Nioec SP 70 01

NIOEC-SP-70-01(5)
DOCUMENT CODE NO. OF SHEETS: 52

PLAN/PRJ/SUB UNIT PHASE DISCIPLINE DOCUMENT TYPE SERIAL NO. REV. NO. DATE
NIOEC 000 EG IN SP 7001 A5 SEPTEMBER, 2015
NATIONAL IRANIAN OIL REFINING & DISTRIBUTION COMPANY

NATIONAL IRANIAN OIL ENGINEERING
& CONSTRUCTION COMPANY
NIOEC SPECIFICATION
FOR
INSTRUMENTATION
SECOND EDITION
MAY 2009
THIS STANDARD IS THE PROPERTY OF NATIONAL IRANIAN OIL ENGINEERING & CONSTRUCTION COMPANY. IT IS CONFIDENTIAL AND ALL
RIGHTS RESERVED TO THE OWNER. NEITHER WHOLE NOR ANY PART OF THIS DOCUMENT MAY BE DISCLOSED TO ANY THIRD PARTY,
REPRODUCTED, STORED IN ANY RETRIEVAL SYSTEM OR TRANSMITTED IN ANY FORM OR BY ANY MEANS WITHOUT THE PRIOR WRITTEN
CONSENT OF THE NATIONAL IRANIAN OIL ENGINEERING & CONSTRUCTION COMPANY.
SEPTEMBER, 2015 NIOEC-SP-70-01(5)
IN THE NAME OF GOD
FOREWORD
By their very nature, technical Specifications are continuously subject to modifications and
revisions. To strengthen their merit and usefulness, continuous improvements, addendum, deletion
of disparate information and consequently provision of updated revisions are to be made in order to
ascertain that such Specifications meet the current requirements, inclusive of Iranian Petroleum
Standards (IPS) and the recognized and acceptable national and international Standards, as well as
the optimal codes and practices based on the accumulated in-house know-how and plant knowledge
and experiences.
However, in reality, due to several reasons, not to mention the complexity of the matter, the ultimate
goal of continuous direct embedment of the required changes on the relevant Specifications may be
far reaching. Therefore, in the interim periods between the officially issued revisions, the required
changes will appear in other documents related to the engineering and design work of the ongoing
projects.
In response to the initiative of the Design and Engineering Directorate, and considering that the task
of the execution of several important and mega projects for the realization of the new oil refineries,
pipelines and oil terminals as well as improvements of the existing facilities, has been assigned to
NIOEC, it was decided to update the NIOEC Specifications and to issue new official revisions.
The Design and Engineering Directorate was itself entrusted to carry out this important task, and as
such by forming several special technical committees, working in close co-operation and cohesion
and sharing their expertise and knowledge, the updated and revised NIOEC Specifications were
successfully prepared and complied.
These Specifications are intended to be used for Oil Refineries, Distribution Depots, Oil Terminals,
Pipelines and Pump Stations within NIOEC's projects, and have been proven to be of high value for
such purposes. It must however be appreciated that these Specifications represent the minimum
requirements and should in no way be interpreted as a restriction on the use of better procedures,
engineering and design practices or materials.
We encourage and highly appreciate the users and other clear sighted and experts to send their
comments on the Specifications to the Design and Engineering Director of NIOEC for evaluation
and approval.
REVISION INDEX
REV. REV. REV. REV.
PAGE 1 2 3 4 5 PAGE 1 2 3 4 5 PAGE 1 2 3 4 5 PAGE 1 2 3 4 5
1 26 X X X 51 76
2 X 27 X X X 52 77
3 X 28 X 53 78
4 29 X X 54 79
5 X X X 30 X 55 80
6 X X 31 X 56 81
7 X X 32 X X 57 82
8 X X X X 33 X X 58 83
9 X X X X 34 X 59 84
10 X X X 35 X 60 85
11 X X X X 36 X 61 86
12 X X 37 62 87
13 X 38 X 63 88
14 X X X X X 39 X 64 89
15 X X X X X 40 X 65 90
16 X X 41 X 66 91
17 X X X X 42 67 92
18 X X X 43 X X 68 93
19 X X 44 X X X 69 94
20 X X 45 X X X 70 95
21 X X X X 46 X 71 96
22 X X X 47 X X 72 97
23 X X 48 X X 73 98
24 X X X 49 74 99
25 X X 50 X X 75 100
NOTES:
1) THIS SHEET IS A RECORD OF ALL REVISIONS TO THIS SPECIFICATION.
2) WHEN APPROVED EACH REVISION SHALL BE CONSIDERED AS A PART OF THE ORIGINAL DOCUMENT.
3) NUMBER OF PAGES EXCLUDES THIS SHEET AND THE COVER SHEET.
5 SEPTEMBER, 2015 F. FAZLI H. SHIRINPOUR M. ORDOOBADI A.A.MOGHADAM

4 MAY, 2009 INST. DISCIPLINE KHATIB FARZAM SAJEDI
3 FEBRUARY,2007 JOUHARI ORDOOBADI FARZAM SAJEDI
2 JULY, 2006 KHARAZI ORDOOBADI FARZAM SAJEDI
1 JULY, 2005 KHARAZI ORDOOBADI FARZAM SAJEDI
REV. DATE PREPARED CHECKED APPROVED AUTHORIZED
CONTENTS: PAGE NO.
1. SCOPE.........................................................................................................................................3
2. REFERENCES ...........................................................................................................................4
3. UNITS ..........................................................................................................................................6
4. ABBREVIATIONS ....................................................................................................................6
5. DESIGN BASIS ..........................................................................................................................7
5.1 General ..................................................................................................................................7
5.2 Instrument Accessibility ......................................................................................................7
5.3 Instrument Air Supply .........................................................................................................7
5.4 Electrical Power Supply.......................................................................................................8
5.5Instrument Protection ...........................................................................................................8
5.6 Environmental Protection ...................................................................................................9
5.7 Hazardous Area Classification ............................................................................................9
5.8 Data Sheets ............................................................................................................................9
5.9 Instruments Symbols and Legends .....................................................................................9
6. FIELD INSTRUMENTATION ................................................................................................9
6.1 General ..................................................................................................................................9
6.2 Flow Measurement .............................................................................................................15
6.3 Temperature Measurement ...............................................................................................25
6.4 Pressure Measurement ...................................................................................................... 27
6.5 Level Measurement ............................................................................................................29
6.6 Traps, Drainers And Strainers .........................................................................................32
6.7 Battery Limit Isolation Requirements..............................................................................33
7. CONTROL VALVES ..............................................................................................................33
7.1 General ................................................................................................................................33
7.2 Control Valve Sizing ..........................................................................................................33
7.3 Sizing Pressure Drop ..........................................................................................................33
7.4 Noise Level ..........................................................................................................................34
7.5 Characteristics ....................................................................................................................34
7.6 Stroking Time .....................................................................................................................36
7.7 Body and Bonnet ................................................................................................................36
7.8 Trim Construction..............................................................................................................37
7.9 Actuators .............................................................................................................................38
7.10 Accessories ........................................................................................................................39
7.11 Control Valve Manifolds ................................................................................................. 41
8. ESD VALVES ...........................................................................................................................44
8.1 General ................................................................................................................................44
8.2 Stroking Time .....................................................................................................................44
9. AUTOMATIC ON/OFF VALVES AND SWITCHING VALVES .....................................44
10.PRESSURE RELIEF VALVES ..............................................................................................45
11.ANALYTICAL INSTRUMENTS ...........................................................................................45
11.1 General ..............................................................................................................................45
11.2 Sample Tapping ................................................................................................................46
1
12.TANK GAUGING SYSTEM ..................................................................................................47

13.FIRE AND GAS DETECTION ..............................................................................................47
14.CABLING .................................................................................................................................47
15.JUNCTION BOXES ................................................................................................................48
16. PLANT CONTROL AND SAFEGUARDING PHILOSOPHY .........................................48
17.CONVENTIONAL CONTROL PANELS .............................................................................48
18. NAMEPLATES .......................................................................................................................48
19.CONTROL CENTERS ............................................................................................................49
20. INSTRUMENT TESTING, CALIBRATION AND INSPECTION ...................................49
21.PREPARATION FOR SHIPMENT .......................................................................................49
22.GUARANTEES ........................................................................................................................50
23.REQUIRED DOCUMENTATION ........................................................................................50
23.1 General ..............................................................................................................................50
23.2 Specific Requirements for the Documents .....................................................................51
2
1. SCOPE
1.1. This specification defines NIOEC’s general requirements for the design of field
instrumentation, control and safeguarding systems.
Deviations from this specification will only be permitted on obtaining written approval from
NIOEC.
Resolution on cases not explicitly stipulated in this Specification, or on cases where conflicts
may arise among the requirements of the referenced IPS and the international standards, shall
be made through written consent and approval of NIOEC.
1.2. Specific specifications for major instrumentation equipment, instrument installation, material
and P&ID abbreviations, legends and symbols are covered in the following NIOEC
specifications:
- NIOEC-SP-70-02 NIOEC Specification for Instrument Installation
- NIOEC-SP-70-03 NIOEC Specification for Instrument Installation Material
- NIOEC-SP-70-04 NIOEC Specification for Electric Motor Operated Valves
- NIOEC-SP-70-05 NIOEC Specification for Instrumentation Control Cables, Cable
Trays, Conduits, Junction Boxes and Cable Glands
- NIOEC-SP-70-06 NIOEC Specification for Bidirectional Meter Provers
- NIOEC-SP-70-07 NIOEC Specification for Instrumentation & Control System
Calibration, Inspection and Tests
- NIOEC-SP-70-08 NIOEC Specification for Process Control System (PCS)
- NIOEC-SP-70-09 NIOEC Specification for Safeguarding Systems
- NIOEC-SP-70-10 NIOEC Specification for Tank Gauging Equipment
- NIOEC-SP-70-11 NIOEC Specification for Instruments Of Fire-Fighting and
Detection Equipment
- NIOEC-SP-70-12 NIOEC Specification for Volumetric Liquid Measurement
Methods
- NIOEC-SP-70-13 NIOEC Specification for Electrical Power Supply and Distribution
Systems
- NIOEC-SP-70-14 NIOEC Specification for Control Panels and System Cabinets
- NIOEC-SP-70-15 NIOEC Specification for Control Centers
- NIOEC-SP-70-16 NIOEC Specification for General Instrumentation Factory
Inspection and Testing of Instruments and Instrument Systems
- NIOEC-SP-70-17 NIOEC Specification for Instrument Protection
- NIOEC-SP-70-18 NIOEC Specification for Pipeline Instrumentation
- NIOEC-SP-70-19 NIOEC Specification for Miscellanous Instruments
- NIOEC-SP-70-20 NIOEC Specification for Pipeline Automatic Leak Detection
System
- NIOEC-SP-70-21 NIOEC Specification for Programmable Logic Controllers
3
- NIOEC-SD-0100-1 to 4 NIOEC Standard Drawing for P&ID Symbols and Legends

- NIOEC-SD-0101-1/1 NIOEC Standard Drawing for P&ID Abbreviations
2. REFERENCES
The following standards, codes, and specifications, to the extent specified hereinafter, shall
constitute a part of this NIOEC Specification. Latest edition of the undated referenced documents
and the cited edition of the dated references shall apply. The applicability of changes made to the
dated references, after the cited date shall be mutually agreed upon between NIOEC and the
Vendor/Contractor.
ANSI (AMERICAN NATIONAL STANDARDS INSTITUTE)

ANSI/FCI 70-2 "Control Valve seat Leakage"
API (AMERICAN PETROLEUM INSTITUTE)

API MPMS Chapter 5.2 "Measurement of Liquid Hydrocarbons by Displacement
Meters"
API MPMS Chapter 5.3 "Measurement of Liquid Hydrocarbons by Turbine Meters"
API MPMS Chapter 5.6 "Measurement of Liquid Hydrocarbons by Coriolis Meters"
API MPMS Chapter 5.8 "Measurement of Liquid Hydrocarbons by Ultrasonic Flow
Meters Using Transit Time Technology"
API RP 505 "Classification of Locations for Electrical Installations at
Petroleum Facilities"
API RP 551 "Process Measurement Instrumentation"
API RP 553 "Refinery Control Valves"
API RP 555 "Process Analyzers"
ASME (AMERICAN SOCIETY OF MECHANICAL ENGINEERS )

ASME B 1.20.1 "Pipe Threads , General Purpose"
ASME B 16.34 "Valves-Flanged, Threaded and Welding End"
ASME B 16.36 "Orifice Flanges"
ASME B 16.5 "Pipe Flanges and Flanged Fittings"
IEC (INTERNATIONAL ELECTRO-TECHNICAL COMMISSION)

IEC 60079 "Electrical Apparatus for Explosive Gas Atmospheres"
IEC 60529 "Classification Of Degrees Of Protection Provided By
Enclosures"
4
IEC 60534-2-1 "Industrial-Process Control Valves – Part 1: Control Valve

Terminology and General Considerations"
IEC 60534-2-1 "Industrial-Process Control Valves – Part 2-1: Flow Capacity
– Sizing Equations for Fluid Flow under Installed Conditions"
IEC 60584 "Thermocouples"
IEC 60751 "Industrial platinum resistance thermometers and platinum
temperature sensors"
IPS (IRANIAN PETROLEUM STANDARD)

IPS-E-IN-100 Part I "Engineering Standard for General Instrumentation"
ISA (INSTRUMENTATION, SYSTEMS, AND AUTOMATION SOCIETY OF AMERICA)

ISA MC 96.1 "Temperature Measurement Thermocouples"
ANSI/ISA 7.0.01 "Quality Standard for Instrument Air"
ANSI/ISA 75.01.01 "Industrial-Process Control Valves – Part 2-1: Flow Capacity -
Sizing Equations For Fluid Flow Under Installed Conditions"
ANSI/ISA 75.02.01 "Control Valve Capacity Test Procedures"
ISA 75.05.01 "Control Valve Terminilogy"
ISA 75.11.01 "Inherent Flow Characteristics and Rangeability of Control
Valves"
ISA 75.13.01 "Method of Evaluating the Performance of Positioners with
Analog Input Signals and Pneumatic Output Second Printing"
ISA 75.17 "Control Valve Aerodynamic Noise Prediction"
ANSI/ISA 75.19.01 "Hydrostatic Testing Of Control Valves"
ISO (INTERNATIONAL ORGANIZATION FOR STANDARDIZATION)

ISO 5167-1 "Measurement of Fluid Flow By Means Of Pressure
Differential Devices Inserted in Circular Cross-Section
Conduits Running Full- Part 1: General Principals and
Requirements"
Conduits Running Full- Part 2: Orifice Plates"
Conduits Running Full- Part 3: Nozzles and Venturi Nozzles"
ISO/TR 15377 "Measurement of Fluid Flow By Means Of Pressure
Differential Devices - Guideline for the Specification of
Orifice Plates, Nozzles and Venturi Tubes Beyond the Scope
of ISO 5167"
5
NAMUR (NORMENARBEITSGEMEINSCHAFT FÜR MESS UND REGELTECHNIK IN

DER CHEMISCHEN INDUSTRIE)
NAMUR NE 43 "Standardization of the Signal Level for the Failure
Information of Digital Transmitters"
NACE (NATIONAL ASSOCIATION OF CORROSION ENGINEERS)
NACE MR0103 "Materials Resistant to Sulfide Stress Cracking in Corrosive
Petroleum Refining Environments"
ANSI/NACE MR0175/ "Petroleum and Natural Gas Industries — Materials for
ISO 15156 Use in H2S-Containing Environments in Oil and Gas
Production"
NIOEC SP(NIOEC SPECIFICATIONS)

NIOEC-SP-00-10 "Specification for Units"
NIOEC-SP-00-50 "Specification for Design Criteria for Process and Mechanics"
NIOEC-SP-00-55 "Specification for Piping & Instrumentation Diagrams
(P&IDs)"
NIOEC-SP-00-75 "Specification for Pressure and Vacuum Relief Devices"
NIOEC-SP-50-08 "Specification for Winterizing & Heat Conservation"
NIOEC-SP-50-54 "Specification for Pig Lunching & Receiving Trap"
NIOEC-SP-90-52 "Specification for Packing and Packages"
NIOEC-SP-90-02 "Specification for Welding of Plant Piping Systems"
NIOEC-SIP (NIOEC SHOP INSPECTION PROCEDURE)

NIOEC-SIP-70-01 “Shop Inspection procedure for Instruments”
3. UNITS
International System of Units (SI) shall be used in accordance with NIOEC-SP-00-10, unless
otherwise specified.
4. ABBREVIATIONS
Throughout this document the following abbreviations and acronyms are used:
CV: Control Valve.
DCS: Distributed Control System.
ESD: Emergency Shutdown System.
F&G: Fire and Gas Detection.
FAT: Factory Acceptance Test.
FS: Full Scale
HART: Highway Addressable Remote Transducer.
IP: Ingress Protection.
JB: Junction Box
6
LAN: Local Area Network

NPTF: National (American) Standard Pipe Thread Tapered Female.
NPTM: National (American) Standard Pipe Thread Tapered Male.
P&ID: Piping and Instrumentation Diagram.
PCS: Process Control System.
PD: Positive Displacement.
PTFE: Poly Tetra Fluoro Ethylene (Teflon).
SGS: Safeguarding System.
SI: International System of Units.
SIL: Safety Integrity Level.
SPDT: Single Pole Double Throw.
TC: Thermocouple
UPS: Uninterruptible Power Supply.
5. DESIGN BASIS
5.1. General
a) Design of the instrumentation shall be such that adequate control and safety aspects of the
plant during all phases of operation are guaranteed.
b) The instrumentation shall be designed for fail safe operation of the plant, as determined by
NIOEC.
c) All safety and relief valves, control valves and flow meters shall be adequately sized in
order to enable the instruments to cope with both normal operation conditions and the
conditions existing during start-up, shut-down or permissible over capacity operation. The
required over capacity shall be stated on the individual data sheet.
d) Furnaces and boilers shall be provided with approved burner management systems, when
specified by NIOEC.
e) Instrumentation for major package units shall be of the same type and manufacture as for the
main process unit, except when this is not practical; in such case written approval of NIOEC
shall be required.
f) The instrumentation for minor packages such as sampling systems, air dryers, etc. should be
of manufacturer’s standard design and type.
5.2. Instrument Accessibility

Instrument process connections shall be designed to be located for maximum convenience for
operating and servicing of the instruments. Accessibility of the instruments shall be in
accordance with the requirements of NIOEC-SP-70-02.
5.3. Instrument Air Supply

a) All tubing for field-mounted pneumatic equipment shall be PVC coated copper tube unless
ottherwise specified (e.g.) stainless steel for corossive atmosphere. Fittings shall be brass.
The instrument air loop header shall be galvanized carbon steel pipe up to 1.5 inch and plain
carbon steel for 2 inches and above.
7
b) All field mounted pneumatic instruments shall be provided with individual valves for
shutting off the air supply and each instrument shall have an individual air filter/regulator
and gage.
c) The main instrument air supply shall be furnished independent of the plant air supply
without interruption from other general air user requirements.
d) Instrument air quality shall be in accordance with the ISA 7.0.01. Dew point shall be at least
10°C below the Minimum Ambient Temperature. Instrument air shall be dry and oil and
dust free.
5.4. Electrical Power Supply

The plant PCS, SGS, F&G System and Packaged units' instrumentation shall be fed with at
least one electrical power feeder from the UPS. The UPS , which shall be dual redundant, shall
be sufficiently sized to provide 230 VAC, 50 Hz power to all connected systems for at least 30
minutes.
All field instruments shall be supplied by the internal power supplies of the PCS, SGS, and
F&G Systems.
For details reference shall be made to NIOEC-SP-70-13.
5.5. Instrument Protection

Instruments shall be protected to ensure proper and dependable operation under all operational
and climatic conditions.
Instruments in the following conditions require special provisions:
i) Instruments handling fluids which solidify (or have high viscosity) at 20°C. Such fluids
shall not be allowed to enter the instrument, because shop repair would be impractical.
ii) Instruments handling fluids which solidify at the lowest ambient temperature (including
water at sub-zero temperatures). Such fluids shall not be allowed to enter the instruments or
pressure piping to prevent malfunctioning and/or damage.
Where the above provisions are not practical, heating of impulse lines (hook ups),
instrument valves and instrument wetted parts shall be adopted and due care shall be taken
such that the instrument is not overheated.
iii) Instruments in gas measurement services, where hydrate formation may occur at low
temperatures, and instruments handling fluids containing solids (including coke particles).
Diaphragm seals shall be utilized to protect the instruments.
In addition, for the fluids containing solids the process connection shall be made large enough
to prevent plugging.
Diaphragm seals shall be shown on the P&IDs.
For detailed requirements of instrument protection, including heat tracing reference shall be
made to NIOEC-SP-70-02 and NIOEC-SP-70-17.
8
5.6. Environmental Protection

All field equipment shall be suitable for the ambient temperature as specified in the project
documents and the material and construction shall be resistant to saliferous dust, insect attacks,
and moisture and fungus growth. Sunshades shall also be provided for protection against
sunlight wherever required.
Outdoor equipment (instruments, panels and enclosures) shall be watertight to IEC 60529, IP
65 as a minimum. Large size outdoor local panels, for which IP 65 may not be applicable, shall
be pressurized.
5.7. Hazardous Area Classification

a) All electrical instrumentation, panels, junction boxes and enclosures, which will be installed
in hazardous areas, shall generally be of intrinsically safe type suitable for the hazardous
area classification. For equipment that intrinsically safe type is not available or the working
supply voltage precludes the use of intrinsically safe circuits, explosion proof or pressurized
type may be specified.
b) Hazardous area classification shall be as per API RP 505 and IEC 60079.
c) For details on instrument selection in hazardous area, reference shall be made to IPS-E-IN-
100 Part I.
5.8. Data Sheets

Unless otherwise specified, ISA instrument data sheets will be used for all instrumentation.
5.9. Instruments Symbols and Legends

Reference shall be made to the following documents:
NIOEC-SD-00-0100-1 to 4 "Standard Drawing for P&ID Symbols and Legends",
NIOEC-SD-00-0101-1/1 "Standard Drawing for P&ID Abbreviations".
6. FIELD INSTRUMENTATION
6.1. General
6.1.1. Transmitters
a) Transmitters shall be smart type, commensurate with the type of the PCS, i.e., 4-20 mA
type (HART support), Foundation Fieldbus or Profibus compatible type. Integral digital
indicators shall be supplied for each transmitter.
b) All transmitters (pressure, flow, temperature etc.) shall be provided with burnout
protection.
c) Alarm (burnout) and saturation current limits shall be NAMUR-NE-43 compliant as
follows:
i) If the process variable applied to the transmitters falls outside of the lower or upper
range settings, the output signal shall saturate at the following values:
ii) Under range; 5% of transmitter lower range
9
iii) Over range: 2.5 % of transmitter upper range

iv)The integral indicator shall flash to signify the "out of range" reading.
v) In case of transmitter failure, the output shall be driven to less than 10 % of lower range
or greater than 5% of upper range (user configurable), with the integral indicator
displaying "Alarm" to indicate the failure status.
d) Selection of transmittres shall be subject to their performance characteristics including the
low figure of long term full scale drift, low figure of full scale temperature effect, their
insensitivity to vibration, repeatability, hysterisis and overrange protection. The pressure
and differential pressure insruments having diaphragm seals shall have high "spring rates"
to minimise the error due to seal liquid expansion at elevated ambient temperatures.
6.1.2. Switches
Field mounted transmitters should be used in lieu of field mounted switches according to the
following:
- For SGS services, SIL III transmitters shall be used.
- In case of voting systems, transmitters of types other than SIL III may be used.
- For PCS and alarming services appropriate type of transmitters or switches may be used.
6.1.3. Signal Levels

a) All field mounted transmitters in connection with the plant PCS shall operate on 24 VDC,
4-20 mA signals and shall support HART protocol if PCS is of conventional DCS type,
and shall operate on the appropriate digital signals if the selected PCS is of Fieldbus type
(e.g. Foundation fieldbus or Profibus).
b) All field mounted transmitters in connection with the plant SGS shall operate on 24 VDC,
4- 20 mA signals and shall support HART protocol.
c) Field mounted switches, if any shall operate on 24 VDC, volt free contacts.
d) Solenoid valves shall be intrinsically safe type operating on 24 VDC.
e) Local loops, i.e., those not required to be connected to the PCS shall be pneumatic,
operating on 0.2-1.0 Barg signal.
f) Digital (serial) communication between field sensors and SGS shall be prohibited. For
detailed requirements, reference shall be made to NIOEC-SP-70-09 section 9.1.
6.1.4. Power Supply

a) The 24 VDC power to all field instruments shall always be supplied by the plant PCS
and/or SGS. As such all transmitters shall be of "current sinking" type.
6.1.5. Accuracy of Instruments

Instruments shall conform to the following accuracies, unless otherwise specified in the
detailed specification approved by company.
10
Instrument Accuracy
Temperature Gauge ±1.0% F.S. or Class 1 per EN 13190

Pressure Gauge ±1.0% F.S.
±2.0% F.S.
Variable Area Flow Meter
±4.0% F.S. (Metal tube purge meter)
Displacement Type Level Transmitter ±0.5% F.S.
Pressure / DP / Temperature Transmitter ±0.2% F.S.
Positive Displacement Type Flow Meter ±0.2% of reading at relevant flow condition
Thermocouple Class 1 as per IEC 60584
RTD Class A as per IEC 60751
Mass Flow Meter Better than ±0.2% of full scale (at liquid base)
±3 mm (less than 10m)
Guide wire radar meter ±0.03% of measuring range
(over 10m and less than 30m)
A/D Converter (cabinet mounting type) ±0.1% span
D/A Converter (cabinet mounting type) ±0.3% span
FF/P Signal Positioner ±0.5% (for linearity)
6.1.6. Instruments Cable Entry

Instrument cable entry size shall be M20×1.5 for single pair cable connection with the
appropriate cable gland. For instruments with other than single pair cable connection,
appropriate size with the cable gland shall be specified.
6.1.7. Material
a) All instrument wetted parts in connection with the process shall generally be AISI 316,
unless higher grades are required by the process conditions. Instruments wetted part
material in sour services shall comply with NACE standard MR0175.
b) Unless otherwise specified in this document, material of Control valve bodies, ESD valve
bodies, Orifice flanges, in-line flow instruments flanges and displacer type level
instrument flanges shall conform to the piping flange/valve materials in accordance with
the related NIOEC Piping Specification.
6.1.8. Pressure/Temperature Rating of Instruments and Valves

Minimum rating of inline instruments and control/safety valves shall be in accordance with
the piping specification. However rating of orifice plates and orifice flanges, body and flanges
of control valves, ESD valves and On/Off valves shall be ANSI 300 # minimum.
6.1.9. Impulse Lines

a) In general, in ANSI flange class 300 and 600 services, all instrument impulse lines (hook
ups) downstream of the first process isolating valve, shall be ½ inch OD, 316 Stainless
Steel seamless tubing with wall thickness of 0.065 inch minimum, and 316 Stainless Steel,
bar stock double-ferrule compression type fittings. Byte type fittings are not permitted.
11
b) For ANSI flange class of above 600 , or cases where the impulse lines (hook ups) are
subject to physical expansion, or the line classes as specified in NIOEC-SP-70-03, impulse
lines (hook ups) shall be ½ " OD, seamless pipes.
c) For service with pressure of greater than 40 Barg, fully butt-welded construction with
heavy wall tubing or line pipe shall be provided.
d) Tubing diameter for analyzer fast loop shall be selected considering the lag time
calculation.
6.1.10. Manifold valves

a) In addition to the process (or piping) isolation valve at the measurement take-off point,
each pressure instrument (except diaphragm seal) shall be provided with a dedicated
manifold valve to enable maintenance, in-site calibration, venting and draining. The
manifold valves shall be provided as follows:
 2-valve for pressure gauges, pressure transmitters and switches.
 3-valve (double block and bleed type) for pressure gauges, pressure transmitters and
switches in services of ANSI Class 900 and above.
 5-valve for DP type transmitters
b) Process connection of the manifold valves shall be ½ inch NPTF. However but welded
NPT connection may also be required as per project requirements.
c) The manifold valves on Pressure and differential transmitters shall be bracket mounted
type with the base bracket mounting holes such that the instruments can be directly
connected to the manifold valves by flush mounting, and the assembly can be installed
and supported on 2" stanchions by bracket mounted manifolds.
d) As a minimum, material of the manifold valves shall be AISI 316 stainless steel.
6.1.11. Process Isolation Valve

Process isolating valves shall be sized as follows:
a) Pressure Gauges, pressure switches, pressure transmitters on process lines: Globe valve,
¾ inch.
b) Pressure Gauges, pressure switches, pressure transmitters on vessels: Flanged Globe
valve, 1 inch.
c) Orifice Plate isolating valves: Gate valves, ½ ", and Globe valve ½ " for ASME flange
class 900 and above.
d) Side mounted external displacer type level transmitters: Flanged Gate valve, 1-1/2 inches.
e) Top mounted internal displacer type level transmitters or level switches: 6 inches flanged
Gate valve (if specifically required in the project specification),
f) Side mounted external displacer type level switches: Flanged Gate valve, 1 inch.
g) Level gauges: Flanged ¾ inch gate valve on standpipes, and 1 inch flanged gate valve on
direct vessel connections. For hydrogen service, the valve shall be 1 inch flanged gate
valve, both on standpipe and on vessels. Level gauges shall be connected to the isolating
valves through automatic gauge valves.
12
h) All level instruments except level gauge connections on 3" standpipe shall be the same as
that of direct to vessel connections.
The process isolating valves are within the battery limit of the Piping discipline and the
Instrument discipline battery limit starts at downstream of the valves.
6.1.12. Instrument to Process Connection

The following table shall be conformed for instrument to process connection size and type:
Connection to Equipment Instrument
Vessel Pipe Connection
Size Type Size Type Size Type

Without Diaphragm Compression
Pressure/DP 1" Flanged ¹ 3/4" 1/2" NPT
Seal Fitting ²
Transmitter
With Diaphragm Seal 2" Flanged (1" , 1 1/2" , 2" ) 3 Flanged 1/2" NPT
Pressure/DP Without Diaphragm Compression

1" Flanged ¹ 3/4" 1/2" NPT
Gauge or Seal Fitting ²
Switch With Diaphragm Seal 1 1/2" Flanged ( 1" , 1 1/2" ) 3 Flanged 1/2" NPT
External Side Mounted 1 1/2" Flanged - - 1 1/2" Flanged
Level
Displacer Internal Side Mounted 4" Flanged - - 6" Flanged
Transmitter Internal Top Mounted 6" Flanged - - 6" Flanged
Without Diaphragm
DP Level 1" Flanged - - 1/2" NPT
Seal
Transmitter
With Diaphragm Seal 2"/3" Flanged - - 1/2" NPT
Level Gauge 1" Flanged - - 1" Flanged
External Displacer/
Float Type Side 1" Flanged - - 1" Flanged
Mounted
Level Switch Internal Displacer/ Float
4" Flanged - - 4" Flanged
Type Side Mounted
Internal Top Mounted 4"/6" Flanged - - 4"/6" Flanged
Level Standpipe 3" Flanged - - - -
Radar Level
Tank 6"/8" Flanged - - - -
Transmitter
Gauging
Thermo Element 4" Flanged - - - -
- Compression
DP Flow Transmitter - 3/4"
Fitting ²
1/2" NPT
Thermo-well 1 1/2" Flanged 1 1/2" Flanged 1/2" NPT
1- Connection to flanged globe isolating valve will be by blind flange with 1/2" threaded hole instrument hook-up tubing connection.
2- Connection to globe isolating valve will be by 3/4" NPT x 1/2" O.D. male connector (Compression Fitting) for instrument hook-up tubing
connection.
3- Diaphragm seal type pressure gauge/transmitter on pipe connection size shall be specified according to diaphragm seal application and process
requirements.
6.1.13. Instrument Nozzle Rating on Vessels

Minimum flange rating for instrument nozzles on vessels shall be as follows:
13
a) Level instrumentation standpipes: ANSI 300 #.

b) Pressure relief valve: ANSI 300 #.
c) All nozzle sizes equal or lower than 1-½ inches: ANSI 300 #.
6.1.14. Welding
Any welding work related to the instrumentation shall be in accordance with NIOEC-SP-90-
02.
6.1.15. Local Indicators

a) Pressure switches (if any), back pressure valves, pressure reducing valves, pressure
balanced type valves and blind type pressure transmitters or controllers (if any) shall be
specified with local gauges mounted in proximity.
b) If a transmitter or any of the above mentioned instruments, serving a control valve, has
an integral indicator or a local gauge not readable from the location of the control valve,
a supplementary readable indicator or gauge shall be provided.
c) On all control loops connected to the PCS, and all transmitters connected to the SGS, a
local gauge, i.e., pressure, temperature or level gauge, shall be provided and installed
adjacent to the control loop transmitter, to verify transmitter reading.
6.1.16. Diaphragm Seals

a) A diaphragm seal system consists of a pressure transmitter, one or two diaphragm seals, a
fill fluid, and either a direct mount or capillary style connection Transmitter. Diaphragm
seal systems should be considered when:
 The process temperature is outside of the normal operating ranges of the transmitter and
cannot be brought into those limits with impulse piping.
 The process is corrosive and would require frequent transmitter replacement or specific
exotic materials of construction.
 The process contains suspended solids or is viscous and may plug the impulse piping.
 The application requires the use of sanitary connections.
b) All pressure elements with diaphragm seal shall have capillary bleeder. The entire system
above the diaphragm, including the element shall be evacuated and entirely filled with an
inert liquid. The bottom section shall be removable for cleaning.
c) Where remote diaphragm seals are used, the capillary tube shall be stainless steel 316
with stainless steel 304 armor as a minimum.Seal liquid shall be selected such that the
adverse effect of ambient temperature change be kept to the minimum possible.
d) Where flush mounted diaphragm seals are used, a flushing ring with two 1/2" NPTF
connections shall be provided for flushing valves connection.
14
6.2. Flow Measurement

6.2.1. General
a) Field mounted flow transmitters shall be used on all flow control loops, monitoring, ESD
and interlock services.
Notes:
1. Flow transmitters include differential head producers in combination with a DP-
transmitter, Coriolis meters, etc., however exclude transmitters with variable
area meter.
2. Instruments for mass balance calculations (when identified as such on the
P&IDs) are to be specified with no relaxation on any of the design factors
affecting accuracy. These include the physical restraints such as straight lengths,
etc., but may also cover requirements for density and temperature corrections
and other physical variables, when indicated on the P&ID.
3. Instruments used for fiscal metering (when identified as such on the P&ID) shall
be approved by the local authorities. This will include the primary element,
transmission system and instruments required for density corrections (e.g.
temperature).
b) Seal Chambers
Seal chambers will normally be furnished in the following services:
Where corrosive materials may be present,
Where materials of high viscosity may be present during normal operation or start-ups
which may plug the impulse line (hook up) in normal operation.
c) Adequate Purge Systems will be provided when orifice or pressure tap plugging may be
expected.
d) Local Recorders shall not be used for accounting purposes in remote off-site locations.
e) Special Flow Requirements can call from time to time for special measurement devices
such as target meters, turbine meters, magnetic meters, weirs, floats, etc. Each situation
shall be considered individually by NIOEC and the most suitable type of meter shall be
specified.
6.2.2. Instrument Types

The following types of instruments may be selected for the measurement of liquids, vapors
and gasses, when their selection can be justified:
6.2.2.1. Differential Pressure Transmitter

a) General
Differential pressure transmitters may be used in combination with any of the following
primary elements as required:
 Square edge orifice plate with flange tapping (above 14" radius taps shall be used)
 Venturi or Dall tube flow meter (Where low pressure loss is essential) for ISA nozzle
with DP-transmitter
 Conical entrance or quarter circle (quadrant edge) orifice plates (For low pipe
Reynolds numbers)
15
 Averaging pitot tube (Where no appreciable pressure loss can be tolerated, on clean
service only)
 Segmental or eccentric orifice plates (may be used in horizontal lines where the liquid
contains large amounts of solids).
b) Installation and Construction
 Pre-fabricated metering runs shall be used for line sizes below 2". Sizes smaller than
2" shall only be used if it can be shown that swaging up to 2" is not viable. Integral
orifices will be considered for very small flows (line sizes 1/2")
 The transmitters shall be able to withstand the application of the maximum service
static pressure to the "low" pressure side, with the "high" side at atmospheric pressure,
without any adverse effect or requiring recalibration.
 Square root extraction shall be included in the transmitter.
6.2.2.2. Vortex Flow Meters

a) General
Vortex meters shall not be employed without the written approval of NIOEC, and in any
case vortex flow meters shall not be used in the following applications:
 Wet steam,
 Liquids with high vapor pressures (see note),
 Viscous fluids,
 When the fluid of a control valve mounted upstream or downstream of the vortex flow
meter is flashing or cavitating,
 Pulsating flow (e.g. downstream reciprocating compressors),
 When the pipeline in which the vortex flow meter is installed is subject to vibration.

If the process fluid is flammable, then wafer type vortex flow meters are not permitted.
Vortex meters shall be flanged type, installed in straight lengths of process pipe work in
accordance with the Manufacturer’s instructions. Shorter straight lengths may be
accepted when flow is measured for control, safeguarding, indication and alarm loops
and the additional inaccuracy does not exceed 0.5% of flow rate.
6.2.2.3. Variable Area Meters (Rotameters)

a) General
Variable Area flow meters may be used for small flow rates where local indications,
recording and/or controlling is required. They may also be used where rangeability, non-
linearity, viscosity or the hazardous nature of fluid makes the differential pressure-type
instrument unsuitable.
16

Variable Area flow meters shall normally be the armored type with magnetic sensing
element. Variable area meters shall be installed so that repair, maintenance and
replacement will not disturb the operation of the plant. If isolation valves be required,
they shall be gate type of the same size as the meter connections. The bypass valve, if
required, should be a gate type and sized the same as main line size. In general, metal
tube VA meters shall be used. Glass type variable area meters may only be used in low
pressure/temperature services and if the fluid cannot cause a hazardous situation in case
of a broken glass. Meters shall be equipped with inlet and outlet float stops.
6.2.2.4. PD Meters
a) General
Positive Displacement Meters will be used to measure the flows where integrated
flowing quantity and high accuracy is required.
The meters shall be suitable the operation of being proved from a proving system.
The meters shall have an upstream strainer with pressure taps for differential pressure
transmitter with an alarm signal. The strainer mesh size shall be as recommended by the
PD meter vendor. Careful consideration shall be given to bearing type, lubrication and
protection against abrasive materials. Each product transfer meter shall be equipped with
a transmitter wired to its own individual printing counter. Six-digit readout in decilitres
will be used. In addition Air eliminator & flow control valve shall be provided.
Meter bodies shall be constructed for minimum pressure drop and have calibration
controls and integrated automatic temperature compensation.
Local counter shall be weatherproof and shall include a totalizer, which cannot be reset.
Each meter shall be supplied a high-resolution pulse transmitter whose output signals are
used for custody transfer totaling and meter proving.
P.D. meters for product transfer shall have remote print out in the tankage control room.
The accuracy of the meters shall be ±0.2% or better.
The pulse amplifier/converter shall be mounted as close as possible to the PD meters.
Body material shall conform to piping material specifications.
Positive Displacement Meters shall meet the requirements of API Manual of Petroleum
Measurement Standards-chapter 5.2 "Measurement of Liquid Hydrocarbons by
Displacement Meters".
For further details reference shall be made to NIOEC-SP-70-12: "Standard Specification
for Volumetric Liquid Measurement Methods".
17
6.2.2.5. Coriolis Type Mass flow Meters

a) General
 Coriolis meters will be used in applications where accurate measurement of mass flow
or density is required or in applications where the nature of the process fluid renders
other process intrusive instruments unsuitable.
 Coriolis meters are not suitable on liquid services containing significant gas content, or
on gas services with low in-line pressure.
 In custody transfer applications, the requirements of API, Manual of Petroleum
Measurement Standards, Chapter 5, Section 6 shall be followed.
 Coriolis meters on high temperature services shall have remote mounted transmitters.
The temperature limit shall be checked with the meter vendors.
6.2.2.6. Ultrasonic Flow meters

a) General
 Ultrasonic meters may be used for applications where the minimal pressure loss is
required due to the presence of flow meter, in pipelines applications with pigging
requirements, or in flare lines.
 The presence of bubbles or impurities within the process fluid causes erroneous
meter reading and as such care has to be taken in their application. Ultrasonic meters
shall not be used in two-phase flow services.
 If air or vapor is present in the flowing stream, eliminators shall be provided to
minimize measurement error.
 Meters shall be adequately protected from excessive pressure through the proper use
of pressure relief devices. (This kind of protection may require the installation of
surge tanks, expansion chambers, pressure-limiting valves, pressure relief valves,
and/or other protective devices).
 If the meter is utilized in bi-directional flow, an upstream flow-conditioning section
shall be installed on both inlets of the meter.
 If a meter is utilized more often in one flow direction than the other, temperature,
pressure and/or density instrumentation shall be located downstream of the meter run
relative to this direction.
 An un-interruptible regulated power supply (UPS) shall be required for continuous
meter operation.
 Ultrasonic Flow meters shall be transit-time type.
 The meter shall have minimum dependency on viscosity.
 The position and number of transducers shall be capable of covering all regimes of
flow including laminar, turbulent, transition and it shall be independent of the
Reynolds number.
18
 In order to minimize the effects of air or sediment, the transducer shall not be located
on top or bottom of the pipe.
 Failure of each transducer shall be alarmed at the meter transmitter.
 System accuracy (meter and all compartments) shall be less than 2% of full scale.
Error shall be reduced by careful determination of pipe ID and by increasing number
of paths.
 Transducer replacement within operation shall be preferred without operation
interruption.
 The transmitters shall comply with the principles of ISO 6551 "cabled transmission
of electric pulse data".
 Replacement of sensor, electronics or sensor cables shall require that the meter to be
reproved.
 In custody transfer applications, the requirements of API, Manual of Petroleum
Measurement Standards, Chapter 5, Section 8 shall be followed.
 Note shall be taken that ultrasonic meters require high volumes for proving; hence
compact provers shall not be used to prove these meters.
 Air eliminator and flow control valve shall be provided.
 Straight pipe lengths of 10 pipe diameters with a flow conditioner (or 20 or more
pipe diameters without a flow conditioner) upstream of the meter and 5 pipe
diameters downstream of the meter may provide effective conditioning, unless the
meter manufacturer’s recommendations or flow research support different lengths.
 The preferred location of the flow or pressure-control valves shall be downstream of
the meter run and prover takeoff valves, and be capable of smooth operation to
prevent shocks and surges.
 Valves, particularly those between the meter and prover (e.g., the stream diversion
valves, drains, and vents) require leak proof shutoff, which may be provided by a
double block-and-bleed valve with telltale bleed.
6.2.2.7. Turbine Flow Meters

Turbine meters may be used for process flow measurement where highly accurate, wide
range measurement of very small flow rates is required.
The meter shall be bi-directional with the rotor and blades shall be made in one piece,
requiring no welding. Flow Strainer shall be used in the upstream of Turbine flow meters.
The rotor arrangement shall be such that the meter shall cater for variations in density,
viscosity and temperature with little or no effect on the meter K-factor.
In custody transfer applications for light products or light crude oils, the requirements of
API Manual of Petroleum Measurement standards, Chapter 5, Section 3 shall be followed.
Where a power supply interruption could result in a significant error in measurement,
provision for an uninterruptible power supply shall be considered.
The installation shall ensure a maximum, dependable operating life. Strainers, filters,
air/vapor eliminators, or other protective devices may be provided upstream of the meter to
19
remove solids that could cause premature wear or gases that could cause measurement
errors.
6.2.2.8. Flow Switches

Flow switches might be derived within a PCS/SGS system from an analogue loop signal.
6.2.3. Orifice Plates, Venturies and Flow Nozzles

6.2.3.1. Orifice Plates
a) Orifice Types and Selection
 Orifice Plates in line 1-1/2 inch nominal size and larger shall be of the square edged
except where unsatisfactory for the application.
 Concentric orifice plates shall be used for clean liquids, gases, and steam flows when
Reynolds numbers range from 20,000 to 107 in pipes under six inches. Concentric
orifice plates should not be used for multi-phase fluids in horizontal lines because the
secondary phase can build up around the upstream edge of the plate, which in extreme
cases, may clog the opening, or it can change the flow pattern, creating measurement
error. Eccentric and segmental orifice plates are better suited for such applications.
Because the basic orifice flow equations assume that flow velocities are well below
sonic, a different theoretical and computational approach is required if sonic
velocities are expected. Because of the minimum Reynolds number consideration,
square-edged orifices should not be used on viscous fluids. Quadrant-edged and
conical orifice plates are recommended when the Reynolds number is under 10,000.
Flange taps can be used with quadrant-edged orifices, but only corner taps should be
used with a conical orifice.
 Concentric orifices are still preferred for multi-phase flows in vertical lines because
accumulation of material is less likely and the sizing data for these plates is more
reliable. If the secondary phase is a gas, the opening of an eccentric orifice will be
located towards the top of the pipe. If the secondary phase is a liquid in a gas or slurry
in a liquid stream, the opening should be at the bottom of the pipe. The drainage area
of the segmental orifice is greater than that of the eccentric orifice, and, therefore, it is
preferred in applications with high proportions of the secondary phase. These plates
should be used in pipe sizes exceeding four inches in diameter, and must be carefully
installed to make sure that no portion of the flange or gasket interferes with the
opening. Flange taps are used with both types of plates, and are located in the
quadrant opposite the opening for the eccentric orifice, in line with the maximum dam
height for the segmental orifice. Eccentric and Segmental type orifice plates shall
have bottom of the orifice bore or arc flush with I.D. of the pipe.
 For the measurement of low flow rates, a d/p cell with an integral orifice may be the
best choice. In this design, the total process flow passes through the d/p cell,
eliminating the need for lead lines. They are recommended for clean, single-phase
fluids only because even small amounts of build-up will create significant
measurement errors or will clog the unit.
 Restriction orifices are installed to remove excess pressure and usually operate at
sonic velocities with very small beta ratios. The pressure drop across a single
20
restriction orifice should not exceed 500 psi because of plugging or galling. In multi-
element restriction orifice installations, the plates are placed approximately one pipe
diameter from one another in order to prevent pressure recovery between the plates.
b) Orifice Plates Construction

 Concentric orifice plates with bores larger than 1" shall be provided with drain holes
at the bottom of the plate to prevent buildup of entrained liquids in gas and steam
streams, or with vent holes at the top of the plate for venting entrained gases in liquid
services. The unmeasured flow passing through the vent or drain hole is usually less
than 1% of the total flow if the hole diameter is less than 10% of the orifice bore. The
effectiveness of vent/drain holes is limited, however, because they often plug up.
 Orifice plates shall be 316 stainless steel in material as a minimum, with 1/8"
thickness in sizes 6" and smaller, 1/4" thickness in sizes 8" to 16", and 3/8" inch
thickness in sizes 18" and larger.
 On special and monel orifice plates, if holding ring is required, it shall be cadmium
plated carbon steel. Orifice plate and holding screws or snap ring (if required) shall be
monel. Stainless steel and asbestos gaskets shall not be used.
 Each plate shall be provided with a tab with projects beyond the flange. The symbol
number, plate material, the actual measured bore and the I.D. of the pipe shall be
stamped on this tab. The tab shall be in line with the drain or weep hole.
 Orifice plates shall be manufactured in accordance with the dimensions and
tolerances given in ISO 5167-2 and shall conform to the latest ASME Flow
Measurement Supplement to the ASME Power test Codes.
 For steam and wet gas applications in horizontal lines, the orifice plate shall be
provided with a drain hole. For liquid applications, the orifice may contain a vent
hole.
 Orifice flanges shall be consistent with ASME B16.36 and shall be of the welding
neck type.
 In flammable gas service and steam, pressure taps shall be provided with reinforced
butt-welded nipples. For other services screwed nipples may be used if permitted by
the applicable piping specification.
 The flange material, facing and type of gasket shall be consistent with the applicable
piping specification.
 The use of flange facing other than raised face shall be as called for in Piping
Specification. For dimension of orifice flanges ASME B 16.36 shall be referred.
 Orifice flanges shall be provided with spare pressure taps.
 The minimum length of straight pipe preceding an orifice plate shall generally be in
accordance with NIOEC-SP-70-02. Wherever possible meter runs shall be provided
on the basis of d/D ratio not less than 0.70.
 The position of the pressure tapping on the horizontal lines shall be as follows:
i) Dry Clean Gas: Pressure taps shall be vertically up,
21
ii) Wet Gas (excluding steam): Pressure taps shall be horizontal, (draining into the
process is required),
iii) Steam: Pressure taps shall be horizontal ,
iv)Clean Liquid and Condensate: Pressure taps shall be horizontal, at the horizontal
center line,
v) Liquids which boil at or below the maximum design ambient temperature at
operating pressure: Pressure taps shall be vertically up, (draining into the process is
required).
vi) Installation of flow element on the vertical lines is not preferred. In rare cases if
such installation cannot be avoided the direction of the flow shall be upwards for
the liquid services and downwards for the steam and gas services.
 45o taps on the orifice flanges may be used in special cases with NIOEC's approval.
 Ring Type Plate Holders shall be manufacturer’s standard plate mounting.
6.2.3.2. Venturies and Flow Nozzles

i) Venturies and flow nozzles shall be installed in straight lengths of process pipe work in
accordance with ISO 5167-3 or equivalent standard. The values in parentheses, given in
section 1.1 are the minimum required for control, safeguarding, indication and alarm
loops, however the values given without parenthesis are preferred. When measurement
is required for material balance (to be indicated on the P&ID) the values without
parentheses shall be used.
ii) Pitot and pitot Venturi Elements may be used where high accuracy is not required, or
the pipe diameter is too large for acceptable orifice plate design. Instrument accuracies
shall conform to the table in section 6.1.5 of this specification.
iii) Other Types of Flow Elements should be considered where their use is desirable and the
above mentioned elements are not applicable.
6.2.3.3. Sizing Requirements

i) Orifice plates, used on differential pressure flow measurement installations, shall be
sized to ISO 5167-2 or equivalent standard. Sizes below 50 mm (2"), not covered by ISO
5167-2, shall be calculated in accordance with ISO/TR 15377.
ii) Differential pressure range shall normally be 0.25 bar (100" water column), however, for
gas and vapor service the differential pressure range in inches of water shall normally
not exceed the flowing pressure in psi (a).
iii) The d/D Ratio of the orifice plate shall normally be between 0.25 and 0.70, with orifice
bores of less than 0.125 inches to be avoided.
iv)Maximum flow rate shall be chosen so that a rounded flow factor is available.
v) Orifice shall be sized so that the maximum flow rate falls at approximately 75% of
maximum meter range and the minimum flow does not be less than 25% of maximum
meter range.
22
6.2.4. Meter Provers

Meter Prover Loops of the bi-directional, skid mounted, U-type, with local permanently
connected proving facility shall be provided where specified. For detail refer to NIOEC-
SP-70-06.
6.2.5. Flow Meter Selection Table

The following table which is based on ISA Comprehensive Survey and Guide to Flow
Meters Selection is intended to give a guideline to the selection of various types of flow
meters.
Ultrasonic
Rotameter
Magnetic
Pd Meter
TRANSIT TIME
Coriolis
Turbine
Venturi
Orifice
Nozzle
Vortex
Thermo-Physical Pitot
DOPPLER
Features
Water
S
S
Low Viscosity
S (2)
S(3)
SS
S
S
Organic Liquis
High Viscosity
S (4)
S (2)
S(5)
US
US
US
US
SS
SS
SS
SS
S
Organic Liquis
Gases At Near
S(5)
S(5)
US
US
SS
SS
S
Atmospheric Pressure
SS(13)
Gases At High
US
SS
SS
SS
S
Pressure
Hot Liquids
S(8)
US
US
SS
SS
SS
S
T>200 ◦C
Hot Gases And Steam
US
US
US
US
US
SS
SS
S
T>200 ◦C
Suspension Of Solids
SS(1)
US
US
US
US
US
US
SS
S
In Liquids
SS(1)
S(7)
US
US
US
US
US
US
US
Two Phase Flow

SS
SS
23
Coriolis S S S US S
NIOEC-SP-70-01(5)
US Coriolis US US US S
DOPPLER S S US US S US
DOPPLER S US S S
Ultrasonic
Ultrasonic
TRANSIT TIME S S US US S S TRANSIT TIME S US S S
Magnetic SS US S S(12)
Magnetic S S S US S S
Vortex US(6) US(6) US(6) S
Vortex US US US US S S
Turbine US US SS US S S Turbine US(6) US(6) SS(6) US
Pd Meter S S S S S(10) US Pd Meter US US SS US
SEPTEMBER, 2015
24
Rotameter SS SS S S S SS Rotameter US US S SS
Pitot SS US S(9) SS(9) US US Pitot S S S S
Nozzle US US US US US SS(9) Nozzle US US US S
Venturi US US S SS(5) US SS(9) Venturi S S S S
Orifice US S(4) SS(5) US US SS(9) Orifice SS(5) SS(5) US S
Very Small Gas Flows

Reynolds Number ≤
Low Pressure Losses

2000 ≤ Reynolds ≤
Very Small Liquid
Long Life Without

Very Large Air Or
Very Large Water
Fluid Dynamic
Pulsating Flow
Plant Features
Rangeability
Recalibration
Very Wide
Features
Gas Ducts
Flows
2000
6000
Pipes
Table Cont'd
Table Cont'd
Table Cont'd
Ultrasonic
Rotameter
Magnetic
Pd Meter
TRANSIT TIME
Coriolis
Turbine
Venturi
Orifice
Nozzle
Vortex
Pitot
DOPPLER
Plant Features
Liquid High Accuracy
US
SS
SS
SS
SS
SS
SS
S
S
Flowrate Measurement
Liquid High Accuracy
US
US
US
US
US
S
Quantity Measurement
Gas High Accuracy
SS(11)
US
US
US
US
US
Flowrate And
SS
SS
SS
S
Quantity Measurement
Notes on the Table 6.2.5.:
S: Suitable
US: Unsuitable
SS: Sometimes Suitable
(1) Eccentric orifice
(2) Conductive fluids
(3) The flow range decreases as the dynamic viscosity increases.
(4) Eccentric and conical entrance orifices.
(5) Depending on the pressure losses.
(6) Suitable for insertion type.
(7) Unsuitable for high concentration at the secondary phase.
(8) A calibration to the measuring fluid temperature is required.
(9) Depends on the secondary elements.
(10) The flow range for gas flows is wider than the flow range for liquid flows.
(11) Only for high pressure (heavy gas).
(12) A periodic cleaning of the electrodes is required.
(13) Only for metal tubes.
6.3. Temperature Measurement

6.3.1. General
Field mounted temperature transmitters shall be used on all temperature control loops,
monitoring, ESD and interlocks.
6.3.2. Temperature Elements

a) Temperature element wires shall be mineral insulated and metal sheathed.
b) The temperature elements shall be provided with a weatherproof head with element
wires connected to terminals.
c) Duplex temperature elements will be provided if indicated on the P&IDS. The
termination head for duplex elements shall be provided with two separate cable entries.
If temperature measurement is required for both control and ESD functions, two
elements, each having their own protection wells, shall be provided. Exceptions are
made for multipoint temperature assemblies on reactors.
d) For remote indication, control and shutdown functions, the following type of
temperature sensing elements will be selected for process temperature measurement:
25
Minimum/Maximum
Sheath Sensor type
Operating Temperature ◦C
3-Wire PT-100 or
-200 TO 350 AISI 316 T type TC
4-Wire PT-100
0 TO 500 Inconel K type TC 3-Wire PT-100 J type TC
0 TO 950 Inconel K type TC

Aluminium
R type TC B type TC
950 TO 1250 (flue Gas Oxide
only)
Nicrobell N type TC
Note 1:
Thermocouple measuring junction shall be ungrounded.
For monitoring heater tubes skin temperature, knife-edged type thermocouple elements
shall be used.
6.3.3. Temperature Transmitter

 The output signal of temperature transmitters shall be linear with temperature.
 Thermowells shall be standardized on 1-1/2" flanged type. The material shall be AISI 316
SS, unless higher grades are required by the process conditions.
 Head mounted transmitters shall normally be used.
6.3.4. Thermowells
a) All temperature elements and temperature gauges shall be installed in protecting wells.
b) Thermowells material shall be 316 stainless steel bar stock or better if dictated by the
process.
c) All thermowells in process piping and pressure vessels shall have pressure rating as per
piping specification. Thermowells installed in process piping or process pressure vessels
in other than steam services, shall meet the requirements of the latest edition of the
American Society of Mechanical Engineering Code for unfired pressure vessels. For steam
service, all thermowells shall meet the requirements of the latest editions of the American
Society of Mechanical Engineers Code for boilers.
d) Thermowells connection shall be 1-1/2" flanged type as per ASME B16.5. Flange material
shall be the same as specified for the associated thermowells.
e) Multipoint thermocouple assemblies and long thermowells which cannot be made from bar
stock may be fabricated, however only full penetration butt-welds are permitted which
shall be 100% radiographic examined.
f) Flange-well welding shall be a full penetration weld.
g) In process lines smaller than 6", the required insertion length shall be obtained by one of
the following:
 Partly enlargement of the line diameter to 6";
26
 Insertion in a bend of the line (against flow direction). The minimum bent line diameter
in this case shall be 3 inches.
6.3.5. Thermometers
a) Locally mounted indicators shall be adjustable angle bimetallic thermometers type, having
weatherproof dials of approximately 150 mm diameter.
b) Scales shall be direct reading and shall conform to manufacturer’s standard ranges as far as
possible. Ranges shall be selected so that normal operating temperature indication is
approximately mid-scale.
c) Standard over-range protection shall be specified.
d) Thermometers shall be provided with protective thermowells. Specification for the
thermowells shall be as per paragraph 6.3.4.
e) Thermometers of the filled capillary type shall be used in services where the stem length
exceeds 610 mm, where service conditions are too severe or in applications where remote
reading is required.
6.3.6. Temperature Switches

Temperature switching signals might be derived within a PCS/SGS system from an analogue signal
loop. In special cases, locally mounted field system shall be used.
6.4. Pressure Measurement

6.4.1. General Requirements
a) Pressure Instruments shall be located so that the head of the liquid between the instrument
and the point of measurement does not exceed the ratio span of the instrument.
b) Adjustable pulsation dampeners shall be furnished for all pressure instruments and gauges
on the discharge of reciprocating pumps and the suction and discharge of reciprocating
compressors, and pulsating services. Pulsating dampeners shall be externally adjustable
type.
c) Instruments shall be designed and installed for absolute protection of viewer in the event of
element rupture.
6.4.2. Pressure Gauges

a) All pressure gauges shall be "Bourdon" tube type with safety pattern design (solid front)
and shall have blow-out protection at the back and shall be provided with shatterproof
windows.
b) In pulsating or high-pressure services, adjustable pulsating dampeners shall be provided.
c) Pressure Gauge Sizes shall be 150 mm for all standard gauges, and nominal 50 mm for
standard valve air signal gauges.
d) Connections shall normally be 1/2 inch NPTM for 150 mm locally mounted process gages
and 1/4 inch NPTM for nominal 50mm and receiver gages.
e) Pressure Elements shall normally be AISI 316 stainless steel except where the process
27
requires higher grades.

f) Pressure Gage movements shall be hardened stainless steel.
g) Sockets and Tips material shall be the same as the associated bourdon tubes.
h) Over-Pressure protection shall be 1.3 times the maximum tube rating to prevent permanent
set or loss of calibration from continuous over-pressure. Over-rang stops shall be provided
where required.
i) Cases for gauges in the process areas and in process service shall be solid front, cast
aluminium, with snap ring.
j) Weep holes shall be provided on the case bottom of all gauges located in humid areas
unless the case already has sufficient ventilation.
k) Dials shall be white, non-rusting metal or plastic, with black figures. For vacuum part, red
figures shall be used. Pointers shall be adjustable.
l) For high pressure services, excess flow check valves shall be provided.
m) Where diaphragm seal elements are used, they shall be directly connected to the pressure
element and furnished as an integral part.
n) All pressure gauges shall normally be equipped with a "Two-valve" manifold valve.
o) Gauge Siphon assembly shall be used instead of "Pigtail" siphon. Siphons shall be
provided on hot water or steam service when the temperature exceeds 104 oC.
p) Range shall be specified such that the gauges shall normally operate in the middle third of
the scale. Gauge ranges shall normally be specified for not less than 1.2 times the relief
valve setting.
q) Special cases such as vacuum unit will be considered individually.
6.4.3. Pressure and Differential Pressure Transmitters

a) Smart type transmitters shall normally be specified for conventional and DCS control
systems with 4-20 mA output signal (HART support).
b) Field mounted pressure transmitters shall be used on all pressure control loops, monitoring,
ESD and interlocks.
c) Pressure and differential pressure transmitters shall be diaphragm type.
d) Direct connected self-actuated pressure regulators may be used for air and utility services
where a deviation of ten percent from the control point is allowable.
e) Suppressed range instruments may be furnished with NIOEC approval where necessary to
provide additional measurement sensitivity for control purposes.
f) Application of pneumatic transmitters in pneumatic loops shall be considered according to
the requirements mentioned in item 4 here before.
g) Pressure range of transmitters shall be selected so that, normal operating pressure will be
within 50% and 85% of calibrated range.
h) Instruments shall be specified to have over-range protection equal to 1.3 times of
maximum operating pressure to which they may be exposed.
28
6.4.4. Pressure Switches

- Pressure switches' functions might be derived within a PCS/SGS system from an analogue
loop signal or by means of local switches.
- When using local switches, pressure switches of diaphragm type shall be used.
- Set point of the pressure switch shall be adjustable in the middle third of the calibrated
range, as a minimum.
6.5. Level Measurement

6.5.1. Design General
 Every level instrument shall have a gage glass mounted adjacent to it for cross reference,
including displacers, ball float, differential pressure types, and hydrostatic head types,
except if prohibited by the vessel code.Level gauges shall cover the complete operating
range of any other level instrument installed on the same vessel section,
 The range of liquid level controllers will be based on process conditions, such as the surge
or residence time required in a vessel.
 Boiler level instruments shall be connected to the approved water columns. Two assemblies
shall be provided, one at each side of the boiler.
 Waste heat boiler drums will be equipped with only one water-column. The water column
and attachments shall meet the requirements of the latest edition of ASME code for boilers.
6.5.2. Displacer Type Level Instruments

 External displacement type level transmitters shall be used for maximum length of 2800
mm.
 Displacer Type instruments shall normally have carbon steel body material, with alloy
coated internal, with stainless steel displacer and Inconel torque tube unless higher grade
material is required. Air fins shall be used for temperatures above 200oC.
 Direct Operated Type Level Controls (ball float and mechanically linked valve) shall not be
used.
 All external displacement type instruments with a side connection shall have rotatable
heads. The bottom of all float cages with a side bottom connection shall be drilled and
tapped 3/4" NPT for drain piping.
 Floats shall have limit stops. When ring joint flanged equalizing connections are specified,
the float cage body, flanges, head flanges, and torque tube and arm flanges must also be of
ring joint construction or have retaining gaskets.
 All level instruments shall have vent and drain valves.
6.5.3. Radar Type Level Instruments

 Radar type level instruments may be used upon NIOEC's written approval.
 In using radar type instruments it must be noted that radar's main limitation is found in the
29
dielectric of the material it is shooting. Low dielectrics (good insulators, poor conductors
like hydrocarbons) can be problematic for radar. Radar shoots through low dielectrics.
 Radar shoots through vacuum and vapors without a problem.
 To ensure a reliable operation care shall be taken to specify accurate and high signal to
noise ratio type of instruments with transmitter waveguide less susceptible to coating with
the Condensation Resistant Antenna and with reduced echoes from obstacles / tank walls.
Note : In domed top tanks, some radars can't take mounting in the center of a domed top
because the parabolic effect of the dome gives them problems.
6.5.4. Ultrasonic Type Level Instruments

 Ultrasonic type level instruments may be used upon NIOEC's written approval.
 In using ultrasonic type instruments it must be noted that ultrasonic can not shoot through
vacuum. Ultrasonics might handle vapors and steam on a case by case basis. Ultrasonics do
not operate properly with carbon dioxide (CO2) blankets.
 A constant temperature and sound velocity within the measuring path enable a high degree
of accuracy to be achieved. The effects of large temperature variations within the
measuring path and changing gas mixtures must be calculated and programmed
accordingly. The instrument shall use an integrated temperature sensor for time-of-flight
correction to produce accurate measurement even in fluctuating temperature in any unit
system.
 If internal fixtures are present in the vessel, then careful alignment of the sensor is critical
in order to keep the interference echoes as low as possible. The ultrasonic pulse should
travel unimpeded to the surface of the material. Edges, internal fixtures, etc. within the
sound cone are of greatest importance in the first third of the range as the energy of the
beam is highly concentrated. The energy in the last third of the range is distributed over a
larger area, so that internal structures and edges are not as critical.
6.5.5. Level Gauges

6.5.5.1. Gauge Glasses
 Reflex Type Gauge Glasses shall be used where a liquid-gas interface exists and the
liquid is clean.
 Transparent Through-Vision Type Gage Glasses shall normally be used in all cases
where a liquid-liquid interface exists, on services involving acid, caustic or dark colour
materials, on heavy and viscous oil service, and on steam generating equipment, and
liquids requiring protecting shield. They shall be equipped with illuminators for all
services. Illuminators shall be 40 watts as a minimum. For hazardous areas the electrical
classification of the illuminators shall meet the requirements of NEC code for the
specified area. Illuminators shall be watertight to IEC 60529, IP 65.
 Minimum Pressure Rating shall be based on manufacturer’s pressure temperature charts
as published, using #8 glass (300 mm visibility). The minimum rating for both reflex and
transparent gages shall be 69 barg at 380 oC.
 Body Material and Cover Material shall normally be carbon steel. 316 stainless steel
construction shall be used for all wetted parts where the application requires it.
30
 Frost Extensions shall be provided where operating temperatures are below 0 oC.
 Level gauges shall be connected to the process isolating valve through automatic offset
cock valves. Offset valve connection to the isolating valve shall be flanged.
 Connection of gauge glasses to the offset valves shall normally be 3/4" NPTF screwed,
top and bottom. They shall be connected as close as possible to the vessel with the
minimum number of fittings.
 Automatic offset cock valves shall be quick closing, lever operated, offset angle type
furnished with either vacuum tail piece or ball checks according to the service
conditions.
 Installation shall be in accordance with NIOEC-SP-70-02 and NIOEC standard
drawings.
 Protective MICA of Kel-F Shields shall be provided on steam or condensate service at
operating pressures above 17 bar (g) and in applications involving corrosive fluids.
 Visible Length of Gage Glass shall cover the operating range or the level instrument. For
vessels with both alarm and shutdown devices the visible range of the gage glass shall
cover the alarm point.
 Special Problems requiring special consideration, such as high temperature and coking
service shall be considered individually and the most suitable type specified.
 Integral heat tracing shall be used in gauge glasses requiring heat where they contain
heavy viscosity liquids (like slop, fuel oil, etc.) and water or water interfaces with
hydrocarbon.
 The maximum coverage with a single gauge glass shall be limited to (5) #8 sections.
(1500 mm visible glass). Where greater coverage is required, multiple gauge glasses
with independent, overlapping vessel connections shall be preferred to standpipes, (for
details refer to NIOEC-SP-70-02).
 Gauge glasses shall be readable from the operating area of the related control valves.
Boiler level gage glasses shall be readable from the operating area.
 Tubular type gauge glasses shall not be used.
6.5.5.2. Magnetic Gauges

 Magnetic-type gauges are used in gauging liquids where:
a) Glass failure is likely to occur due to fluids being handled
b) The release of toxic gasses, flammable liquids, and so forth is to be avoided.
 Typical construction consists of a float inside a sealed non-magnetic chamber, and an
indicator mounted outside of the chamber, actuated or coupled magnetically to indicate
level. Mounting to vessel usually is accomplished by means of flanged connections, and
valves similar to flanged-type external displacement units.
 An external magnetic guide controls the orientation of the float which contains the
actuating magnet. The actuating magnet has a greater magnetic force than the edges of
the magnetized wafers of the indicating scale. As the actuating magnet passes the wafers,
theuy are rotated 180 degrees presenting the opposite face and color to the observer.
31
 Magnetic gauges should be operated in areas free of forces or matter that will affect the
magnetic fileds. This would include items such as steel support straps, heater wires, and
steam tracing tubing.
6.5.6. Process Connections for Level Instruments

a) Connections shall be in accordance with the requirements of section 6.1.9 to 6.1.10 of this
specification.
b) On towers, vertical or horizontal vessels, all of the level instruments may share the same
standpipe with the level gauges, except level instruments on level shutdown/SGS services
for which independent direct vessel connections shall be made.
6.5.7. Differential Pressure (DP) Level Instruments

The wet leg installations are used when the process vapors would otherwise condense into
the leg, thereby exposing the low-pressure side of the d/p cell to unpredictable heads, or
when the transmitter must be sealed from corrosive vapors. The leg is filled through a seal
pot. The prefilled wet leg creates a constant pressure on the low pressure side. It is desirable
to make this seal pot out of a sight flow indicator so that the level of the filling liquid is
visible to the operator.
6.5.8. Drain valves for Level Instruments

Drain valves shall be ¾ inch, and shall be installed on the bottom connection to level
instruments, level switches and gage glasses. Drains should be piped away from the
instruments to a safe area of disposal. Vent valves shall be ¾ inch and shall generally be
piped to safe location.
6.6. Traps, Drainers and Strainers

 Impulse type steam traps, shall be used per NIOEC-SP-50-08 for general service such as
headers, branches, and tracing as detailed in relevant Piping Specifications.
 Inverted bucket traps shall not be used without written permission of NIOEC.
 Vacuum of lift traps shall be used for draining condensate from low pressure systems where
the available pressure differential is too low for other types of traps.
 Automatic drain valves, either float or diaphragm type for draining condensate or liquid from
air or gas lines and receivers shall be used.
 Ball float traps (continuous drainers) shall be used for modulating service such as draining
condensate from temperature controlled re-boilers, for trapping liquid in gas or air streams,
and for venting air or gas from liquid streams.
 Strainers shall be installed in the piping upstream of all continuous drainers. Metallic gaskets
shall be used for steam pressure above 20 bar (g). Integral strainers are preferred.
 The body material for ball float traps and automatic drain valve shall be as follows:
- 17 bar(g) and lower, cast steel.
32
- Over 17 bar(g) forged steel or stainless steel as applicable.

- Trim material for traps and strainers shall be stainless steel.
- The body material for steam tracing traps shall be stainless steel.
- End connections shall conform to piping specifications, except for steam tracing traps
which shall be screwed type.
- Minimum body size shall be 1/2" for traps in steam tracing or unit heater services.
Minimum size shall be 3/4" for all other traps.
6.7. Battery Limit Isolation Requirements

Reference shall be made to NIOEC-SP-00-50.
7. CONTROL VALVES
7.1. General
All control valves and the accessories shall generally comply with the requirements stipulated
in ANSI/ISA 75.01.01 and IEC 60534-2-1 standards and recommendation practices.
All terminology shall follow ISA/IEC standards.
7.2. Control Valve Sizing

Control Valve CV shall be calculated at minimum, normal and maximum flows. The selected
CV shall be such that valve opening falls at 20% of its full opening at the minimum flow and
80% of its full opening at the maximum flow. The valve shall never have less than 20%
opening at minimum flow. The sizing pressure drop (DP sizing) shall be sufficient as per
requirements of this section and to obtain good regulation at the normal minimum quantity
within the range-ability of the selected valve. If in primary design stage maximum flow is not
available, then valves shall be selected to have twice the CV required for normal design flow at
specified conditions.
7.3. Sizing Pressure Drop

 The sizing pressure drop (DP sizing) shall be sufficient to yield good regulation at normal
minimum quantity within the range-ability of the selected valve.
 The pressure drop across the control valve at the maximum flow shall be at least 20% of the
pressure drop across the control valve at normal flow.
 For control valves at the discharge of reflux, charge and recycle pumps, valve pressure drops
at normal and maximum design rate are calculated as follows:
i) At normal rate, one-third of the total variable system pressure drop including pressure
drop of the control valve.
ii) At maximum design rate (i.e., the rated flow on the pump data sheet is up to 125% of the
normal flow rate), 15% of the total variable system pressure drop including pressure drop
of the control valve.
33
iii) At maximum design rate (i.e., the rated flow on the pump data sheet is higher than 125%
of the normal flow rate), 10% of the total variable system pressure drop including
pressure drop of the control valve.
iv) Except for low-pressure services, in any other cases minimum pressure drop shall be 0.7
bars.
 For control valves in the steam line to re-boilers, allow a pressure drop of 5% to 10% of the
initial absolute steam pressure or, when operating with low pressure steam of 2 bar or less,
use a minimum drop of 0.35 bar unless otherwise system operating pressure requires a lower
drop. The same criteria shall be applied to vapors and gases other than steam.
 If the viscosity of the liquid at the operating temperature is above 10 C St, the effect of
viscosity on the control valve shall be applied
 Fouled condition pressure drop such as vacuum heater, Visbreaker heater, and filter shall be
added in to the variable system pressure drop.
7.4. Noise Level

The maximum allowed A-weighted sound pressure level , measured at 1 meter downstream of
the control valve at a distance of 1 meter from the pipe, shall not exceed 85 dB (A) under any
of the operating conditions (min./norm./max. flow).
7.5. Characteristics
a) Control valve characteristics shall generally follow the following guidelines:
34
LIQUID LEVEL SYSTEMS
Control Valve Pressure Drop Best Inherent Characteristic
Constant ΔP Linear
Decreasing ΔP with increasing load, ΔP at maximum load > 20% of minimum
Linear
load ΔP
Decreasing ΔP with increasing load, ΔP at maximum load < 20% of minimum
Equal-percentage
load ΔP
Increasing ΔP with increasing load, ΔP at maximum load < 200% of minimum
Linear
load ΔP
Increasing ΔP with increasing load, ΔP at maximum load > 200% of minimum
Quick-opening
load ΔP
PRESSURE CONTROL SYSTEMS
Application Best Inherent Characteristic
Liquid process Equal-percentage
Gas process, small volume, less than 10 ft of pipe between control valve and
Equal-percentage
load valve
Gas process, large volume (process has a receiver, distribution system, or

transmission line exceeding 100 ft of nominal pipe volume), decreasing ΔP with Linear
increasing load, ΔP at maximum load > 20% of minimum load ΔP
Gas process, large volume, decreasing ΔP with increasing load ΔP at

Equal-percentage
maximum load < 20% of minimum load ΔP
FLOW CONTROL PROCESSES
Best Inherent Characteristic
Small Range of Flow but

Location of Control Valve
Flow Measurement Wide Range of Flow Large ΔP Change at
Relation to Measuring
Signal to Controller Setpoint Valve with Increasing
Element
Load
Proportional to Q In series Linear Equal-percentage
Proportional to Q In bypass* Linear Equal-percentage

2
Proportional to Q
In series Linear Equal-percentage
(orifice)
Proportional to Q2
In bypass* Equal-percentage Equal-percentage
(orifice)
*When control valve closes, flow rate increases in measuring element.

Q: flow rate.
35
7.6. Stroking Time

The stroking time of a control valve is defined as the time required to stroke the valve from 2%
opening to 98% opening and vice versa while it is at operating (min. to max.) differential
pressure.
The maximum stroking time of a control valve shall not exceed the values of the following
table:
Valve size Stroking time Valve size Stroking time Valve size Stroking time
(inches) (seconds) (inches) (seconds) (inches) (seconds)
1 4 3 8 8 14
1-1/2 4 4 10 10 16
2 5 6 12 > 10 16
Notes:
1. Maximum allowed stroking time of the purge gas firing control valve is 10 seconds,
irrespective of the valve type and size.
2. Local authority rules shall be adhered to, regarding limitations of fluid emissions along the
control valve stem packing, i.e. mitigation of fugitive emissions.
7.7. Body and Bonnet

a) Control valve connections shall generally be flanged for 1" body size and larger except
where piping specification specifies otherwise. Control valves with welded ends, if any,
shall be top-entry type where the trim can be removed with the valve in situ. Minimum body
and connection rating shall be 53 Barg for screwed connections. The flange rating shall
generally be in accordance with the piping class but for carbon steel bodies the flange rating
shall be class 300 minimum.
b) Flanged valves shall have flanged connection integral with the body. Slip on flanges shall
not be used.
c) Wafer type valves shall only be used in water lines and air services.
d) Body size shall normally be 1" minimum. The use of odd size such as 1-1/4" and 5" shall be
avoided. Body sizes smaller than 1" may be used for special applications with ½" and
smaller line sizes, and for pressure regulator services. For valves sizes smaller than 1"
reduced trim in 1" size bodies, will normally be preferable.
e) Bonnets, bottom flanges, closures, and other wetted pressure containment assemblies shall
be of the same material as the valve body. Bonnets shall be of the integral or bolted type
construction with fully retained gasket. Threaded bonnets are not acceptable. Bonnet bolts
shall not be used to attach actuators or mounting brackets.
f) Valves in hydrogen or hydrogen effluent services shall have bonnet flange and lower blind
flange fitted with retained metallic or spiral wound gaskets suitable for this service.
g) Split body globe valves shall be of through bolted construction. Body flanges shall be either
ring type joint or have fully retained gaskets. Body gaskets shall be solid Teflon.
h) Extension Bonnets shall be provided on services below 0˚C and Fin types shall be used on
services above 230˚C or in accordance with the manufacturer’s recommendation.
36
7.8. Trim Construction

a) Stelliting
Plug, seat and the guiding shall be stellited in the following cases:
i) When the process fluid is a liquid with suspended solids,
ii) In the presence of liquids that vaporize in the valve body with resulting phenomena of
flashing and cavitations,
iii) When in liquid services, the pressure differential across the valve ports at maximum
flow-rate is greater than or equal to 10 bar (greater than or equal to 5 bar for steam),
iv) When operating temperature is greater than 280°C,
v) Erosive service,
vi) Wet gas or saturated steam,
vii) In dry/clean gas when:
Pressure drop exceeds 20 bars for valves < 4",
Pressure drop exceeds 12 bars for valves  4",
When flow is choked,
Flashing liquids,
Incipient cavitations (see note).
Notes:
1. Full-developed cavitations shall be eliminated by selecting specially designed anti-
cavitations trim.
2. Hard facing of trim will be applied to the seating contours of the plug and seat.
b) Closure Member Form

i) The closure member form shall be solid contoured, tapered, splined, or solid V-ported.
Where low lift V-port plugs are specified, they may be of hollow construction. Acorn
type plugs are not acceptable for angle valves regardless of valve size.
ii) Valve flow characteristics shall be as defined in ISA S-75.05.01.
c) Three-Way Valve Closure Members' Seating

For diverting services, top and bottom guided three- way valve closure members shall seat
from outside the inlet chamber. For combining services, closure members shall seat from
inside the outlet chamber. Cage guided three way valve trim, including metallurgy, shall be
designed to minimize the risk of galling.
d) Separable Closure Member and Stem Connection

Separable closure members and stems for sliding stem valves shall be connected by tapered
or proprietary thread design and be pinned.
e) Rotary Valve Shaft Blowout

Rotary valves shall have a shaft design that eliminates the possibility of blowout.
37
f) Unbalanced Single Ported Globe

Unbalanced, single ported globe valves shall be closure member guided. Stem guided valves
are not acceptable.
g) Balanced Single Ported Globe
Balanced, single ported globe valves shall be cage guided. Trim, including metallurgy shall
be designed to minimize the risk of galling.
h) Balanced Double Ported Globe
Balanced, double ported globe valves shall be top and bottom guided. For 6" and larger
valves, the post and guide bushing shall be designed to prevent rotation of the closure
member and stem.
i) Split Body Globe
The split body globe valve's closure member shall seat from the top regardless of actuator
action. Seat ring shall be of clamped-in design.
j) Shaft Deflection
Rotary stem valves (butterfly, ball, eccentric plug, eccentric disc, etc.) shall incorporate a
shaft design and suitable guiding to prevent excessive shaft deflection at till specified valve
positions and corresponding pressure drops.
7.9. Actuators
7.9.1. Actuator Types
a) Pneumatic spring diaphragm actuators: On air failure, the actuator shall move the valve to
the position specified on the P&ID.
b) Pneumatic spring piston actuators: On air failure, the actuator shall move the valve to the
position specified on the P&ID.
c) Pneumatic double acting piston actuators: A volume tank and accessories shall be
connected to the actuator to move the valve to the position specified on the P&ID upon air
failure. The volume tank shall be sized to fully stroke the valve through two cycles and
construction shall be in accordance with local codes for pressurized vessels.
Note: In case that instrument air is not available, electrical or electrical-hydraulic actuators
can be used.
7.9.2. Yoke and Stem/ Shaft

a) Yokes shall be of suitable rigid material for open type construction,
b) Actuator stems / shafts shall be designed for the maximum developed thrust of the actuator
without measurable deflection.
c) Valves for modulating service shall have a clamped valve stem/shaft to actuator shaft /
lever connection in order to eliminate backlash.
d) All valves shall be equipped with a valve stroke indicator.
38
7.10. Accessories
7.10.1. Air Filter Regulators
For each control valve and each accessory that shall be powered by instrument air and be
mounted on the valve, the vendor is required to supply a pressure regulator equipped with a
filter and individual pressure gauges on input air supply and output air signal lines.
7.10.2. Electro-Pneumatic Transducers and Positioners:

 Positioners shall generally be smart type unless otherwise under NIOEC's approval.
 Positioners shall be used on all modulating control valves in order to achieve the required
dynamic performance.
 Positioners shall have adjustable gain.
 In case of digital positioners, diagnostic capabilities to test for correct valve setup and to
test for the dynamic performance shall be utilized.
 Positioners shall have pressure gauges to indicate the air supply to the positioner, the air
supply to the actuator and the control signal if pneumatic.
 Positioners shall meet the following environmental storage and shipment conditions:
Temperature limits -40°C to 80°C.
Temperature effect less than 1% per 28°C.
Humidity between 0%-100%.
 Positioners' vibration effect shall be less than 1% of span when tested per ISA S75.13.01.
The conformity (linearity), hysteresis and repeatability shall be equal to or better than
0.5%.
 Temperature effect shall be less than 1% per 28°C.
 The total length of tubing between the electro-pneumatic transducers and control valve
shall not exceed 3 meters.
 An output gauge shall be furnished.
7.10.3. Auxiliary Hand-wheel:

Unless otherwise indicated on the individual data sheets, handwheels shall be fitted to
control valves over 3", except in case of shut-off valves or where special process flow
characteristics require the use of bypasses.
The handwheel must permit the actuator to be operated in the absence of the power medium
and in the heaviest duty operation of the valve.
The handwheel shall also have a manual release facility, remain stable in position, be
equipped with a lock or lead seal, if required, and have an irreversible transmission
mechanism.
Side connected handwheels are preferred. Automatic operation shall overrule the manual
operation without danger to the operating personnel.
When the handwheel is in the neutral position, which has to be clearly indicated, the valve
shall operate automatically without any part of the mechanism interfering with the
39
movement of the valve. The handwheel shall cause the valve to close when it is turned in a
clockwise direction.
Manual loading type hand operators shall be considered in lieu of side mounted handwheels
in relatively low pressure drop applications, where handwheel may cause a hazardous
condition for automatic start-up or shutdown of the related equipment.
These hand operators shall consist of three-way air switch and a handwheel operated air
regulator. The handle and ports shall be clearly marked as MAN-AUTO.
The regulators may be common to other components.
Handwheels specified for use with pressure balanced valves shall be of the diaphragm case
mounted type.
All side-mounted handwheels shall be suitable for use as an adjustable travel limit stop in
both directions and shall incorporate a neutral position.
Gears and screw threads of the side mounted (continuously connected) type shall be
enclosed and have a minimum of backlash.
7.10.4. Volume Boosters

A volume booster repeats the controller output pressure and provides a high capacity output.
It can be used to reduce the time lag in a control system that requires fast response.
7.10.5. Lock-up Valves

When a pneumatic lock-up device is required, it shall block-in the air on the valve
diaphragm when the air supply pressure falls below the preset value, and thereby ensure that
the valve maintains the last position reached for at least 20 minutes, unless otherwise
specified.
On piston operated (double acting) valves two lock-up valves are required.
7.10.6. Valve Trip System

A valve trip system is required to move a pneumatic piston actuator operated valve to a safe
position upon air failure.
7.10.7. Solenoid Valves

When a solenoid valve is requested, it shall be installed by the vendor in the actuator
pneumatic control signal circuit.
Solenoid valves shall be 3-way type with reversible inlet and outlet and, in general, with
direct action and spring return.
Unless otherwise indicated in the individual data sheets, solenoid valves shall be suitable for
operation with instrument air and for maximum pressure differential of 7 bar.
The vendor has the responsibility to design the port size to meet the requirements for the
quick actions.
40
The coil shall normally be sealed in epoxy resin, and shall be rated for continuous service
with tolerance on nominal voltage as per the individual data sheets. Unless otherwise
indicated in the standards quoted in the individual data sheets, connections of the power
supply cable shall be effected using a junction box complete with terminal blocks, ground
terminal, and cable gland clamping the cable armoring.
When a manual reset facility is required, this shall permit manual reset only when electrical
power is present.
Where solenoid valves are installed on control air supplies for pneumatically operated
valves in order to “seal in “ the diaphragm pressure in case of electrical supply failure, the
solenoid valves shall incorporate a time delay and hand reset to prevent inadvertent
operation resulting from transient interruption of the electrical supply.
7.10.8. Pressure Gauges

Pressure gauge size shall be nominal 50mm.
Connections shall normally be 1/4" NPT for nominal 50mm gauges.
Pressure elements (bourdon tubes) and pressure gauge movements shall be made of bronze.
Socket and tips shall be made of brass.
Dials shall be white, non-rusting metal or plastic with adjustable black figures pointer.
The range of each gauge shall be selected from the Vendor's standard ranges with the unit of
BARG.
7.10.9. Limit Switches

Where specified on the individual data sheet, limit switches shall be installed on the control
valves.
Limit switches shall be hermetically sealed type, suitable for mounting on the valve. The
switches shall not be affected by vibration, mechanically or functionally when so mounted.
Limit switch shall be magnetically operated type.
Limit switches shall be adjustable to any point of the travel and the securing system adopted
for the switches shall be positive locking.
Contact shall be SPDT type with appropriate rating.
The limit switches shall be provided with the screwed terminals suitable for external wiring.
7.10.10. Max/Min Travel Stop

Max/Min travel stop shall be provided, when it is specified on the individual data sheet.
7.11. Control Valve Manifolds

7.11.1. Control Valves with Block and Bypass Valves
The following services should be provided with block and bypass valves:
41
 Services where omission of valves will jeopardize the safety or operability of the Unit;
 Services containing abrasive solids or corrosive fluids result in damage of trim of control
valve, and require the repair;
 In lethal services;
 In product rundown and feed supplying services;
 In fuel supply system;
 In cooling medium supply service;
 Control valves less than 2 inch size. The block and bypass valves are required due to small
diameter of trim, and may have a possibility of plugging of sludge or foreign matters;
 In services that are flashing or at high differential pressure.
7.11.2. Control Valves without Block and Bypass valves

Block and bypass valve system may not be necessary where the process can be shut-down to
repair the control valve without significant economic loss or where the process cannot be
feasibly operated through the bypass. However, the consequences of shutting down a
process unit to perform a simple task (such as replacing control valve packing) should
always be considered. In cases where the block and bypass valves are not used, the control
valve should be equipped with a hand wheel or other operating devices.
Block and bypass valves are not always necessary in the following cases:
i) In instances where it is desirable to reduce the sources of leakage of hazardous fluids,
such as hydrogen, phenol, or hydrofluoric acid;
ii) In clean service where the operating conditions are mild, and mission of valves will not
jeopardize the safety or operability of the Unit;
iii) In temporary services such as start-up or shut-down, and where the other operation
modes are possible while the repairing of control valve, such as blending system of oil;
iv) Pressure self regulating valves;
v) Shut-off valves
7.11.3. Additional Requirements for Control Valves

Notwithstanding the requirements outlined in articles 7.11.1 and 7.11.2 above the following
notes should also be considered:
i) Provide an upstream isolation valve for all control valves unless the upstream system is
to be shutdown on control valve failure.
ii) Provide a downstream isolation valve whenever the downstream side of the control
valve cannot be isolated from other continuously operating pressure sources.
iii) Provide a drain valve upstream of all control valves.
iv) Provide a drain valve downstream of the control valve only when the process fluid is
toxic or corrosive and for tight shut-off services.
42
7.11.4. Block and Bypass Valves Size

i) Following table, which is based on API-RP-553, shall be followed for control valve
manifold block and bypass valve sizing.
ii) Block valves shall be gate valve type. Bypass valves shall be globe valve type for block
valve sizes smaller than 8 inches. For block valve sizes of 8 inches and larger, bypass
valves shall be gate valve type.
CONTROL VALVE BLOCK AND BYPASS VALVES SIZES

Line Size
1/2 3/4 1 1-1/2 2 3 4 6 8 10 12

Control Valve Size
Bypass
Bypass
Bypass
Bypass
Bypass
Bypass
Bypass
Bypass
Bypass
Bypass
Bypass
Block
Block
Block
Block
Block
Block
Block
Block
Block
Block
Block
1-1/2
1-1/2
1/2
1/2
1/2
3/4
3/4
1-1/2
1-1/2
3/4
3/4
3/4
1
2
1-1/2
1-1/2
1
1
1-
1-1/2
1-1/2
1/2
2
2
3
3
4
4
6
10
10
6
8
10
10
10
8
10
10
10
12
10
12
12
12
All Sizes in Inches
43
8. ESD VALVES
8.1. General
i) Single port globe valves shall be used for ESD applications, except for flammable gas or
H2S services, where ball (full bore or reduced bore) styles/trim designs shall be used.
ii) Emergency valve operation shall be carefully analyzed to determine whether valve should
be energized or de-energized in the event of power and air failure.
iii) ESD valves shall have flanged or welded process connections. ESD valves with welded
ends shall be top-entry where the trim can be removed with the valve in situ.
iv) ESD valves shall have fire safe body with diaphragm/spring or piston /spring actuators.
v) Packing material shall be PTFE for temperatures of up to 230 ◦C and Graph oil/Graphite for
higher temperatures.
vi) Solenoid valves serving the ESD valves shall be direct acting and air filter regulators with
gauges shall be supplied.
vii) Appropriate requirements of article 7 above shall also apply to the ESD valves.
viii) ESD valves shall never be replaced with a control valve with a solenoid valve.
8.2. Stroking Time

i) The stroking time of ESD valve is defined as the time required for the valve to travel to its
fail safe position (i.e. fully closed or fully open) from the moment the electrical power is
removed from the solenoid valve
ii) The maximum allowed stroking time of an ESD valve (travelling to its fail safe position)
shall not exceed the values in the following table:
Stroking Stroking Stroking

Valve size
time Valve size time Valve size time
(inches)
(seconds) (seconds) (seconds)
1 4 3 6 8 8
1-1/2 4 4 6 10 8
2 4 6 8 > 10 10
Notes:
1. Maximum allowed stroking time of the Fuel gas and purge gas for firing ESD valves is 3
seconds, irrespective of the valve type and size.
The time required to reset the ESD valve shall not exceed the stroking time requirements
specified for control valves.
2. Local authority rules shall be adhered to, regarding limitations of fluid emissions along
the ESD valve stem packing.
9. AUTOMATIC ON/OFF VALVES AND SWITCHING VALVES

a) On/off and switching valves shall have flanged or welded process connections. On/off and
switching valves with welded ends shall be top-entry where the trim can be removed with the
valve in situ. Butterfly type valves are only permitted in water lines and air.
44
b) Instrument on/off valves may be employed when isolation of equipment/pipe sections of the
plant is required, e.g. batch processing. If an on/off valve is part of a system classified as SIL
2 or higher then it shall meet the requirements of an ESD valve.
c) Stroking time of on/off valves shall be determined per application. On/off valves shall have
fire safe bodies with diaphragm/spring or piston /spring actuators.
d) Packing material shall be PTFE for temperatures of up to 230 C and Graph oil/Graphite for
higher temperatures.
e) Solenoid valves shall be direct acting or pilot type and air filter regulator with gauges shall be
supplied.
Notes:
1. Control valves may, by addition of a solenoid valve, replace an on/off valve for non-critical
interlocks.
2. Local authority rules shall be adhered to; regarding limitations of fluid emissions along the
on/off valve stem packing.
3. On/off valve accessories, such as solenoid valves and air filter regulator, shall be mounted
on the valve as an integral part of the on/off valve assembly.
10. PRESSURE RELIEF VALVES

11. ANALYTICAL INSTRUMENTS

11.1. General
i) Analytical Instruments will be smart type preferably with integral indicators.
ii) All process analytical instrument readings required by the operators shall be available in
the PCS. The instruments will be capable of providing linearised output signals to the
PCS.
iii) Analytical instruments shall be furnished complete with pre-assembled and pre-tested
sample systems.
iv) The measuring systems for chromatographs, Infrared and Thermal Conductivity
Analyzers and similar instruments, along with their sample treating systems, shall be
installed in suitable houses located in the process areas.
v) Houses or shelters provided for Analyzers shall be as close to the process sample point as
practical, more than one analyzer may be installed in a single house if the sample line
length is within the analyzer manufacturer’s specifications. These houses must provide
weather protection and adequate space for complete servicing and calibration of the
analyzer and should be "walk-in" type house for most process stream analyzers.
vi) The analyzer shall be suitable for remote installation (in the main control room) of the
amplifiers, programmers, manual stream selector switches and other control equipment
required for their operation.
vii) The equipment, other than the manual stream selection switches and trend recorders, for
the analyzers located in the main control room shall be mounted on a single rack located
45
in the back of the main control board.

viii) Samples for initial standardization and calibration are required. Sample cylinders must
be at least 75% full for liquids or contain 110 bar (g) gas and must be clearly tagged to
give of all components inside when delivered to the field. Custody transfer of title on all
cylinders to NIOEC is required.
ix) With large instruments such as analyzers that cannot be mounted in an explosion proof
box, air purging must be required. If possible, analyzer should be mounted in
nonhazardous areas.
x) Each analyzer shall have an over current protective device (a magnetic type circuit
switch or a fuse). Local disconnect switches shall also be provided so that the
instruments can be safely serviced. Cabinet heaters, circulating pump motors and other
devices which draw relatively high currents may be powered locally.
xi) Signal wiring shall be run to the control room in separate conduit or cable, if signal level
is other than 4-20 mA. It shall be routed to the receiver instrument by the shortest most
direct route which is feasible.
xii) Process control loops which include an analyzer shall normally be cascaded. In some
cases where the analyzer output is continuous and not delayed, direct control may be
provided.
xiii) Cylinders used for operation of analyzers shall be located in a well sheltered area and
properly secured on the side of the analyzer room. Cylinders shall not be kept inside.
xiv) Gas cylinders shall be connected in pairs by means of a double needle valve for
continuous and uninterrupted operation of the analyzer.
11.2. Sample Tapping

Sample tappings for gas samples shall be from the top of the main line.
For liquid sample tapping shall be from the side.
Sample conditioning systems are as important as the choice of the analyzer. Normally the
sample system is furnished by the same vendor who supplies the analyzer.
i) Gas and Vapor Systems
The system volume shall be kept to a minimum; normally 3/8" stainless steel tubing shall
be used. Other materials may be used if sample compositions and conditions permit.
For gas samples, the pressure should be reduced at the sampling point to increase the
velocity through the sample system and reduce time lag.
This pressure reducing valve is not normally included in the sampling system supplied by
the instrument vendor.
Sample bypasses around the analyzers shall be supplied. This insures that the sample lines
are purged and it reduces the time lag of sampling. The sample bypass is either vented to
atmosphere or back to a lower pressure part of the process.
The sample must be clean and free of particles. Install a "Y" strainer immediately ahead of
the primary pressure reducer.
46
Additional filters, strainers and drainers which may be required should be specified as part
of the system.Water washing of the stream may be required with dirty samples such as
stack gas. The water should be recycled with only a small makeup and drain stream to
minimize composition changes.
Normally dessicants should be avoided when drying a sample stream. Chilling and
trapping the moisture is prefered. Desiccants may become spent and not function or they
may absorb constituents other than water.
Heat tracing or insulation of the sample line is required if condensation of the sample can
occur at ambient conditions. A heated cabinet shall be provided by the manufacturer for
the sample conditioning system if there is danger of condensation.
ii) Liquid Systems
When a liquid stream must be taken to the analyzer, the sampling problem is similar to a
gas or vapor system.Filtering, pressure reduction, cooling or heating may be required. The
extent of sample conditioning required will be determined by process stream.
Liquid bypasses around the analyzer shall normally be provided to reduce sampling lag.
They shall be drained to a sewer or a lower pressure part of the process.
PH, electrolytic conductivity or similar probes shall be installed in the bypass line so that
it is not necessary to interrupt the process to service the electrodes.
12. TANK GAUGING SYSTEM

Automatic Tank Level Gages and averaging type temperature measurement with electronic
transmission to remote indication station will be installed for all feed, product, and slops storage
tanks. Accuracy of better than ±3 mm is required of the system.
Reference shall be made to NIOEC-SP-70-10 "Tank Gauging System".
13. FIRE AND GAS DETECTION

Reference shall be made to "Specification for Fire and Gas Detection Systems", NIOEC-SP-70-11.
14. CABLING
a) Cabling and tubing within the battery limit of the units shall be above-ground via cable trays.
b) Conventional DCS, SGS, F&G Systems
Instruments shall be connected via tray mounted over-ground single pair armored cables to
junction boxes. From the junction boxes, lead sheathed or hydrocarbon-resistant type multi pair
armored cables will run direct buried, underground to the control room.
Separate junction boxes will be used for different categories of signals as follows and terminal
strips and each point will be identified and suitably with polarity indicated:
 Intrinsically safe analogue signals (4-20 ma)
 Non intrinsically safe analogue signals
 Intrinsically safe digital signals
 Non intrinsically safe digital signals
 Ac power supplies.
47
 Separate conduits, marshalling boxes, trays shall be used for control signals and instrument
AC power.
 Junction boxes shall generally be suitable for 12 single pair cables and one 12-pair cable.
c) Fieldbus-oriented PCS
Segment bus shall be armored, above ground in accordance with the PCS vendor specification.
Each instrument shall be connected to the segment via a short –circuit proof junction box.
Battery limit connection to the control room shall normally be via fiber optic cables, running
direct buried, underground to the control room. The construction of fiber optic cables shall be
suitable for direct buried, underground work.
For details reference shall be made to NIOEC-SP-70-05.
15. JUNCTION BOXES

Each junction box shall have two stainless steel tag plates, one affixed on the front of box, and the
other affixed on the lid of the box by stainless steel screws to indicate following items as a
minimum:
• Tag number,
• Intrinsically safe execution,
• Analogue or digital signals,
• Relevant safety approval details,
• Warning notices against opening of the boxes while in service, purchase order number and date.
16. PLANT CONTROL AND SAFEGUARDING PHILOSOPHY

Reference shall be made to NIOEC’s Standard Specification for PCS; NIOEC-SP-70-08 and
NIOEC’s Standard Specification for SGS; NIOEC-SP-70-09.
17. CONVENTIONAL CONTROL PANELS

In case of any requirement for conventional control panels, reference shall be made to NIOEC-SP-
70-14.
18. NAMEPLATES
Stainless steel nameplates shall be affixed to all of the instruments by screw, unless technically
impractical in which case stainless steel wires may be used for plate attachment. Nameplates shall
include following items:
a) Instrument tag number,
b) Manufacturer's name and date of production,
c) Model number and serial number,
d) Adjustable measuring range, Instrument range,
e) Calibration range,
f) Materials of parts exposed to process fluids.
48
As applicable, nameplates shall also carry information relating to voltage, frequency, Max./Min.
operating limit, Max. static working pressure, electrical "Ex" class, Ingress protection and
hazardous area classification.
19. CONTROL CENTERS

Requirements for the design of the control centers shall follow the specifics of the Project and the
requirements of NIOEC-SP-70-15.
20. INSTRUMENT TESTING, CALIBRATION AND INSPECTION

a) As a minimum, all instruments and instrument systems shall be tested in accordance with the
Manufacturer's standard and, if applicable, as demanded by local authorities and standards. If
shop inspection is specified the inspector representing NIOEC shall have right of entry to the
plants including sub-vendor’s plants where work on or testing of the equipment and
instruments are being performed. All tests and inspections shall be performed in accordance
with the relevant NIOEC inspection and test procedures including Shop Inspection Procedure
(NIOEC-SIP-70-01).
b) The vendor shall perform all necessary operational tests (defined by the instrument
characteristics) on completed systems so as to assure performance with the requirements of
this specification.
c) Where pressure testing is required it shall be in conformance with NIOEC-SP-70-07.
d) Certified test reports shall be provided for each instrument.
e) In line instruments shall generally follow the same standard as the line in which they are
mounted with respect to examination.
f) Complete Electronic and/or Pneumatic tests must be performed on all systems, instruments,
control and relieving valves instruments prior to shipment.
g) Both the PCS and the SGS shall be 100% functionally tested, as part of the FAT, at the system
Manufactures workshop. NIOEC’s definition documents such as narratives, functional block
diagrams, cause and effect diagram, alarm and trip setting list etc. shall be used as basis of the
functional testing.
h) If shop inspection is specified the inspector representing NIOEC shall have right of entry to
the plants including sub-vendor’s plants where work on or testing of the equipment and
instruments are being performed.
i) NIOEC reserves the right to reject individual equipment or instruments for bad workmanship
or defects.
Detailed inspection requirements are specified in NIOEC-SP-70-16.
21. PREPARATION FOR SHIPMENT

Each "Shipping Section" of stationary structures shall be provided with removable lifting angles
and/or plates suitable for crane hooks or slings.
Packed for shipment in wooden cases, each instrument shall be enveloped in a polythene bag
containing silica gel or similar dessicating compound. To avoid damage during shipment or
49
handling each item shall be embedded in shock absorbing filling material. Each instrument shall be
provided with a tag specifying the unit it belongs to. When instruments are packed in several layers
in the same case horizontal wooden partitions shall be provided suitably spaced and secured to case
frame. Instruments shall be packed with dials upwards. Case's targets must indicate type of storing
advised by the vendor.
Packing and marking shall be in accordance with NIOEC- SP- 90-52.
22. GUARANTEES
Vendors shall guarantee that he is able to support and supply spare parts for the supplied hardware,
software and firmware for at least 10 years from the date of shipment.
If the Vendor believes that parts of the system will be withdrawn from sale after 10 years, he shall
provide a statement detailing the equipment to be withdrawn, the timing and how updated parts can
replace the withdrawn parts.
The Vendor shall also guarantee that the equipment supplied is free from fault in design,
workmanship and material, and is of adequate design and proper material to fulfil satisfactorily the
specified operating conditions.
Should any failure or defect in design, material, workmanship or operating characteristics develop
under the start-up and commissioning periods or during the first 12 months of operation, but not
later than 24 months from the date of shipment, the Vendor shall make all required repairs,
alterations or replacements of the defective equipment, free of charge, and shall pay transportation
fees involved to and from NIOEC’s site.
23. REQUIRED DOCUMENTATION

23.1. General
a) Contractor shall, according to the nature of the Project, furnish adequate documentation for
the engineering, procurement, installation, operation and maintenance of the
instrumentation and control/safety systems.
b) Project specifications and data sheets shall, as a minimum, include specifications and data
sheets for pressure, temperature, flow and liquid level transmitters, control valves,
analyzers, pressure gauges, temperature indicators, gauge glasses, alarm signals, interlocks
and PCS and SGS.
c) Applicable process data including material and instrument operating range shall be
provided for all data sheets.
d) Calculated CVs, estimated valve sizes as per manufacturer catalogue , flow rate and
operating range, operating conditions, applicable physical properties of process and utility
streams, action of the measured variable, flashing status of the fluid and air failure
positions shall be provided for all types of control valves.
e) Calculated orifice bore, including all required process data shall be furnished, and for all
pressure relief valves the calculated orifice together with the pertaining process data shall
be included.
f) Calculated orifice designations for safety valves, flow rate and set pressures, operating
conditions, applicable physical properties of process and utility streams shall be provided
for all types of safety valves.
50
23.2. Specific Requirements for the Documents

a) Instrument List (Index)
This document shall be a list of all instruments shown on P&IDs including all loop
components. This list shall indicate tag. number, service, P&ID number,data sheet number,
location (Basic Design), location layout drawing number, installation drawing number, P.O.
number, manufacturer name, etc. for each instrument (Detail Design).
b) Instrument Data-Sheet
Data sheets shall cover definitively decided specifications per tag No. relating to the type,
measurement range, transmission type, service fluid to be measured, measurement
conditions, connection conditions, etc. of instruments, as per NIOEC data sheet format.
c) I/O List
The list shall cover all inputs and outputs to the PCS/SGS systems. The minimum data on
the list shall, as a minimum, include instrument tag numbers, service, P&ID number,
ranges, engineering units, set points, locations, signal type, safety execution type, loop
diagram numbers, junction box numbers, control action of the controllers, control valve
failure action, information regarding cascade loops, etc.
d) Alarm/Trip Set Point List

The list shall show tabulated setting values for functioning contacts per tag number of
instruments which have alarm contacts or interlock contacts.
e) Instrument Loop Diagram

The drawings shall schematically show connections of detectors and control valves, and
those of digital control system to be provided in the control room.
Based on this instrument loop diagrams and instrument wiring connection list the supplier
of instrumentation system shall develop detailed wiring diagrams for each loop, terminal
strips for each control room cabinet and wiring interconnection drawings.
f) Interlock and Sequence Logic Diagrams

The drawings shall show schematically interlock circuits including relative alarms in the
order of the lapse of time of the functioning of relays and opening and closing of contracts.
g) Instrument Power Supply Diagrams

Instrument power supply diagrams shall show schematically instrument power supply to
operator consoles, cabinets, panels, compressor local panels, analyzers, etc., and contain
the grounding system.
h) Layout of Instrument Panels

The drawings shall show front and rear arrangement of instruments at instrument panels
and construction of panels.
51
i) Typical Installation Method for Instrument

The drawings shall illustrate typical methods of instrument wiring and air piping work
around the transmitters, controllers, converters, control valves and other major instrument
equipment and indicate a typical materials table if necessary.
j) Instrument Pressure Piping Hook-up Drawings

The drawings shall give a summary of typical work methods of process piping to
instruments among instrumentation work items, and shall show how these methods are
applicable per instrument. The drawings shall also show a typical materials table.
k) Analyzer Piping Hook-up Drawings

The drawings shall illustrate instrumentation piping and wiring methods around the
analyzer including analyzer housing, and show sizes, symbols and quantities of piping,
piping component parts, wiring materials and other work materials for the instrumentation.
l) Layout of Instrument Main Cable

The drawings shall show the aboveground and underground routing of main instrument
cable from their junction boxes in the field to their termination points in the control room.
m) Layout of Control Room

These drawings shall show arrangement of operator consoles, cabinets, panels and racks,
etc. in the control rooms and computer room.
n) Location Layout of Field Instruments

The drawings, being superimposed on simplified plot plan, shall show the location and
elevation of field instruments, local panels, junction boxes and instrument air supply
headers.Each instrument shall be shown by its tag number , elevation and the junction box
or the panel it is connected to.
o) Instrument Wiring Connection List

The drawings shall show cable connections at termination points in the control room and
the field including tag, numbers, cable number, pair numbers, colour code of wires,
terminal identification, etc.
p) Junction Box Data Sheet

Each junction box shall have its own data sheet containing all design data, specification
and drawing showing all cables, connections, terminal numbers and instrument tag
numbers.
52

Nioec SP 70 01

Uploaded by

Copyright:

Available Formats

Nioec SP 70 01

Uploaded by

Document Information

Original Description:

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Nioec SP 70 01

Uploaded by

Copyright:

Available Formats

What are the different types of drawings required for instrumentation?

What are the different types of drawings required for instrumentation?

What information is required in an I/O list?

What information is required in an I/O list?

NIOEC-SP-70-01(5)

DOCUMENT CODE NO. OF SHEETS: 52

NATIONAL IRANIAN OIL REFINING & DISTRIBUTION COMPANY

5 SEPTEMBER, 2015 F. FAZLI H. SHIRINPOUR M. ORDOOBADI A.A.MOGHADAM

CONTENTS: PAGE NO.

12.TANK GAUGING SYSTEM ..................................................................................................47

- NIOEC-SD-0100-1 to 4 NIOEC Standard Drawing for P&ID Symbols and Legends

ANSI (AMERICAN NATIONAL STANDARDS INSTITUTE)

API (AMERICAN PETROLEUM INSTITUTE)

ASME (AMERICAN SOCIETY OF MECHANICAL ENGINEERS )

IEC (INTERNATIONAL ELECTRO-TECHNICAL COMMISSION)

IEC 60534-2-1 "Industrial-Process Control Valves – Part 1: Control Valve

IPS (IRANIAN PETROLEUM STANDARD)

ISA (INSTRUMENTATION, SYSTEMS, AND AUTOMATION SOCIETY OF AMERICA)

ISO (INTERNATIONAL ORGANIZATION FOR STANDARDIZATION)

NAMUR (NORMENARBEITSGEMEINSCHAFT FÜR MESS UND REGELTECHNIK IN

NIOEC SP(NIOEC SPECIFICATIONS)

NIOEC-SIP (NIOEC SHOP INSPECTION PROCEDURE)

LAN: Local Area Network

5.2. Instrument Accessibility

5.3. Instrument Air Supply

5.4. Electrical Power Supply

5.5. Instrument Protection

5.6. Environmental Protection

5.7. Hazardous Area Classification

5.8. Data Sheets

5.9. Instruments Symbols and Legends

iii) Over range: 2.5 % of transmitter upper range

6.1.3. Signal Levels

6.1.4. Power Supply

6.1.5. Accuracy of Instruments

Temperature Gauge ±1.0% F.S. or Class 1 per EN 13190

6.1.6. Instruments Cable Entry

6.1.8. Pressure/Temperature Rating of Instruments and Valves

6.1.9. Impulse Lines

6.1.10. Manifold valves

6.1.11. Process Isolation Valve

6.1.12. Instrument to Process Connection

Size Type Size Type Size Type

Pressure/DP Without Diaphragm Compression

Thermo-well 1 1/2" Flanged 1 1/2" Flanged 1/2" NPT

6.1.13. Instrument Nozzle Rating on Vessels

a) Level instrumentation standpipes: ANSI 300 #.

6.1.15. Local Indicators

6.1.16. Diaphragm Seals

6.2. Flow Measurement

6.2.2. Instrument Types

6.2.2.1. Differential Pressure Transmitter

6.2.2.2. Vortex Flow Meters

b) Installation and Construction

6.2.2.3. Variable Area Meters (Rotameters)

b) Installation and Construction

6.2.2.5. Coriolis Type Mass flow Meters

6.2.2.6. Ultrasonic Flow meters