate; tight shut off and handling required quantity of spray water. Typical Rangeability shall be of the order of 45:1.

11.2. Variable Geometry Mechanically Atomising Desuperheater

11.2.1. This type shall be used only for steam attemperation. Typical Rangeability shall be 40:1 capable of handling fluctuating load.

11.3. Fixed Geometry Mechanically Atomising Desuperheater

11.3.1. This shall be used only for steam attemperation where load is not of fluctuating nature. Typical Rangeability upto 3:1.

11.4. Fixed Area Annular Spray Mechanically Atomising Desuperheater

11.4.1. This shall be generally used for steam lines having diameter between 1” & 4”. Typical rangeability shall be of the order of 10 : 1

11.5. Steam Assisted Desuperheater

11.5.1. These shall be used for installation where high fluctuation of load is expected. Typical rangeability shall be 50:1.

12. CONTROL SYSTEM

This shall consist of outstations (including plant interface), operator stations, communications and all other equipment and software required for normal operation of the plant .The control console in the operator control centre shall allow the operator to monitor and control the process .The instrumentation connected to the control system shall continuously provide process and utility data .The control system is essential for plant operation.

12.1. Rack Room Facility

12.2. It shall consist of plant I/O interface & marshalling cabinets.

12.3. To maintain the integrity of data communications between various equipment in different locations, there shall be dual communication highways routed separately to their location




12.4. The scan time shall be 500 msec for close loops and 1 sec for open loops. Controller shall not be loaded more than 60% of its capacity in terms of I/O and memory, whichever is lower.

12.5. In case of hazardous areas, the I/O cards shall be intrinsically safe certified. If not, external-isolating barriers shall be provided. For I/O cards number of input/output channels shall be as per manufacturer standard. However maximum number of channels for analogue card shall be 16 and for digital shall be 32.

12.6. Plant Input/Output Interface

It shall comprise of the following

- Analogue input signals

- Analogue output signals

- Digital input signals

- Digital output signals

- Pulse train inputs

12.6.1. The analog input cards shall accept 4~20 mA DC two wire or four wire signals, 1~5VDC signals. Two wire transmitters shall be powered from the system.

12.6.2. The analog output cards shall drive 4~20 mADC signal to an I/P converter. Output scaling, direct/reverse output, selectable fail safe value viz. last good value/preset value/zero value configuration shall be provided.

12.6.3. Digital input cards shall be 24VDC .All digital inputs are potential free contacts, card shall provide interrogation voltage to the input. These cards shall have channel LED for status indication.

12.6.4. Digital output cards shall be 24V DC. Where required an interposing relay shall be used. Atleast one NO contact shall be wired to the terminals. Relay contact rating shall be 230VAC, 5A.Dc relays shall have built in free wheeling diode. All relays shall have LED for status indication. Number of relays shall be equal to the number of digital output channels.

12.7. Control room facilities

12.7.1. The functions required from central facility include the following

- Communication

- Plant history

- Alarm /Event Handling

- Performance monitoring

- Application programs

- Operator communications

12.8. Operator control centre(OCC)




The operator interface for the OCC shall comprise of

- Operator control console

- Event/report printers

- Emergency pushbuttons wherever required.

The equipment shall be designed to satisfy the following operational requirements.

- The movement necessary for the operator to effectively control the plant shall be minimised.

- The layout of the individual items shall be ergonomically correct to ensure ease of operation.

12.9. Database

The control system shall maintain a database which shall allow the operator to view the information directly and indirectly related to the plant being monitored and controlled. The control system shall handle data which shall reflect:

- general alarms, group status alarms and shutdown alarms and pre-alarms.

- setpoints ,measured variable and control elements status/position of all control loops

- equipment status (e.g. running , stopped ,tripped,off-load,isolated for maintenance or start-up etc)

12.10. System Integrity

The control system is an essential part of the plant operability and safety. Therefore it shall maintain a high availability with high level of integrity. This shall be achieved by using high reliability components, hardware redundancy where appropriate and good diagnostic capability for trouble shooting.

12.11. Reliability

The control system shall have a high degree of tolerance to malfunction of hardware, software and operator miskeying .Any fault developed shall have its effect to localized to that part of the control system which remains operational, with a possible reduction in level of functionality. The availability of the control system for control and process monitoring shall be in excess of 99.95%.

12.12. The system shall be so designed such that operator will always have atleast manual access to the control loops final element.




13. EMERGENCY SHUTDOWN SYSTEM WHEREVER REQUIRED

It shall be either of the following types

1. Hardwired relay logic

2. Programmable logic controller

The above PLC’s shall meet anyone of the System Integrity Level (SIL) 1, 2, 3 as per IEC 1508.

13.1. Hardwired relay logic

13.1.1. Logic shall be implemented with hardwired relays.

13.1.2. Only high integrity relays are to be used.

13.1.3. Relays shall be of hermetically sealed type.

13.1.4. Relay contacts shall be gold plated.

13.1.5. The relay coil shall have gravity dropout or dual springs.

13.1.6. The mechanical life expectancy of the relays shall be 100 x 106 min.

13.1.7. Relays shall be of plug-in type into a base unit.

13.1.8. Base unit shall preferably be a DIN rail mounting type and it shall be with screwed terminals

13.2. Programmable logic controllers for ESD

13.2.1. PLC’s shall be Fail-safe & microprocessor based which shall be used for plant Emergency shutdown.

13.2.2. The system shall allow dependable and effective control of the plant and shall be designed for maximum integrity and reliability. Integrity shall be maintained by providing a fail-safe system. The system shall be TUV approved.

13.2.3. The system shall have facilities to replace failed equipment such as processors, I/O cards, microprocessor, and batteries on-line without a shutdown.

13.2.4. The system shall have high integrity including automatic crosschecking, integral self-test facility of input circuits, output circuits, and processors and provide failure indication for operator information and action.

13.2.5. The system shutdown shall only occur in the event of an emergency situation and not as a result of single point failure within the system. A single system fault shall not prevent correct response to a shutdown demand.

13.2.6. The system shall be modular in construction.




13.2.7. The types of modules shall be kept to as minimum as possible in order to have interchangeability and low spares inventory.

13.2.8. The system shall have extensive set of self-diagnostics for hardware and software for easy maintenance.

13.2.9. The system shall be immune to noise and shall ensure safe and reliable operation when subjected to RFI and electromagnetic disturbances.

13.2.10. The system shall be able to operate satisfactorily from 150C to 300C and 20% to 80% non-condensing humidity unless otherwise specified.

13.2.11. Operation of the system shall be completely unaffected if there is a momentary powerless of the order of 20 milliseconds, unless otherwise specified.

13.3. The system shall be supplied with necessary programming tools and related accessories.

14. CONTROL ROOM

14.1. The control room and rack room shall be located in a conventional building in a non-hazardous area. Heating, ventilation and air conditioning systems shall be included to maintain an acceptable operating environment. Process fluids shall not be piped into the control room.

14.2. The rack room shall be located close to the control room and shall house the following

- Marshalling cabinets

- Control system I/O cabinets

- Engg. Station

- Fire and Gas cabinets

- Instrumentation Power supply distribution boards

Other Miscellaneous instrumentation.

14.3. The control room shall house all operator interfaces such as screens,keyboards, printers,ESD push buttons and override switches etc.

14.4. The control rack room shall have false flooring and false ceiling .The false flooring depth shall be 650 mm minimum .The false flooring shall be supported on aluminum framework and cabinets on structural steel framework .The distance between top of false floor and bottom of false ceiling shall be minimum 3 metres.

14.5. The lighting in the control room shall be such that there is no glare on the screens and the minimum lux level shall be 400 lux.

14.6. The temperature inside the control room shall be minimum 21 deg C for equipment and operator comfort.

14.7. The flooring of the control room shall be anti-static and dust-free.

14.8. The air conditioning inside the control room shall be such that supply air diffusers should not be on the top of caibinet. The return air diffusers shall be on the top of cabinet.




14.9. Single/Multicore cables taking signals to/from the field shall enter the rack room through sealed openings to maintain the environment within the control building.

15. UTILITY SUPPLIES

15.1. Instrument power supplies

15.1.1. The primary electrical supply for instrumentation shall be single-phase supply supported by an uninterruptable power supply (UPS), sized to supply emergency power on mains failure for a minimum period of 30 minutes.

15.1.2. The UPS shall be a no break change over type. A standby supply and bypass switch shall be provided for maintenance purposes.

15.1.3. Supplies for instrumentation shall be derived from 230Vac / 24Vdc redundant power supply units. Instrumentation power shall be wherever possible 24Vdc. Where this can not be achieved 230Vac may be used as an alternative. Voltages greater than 230 volts must not be used for instrument supplies.

15.2. Instrument air supplies

15.2.1. The air supply for instrumentation shall be derived from the site compressed air system. The instrument air quality shall be in accordance with ISA S7.01 1996

The pressure dew point as measured at the dryer outlet shall be atleast10 C below the minimum temperature to which any part of the instrument air system is exposed .The pressure dew point shall not exceed 4 C at line pressure.

Particle size in the instrument air upto 40 micron is acceptable.

The lubricant content shall be close to zero as possible and the instrument air shall be free of contaminant.

15.2.2. Instrument air headers and sub-headers shall be galvanised carbon steel and routed from the main compressed air header to locations determined by the Instrument Engineer.

15.2.3. Connections to instruments shall be via instrument air distribution manifold and 6mm / 12 mm OD tubing.

15.2.4. Local filters or filter regulators and gauges shall be supplied where appropriate.




16. INSTRUMENT CONNECTIONS

16.1. Standard connections

16.1.1. Inline instrument process connections shall be generally flanged type to ANSI B16.5 in accordance with the piping specification. In case of food grade or pharma applications Tri-clamp or weld in connections shall be used.

16.1.2. Standard connection sizes on piping and equipment shall be used in accordance with the table listed in appendix C.

16.2. Instrument process piping

16.2.1. Impulse lines shall be kept as short as possible. Piping up to and including the first process block valve and in-line instruments shall conform to the line or vessel classifications concerned. The first block valve shall be installed as close as possible to the line or vessel.

16.2.2. Instrument piping after the first block valve may be an alternative equal or better material to that of the main process line or vessel. The minimum standard being seamless 12mm OD 316 stainless steel tubing with 1.5mm wall thickness.

16.3. Instrument air tubing

16.3.1. Instrument air supply tubing shall be stainless steel or PVC covered copper tubing as indicated in the hook-up diagram.

16.3.2. Larger diameter tubing may be used for high speed or large volume applications.

17. INSTRUMENT CABLE AND WIRING

17.1. Cable

17.1.1. Standard instrumentation cable shall be used in accordance with BS5308 part 2; PVC insulated, with a single collective screen.

17.1.2. Analog Input / Output & Digital Inputs (Switches)

Main cable runs between control room and field junction box shall be multipair, twisted, stranded 1.0 sq.mm, annealed bare copper conductors, PVC insulated, overall screen and with 0.5mm2 annealed tinned copper drain wire, galvanised wire armoured, overall PVC sheathed. Multipair cables shall be supplied in the following standard pair 1,2,5,810,16,20& 30 pair depending on the local grouping of field instruments.

17.1.3. Cables between Instruments and junction boxes shall be of same specification as 17.1.2. but will be of single pair instead of multipair.

17.1.4. Cables for Solenoid Valves (110VAC/230 V AC)




17.1.4.1. Main runs between control room and field junction boxes shall be multipair, twisted, stranded 1.5 sq.mm. Annealed bare copper conductor, PVC insulated, single layer galvanised wire armour, and overall PVC sheathed.

17.1.4.2. The cable outer PVC sheath shall be coloured blue for intrinsically safe cable and black for non-intrinsically safe cables.

17.1.5. Termination

17.1.5.1. Terminations shall normally be of the rail mounted, preferably Wago or equivalent make.

17.1.5.2. Both ends of all cables and their used cores shall be identified by individual cable marker rings as per drawing.

17.1.5.3. To achieve insulation and continuity of the screen, the drain wires shall be accommodated using terminals with in the box.

17.1.5.4. Instrument gland entries shall be ½” NPT.

17.1.6. Power cable colour code shall be:

230Vac: Phase Red

Neutral Black

Earth Green

24Vdc: Positive Red

Negative Black

17.2. Junction boxes (Field)

17.2.1. All junction boxes shall be identified by permanently fixed label.

17.2.2. Junction boxes shall be certified suitable for the degree of protection, explosion proof wherever required. Boxes shall be weatherproof to IP 55 minimum and be provided with doors having gaskets.

17.2.3. Cables shall only enter from bottom or side inside the junction boxes. All gland plates are to be undrilled and removable. Cable glands shall be double compression type Cd plated brass. These shall be ex-proof wherever specified and weather proof IP 55 to minimum.

18. SEGREGATION AND INSTALLATION

18.1. No multipair cables shall contain both intrinsically safe and non-intrinsically safe circuits. Calculations shall be done for each intrinsically safe loop to prove that the cable capacitance and inductance do not invalidate the certificate for intrinsic safety.

18.2. Only circuits carrying the same voltage shall be contained in the same multipair cable.




18.3. Instrument signal cables shall be run separate to power cables, the separation shall be at least 300 mm. Where crossovers of instrument and electrical signals is unavoidable, they shall be so arranged to cross at right angles.

18.4. Intrinsically safe signal cables shall be normally routed separately to other signal types. Where this is not practical, physical separation shall be achieved by means of a metal dividing plate.

18.5. Cables shall be routed away from access areas; high temperature equipment and areas of potential attack by leakage of chemicals, specially solvents.

18.6. Cables shall be routed from instrument equipment rooms to field junction boxes on galvanised steel cable ladder rack. Cables to individual instruments shall be routed in open tray

18.7. Control and Marshalling cabinets

18.7.1. Cabinets shall be freestanding enclosed type and shall be designed for bottom entry cables. Removable gland plates for glanding cables shall be provided.

18.7.2. Cabinets shall be fabricated from CRCA sheet with a minimum thickness of 2mm and shall be reinforced to prevent warping and buckling.

18.7.3. Cabinet doors shall be fabricated from CRCA sheet with a minimum thickness of 1.6mm. Cabinets shall be with front and rear access. Flush pull handle with keylock shall be provided to all access doors.

18.7.4. All cabinets shall be fitted with removable eyebolts for lifting the cabinets. Also blanking plates for eyebolts shall be provided.

19. EARTHING

19.1. The following earth systems shall be provided when applicable

- Instrument System Earth (Clean Earth) – for signal earths, screens etc.

- Control Cabinet Earth (Dirty Earth) – For Signal earths, screens etc.

- Barrier Device Earth – for barrier system earth requirements (where intrinsically safe zener barrier devices are included).

19.1.1. Cable screens shall be earthed at one location only and this shall generally be at the control room terminal location area.

19.1.2. The Barrier Device earth shall be insulated from the Control Panel Earth and run separately to the instrument system earth-electrodes.

19.1.3. For Instrument System and Barrier Device earths the total earth loop impedance on any circuit shall be less than as specified by control system vendor.




20. PACKAGE EQUIPMENT

20.1. Instrumentation requirements for package equipment shall be in accordance with specification INST/515/02.

21. DOCUMENTATION

Documentation for instrumentation shall generally comprise of

General specifications

Data sheets, specifications and requisitions.

Instrument schedules

Interlock and trip diagrams.

Instrument layout and routing drawings

Field wiring diagrams

Cable schedules

Hook up drawings

Loop diagrams

Instrument material take off

21.1. As built Drawings

“As built” drawings shall be supplied for all documents appropriate to the operation and maintenance of the plant.

22. TESTING AND INSPECTION

Testing and inspection shall be carried out at vendor’s works as per inspection / test requirements attached with each specification

Final inspection shall be performed only after the Vendor has satisfactorily completed his test. The tests shall be a complete repeat of those tests performed by the Vendor with any additional tests that the Purchaser shall find necessary to ensure proper operation of the equipment/system

23. INSTALLATION

23.1. Installation of all field instrumentation and equipment shall comply with the requirements of CCI P/1 and CCI P/2 Instrument installation specification (Contractor committee on Instrumentation) of Energy Industries Council U.K.




APPENDIX - A

UNITS OF MEASUREMENT AND SCALES

UNITS OF MEASUREMENTS

Volume : M3

Heat duty : kWTemperature : 0CLength : mm, mMass : Kg, tTime : Sec, min, hrPressure : Bar a, Bar g, mm H2O, kpa.Mass Flow : Kg/ hr , t/hrVolume Flow : M3 / hr, Nm3 / hrDensity : Kg/ m3

Viscosity : Cp.Voltage : VCurrent : APower : kW, MwRotation : RpmNoise : dBA

SCALESGraduation of scales shall be as follows :PARAMETER SCALEFlow (orifice) : 0-10 sq. rootFlow ((linear) : 0-100 linearFlow (variable area) : 1-10 linearLevel : 0-100 linearPressure : Direct reading (Dual Scale)Temperature : Direct reading




APPENDIX - B

INSTRUMENT CONNECTIONS ON VESSELS

SR NO INSTRUMENT VESSEL CONNECTION

FIRST BLOCK VALVE

INSTRUMENT CONNECTION

1 Displacer LT- External 2” Flanged 2” Flanged 2” Flanged

2 Displacer LT- Internal 4” Flanged ---- 4” Flanged

3 Level Gauges 1” Flanged 1” Flanged 1” Flanged

4 D.P. Instrument on Vessel 1” Flanged 1” Flanged ½” NPT

5 Flush Diaphragm DP cell - HP

3” Flanged 3” Flanged 3” Flanged

LP

1” Flanged ½” NPT(F) 1/2” NPT(F)

6 Remote Seal DP Cell - HP 3” Flanged 3” Flanged 3” Flanged

LP


7 Capacitance Type Inst. 2” Flanged ----- 2” Flanged

8 Level Switch- Internal Float 4” Flanged ----- 4” Flanged

9 Float & Tape Level Instrument

3 x 1.5” Flanged ------ 3 x 1.5” Flanged

10 Ultrasonic Level Instrument 4” Flanged ----- 4” Flanged

11 Tuning Fork Type Level Switches

1.5” NPT (F) ------- 1.5 NPT(M)

12 Pressure Transmitter 1” Flanged ½” NPT(F) 1/2” NPT(F)

13 Pressure Gauges 1” Flanged ½” NPT(F) 1/2” NPT (M)

14 Pressure Transmitter - Seal Type


15 Pressure Gauges – Seal Type 2” Flanged 2” Flanged 2” Flanged

16 Thermowell 3/4” NPT ----- 3/4” NPT

NOTES:

1. For any other instrument not referred above, connection shall be as per individual requirement.

2. For serial number 14, 1” flanged connection shall be used based on availability.

3. In case of direct mounted flanged instruments, or where first block valve is specified, bolting and gasket shall be by Piping.

All flanged connection shall be ANSI




APPENDIX - C

ENVIRONMENTAL CONDITIONS

(Project Specific – Reference shall be made in this Appendix)

Local Conditions shall be as per document :




APPENDIX – D

INSTRUMENT CODES / STANDARDS

SR.NO ITEM DESCRIPTION STANDARD EDITION

1 Control Valves Face to Face & End to End Dimensions of Valves

ANSI B 16.10

Control Valve Seat Leakage ANSI/FCI 70.2

Hydrostatic Testing of Control Valves

ISA S75.19

2 Safety valves Design & Installation of Pressure Relieving Systems in Refineries

API RP 520 PART-I

API RP 520 PART-II

Flanged Steel Safety Relief Valves API RP 526

Seat Tightness of Pressure Valves API STD 527

Boiler & Pressure Vessel Code ASME SEC VIII with addendum upto 1994

Bursting Discs and Bursting Disc Devices

ISO 6718

3 Orifice Plates Steel Orifice Flanges

Measurement of Fluid Flow

ANSI B16.36

ISO 5167

4 RTD Industrial Platinum Resistance Thermometer Sensors

IEC 751

5 Thermocouple Thermocouples-Reference Tables IEC-584 Part 1

Thermocouples-Tolerances IEC-584 Part 2

Thermocouples-Extension and Compensating Cables-Tolerances and Identification System

IEC-584 Part 3

6 Instrument Cables

Instrumentation Cable BS 5308 Part-I & II

Specification for PVC insulated (Heavy Duty) Electrical Cables

IS 1554 Part – I

Specification for PVC Insulation & Sheath of Electrical Cables

IS 5831

Specification for PVC Insulated Cables

IS 694

Specification for Conductors for Insulated Electric cables and flexibles

IS 8130

7 Miscellaneous Instrumentation Symbols and Identification

ISA S5.1

Graphic Symbols for DCS Systems

ISA S5.3





Instrument Loop Diagrams ISA S5.4

Annunciation Sequence and Spec ISA S18.1

Quality Standard for Inst. Air ISA S7.0.01

Degree of Protection provided by Enclosures

IEC 529

Electromagnetic Compatibility for Industrial Process Measurement and Control Equipment

IEC 801

Operating Conditions for Industrial Process Measurement and Control Equipment

IEC 654

8 Hazardous Area Protection

Electrical Apparatus for Explosive Gas Atmosphere-Construction and Verification of Flameproof Enclosure of Electrical Apparatus

IEC 79-1

Electrical Apparatus for Explosive Gas Atmosphere-Electrical Apparatus Type of Protection ’p’

IEC 79-2

Electrical Apparatus for Explosive Gas Atmosphere-Classification of Hazardous Area

IEC 79-10

Electrical Apparatus for Explosive Gas Atmosphere-Intrinsic Safety “i”

IEC 79-11

Electrical Apparatus for Explosive Gas Atmosphere-Artificial Ventilation for protection of Analyser Houses

IEC 79-16

Electrical Apparatus for use in Class-I, Zones -0&1 Hazardous(classified) Locations-General Requirements

ISA S12.0.01

Purged and Pressurised Enclosure for Electrical Equipment

NFPA 496

ISA S12.4

Wiring Practices for Hazardous(Classified) Locations Instrumentation Part I-Intrinsic safety

ISA RP 12.6

Intrinsically Safe System Assessment using the Entity Concept

ISA TR12.2





9 Flanges and Threads

Screw Threads-Pipe Threads General Purpose(inch)

ANSI/ASME B1.20.1

Ring Joint gaskets and groove for Steel Pipe Flanges

ANSI/ASME B16.20

Large Diameter Steel Flanges NPS26 through 60

ANSI/ASME B16.47

Steel Pipe Flanges & Flanged Fittings

ANSI B 16.5

NOTES: 1. Unless otherwise specified latest edition of the standard shall be referred

instrument design basis_akpg

Documents

explosive gas atmosphere

barrier device earth

instrument design basisrev

small pressure drop

pressure dew point

operator control centre

field junction boxes

electrical cables specification