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B03 Issued for Use Mike T Brown 26 Aug 2015 Michael Ho 26 Aug 2015 Nathan Barrett 26 Aug 2015

B02 Issued for Use Mike T Brown 03 Sep 2014 Michael Ho 03 Sep 2014 Nathan Barrett 03 Sep 2014

B01 Issued for Use Mike T Brown 25 Jul 2013 Michael Ho 25 Jul 2013 Mike T Brown 25 Jul 2013

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This document is copyright and shall not be reproduced without the permission of BP

Rev

GPO-EN-SPE-30253 B03

Specification for Field Instruments

GPO-EN-SPE-30253 Page 2 of 3 Rev: B03

© BP p.l.c. BP Internal

Foreword

This is a revised issue of GIS 30-253. This document incorporates the following technical changes:

• Clause 6.1m added to require transmitter heads to have rotation adjustment

• Clauses 8.2.d.2 and 3 deleted

• Clause 8.2.q added to clarify requirements for thermowell design

• Clause 8.3.c.2 clarified and new clause 8.3.c.3 added

• Clause 8.4.c clarified and new clause 8.4.d added

• Clause 8.6.a.2 snap acting requirement removed

• Former clause 8.6.a.3 deleted

• Clauses 8.6.a.3 and 8.6.a.7 clarified to apply to electronic switches

• Clause 8.6.b clarified to apply to mechanical temperature switches

• Clause 9.1 clarified

• Clause 9.2.a.2 snap acting requirement removed and clauses 9.2.a.3 - 6 deleted

• Clause 9.4.1.d updated to remove zero stop requirement

• Clause 9.4.1.f dampening requirement clarified

• Clause 9.4.1.g updated to change size requirement into a nominal size

• Clause 9.4.1.o updated to allow alternatives to be specified on data sheets.

• Clauses 9.5.g, j and m clarified

• Clause 10.1.c updated to clarify requirement

• Clause 10.2.3.f updated to clarify requirement

• Clause 10.2.4.a. updated to clarify requirement

• Clause 10.2.4.c updated to relax requirement

• Clause 10.2.4.e updated to clarify requirement

• Clause 10.2.6.b updated to relax requirement

• Clause 10.2.6.e updated to clarify requirement

• Clause 10.3.e updated to relax accuracy from 2% to 10%

• Clause 10.4.a updated to clarify overpressure protection requirement for Coriolis flow meters

• Clause 10.7.a cross reference updated

• Clause 10.7.h updated to clarify requirement

• Clauses 10.8.a and c updated to clarify requirements

• Clauses 10.9.b and d updated to clarify requirement

• Clause 10.10.d updated to clarify requirement

• Section 10.12 updated and renumbered to remove optical flare gas flow meters

GPO-EN-SPE-30253 Page 3 of 3 Rev: B03

© BP p.l.c. BP Internal

• Clause 10.12.g updated to relax turn down requirement

• Clause 11.12.i deleted and clause 11.12.k clarified

• Clauses 11.13.b, d and k clarified

• Clause 11.14.a updated to clarify that reflex type is acceptable.

• Section 11.15 added to clarify requirements for vents on level measurement chambers

• Clause 12.2.b updated

Technical changes to this document are indicated by a bar in the left margin.

This document has been prepared in accordance with the BP Standardisation Strategy. This document will be used in conjunction with other standardisation initiatives to define the standardisation requirements for equipment and components.

This is an interim issue of GIS 30-253 pending formal ETP approval. This GPO number has been allocated so that projects use the same document and vendors start to see a consistent number on the specifications.

This document will be removed from the GPO library as soon as this GIS is formally issued in the ETP Library.

The embedded document below is the copy that should be sent to Suppliers and has the commentary text deleted.

GIS 30-253 Specification for Field Instruments.pdf

26 August 2015 Engineering Technical Practice Engineering

Group Instruction for Supply

GIS 30-253


Copyright © 2015 BP International Ltd. All rights reserved.

This document and any data or information generated from its use are classified, as a minimum, BP Internal. Distribution is intended for BP authorised recipients only. The

information contained in this document is subject to the terms and conditions of the

agreement or contract under which this document was supplied to the recipient's organisation. None of the information contained in this document shall be disclosed

outside the recipient's own organisation, unless the terms of such agreement or contract

expressly allow, or unless disclosure is required by law.


Page 2 of 43 GIS 30-253 26 August 2015

Table of Contents

Page

1 Scope .................................................................................................................................... 6

2 Normative references ............................................................................................................. 6

3 Terms and definitions ............................................................................................................. 8

4 Symbols and abbreviations .................................................................................................... 8

5 Order of precedence .............................................................................................................. 9

6 General technical requirements ........................................................................................... 10

6.1 General ..................................................................................................................... 10

6.2 Hazardous area classification ................................................................................... 11

6.3 Materials ................................................................................................................... 11

6.4 Painting and coating requirement .............................................................................. 11

7 Transmitters ......................................................................................................................... 12

7.1 Conventional ............................................................................................................. 12

7.2 Wireless transmitters ................................................................................................ 13

8 Temperature instruments ..................................................................................................... 14

8.1 General ..................................................................................................................... 14

8.2 Thermowells ............................................................................................................. 14

8.3 Resistance temperature device ................................................................................. 15

8.4 Thermocouples ......................................................................................................... 16

8.5 Special temperature sensors .................................................................................... 16

8.6 Temperature switches ............................................................................................... 17

8.7 Temperature transmitters .......................................................................................... 17

8.8 Filled thermal systems .............................................................................................. 18

8.9 Temperature gauges ................................................................................................. 18

9 Pressure instruments ........................................................................................................... 19

9.1 General ..................................................................................................................... 19

9.2 Pressure switches ..................................................................................................... 19

9.3 Pressure and differential pressure transmitters ......................................................... 19

9.4 Pressure gauges ....................................................................................................... 20

9.5 Diaphragm seal assemblies ...................................................................................... 21

10 Flow Instruments ................................................................................................................. 22

10.1 General ..................................................................................................................... 22

10.2 Differential pressure flow measurement .................................................................... 22

10.3 Variable area (VA) flow meter ................................................................................... 25

10.4 Coriolis flow meters ................................................................................................... 25

10.5 Turbine meters .......................................................................................................... 26

10.6 Electromagnetic flow meters ..................................................................................... 26

10.7 Ultrasonic flow meters ............................................................................................... 27

10.8 Multiphase flow meter ............................................................................................... 27

10.9 Vortex flow meters .................................................................................................... 27



10.10 Positive displacement flow meters ............................................................................ 28

10.11 Weirs ........................................................................................................................ 28

10.12 Flare gas flow meters ................................................................................................ 28

10.13 Thermal flow ............................................................................................................. 28

11 Level instruments ................................................................................................................. 28

11.1 DP level transmitters ................................................................................................. 29

11.2 Bubbler level devices ................................................................................................ 29

11.3 Diaphragm seals ....................................................................................................... 29

11.4 Flushing rings ........................................................................................................... 29

11.5 Displacer instruments ............................................................................................... 29

11.6 Magnetic level ........................................................................................................... 30

11.7 Tension wire float transmitter .................................................................................... 30

11.8 Non contacting radar gauge ...................................................................................... 31

11.9 Guided wave radar (GWR) ........................................................................................ 31

11.10 Ultrasonic level ......................................................................................................... 31

11.11 Capacitance instruments ........................................................................................... 32

11.12 Nucleonic level .......................................................................................................... 32

11.13 Level switches .......................................................................................................... 33

11.14 Gauge glass (reflex / transparent) ............................................................................. 33

11.15 Level Measurement Chambers ................................................................................. 34

12 Corrosion, erosion and sand monitors ................................................................................. 34

12.1 General ..................................................................................................................... 34

12.2 Insertion probes ........................................................................................................ 35

12.3 Acoustic detector ...................................................................................................... 35

12.4 Ultrasonic detector .................................................................................................... 35

13 Density or specific gravity devices ....................................................................................... 35

13.1 General ..................................................................................................................... 35

13.2 Hydrostatic head density ........................................................................................... 36

13.3 Displacer density....................................................................................................... 36

13.4 Coriolis density ......................................................................................................... 36

13.5 Vibrating fork ............................................................................................................. 36

13.6 Vibrating cylinder ...................................................................................................... 36

13.7 Nucleonic density ...................................................................................................... 36

14 Position measurement ......................................................................................................... 36

14.1 Single-point position devices (limit or proximity switches) ......................................... 36

14.2 Linear location or position transmitters ...................................................................... 36

15 Miscellaneous equipment..................................................................................................... 36

15.1 Manual pushbuttons .................................................................................................. 36

15.2 Remote local indicators ............................................................................................. 37

15.3 Beacons and sounders ............................................................................................. 37

16 Quality management ............................................................................................................ 37

17 Inspection, test and certification ........................................................................................... 37

17.1 Inspection and test plan ............................................................................................ 37



17.2 Inspection access ..................................................................................................... 37

17.3 Equipment specific inspection requirements ............................................................. 38

18 Packing, preservation, marking and shipping ....................................................................... 38

19 Deliverables ......................................................................................................................... 38

Annex A (Informative) Typical thermowell dimensions .................................................................. 39

Bibliography .................................................................................................................................. 43

List of Tables

Table 1 - Communication to ICSS ................................................................................................. 12

Table 2 - Limits of thermowell frequency ratio ............................................................................... 15

Table A.1 Thermowell nomenclature ............................................................................................. 39

Table A.2 Typical insertion length “U” ........................................................................................... 39

Table A.3 Typical thermowell lengths “L” ...................................................................................... 40

Table A.4 Typical sensor lengths “S”............................................................................................. 40

List of Figures

Figure A.1 - Flanged thermowell typical dimensions ..................................................................... 41

Figure A.2 - Flanged thermowell with extension typical dimensions .............................................. 42



Foreword

This Specification conforms to the BP Standardisation Strategy to transform GISs

into engineering technical specifications with no cross references to GPs.

At the date of publication, this Specification conforms to the Engineering Technical

Practices (ETPs) listed in the Bibliography and any approved deviations from these

ETPs.

This Specification together with other BP documents and project specific documents

defines the scope of supply for the equipment. The applicable BP and project

specific documents will be identified in the Purchase Order documentation.



1 Scope

a. This Specification provides requirements for the design, materials, fabrication, inspection,

testing, documentation and preparation for shipment of field instruments.

b. This Specification excludes requirements for equipment associated with subsea systems.

c. This Specification excludes requirements for custody transfer metering.

d. This Specification excludes requirements for weighing systems.

2 Normative references

The following documents are referenced in one or more requirements in this document. For dated

references, only the version cited applies. For undated references, the latest version of the referenced

document (including any amendments) applies.

Company documents

GIS 06-602 Specification for Coating and Painting of Supplier Equipment.

GIS 30-251 Specification for Instrument Tubing and Fittings - Metric Units.

GIS 30-252 Specification for Instrument Tubing and Fittings - Customary Units.

GIS 30-351 Specification for Actuators for On/Off Valves.

GIS 30-353 Specification for Control Valves and Pressure Regulators.

GIS 36-320 Material Specification for 22% Cr and 25% Cr Duplex Stainless Steel.

Project documents will be provided as listed below:

Data Sheets.

Nominated Items List.

Package Contents List.

Purchase Order Quality Requirements.

Site Data Specification.

Specification for Packing, Marking and Shipping.

Supplier Deliverable Requirements List.

Supplier Information Requirements Specification.

Supplier Quality Requirements Specification.

The document numbers for project specific documents will be identified by the

project in the Package Contents List or as otherwise stated in the Purchase Order.

American Petroleum Institute (API)

API Specification Q1 Specification for Quality Management System Requirements for

Manufacturing Organizations for the Petroleum and Natural Gas Industry.

API MPMS Manual of Petroleum Measurement Standards.

American Society of Mechanical Engineers (ASME)

ASME B16.36 Orifice Flanges.

ASME B40.100 Pressure Gauges and Gauge Attachments.

ASME PTC 19.3 TW 2010 Thermowells - Performance Test Codes.



British Standards Institute (BSI)

BS 3463 Observation and gauge glasses for pressure vessels.

European Standards

EN 837-1 Pressure gauges Part 1. Bourdon tube pressure gauges - Dimensions,

metrology, requirements and testing.

EN 837-3 Pressure gauges Part 3: Diaphragm and capsule pressure gauges -

Dimensions, metrology, requirements and testing.

EN 10204 Metallic products - Types of inspection documents.

EN 60584-1 Thermocouples - Part 1: Reference tables.

EN 61326 Electrical equipment for measurement, control and laboratory use - EMC

requirements.

FOUNDATION™ Fieldbus

AG-181 System Engineering Guidelines.

International Electrotechnical Committee (IEC)

IEC 60079 (all parts) Explosive atmospheres.

IEC 60381-1 Analogue signals for process control systems. Part 1: Direct current

signals.

IEC 60529 Degrees of protection provided by enclosures (IP Code).

IEC 60751 Industrial platinum resistance thermometers and platinum temperature

sensors.

IEC 60770-1 Transmitters for use in industrial-process control systems – Part 1:

Methods for performance evaluation.

IEC 61000 Electromagnetic Compatibility (EMC).

IEC 61508 Functional safety of electrical/electronic/programmable electronic safety-

related systems.

IEC 61520 Metal thermowells for thermometer sensors - Functional dimensions.

IEC 62591 Industrial communication networks – Wireless communication network

and communication profiles – WirelessHART™.

International Organisation for Standardisation (ISO)

ISO 5167 Measurement of fluid flow by means of pressure differential devices

inserted in circular cross-section conduits running full.

ISO 5168 Measurement of fluid flow - Procedures for the evaluation of

uncertainties.

ISO/TR15377 Measurement of fluid flow by means of pressure-differential devices -

Guidelines for the specification of orifice plates, nozzles and Venturi

tubes beyond the scope of ISO 5167.

ISO 9001 Quality management system - Requirements.

ISO 15156 Parts 1 to 3 Petroleum and natural gas industries — Materials for use in H2S-

containing environments in oil and gas production

(ANSI/NACE MR 0175).

International Society of Automation (ISA)

ISA-100.11a Wireless systems for industrial automation: Process control and related

applications.



NACE International

NACE MR 0103 Materials Resistant to Sulfide Stress Cracking in Corrosive Petroleum

Refining Environments.

National Electrical Manufacturers Association (NEMA)

NEMA 250 Enclosures for Electrical Equipment (1000 Volts Maximum).

3 Terms and definitions

For the purpose of this Specification, the following terms and definitions apply:

Company

BP p.l.c., an associate or subsidiary, or other organisation acting as owner, purchaser, or customer as

designated in the Purchase Order.

Company responsible engineer

Company engineer responsible for the technical requirements of the item.

Manufacturer

Entity or sub-supplier producing the equipment item.

Supplier

Entity entering into a contract with Company to provide materials, goods, supplies, equipment, or

plant and includes the successors and (or) permitted assigns of such entity.

4 Symbols and abbreviations

For the purpose of this Specification, the following symbols and abbreviations apply:

AWG American wire gauge.

DP Differential pressure.

EMC Electromagnetic compatibility.

ESD Emergency shutdown.

FF FOUNDATION™ Fieldbus.

GWR Guided wave radar.

HART Highway addressable remote transducer.

HW Hard wired.

ID Internal diameter.

ITP Inspection and test plan.

LVDT Linear variable differential transformer.

MAWP Maximum allowable working pressure.



NPT National pipe thread taper.

PAS Process automation system.

PVC Polyvinyl chloride.

PTFE Polytetrafluoroethylene.

RFI Radio frequency interference.

RTD Resistance temperature detectors.

SIL Safety integrity level.

SIS Safety instrumented system.

SS Stainless steel.

VA Variable area.

5 Order of precedence

a. The order of precedence of the codes and standards quoted in the specifications shall be:

1. International and local statutory regulations.

2. Project data sheets.

3. Project specifications.

4. This Specification.

5. Referenced Company documents.

6. Referenced national and international codes.

b. Areas of apparent conflict between documents shall be brought to the attention of

Company for resolution.

c. In the event of a conflict between this document and a relevant law or regulation, the

relevant law or regulation shall be followed. If the document creates a higher obligation, it

shall be followed as long as this also achieves full compliance with the law or regulation.

d. Design, engineering, procurement, and construction for equipment shall comply with the

statutory laws and regulations of the final location of the asset. Refer to documents

identified in the Purchase Order for a list of these regulations.

e. For projects where the final location of the asset is in the EU:

1. Products supplied shall be confirmed to comply with applicable EU directives.

2. A Declaration of Conformity shall be provided.

3. The CE mark shall be affixed to the nameplate or to the body of the instrument.

4. Components supplied shall be listed together with the EU directives with which they

comply and the rationale by which compliance has been achieved.

5. A Technical File in compliance with applicable EU directives shall be compiled and

retained for a period of 10 years.

f. For Projects where the final location of the asset is outside the EU (not subject to ATEX

requirements), Supplier is responsible for confirming that the products supplied are

certified to the IECEx scheme in conformance to IEC 60079.



6 General technical requirements

6.1 General

a. Suppliers shall have single point responsibility for all aspects of instruments.

b. Instruments shall be designed for use under the conditions specified in the Site Data

Specification or other documents included in the Purchase Order.

c. Project data sheets will be provided by Company and shall be developed into

comprehensive data sheets containing process and Supplier information.

d. Operating voltage shall be:

1. Loop powered instruments - 24 VDC.

2. Instruments requiring an external power supply, as specified on data sheets.

24 VDC, 110 or 230 VAC depending on project instrument power supply and

requirement for long cable runs.

3. Instruments with external power supplies shall have the facility to be electrically

isolated.

e. Instrument housings for outdoor use shall, as a minimum, be one of the following, as

specified on data sheets:

1. IP 66 in conformance to IEC 60529.

2. NEMA 4X in conformance to NEMA 250.

NEMA 4X for North America and IP 66 for the rest of the world are not directly

equivalent but are both acceptable. Project should review the specific application

and ensure the requirement is appropriate.

f. Housing material shall be Supplier’s standard for the environment, unless specified

otherwise on data sheets.

g. In-line and close coupled instruments shall be designed to operate at the design

temperature and pressure of the pipe or equipment on which instruments are installed.

h. If specified on data sheets, instruments shall be designed to operate with an effect of less

than ± 0,1% of range during vibration up to 0,21 mm (0,008 in) from 10 Hz to 2 000 Hz or

as defined on data sheets.

Project can consider the vibration and seismic impact for each instance, if

applicable and define the appropriate limits on the data sheets. The figures given

are based on conforming to IEC 60770-1.

i. Instruments requiring a vent opening shall have a self-draining, bug proof, breather screen.

j. Instrument measurement technologies will be defined on data sheets but alternative devices

which provide advantages for the application may be proposed but shall only be used

subject to Company agreement.

k. Protection for EMC shall meet EN 61326.

l. If specified on data sheets, instruments shall be supplied with a kit for mounting on a

50 mm (2 in) pipe stand.

m. Transmitter head shall have rotation adjustment.

n. Instruments shall be supplied with one or more permanently attached SS nameplates with

the following information in characters at least 1,6 mm (1/16 in) high:

1. Supplier’s name.

2. Model, type and serial no.



3. Operating voltage.

4. Hazardous area certification details.

5. Date of manufacture.

o. Instruments shall be identified with a permanently attached tag number, as specified on

data sheets which shall be on the nameplate or a separate SS tag, attached with SS wire.

6.2 Hazardous area classification

If instruments are to be located in a hazardous area, data sheets and Purchase Order will specify

one or more certifications required:

a. Certified in conformance to IEC 60079.

b. ATEX certification.

c. IECEx certification

d. FM, UL or CSA certification.

For installations in EEA areas certification to ATEX with CE marking.

For installations in North America and the rest of the world, certification to IECEx.

For installations in North America certification includes UL, FM or CSA

certification.

The project should determine which of the above to specify according to area and

site requirements.

6.3 Materials

a. Materials in contact with process fluids shall be:

1. As defined on the data sheets.

2. Confirmed by Supplier.

3. Resistant to corrosive and erosive properties of fluids at temperatures to which they

are exposed.

b. Flanges of instruments and thermowells specified as duplex or super duplex shall be made

of materials that conform to GIS 36-320.

c. Copper, silver, mercury or alloys containing these metals (except Alloy 400) shall not be

used in contact with process fluids.

d. Instruments shall not contain:

1. Mercury.

2. Asbestos or ceramic fibres.

e. Instrument parts exposed to process fluids containing hydrogen sulphide or if specified on

the data sheets shall be specified and installed to conform to ISO 15156

(ANSI/NACE MR0175) or NACE MR 0103.

6.4 Painting and coating requirement

a. Instruments shall be supplied in conformance to Supplier’s standard coating specification

for a saline marine environment, unless otherwise specified on data sheets.

b. Full details of coating specification shall be provided to allow Company to assess its

suitability and approval.



c. Method statements shall be provided from sub-suppliers detailing procedures and products

to be used for surface preparation and coating of equipment.

d. If Supplier is unable to offer specifications and procedures or Company considers

Supplier’s coating specifications and procedures unacceptable, GIS 06-602 shall be used.

e. Instruments with SS bodies or enclosures shall not require painting unless otherwise

specified on data sheets.

7 Transmitters

7.1 Conventional

a. Transmitters shall be fitted with an integral local indicator unless otherwise specified on

data sheets, failure or removal of which shall not affect the transmitted signal.

b. Communications for transmitters shall be as specified on data sheets:

Table 1 - Communication to ICSS

Instrument type Process variable Status & diagnostics

Process control FF or HW 4-20 mA FF or HW 4-20 mA with HART or wireless

SIS HW 4-20 mA FF or HW 4-20 mA with HART

c. Signals from specialised instruments e.g. downhole pressure and temperature sensors, may

not conform to this and will be detailed on data sheets.

d. FF transmitters shall be approved by the certifying body for FOUNDATION™ Fieldbus

and carry the FF check mark in conformance to AG-181.

e. Transmitters shall be certified for use in loops at the relevant SIL rating if specified on the

data sheets.

f. SIL certification and documentation including product safety manual to IEC 61508 shall

be supplied for SIS transmitters.

g. Transmitters shall be designed to fail to a designated failsafe position or output as specified

in data sheets.

h. Process connection shall be as specified on data sheets.

i. Zero adjustment shall not affect span calibration.

j. Transmitters shall meet or exceed these performance requirements:

1. Turndown shall be at least 20 to 1 at specified accuracy.

Note this relates to the primary transmitter not the overall process measurement,

e.g. the overall turndown for a DP flow measurement will be significantly less due to

the square root extraction.

2. Ambient temperature effect shall be no greater than ± 0,25% of span per 30°C (54°F)

at maximum span.

3. Long term drift shall be equal to or less than ± 0,2% of upper range limit for

12 months.

4. Supply voltage effect shall be less than 0,005% of span per volt change.

5. RFI effects shall be limited to ± 0,1% of span over a range of 80 MHz to 1 000 MHz

in 10 V/m field.



k. Cable entries into instrument housings shall be one of the following, as specified on the

data sheets:

1. M20 x 1,5 mm ISO (female).

2. 1/2 - 14 NPT (female).

l. Wire connections shall be by screw terminals.

m. Electronics shall be:

1. Mounted in a sealed section of transmitter housing separate from field terminations.

2. Reverse polarity protected.

3. Electrically isolated from a separate power supply, if fitted.

n. Transmitters shall:

1. Have lightning and surge protection, unless otherwise specified on data sheets.

2. Maintain configuration data on loss of power.

o. Transmitters shall be smart type and shall:

1. Provide self diagnostic function to identify faults in transmitter electronics and

sensor.

2. Allow re-ranging to be performed without requiring recalibration.

3. Allow software configuration, re-ranging, testing, loop checking, and operations

diagnostics to be performed with “communicator” type device or via ICSS over

transmitter signal wiring.

4. Be preconfigured with instrument tag, range and other data.

Transmitters purchased for use as spares can be tagged “SPARE1”, “SPARE2”,

“SPARE3”, etc.

5. Include a write protect switch or password protection.

7.2 Wireless transmitters

a. Wireless transmitters may be specified in certain applications and shall:

1. Comply with applicable local regulations.

2. Conform to IEC 65291 or ISA-100.11a, as specified on data sheets.

b. Wireless transmitters shall:

1. Be designed to allow replacement of battery in the field without physical

disconnection.

2. Provide adjustment of update rate to meet requirements of the application and

maximise battery life.

3. Provide battery % remaining indication and configurable “end of life” warnings

through the HART or equivalent diagnostics set.

c. Hybrid transmitters, with cabled primary signal connection and wireless diagnostics and

secondary data transmission may also be specified.



8 Temperature instruments

8.1 General

a. Temperature elements shall be supplied with a matching thermowell in conformance to 8.2

unless otherwise specified.

b. Resistance temperature detectors (RTD) or thermocouples shall be supplied for remote

indication and control, as specified on data sheets.

c. RTDs or thermocouples shall be supplied as specified on data sheets, with:

1. Head mounted transmitters, or

2. Terminations in head for use with remote transmitter.

Temperature elements will only be used without transmitters in special applications

i.e. machine monitoring.

d. Head mounted transmitters shall allow for the orientation of the head to be adjusted so that

a local indicator can be seen.

e. Extensions shall be provided with a union to allow calibration and proof testing, if


Union allows element to be removed from thermowell with connections and cable

attached.

f. Elements shall be spring loaded using a 316 SS spring loading assembly.

g. Elements and transmitters shall have weatherproof terminal head assemblies designed for

hazardous area classification.

1. Threaded cover shall be attached to head with a SS chain.

2. Terminal blocks with clamp terminals shall be provided for terminating thermocouple

leads and earth (ground) shield.

3. Terminal blocks shall have polarity marked brass terminals mounted on a ceramic

base.

4. Wire terminations (flying leads) shall be colour coded for thermocouple type, or ends

shall be sleeved and identified by polarity.

h. Terminal heads shall be attached to thermowells with extension pieces providing for a

minimum of 80 mm (3 in) insulation.

8.2 Thermowells

a. Thermowells shall:

1. Be flanged or as specified on data sheets.

2. Have insertion (U) and overall length (L) in conformance to IEC 61520. Refer to

Annex A.

b. Thermowell pressure and temperature ratings, testing and certification requirements shall

be as specified on data sheets.

c. Thermowells shall be of forged bar stock material.

d. Thermowell bores shall:

1. Match RTD or thermocouple sheath, if supply includes element and thermowell.

2. Be concentric within 10% of inside diameter of the well.



e. Thermowells shall be tapered rather than stepped or straight, unless otherwise specified on

data sheets.

f. Screwed thermowells shall undergo internal hydrostatic testing at a pressure of at least

150% of MAWP.

g. Flanged thermowells shall undergo external hydrostatic testing at a pressure of at least

150% of MAWP.

h. If flanges are welded, they shall be attached to thermowells by full penetration welds.

i. Thermowell material shall be as specified on data sheets.

j. Wake frequency calculations shall be performed for all stated process conditions on all

thermowells in conformance to ASME PTC 19.3 TW 2010, fully documented, and

provided for review.

k. Calculated wake frequency shall not exceed the number in Table 2 based on information

on pipe schedule and nozzle arrangement in data sheets.

Table 2 - Limits of thermowell frequency ratio

Parent pipe schedule

Thermowell in a flanged nozzle with 4-way welded gussets

All other thermowells

Schedule 160 or greater < 0,392 < 0,384

Schedule 80 to less than Schedule 160 < 0,384 < 0,372

Schedule 40 to less than Schedule 80 < 0,372 < 0,340

Less than Schedule 40 < 0,340 < 0,168

Note: Treat stainless and non-stainless pipe the same (i.e. Schedule 40S and 40 have the same limit).

l. Calculation method shall be documented and evidence of independent verification of the

calculation provided for review.

m. Thermowells shall be stamped, as a minimum, with size, rating and material.

n. Test thermowells shall be:

1. To same specification as other thermowells.

2. Supplied with a SS plug that is secured by a chain or wire made from corrosion

resistant material.

o. Thermowell dimensions shall be as specified on data sheets.

p. Supplier shall refer to Annex A which lists typical dimensions and defines terminology.

Extension length and thermowell dimensions should be selected according to

standard element length, making allowance for any insulation on the line.

q. Fabricated thermowells shall meet associated pipework specification and welder

qualification shall meet ASME IX requirements.

8.3 Resistance temperature device

a. RTD characteristics shall be in conformance to IEC 60751 Class A.

b. Nominal resistance at 0°C shall be 100 Ohms with a temperature coefficient, α equal to

3,851 x 10-3 °C-1.

c. RTD elements shall be:



1. Encased in high purity mineral insulation material that is firmly compacted within a

sheath made of 316 SS or alternative material if agreed by Company responsible

engineer.

2. For metric applications, 6 mm nominal diameter or 3 mm for special applications

such as mechanical packages and if specified on data sheets.

3. For customary applications, 1/4 in nominal diameter or 1/8 in for special applications

such as mechanical packages and if specified on data sheets.

Construction tolerances should conform to respective standards for metric and

customary sizes.

4. 3-wire, unless a 4-wire option is specified.

5. Duplex, unless otherwise specified.

d. RTD to transmitter connections shall only be on screw terminals within the element head.

8.4 Thermocouples

a. Thermocouples shall be mineral insulated, metal-sheathed type in conformance to

BS EN 60584-1.

b. Sheath material shall be minimum 316 SS or as specified on data sheets.

c. For metric applications, thermocouples shall have duplex elements in a 6 mm nominal

diameter or 3 mm for special applications such as mechanical packages and if specified on

data sheets.

d. For customary applications, thermocouples shall have duplex elements in a 1/4 in nominal

diameter or 1/8 in for special applications such as mechanical packages and if specified on

data sheets.

Construction tolerances should conform to respective standards for metric and

customary sizes.

e. Element tip shall be grounded to sheath, unless otherwise specified on data sheets.

8.5 Special temperature sensors

8.5.1 Optical pyrometers

Optical pyrometers should not be specified for temperatures outside the visible red

range from 760°C to 3 500°C (1 400°F to 6 300°F).

Data sheets will include temperature range, installation type etc. and specialist Suppliers shall

propose a model from their range designed to match these process conditions.

8.5.2 Fibre optics

Fibre optic temperature systems should only be specified for temperature profile

applications below 300°C (570°F), for example, oil and gas well monitoring, and

column profiles.

a. Fibre optic systems shall be accurate to within 0,1°C (0,2°F) for temperatures below 300°C

(575°F)

b. Systems shall allow a minimum 2 point (and preferably 3 point) calibration.

c. Data sheets will include temperature range, installation type etc. and specialist Suppliers

shall propose a model designed to match these process conditions.



8.5.3 Tank gauging - temperature measurement

a. If specified for use in conjunction with non-contacting radar tank gauges, averaging type

resistance temperature elements consisting of multiple RTDs shall be provided.

b. Temperature element arrays shall be designed for tank heights specified on data sheets.

c. RTDs shall be in conformance to 8.3.

8.5.4 Non intrusive skin devices

If trending rather than an absolute temperature value is required, non-intrusive skin

devices can be used. If wake frequency calculations and velocities preclude the use

of thermowells, non-intrusive skin devices should be considered.

a. Non-intrusive RTDs or thermocouples shall be designed to match the mounting

arrangement specified in data sheets.

b. Data sheets will specify if fitting accessories or matching blocks for welding shall be

supplied.

8.6 Temperature switches

a. Temperature switches shall be self-contained devices providing:

1. Adjustable switch points.

2. Minimum 2 independent hermetically sealed changeover contacts.

3. An electronic display showing set points and status for electronic switches.

4. Input and output isolation.

5. Linearising facilities.

6. Facilities for configuration via the front panel with protection against unauthorised

adjustment for electronic switches.

7. Temperature measurement activated by either thermocouples or RTDs for electronic

switches.

b. Mechanical temperature switches shall have adjustable set points or adjustable differential

span settings marked with a reference scale.

c. Temperature switch trip point repeatability shall be ±1% of temperature set point.

d. Switch hysteresis shall be either:

1. Adjustable if defined on data sheets.

2. Non-adjustable, less than 5% of range.

Bimetallic or filled system switches should not be used in process service. However,

bimetallic switches can be proposed in utility services if specified on data sheets.

8.7 Temperature transmitters

a. RTDs and thermocouples shall have temperature transmitters, head mounted type or

remote if specified.

b. Temperature transmitters shall:

1. Have input and output isolation.

2. Accept RTD and thermocouple inputs.

RTD inputs accept both 4-wire and 3-wire measurement circuits.

3. Have an output accuracy of ± 0,04% for a given input to the transmitter.



c. For RTD inputs, transmitters shall have

1. Resistance element linearisation.

2. Accuracy of ± 0,15°C (0,27°F) for the digital conversion of the resistance input

signal.

d. For thermocouple inputs, transmitters shall have

1. Cold junction compensation.

2. Thermocouple linearisation.

3. Accuracy, for the digital conversion of the mV input signal, of:

a) Type E ± 0,35°C (0,6°F).

b) Type K ± 0, 5°C (0,9°F).

c) Type N ± 0,8°C (1,4°F).

d) Type R ± 1,0°C (1,8°F).

4. Burnout protection as follows:

a) Burnout protection action options shall include upscale and downscale.

b) Actions shall be selectable.

c) Designs shall include detection of sensor failures and measurement circuit

wiring faults.

d) Sensor failures shall be alarmed.

e. Outputs shall be stable over 5 years for RTD and 3 years for thermocouple inputs.

f. Output shall be in conformance to 7.1b.

8.8 Filled thermal systems

a. Bulb and capillary materials shall be 316 SS or as specified on data sheets.

b. Capillaries shall be armoured and sheathed (PVC or polyethylene).

c. Maximum capillary length shall be 10 m (33 ft) or as specified.

d. Ambient temperature compensated direct coupled instruments shall be used for both

capillary and direct coupled type.

Filled systems should not be specified except for low risk applications such as air

conditioning.

8.9 Temperature gauges

a. Temperature gauges shall be dial, bi-metallic “every angle” type.

b. Temperature gauges shall have a case and window as follows:

1. Hermetically sealed to exclude moisture and humidity from internal working parts.

2. Weatherproof to IP 66.

3. Cases and rings or bezels shall be 316 SS.

4. Windows shall be of clear safety glass with a gasket to maintain seal integrity.

c. Dials shall be 100 mm (4 in) diameter, supplied with white or luminescent dial with black

markings and black or reflective pointer as specified on data sheets.

d. Stem and connection nut material for dial thermometers shall be 316 SS or as specified on

data sheets.



e. Primary element of dial thermometers shall be as follows:

1. Metal coil in helix form.

2. Diameter in conformance to Supplier’s standard and any thermowell supplied with

the temperature gauge.

3. For temperature ranges below 260°C (500°F), bi-metallic coils shall be damped to

prevent pointer oscillation.

f. Thermometers shall be accurate to within 1% of dial range. A temporary abnormal

operating condition that swings the pointer beyond the end of the scale shall not impair this

accuracy.

g. Normal operating temperature shall be at approximately 50% of full scale, with maximum

temperature at approximately 90% of full scale.

9 Pressure instruments

9.1 General

a. Pressure instrument ranges shall be selected such that normal operating pressure is within

the middle third of the calibrated range and calibrated range is within the manufacturer’s

maximum range and reference accuracy.

Pressure elements for use on applications subject to fluctuating pressures should be

specified to operate below 60% of the maximum range.

b. Pressure devices shall be designed to withstand, without damage:

1. 150% of the upper limit of the range.

2. 150% of MAWP on all process connections, including low pressure side for

differential devices.

c. Differential pressure devices shall be designed to withstand, without damage, differential

equal to MAWP.

9.2 Pressure switches

a. Pressure switches shall be self-contained devices providing:

1. Adjustable switch points.

2. Minimum 2 independent hermetically sealed changeover contacts.

b. Pressure switch trip point repeatability shall be ± 1% of pressure set point or better.

c. Switch hysteresis shall be either:

1. Adjustable if defined on data sheets.

2. Non-adjustable, less than 5% of range.

Mechanical switches should not be used in process service. However, bimetallic

switches can be proposed in utility services if specified on data sheets.

9.3 Pressure and differential pressure transmitters

a. The minimum technical requirements for pressure and differential pressure transmitters

shall be as follows:

1. Accuracy ±0,04% of full range and ±0,1% of specified span.

2. Stability 10 years.

3. Diaphragm 316 SS or as specified on data sheets.



Accuracy is normally expressed as a % of span. If the span is less than the full range

of the transmitter then the required accuracy of the full range becomes less onerous.

b. Transmitters shall be designed with a range able to withstand 150% of system design

pressure without affecting performance, unless otherwise specified.

c. Process connection for pressure and differential pressure transmitters shall be flanged for

direct connection to a manifold as specified on data sheets.

d. Transmitters shall be constructed so that, in case of a pressure element failure, the

pressurised material will not enter the electronics or termination housing.

e. If specified on data sheets, manifolds shall be supplied with transmitters.

f. Manifolds shall conform to GIS 30-251 or GIS 30-252 (version included in Purchase Order

applies).

g. For differential pressure transmitters used for DP flow applications, square root extraction

shall be carried out at the transmitter.

h. Differential pressure transmitters shall include temperature and pressure compensation of

sensor element for increased stability and accuracy.

i. Low pressure side of differential pressure instruments shall be designed to withstand 150%

of MAWP without damage.

j. Vent and drain plugs shall be manufactured from an equivalent material to the transmitter

body.

9.4 Pressure gauges

9.4.1 General

a. Gauges shall be designed to withstand:

1. 150% of full scale range without affecting accuracy of the gauge.

2. 200% of full scale range without rupture of any component.

3. Overrange as described in 9.4.2b.

b. Standard ranges, in conformance to ASME B40.100 or EN 837-1 or 3, shall be provided

for pressure gauges. Normal operating pressure shall be between 50% to 75% of full scale.

c. Pressure gauge sensing elements shall be bourdon type unless otherwise specified on data

sheets.

d. Gauge shall have a means of preventing over range pressure from moving the pointer back

past zero and being indicated as a within scale measurement..

Typically this can be done with an over range stop or other limiting device.

e. Gauge accuracy shall be ± 1% of full scale range or as specified.

f. Pressure gauges shall be liquid filled or have damped movements to reduce effects of

vibration, shocks and surges unless specified otherwise.

g. Dials shall be nominal 100 mm (4 in) diameter, supplied with white or luminescent dial

with black markings and black or reflective pointer as specified on data sheets.

4.5 in is acceptable.

h. Dial legend shall state material of construction of movement.

i. Gauge pointer shall have a micrometer type adjustment feature for zero without removing

the pointer from the shaft.

j. Pressure gauges shall:



1. Have cases constructed of SS unless otherwise specified on data sheets.

2. Be safety pattern.

3. Be equipped with blow out backs.

4. Have clear safety glass.

k. Gauges shall be of welded construction such that sockets, tubes, tips, and movements are

an integral unit and may be removed from cases as complete assemblies.

l. Bourdon tube and socket material shall be minimum 316 SS or as specified.

m. Wetted parts shall be compatible with process fluid.

n. Movement shall be as follows:

1. Material shall be minimum 316 SS.

2. The material for wear points shall be either:

a) A non-hygroscopic, dimensionally stable plastic that provides self-lubricating

frictionless operation. This plastic material shall have good retention of these

critical properties and not deteriorate with UV or thermal effects.

b) Dissimilar hardened materials that provide a self-lubricating combination that

does not gall.

o. Pressure gauges shall have threaded 1/2 in NPT (M) bottom connections unless otherwise


9.4.2 Accessories

Pressure gauges on pulsating service measurements (such as discharge of

reciprocating compressors, pumps.) can be specified with a pulsation damper

(snubber) if required by Suppliers for their equipment.

a. Pulsation dampers shall be specifically designed for damping. A partially closed valve

shall not be acceptable.

b. Overrange protection shall be supplied if design pressure is greater than 150% of gauge

range and the gauge:

1. Shall have a mechanical design limit higher than the MAWP.

2. Shall not suffer loss of containment up to the MAWP.

3. May suffer loss of accuracy or calibration over 150% of range.

9.5 Diaphragm seal assemblies

a. Pressure and pressure differential transmitters shall be provided with either integral or

remote diaphragm seals if specified.

b. Suppliers shall advise if diaphragm seals are required if not specified.

c. For dirty and fouling services diaphragm seals will be specified.

d. Diaphragm seals shall be a minimum of DN 50 (NPS 2).

e. Where diaphragm seals are used they shall be large enough so that the required

measurement uncertainty is achieved.

f. The diaphragm seal shall be either:

1. Directly connected to instruments.

2. Connected via PVC or polyethylene coated 316 SS flexible armoured capillary

tubing.



g. Capillary tubing shall be filled and welded to seals and instruments and provided as a

complete assembly.

h. Diaphragm seal materials shall be chosen to meet applications, considering temperature

and pressure ratings, resistance to corrosion and toxicity of liquid fill.

i. Capillary tubing shall be provided to the length specified on data sheets.

j. Diaphragm seals for corrosive services shall have a 1/4 in NPT minimum flushing

connection as part of the seal or flushing ring on the process side of seal.

k. Seal fill fluid shall be proposed and details submitted for agreement by Company

responsible engineer.

Review fill fluid for suitability, referring to GP 30-05, fluid characteristics,

compatibility with process fluids and site conditions. In most cases, a silicone oil is

appropriate but this should be verified.

l. Seal fluid shall not freeze, boil or become viscous at storage or operating temperatures.

m. Compatibility of seal fluids with process fluids shall be verified for filled leg applications.

n. Instruments shall be permanently marked with seal fluid used and its specific gravity.

o. Seal fluid for oxygen service shall be Fluorolube or equivalent.

p. Glycol, silicon, or white oil may be used as seal fluids where the low pressure leg of a

differential pressure instrument is exposed to vapour service that is subject to condensation

or liquid entrapment.

q. A performance report shall be provided detailing materials, fill fluid and performance

criteria, including calculated range, speed of response and zero offset.

10 Flow Instruments

10.1 General

a. Flow instruments shall be designed for the process conditions on the data sheets including

fluid phase, flow rate, pressure, temperature, density and viscosity for minimum, normal

and maximum design conditions as well as for alternative operating modes such as start-

up.

b. The material of construction, end connections, pressure and temperature rating of the flow

instrument spool piece shall be in conformance to data sheets and designed for process

conditions. Suitability of the proposed device shall be confirmed and Supplier may suggest

an alternative construction.

c. Upstream and downstream piping requirements for the proposed flow instrument shall be

stated on Supplier data sheets.

10.2 Differential pressure flow measurement

10.2.1 Differential pressure transmitters

Transmitters for use with the differential pressure flow meters described below shall conform to

9.3.

10.2.2 Orifice plate

a. Orifice plates shall be fabricated in conformance to ISO 5167-2 or API MPMS 14.3.2, as


b. Calculated d/D ratio (Beta ratio) for orifice plates shall be within the limits of 0,2 and 0,7.



c. Preferred normal differential pressure range for an orifice meter shall be 0 mbar to

250 mbar (0 in to 100 in H2O). If this is not practicable the range shall be one of:

1. 0 mbar to 50 mbar (0 in to 20 in H2O).

2. 0 mbar to 100 mbar (0 in to 50 in H2O, note, not 40 in H2O).

3. 0 mbar to 500 mbar (0 in to 200 in H2O).

d. Data sheets will provide an initial sizing and thickness which shall be confirmed using a

calculation based on a recognised calculation method.

e. The calculation shall be documented and provided for review by Company responsible

engineer.

f. Measurement uncertainty shall be calculated in conformance to ISO 5168.

g. Conical entrance orifice plates shall be specified in conformance to ISO/TR15377,

Sections 6.1, conical entrance orifice plates.

h. Quarter circle orifice plates shall be specified in conformance to ISO/TR15377,

Sections 6.2, quarter-circle orifice plates.

i. Eccentric orifice plates shall be specified in conformance to ISO/TR15377, Section 6.3,

eccentric orifice plates.

j. Segmental orifice plates shall be specified in conformance to the API Manual of Petroleum

Measurement Standards.

k. Drain or vent holes, if specified, for orifice plates in horizontal piping of DN 100 (NPS 4)

or greater, drain holes shall be in conformance to ISO/TR15377.

l. Allowance for additional orifice area shall be made using the following formula:

])/(55,01[( 2dmdhdmd +=

Where:

d = effective orifice diameter

dm = orifice diameter

dh = drain hole diameter

m. Orifice plates shall be 316 SS or as specified on data sheets.

Alternative materials can be specified due to the corrosive properties of the process

fluid or when ISO 15156 applies.

n. Minimum recommended orifice plate thickness shall be in conformance to ISO 5167-2.

o. Orifice plates shall be provided with a tab stamped, or deep engraved, on the upstream face

with the tag number, orifice plate material, measured bore and the ID of the pipe.

p. The tab shall be in line with the drain or vent hole (if applicable).

10.2.3 Orifice flanges

a. If specified on Purchase Order, scope shall include orifice flanges as specified on data

sheets.

b. For low flow rates and line sizes less than DN 50 (NPS 2) integral orifice assemblies

complete with transmitters shall be provided where specified on the data sheets.

c. Integral orifice assemblies shall be either DN 40 (NPS 1 1/2) or DN 25 (NPS 1).

d. Flange taps in conformance to ISO 5167-2 shall be specified for orifice plates in line sizes

DN 50 (NPS 2) and above.



e. Corner taps shall be provided if conical entrance orifice plates are used.

f. Tap fittings shall be 1/2 in NPT unless otherwise specified on data sheets.

g. Location of flange taps for flow meters shall be as specified on data sheets.

h. Orifice flanges shall be fabricated in conformance to ASME B16.36. Minimum rating for

orifice flanges shall be Class 300.

i. Orifice flanges shall have jack bolts that allow flanges to be forced apart for insertion of

the orifice plate and gaskets.

j. If specified, four taps shall be provided to obtain segregation, e.g. transmitter on control

service and transmitter on shutdown service share the same flow measuring element.

k. Orifice flanges and orifice carrier (where specified) material shall be in conformance to

data sheets.

l. Proprietary close coupled manifold arrangements shall be provided if specified on data

sheets. Evidence shall be provided of application of Supplier’s proposed offering in similar

applications.

10.2.4 Venturi and flow nozzles

a. For particular applications an alternative pressure differential device such as a Venturi, or

flow nozzle, shall be provided if specified on data sheets.

b. Venturis and flow nozzles shall, unless otherwise specified on data sheets, be

manufactured in conformance to:

1. ISO 5167-3 for flow nozzles and venturi nozzles.

2. ISO 5167-4 for venturi tubes.

c. Differential pressure range shall be as defined in 10.2.2c unless approved otherwise by

Company responsible engineer.

Venturis are not susceptible to plate deformation, system pressure drop and erosion

considerations that can limit orifice plates, however for maintenance purposes it is

preferred to stay with the same standard transmitter ranges if possible.

d. Materials of construction, flanged ends, pressure and temperature rating of the Venturi

tube shall be in conformance to data sheets.

e. Tap sizes shall be DN 25 (NPS 1) flange unless otherwise specified on data sheets.

f. Venturis and flow nozzles shall have a clearly visible plate stamped with the tag number,

beta ratio, inside diameter of pipe, material of construction and flow direction.

10.2.5 Averaging pitot

a. For particular applications a specialised pressure differential device such as an averaging

pitot, shall be provided if specified on data sheets.

b. Transmitter mounting shall be direct to the device with a close coupled manifold

arrangement.

c. Flow meters shall be retractable if specified on data sheets and supplied with valves to

allow isolation.

d. Proposal shall include any requirement for support on line opposite mounting flange.

e. Flow meters shall have a clearly visible plate stamped with the tag number, inside diameter

of pipe, material of construction and flow direction.



10.2.6 Cone

a. For particular applications a cone type flow meter, such as a V-cone, shall be provided

where specified on data sheets.

b. Differential pressure range shall be as defined in 10.2.2c unless approved otherwise by


Cone flow instruments are not susceptible to plate deformation, system pressure

drop and erosion considerations that can limit orifice plates, however for

maintenance purposes it is preferred to stay with the same standard transmitter

ranges if possible.

c. Materials of construction, flanged ends, pressure and temperature rating of the cone

assembly shall be in conformance to data sheets.

d. Cone assembly tap sizes shall be DN 25 (NPS 1) flange unless otherwise specified on data

sheets.

e. Accuracy of the cone shall be determined by flow calibration against traceable references

across the specified range of flows.

f. Cone assemblies shall be supplied with a clearly visible plate stamped with the tag number,

beta ratio, inside diameter of pipe, material of construction and flow direction in addition

to the details in 6.1l.

10.2.7 Restriction orifices

a. Restriction orifices shall provide the pressure drop or flow restriction specified on data

sheets.

b. Configuration shall be based on an orifice plate used for measurement but proposal shall

include a recommendation if an alternative design may offer a benefit.

c. Data sheets will provide an initial sizing which shall be confirmed using a recognised

calculation method.

d. The calculation shall be documented and provided for review by Company responsible

engineer.

10.3 Variable area (VA) flow meter

a. VA meters shall be transmitting type and have a metal metering tube as standard.

b. Glass tube type VA meters shall not be permitted.

c. Floats shall be self-cleaning and shall be designed for maximum immunity to viscosity

variations and dimensional stability.

d. VA meters shall be fitted with inlet and outlet float stops.

e. VA meters accuracy shall be better than ± 10% of full scale flow.

f. VA meters repeatability shall be better than ± 0,5%.

10.4 Coriolis flow meters

a. Outer cases shall contain line pressure in the event of a tube failure or alternatively be

fitted with a blow out disc, subject to approval by Company responsible engineer.

GN 30-251 can be used to assess secondary requirement risks. Where outer casings

cannot contain line pressure, Company responsible engineer can review options for

casing mechanical overpressure protection, isolation systems or external secondary

containment depending on type of fluid and risks present.



b. Supplier shall provide assistance and documentation to support the risk assessment which

will be carried out to assess the risk of loss of containment.

c. Electronics shall be integral with the meter, except for high temperature applications where

electronics shall be remote mounted.

Some suppliers have remote interface assemblies although the initial processing is

carried out by an integral unit.

d. Meter accuracy shall be better than ± 1% of full scale flow.

e. Meter repeatability shall be better than ± 0,25%.

10.5 Turbine meters

a. Helical blade design may be considered if significant viscosity changes may occur in the

measured stream.

b. Turbine meters shall be:

1. Single pickup or dual pickups depending on size or application.

2. Blade or rim rotor.

3. Tungsten carbide bearing/sleeves.

c. Upstream strainers with turbine meter Supplier’s recommended mesh size shall be

supplied.

d. Meter accuracy shall be better than ± 0,5% of full scale flow.


10.6 Electromagnetic flow meters

a. Electromagnetic flow meters shall have flanged flow tubes constructed from nonmagnetic

material with electrodes, which generate the electric field, insulated from the body.

b. Flow tubes shall be:

1. Supplied with grounding rings, except if lining protectors are specified.

2. Lined with a non-conductive material.

c. Magnetic meters shall not have pockets or restrictions.

d. The pressure drop across the meter shall not exceed the pressure drop across an equal

length of straight pipe.

e. Liners shall be designed for:

1. The service temperature.

2. Pressure range on data sheets including vacuum, if specified.

3. Resistance to deterioration by flowing liquid.

f. Liners shall be supplied with lining protectors, if required for application.

g. Meters shall include an alarm on lining failure.

Alarm to indicate failure means that the process fluid might be in contact with the

flow meter body material, which is not necessarily designed for that fluid.

Operations should make a decision on whether the meter can be kept in operation

whilst a replacement is sourced or should be isolated.

h. Electrodes shall be corrosion resistant materials.

i. Meter accuracy shall be better than ± 1% of full scale flow.



j. Meter repeatability shall be better than ± 0,25%.

10.7 Ultrasonic flow meters

a. This section provides requirements for ultrasonic flow meters excluding flare gas. For

ultrasonic flare gas flow meters refer to 10.12.

b. Ultrasonic meters based on transit time (“time of flight”) method shall be used. Meters

based on the doppler principle shall not be permitted.

c. Ultrasonic flow meter selection shall be either multi-path with flanged spool piece or

clamp-on type, surface mounted.

d. Flow meter spool pieces shall be flanged.

e. Electronics shall be integral with the meter except for high temperature applications when

electronics shall be remote mounted.

f. Clamp-on type shall have separately mounted electronics but shall be supplied with

integral cable assemblies ready for installation with only plug and socket terminations

except for the final signal connections.

g. Flow meters shall be designed to allow removal of sensors without isolating the process or

meter spool. All equipment required shall be stated within the proposal.

h. Meter accuracy shall be application dependent and better than:

1. ± 1% of full scale flow for flanged spool piece type.

2. ± 3% of full scale flow for clamp-on type.

i. Meter repeatability shall be better than:

1. ± 0,10% for flanged spool piece type.

2. ± 0,30% for clamp-on type.

10.8 Multiphase flow meter

a. Multiphase meters shall include:

1. Measurement of oil, water and gas flows.

2. Water cut measurement.

b. Process conditions and the measurements required will be specified on data sheets

including the expected range of percentage of each phase.

c. Proposals shall be made based on available technology subject to agreement by Company

responsible engineer and shall state the accuracy. Evidence of use in similar application

shall be provided with the proposal.

d. Maximum amount of each phase able to be measured at the stated accuracy shall be stated.

10.9 Vortex flow meters

a. Vortex meters shall be sized to cover minimum flow conditions (e.g. during start-up). The

maximum flowrate shall be 75% to 90% of the flow meter maximum rated flow.

Vortex flow meters require a minimum flow before they register any signal and this

is a key factor in sizing. Maximum flow is then limited by considerations of erosion,

etc. This means that a smaller size might be recommended to achieve an output at

the minimum flow on the data sheets.

b. Supplier shall advise if their sizing calculations indicate that the meter size requested on

the data sheet is correct.



c. Electronics shall be integral with the meter, except for high temperature applications when

the electronics shall be remote mounted.

d. Meter accuracy shall be application dependent and better than:

1. ± 1% of full scale for liquid flow.

2. ± 2% of full scale for gas flow.


10.10 Positive displacement flow meters

a. Positive displacement flow meters shall be sized so that the maximum flow rate is 75% to

90% of the flow meter’s rated maximum flow rate.

b. Accessories shall be limited such that torque required for their operation is less than 80%

of rated torque that may be generated by the flow meter.

c. Upstream strainers with flow meter Supplier’s recommended mesh size shall be supplied

unless otherwise specified on data sheets.

Project should review the requirement for a strainer and determine if this can be

supplied by the meter Supplier or by others.

d. Meter accuracy shall be better than ± 0,5% of measured flow rate.


10.11 Weirs

Typically, weirs will be constructed on site and are outside the scope of this Specification.

10.12 Flare gas flow meters

a. Flared gas flow meters shall be of ultrasonic type.

b. Optical flare gas flow meters shall not be used.

c. Flare gas sensors shall be mounted on a prefabricated flanged spool piece.

d. Direction of flow shall be shown on the prefabricated meter spool.

e. It shall be possible to isolate and remove flow sensors from the flare header without loss of

integrity, hazard to personnel, or shutting down the process in anyway.

f. Flare gas meters shall be supplied with transmitters providing an output in conformance to

7.1.

g. Meter accuracy shall be better than ± 5% of full scale flow.

h. Meter repeatability shall be better than ± 0,50%.

i. Meter turndown shall be agreed with Company responsible engineer.

10.13 Thermal flow

Thermal flow transmitters or switches shall conform to process conditions specified on data

sheets.

11 Level instruments

Level instruments shall be designed to suit the level sketches where provided, as part of the Purchase

Order.



11.1 DP level transmitters

DP level transmitters shall meet the following design requirements unless otherwise specified:

a. Accuracy: ±0,04% of full range and ±0,1% of specified span.

b. Stability: 10 years.

c. Cable entry: M20 or 1/2-14 NPT, as specified

d. Diaphragm 316 SS or as specified on data sheets.

e. Process connection: Flanged to manifold or as specified.

Accuracy is normally expressed as a % of span. If the span is less than the full range

of the transmitter then the required accuracy of the full range becomes less onerous.

11.2 Bubbler level devices

Bubbler level devices will be constructed using tubing and fittings based on

GIS 30-251 for metric units or GIS 30-252 for customary units.

Pressure transmitters used within bubbler systems shall conform to 11.1 and pressure regulators

shall conform to GIS 30-353.

11.3 Diaphragm seals

a. Diaphragm seals shall be provided if specified for dirty and fouling services.

b. Suppliers shall advise if diaphragm seals are required.

c. If specified, differential pressure level transmitters shall be provided with either integral or

remote diaphragm seals.

d. Diaphragm seals shall be in conformance to 9.5.

11.4 Flushing rings

a. Flushing rings may be specified for diaphragm seal or other instrument connections for

dirty or fouling service.

b. Material of construction and process connection shall be the same as the instrument flange.

c. Flushing connections shall be as specified on data sheets.

Data sheets should specify connection in line with the applicable pipe specification,

using welded or threaded connections if these are acceptable.

11.5 Displacer instruments

11.5.1 Internal displacers

Internal displacer type instruments shall be glandless.

11.5.2 External displacers

a. Displacers shall be SS or other material as specified and compatible with process fluid.

b. Displacers shall be designed for application size and density.

c. Welded fittings shall be in conformance to type specified on data sheets.



11.6 Magnetic level

11.6.1 Magnetic level gauges

a. Magnetic level gauges shall be provided for all level gauge applications unless otherwise

stated on the data sheets.

b. Level gauges shall be magnetic “flag” type. Floating shuttle type shall not be used.

c. Magnetic level gauges shall be of one piece construction.

d. Top-side and bottom-side gauge connections shall be supplied unless otherwise specified.

e. Magnetic level gauge flags shall be aluminium or other material subject to approval by


Company responsible engineer should refer to Nominated Items List for guidance on

acceptable Suppliers for level gauges, some of which offer plastic flags as standard.

f. Positive action mechanisms shall be used to prevent flags from flapping around due to

motion. They shall only move if the magnetic float passes by.

g. Colours of front and back side of the magnetic flag shall be clearly identifiable:

1. Preferred colours are red (liquid) and white.

2. Colour indicating liquid level shall be clearly visible from 8 m (26 ft) away.

h. Scales shall be replaceable without isolating gauge.

i. Magnetic level gauges shall be supplied with flanged top and bottom complete with vent

connections.

j. Design shall not allow the float to be stuck at the bottom of the tube.

k. Gauge internals shall be removable from the bottom flange.

l. Valves shall be supplied for gauge vents and drains in conformance to data sheets. Valve

body and trim material shall be 316 SS or as specified.

m. Connection size for vents and drains shall be DN 20 (NPS 3/4) minimum.

n. Scales for magnetic level gauges shall be as specified on data sheets.

Maximum length of single gauges are restricted to 6 m (20 ft). Intermediate supports

can be considered. Multiple gauges can be considered for ranges greater than 4 m

(13 ft).

11.6.2 Magnetic level transmitters

Magnetic level transmitters shall:

a. Have a local magnetic bar graph type level indicator.

b. Be magnetostrictive type with 4-20 mA output and support digital protocol.

In some cases a reed switch type might be required due to temperature restrictions.

11.7 Tension wire float transmitter

a. Transmitters shall use a servo motor to maintain a float in equilibrium on the liquid

surface.

b. Floats shall be chosen to match density of the liquid, as specified on data sheets.

c. Accuracy shall be less than ± 2 mm (0,08 in) over the specified range.



11.8 Non contacting radar gauge

a. Non contacting radar gauges shall measure liquid surface elevation and provide 2 high and

2 low alarm settings.

b. The non-contacting radar gauge system shall be type approved by the body defined on data

sheets.

c. If specified, non-contacting radar gauges shall be provided with a keyed padlock locking

arrangement to prevent the unit from being inadvertently opened.

d. Operation for process fluids with dielectric constant less than 2 shall be demonstrated.

e. Echo curves shall be provided for all radar devices and software used to display/interpret

them shall be included in supply.

f. Radar gauges shall have independent channels for level, high level and overfill alarms.

g. Temperature compensation shall be multi point and supplied with the level transmitter.

h. Instrument accuracy shall be ±3 mm (0,12 in) with an overall operating accuracy of

± 5 mm (0,2 in).

11.9 Guided wave radar (GWR)

a. GWR instruments shall be provided for mounting directly on top of the vessel, pointing

straight down, unless otherwise specified.

b. Stilling wells or external chambers may be installed where measurement application

requires and will be defined on data sheets.

c. Stilling wells will be supplied by the tank or vessel supplier.

d. External chambers shall be supplied with the GWR if specified on data sheets.

e. Initial selection of probe type will be detailed on data sheets but shall be reviewed for

correct specification for the application.

f. GWR instruments shall meet the following design requirements unless otherwise specified:

1. Probe material: SS or as specified on data sheets.

2. Flange diameter: DN 80 (NPS 3) minimum.

3. Accuracy: ± 5 mm (± 0,2 in).

4. Linearity: Less than 0,1% of probe length.

5. Hysteresis: Equal to or less than 3 mm (± 0,12 in).

6. Repeatability: Equal to or less than 3 mm (± 0,12 in).

7. Response time: Less than 1 second.

For SIS instruments, response time and damping can be critical and should be

carefully reviewed.

11.10 Ultrasonic level

a. Ultrasonic instruments will be mounted directly on top of the vessel pointing straight down

unless otherwise specified.

b. Suitability of the device for the application shall be confirmed.

c. Stilling wells will be installed where applications require and shall be defined on data

sheets.

d. If an external chamber mounted instrument is specified, the external chamber shall be

supplied with the instrument.



e. Ultrasonic devices shall meet the following design requirements:

1. Materials of construction:

a) Transmitter housing See 7.1i.

b) Flange In conformance to data sheets.

2. Accuracy: ± 3 mm (0,12 in).

3. Linearity: Less than 0,1%.

4. Repeatability: Equal to or less than 2,5 mm (0,10 in).

5. Response time: Less than 1 second.

11.11 Capacitance instruments

a. Capacitance level instruments will not be used in a service if the dielectric constant of the

liquid changes or if the probe can become coated with a viscous liquid. Suitability of the

device for the application shall be confirmed.

b. Capacitance probes shall be PTFE coated if used in conductive process fluids.

11.12 Nucleonic level

a. Nucleonic level instruments shall consist of sources and detectors.

b. Detector type shall be scintillation crystals or plastics. Other types may be proposed

subject to approval by Company responsible engineer.

Company responsible engineer should refer to Nominated Items List for guidance on

acceptable Suppliers for nucleonic level devices, some of which offer alternative

detector technology as standard.

c. The type of source, source strength and mounting shall be subject to Company approval,

the following factors shall be taken into account in design of nucleonic devices:

1. Vessel size.

2. Location of source and detector.

3. Accessibility and maintainability.

4. Device range and linearity.

5. Interference.

Company responsible engineer should verify robustness of design to confirm that

Supplier has followed a rigorous process, and is proposing a solution which does

not present a hazard and is in compliance with local regulations. Refer to GP30-15

and seek advice from subject matter expert (SME) if required.

d. Supplier shall review internal details of vessels, location drawings of vessels, and nuclear

devices and advise:

1. If any additional shielding is required to prevent radiation from one transmitter

affecting another.

2. Maximum background radiation when vessels are empty.

e. Caesium 137 shall be used as the radiation source.

f. Source size shall allow at least a 10 year operating life.

g. Source holders shall have collimating plates designed to restrict radiation to the specific

angle required for the system and to restrict external radiation at detectors.

h. Source shall be supplied with a lockable shutter.



i. Source holders shall have lifting eyes.

j. Source size calculation shall allow for a 25 mm (1 in) thick solid deposit on inside walls of

vessels (in addition to vessel wall thickness, internals, insulation and metallic insulation

sheathing).

k. Sources installed within vessels shall be fully retractable into a shielded container without

shutting down the process.

l. Externally mounted detectors and sources shall be fully maintainable without shutting

down the process.

m. Detectors shall provide an output signal proportional to level of fluid being measured.

n. System shall have a maximum time constant of 15 seconds.

o. Linearity of transmitted signal shall be within ± 10% of specified span.

p. Documentation and other assistance concerning licensing and local regulations for

installation and use of radioactive sources shall be provided to Company who will be

responsible for installation licenses and approval by the appropriate authority.

11.13 Level switches

a. Level switches shall be provided with a means of testing and maintaining switches without

shutting down the process, entering or emptying vessels.

b. If specific gravity of controlled medium significantly affects switching point, Supplier

shall provide an estimate of the impact on the switching level.

c. Level switches shall have hermetically sealed, double pole, double throw type switch

contacts.

d. Switches shall be rated at 24 VDC, 500 mA.

Switches should be gold alloy, platinum or rhodium plated contacts if not

hermetically sealed.

e. Switches using mercury shall not be permitted.

Tuning fork or float type switches can be used for point level detection.

f. Alternative point level types (e.g. capacitance, vibration, microwave) may be proposed if

they offer advantages over ball float devices.

g. Float type switches shall be mounted in external chambers unless otherwise specified.

h. Float operated level switches shall be glandless.

i. In applications where floats are not designed to withstand the test pressure of the chamber,

a label indicating this shall be permanently affixed to instruments.

j. Integral stops shall be provided to limit the angle of float travel, located as near the float as

feasible.

k. Float type switches shall be flange mounted.

l. Float arms and floats shall be sized to pass through nozzles through which they are

installed.

11.14 Gauge glass (reflex / transparent)

Glass level gauges should only be used when magnetic level gauges are unsuitable

for the application or do not meet the process requirements and should be

considered only for atmospheric vessels and clean, non-hazardous liquids at ambient

temperatures. The maximum centre-to-centre dimensions of process connections for

glass level gauges shall be 750 mm (30 in).



Armoured glass gauges are not permitted except with specific Company approval.

a. Gauge glasses shall be of transparent flat glass or reflex type with armoured or toughened

glass. Non-armoured or glass tube gauges shall not be permitted.

Reflex type is preferred for most applications except for viscous liquids and steam

service, where the transparent type should be used.

Transparent gauge glasses with LED illuminators suitable for the area classification

should be specified where visual indication of fluid colour is required.

b. Gauge glasses shall conform to BS 3463.

c. Gauge glasses shall be stamped with the maximum working pressure and temperature.

d. Gauge glass cock valves shall:

1. Be of the offset type.

2. Be quick opening.

3. Prevent excess flow if the gauge glass is broken.

4. Have bolted bonnets, spherical unions and ball checks.

5. Ball checks shall be serviceable without dismantling the valve.

e. Body and trim materials shall be 316 SS unless otherwise specified.

f. Minimum size for vent and drain connections are 3/4 in NPT.

g. Gauge glass gasket material shall be compatible with process fluid.

h. Gauge glasses for temperatures greater than 260°C (500°F) or pressure greater than

70 barg (1 000 psig) shall use Belleville type spring washer construction.

i. Pressure rating (at maximum temperature) for gauge glass shall be at least twice the

maximum operating pressure.

This safety factor is necessary because gauge glasses can be subjected to repeated

thermal and pressure cycling that fatigues the materials over a long period of time.

j. Gauge glass valves directly connected to vessels shall have flanges.

11.15 Level Measurement Chambers

Vent valves on level measurement chambers used for maintenance or calibration shall be needle

valve type.

Needle valve allows for controlled filling of the chamber with liquid for calibration

purposes.

12 Corrosion, erosion and sand monitors

12.1 General

a. Sensor shall be as specified on the data sheets, including:

1. Insertion probe.

2. Acoustic clamp on.

3. Ultrasonic.

b. Monitors shall provide either FF or 4-20 mA output, as defined on data sheets.



c. Other outputs may be specified for direct data connections via Ethernet or similar and will

be specific to certain types of device, as defined on data sheets and approved by Company


Interface to ICSS is possible either directly or through additional equipment which

is part of the supply.

12.2 Insertion probes

a. Insertion probe design shall be an erodible resistance sensor.

b. Insertion probe shall be designed so that measurement is unaffected by mechanical,

electromechanical or flow induced noise.

c. Insertion probe body material shall be Supplier’s standard unless otherwise specified on

data sheets.

d. Wetted materials for insertion probes shall be in conformance to data sheets and selected

for specified line fluids.

e. Sensors shall be designed and fabricated to withstand full design pressure of pipework as

detailed on data sheets.

f. Sensors shall provide real time erosion data, as defined in 12.

g. Insertion probe connections to the pipe shall be flanged, with a minimum size of

DN 40 (NPS 1 1/2). Actual size shall be advised.

h. Insertion probes shall be removable and replaceable from pipes under full line pressure

without isolating or shutting down.

12.3 Acoustic detector

a. Acoustic detectors shall be “clamp on type”.

b. Detectors shall be supplied complete with all parts to allow it to be permanently clamped

to pipes, including coupling medium such as silicon grease.

c. Acoustic detectors and mounting parts shall be manufactured from 316 SS minimum.

d. Sensors shall be designed so that measurement is unaffected by mechanical,

electromechanical or flow induced noise.

12.4 Ultrasonic detector

a. Ultrasonic detectors are used to continuously measure wall thickness of a pipe and shall be

“clamp on type”.

b. Detectors shall be supplied complete with all parts to allow it to be permanently clamped

to pipes, including coupling medium such as silicon grease.

c. Ultrasonic detectors and all mounting parts shall be manufactured from 316 SS minimum.

13 Density or specific gravity devices

13.1 General

a. Density devices shall provide an output in conformance to 7.1b.

b. Process wetted parts shall be in conformance to data sheets and designed for specified line

fluids.

c. Vapour and gas density measurement shall be temperature compensated.



d. Alternative technologies from those listed below, may be proposed if they can demonstrate

a technical or commercial advantage.

13.2 Hydrostatic head density

Differential instruments shall be the same device specified for level in 11.1.

13.3 Displacer density

a. Displacement instruments shall be the same device specified for level in 11.5.

b. Mid range density will be given along with the maximum density that product may reach,

so Suppliers can provide a displacer that does not float in the higher density material.

13.4 Coriolis density

Coriolis (vibrating tube) type density meters shall be the same device specified for mass flow in

10.4.

13.5 Vibrating fork

a. Stability of materials of construction to provide accuracy of measurement shall be

confirmed.

b. Factory certified calibration shall be supplied for vibrating fork devices.

13.6 Vibrating cylinder

a. Stability of materials of construction to provide accuracy of measurement shall be

confirmed.

b. Factory certified calibration shall be supplied for vibrating cylinder devices.

13.7 Nucleonic density

Nucleonic instruments shall be the same device specified for level 11.12.

14 Position measurement

14.1 Single-point position devices (limit or proximity switches)

a. Limit and proximity switches shall be hermetically sealed.

b. Switch activation mechanisms shall be directly coupled to devices being measured.

Inferred measurements shall be avoided.

14.2 Linear location or position transmitters

Position transmitters are sensitive to EMC so particular attention to EMC testing

and specification is recommended.

a. For precise location in short ranges, usually no more than 150 mm (6 in), a linear variable

differential transformer (LVDT) shall be used.

b. Reel type rotary transmitters shall be used for distances up to 15 m (50 ft), or for a rack

and pinion gear train that activates a rotary transmitter for short distances.

15 Miscellaneous equipment

15.1 Manual pushbuttons

a. Local pushbuttons shall be supplied in a housing for surface mounting, unless otherwise

specified.



b. Housings and pushbutton assemblies shall be in conformance to the general requirements

of this Specification, see 6.1, where applicable.

c. Switch types and application will be specified in data sheets.

d. Pushbuttons for ESD application shall be mushroom head, latching and supplied with a

flap to prevent accidental operation.

15.2 Remote local indicators

a. Remote local indicators shall be digital displays in a housing for surface mounting, in

conformance to the general requirements of this Specification, see 6.1, where applicable.

b. Indicator shall be HW or FF, as specified on data sheets.

c. Display shall be:

1. Minimum 4 digit.

2. Have numerical digits minimum 8 mm (5/16 in) high.

d. For HW indicators, span and zero shall be adjustable via controls on the unit with

protection against unauthorised adjustment.

15.3 Beacons and sounders

Beacons and sounders shall be supplied in a housing for surface mounting, unless otherwise

specified.

16 Quality management

The quality management system shall conform to ISO 9001, API Specification Q1, or other agreed

internationally recognised standard to ensure that the products and services provided conform to the

requirements for supplier quality identified in the Purchase Order.

17 Inspection, test and certification

17.1 Inspection and test plan

a. Prior to the start of manufacture, an ITP shall be submitted for approval by Company


Approval is given providing that the ITP meets the surveillance requirements

determined by the criticality rating established by the criticality assessment.

b. The ITP shall include inspection and testing activities to be performed, including those at

sub-suppliers’ works and shall make reference to all testing procedures, control documents,

and resulting records and reports.

17.2 Inspection access

a. Company and the Company appointed representative shall at all times have access to the

workshops and testing facilities, including workshops of sub-suppliers engaged in

supplying material or in fabricating the equipment for the purpose of inspecting the

purchased equipment.

b. Company and the Company appointed representative shall be granted permission to

photograph the equipment in the scope of the Purchase Order during manufacturing,

assembly and test.



17.3 Equipment specific inspection requirements

a. Individual items of instrumentation and associated equipment shall be inspected/tested at

Supplier’s facilities. All associated documentation shall be submitted and approved prior to

inspection.

b. Supplier shall perform ongoing inspection activities in conformance to the approved

Supplier’s Quality Plan.

c. For high criticality items, identified in the Purchase Order, Company reserves the right to

inspect visually all pressure containing components prior to assembly. Any component

may be subjected to dye-penetrant or magnetic inspection at Company's discretion.

d. Transmitters shall be factory calibrated to manufacturer’s standard procedure or as

specified on data sheets. Calibration certificates shall be provided by Supplier with

uncertainty of measurement.

e. RFI immunity to electronic equipment (field or control room) shall be documented for the

proposed instrument type in conformance to 2004/108/EC for equipment to be installed in

the EU.

f. For high accuracy applications, if specified on data sheets, flow transmitters shall undergo

full flow calibration.

g. Testing to IEC 60770-1 shall be required for electromagnetic flow transmitters if specified

on the data sheets.

18 Packing, preservation, marking and shipping

a. Preparation of equipment for transportation shall conform to the packing, marking, and

shipping instructions or other documents identified in the Purchase Order.

b. Instruments shall be prepared for shipment to avoid damage and atmospheric corrosion to

inside or outside surfaces and parts, during storage and while in transit.

1. Machined or threaded exterior surfaces shall be coated with rust preventive products

to protect from corrosion during shipment and subsequent storage.

2. Rust preventative products shall be removable with a petroleum based solvent.

c. Flanged openings shall be blanked or have a secure cover to prevent debris entering the

instrument prior to installation.

d. Threaded openings shall be covered or plugged with plastic or metal thread protection

devices.

e. Cable entries shall be plugged with plastic plugs to prevent debris entering the instrument

prior to installation.

f. The estimated storage period shall be specified on the Purchase Order.

g. Supplier shall provide details of requirements for storage for the period.

19 Deliverables

Technical data, registers, documents, and drawings that together define the scope of the Purchase

Order shall conform to the requirements for supplier information identified in the Purchase Order.



Annex A (Informative)

Typical thermowell dimensions

a. Thermowell insertion lengths are shown with insertion tip within the middle third of the

line size and are for guidance only, specific calculations should be carried out for

individual installations.

Table A.1 Thermowell nomenclature

Table A.2 Typical insertion length “U”

Dimension Letter

Insertion length U

Overall length L

Lagging length T

Head length A

Sensor length S

Extension length N

Insertion length “U”

90 mm (2 in)

120 mm (4 in)

140 mm (7 in)

170 mm (Note 2) (7,5 in) (Note 2)

190 mm (8 in) (Note 2)

225 mm (Note 2) (10 in)

340 mm (13 in)

440 mm (16 in)

540 mm (22 in)

Notes

1. Lengths are based on IEC 61520 Type C flanged

thermowells and typical RTD sensor lengths.

2. Non IEC standard lengths



Table A.3 Typical thermowell lengths “L”

Table A.4 Typical sensor lengths “S”

b. Extension union length “N” can be calculated from the formula:

N = S - U + T + A - 5 mm (0,2 in)

Thermowell length "L"

150 mm (4 in)

200 mm (6 in)

250 mm (9 in)

280 mm (Note 2) (9,5 in) (Note 2)

300 mm (10 in) (Note 2)

335 mm (Note 2) (12 in)

400 mm (15 in)

500 mm (18 in)

600 mm (24 in)

Notes

1. Lengths are based on IEC 61520 Type C flanged

thermowells and typical RTD sensor lengths.

2. Non IEC standard lengths

Sensor length “S”

250 mm (10 in)

300 mm (12 in)

400 mm (16 in)

500 mm (20 in)

600 mm (24 in)

700 mm (28 in)



Figure A.1 - Flanged thermowell typical dimensions



Figure A.2 - Flanged thermowell with extension typical dimensions



Bibliography

[1] GP 30-05, Pressure Instruments.

[2] GP 30-15, Level Instruments.

At the date of publication, this specification conforms to the following ETPs and any

approved deviations from these ETPs.

GP 30-01, Temperature Instruments (17 May 2014).

GP 30-05, Pressure Instruments (23 April 2014).

GP 30-10, Non Fiscal Flow Instruments (17 May 2014).

GP 30-15, Level Instruments (20 April 2015).

GP 30-20, Field Instruments - Miscellaneous (18 August 2014).

GP 30-25, Field Instruments - General (30 September 2013).

DWGOM GP 30-01-1, DWGOM Site Exceptions to GP 30-01

DWGOM GP 30-05-1, Pressure Instruments - Supplement to GP 30-05

DWGOM GP 30-10-1, Supplement to Non Fiscal Flow Instruments (GP 30-10)

DWGOM GP 30-15-1, Supplement to Level Instruments (GP 30-15)

DWGOM GP 30-20-1, Supplement to Field Instruments - Miscellaneous

DWGOM GP 30-25-1,Supplement to Field Instruments - General

DWGOM GP 30-70-1, Supplement to Control and Instrumentation in Vendor

Packaged Equipment

NAG-GP 30-01-1, Temperature Instruments

NAG-GP 30-05-1, Pressure Instruments

NAG-GP 30-10-1, Non Fiscal Flow Instruments

NAG-GP 30-15-1, Level Instruments

NAG-GP 30-20-1, Field Instruments - Miscellaneous

NAG-GP 30-25-1, Supplement to Field Instruments - General

NAG-GP 30-25-1, Supplement to I&C Packaged Equipment

GN 30-011, Thermowell Specification and Evaluation

GN 30-251, Risk Analysis and Mitigation of Instrument Secondary Containment

Enclosures

KBU-GP 30-25-1, Field Instruments - General

Documents

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