Refrigerated hydrocarbon and non-petroleum based liquefied gaseous fuels — General requirements for automatic tank thermometers on board marine carriers and floating storage

ISO 8310:2012 specifies the essential requirements and verification procedures for automatic tank thermometers (ATTs) consisting of platinum resistance thermometers (PRT) and an indicating device used for custody transfer measurement of liquefied natural gas, liquefied petroleum and chemical gases on board ships. Temperature detectors other than PRT are considered acceptable for use in the custody transfer service of liquefied gases if they meet the performance requirements of ISO 8310:2012 and are approved by national regulations.

Hydrocarbures réfrigérés et combustibles gazeux liquéfiés à base non pétrolière — Exigences générales pour les thermomètres de réservoir automatiques à bord des transporteurs de cargaison en mer et des stocks flottants

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Status
Published
Publication Date
04-Nov-2012
Current Stage
9093 - International Standard confirmed
Start Date
27-Mar-2018
Completion Date
27-Mar-2018
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INTERNATIONAL ISO
STANDARD 8310
Second edition
2012-11-01
Refrigerated hydrocarbon and non-
petroleum based liquefied gaseous
fuels — General requirements for
automatic tank thermometers on board
marine carriers and floating storage
Hydrocarbures réfrigérés et combustibles gazeux liquéfiés à base non
pétrolière — Exigences générales pour les thermomètres de réservoir
automatiques à bord des transporteurs de cargaison en mer et des
stocks flottants
Reference number
ISO 8310:2012(E)
ISO 2012
---------------------- Page: 1 ----------------------
ISO 8310:2012(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2012

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any

means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the

address below or ISO’s member body in the country of the requester.
ISO copyright office
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Tel. + 41 22 749 01 11
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Published in Switzerland
ii © ISO 2012 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 8310:2012(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Safety precautions .............................................................................................................................................................................................. 2

4.1 General ........................................................................................................................................................................................................... 2

4.2 Equipment precautions ................................................................................................................................................................... 3

5 Design requirements ........................................................................................................................................................................................ 3

5.1 General ........................................................................................................................................................................................................... 3

5.2 Temperature sensors ......................................................................................................................................................................... 3

5.3 Indicating device ................................................................................................................................................................................... 4

5.4 Installation .................................................................................................................................................................................................. 4

5.5 Provisions for routine maintenance and verification ............................................................................................ 4

5.6 Provision against sudden malfunctions ............................................................................................................................ 4

5.7 Dynamic response ................................................................................................................................................................................ 4

5.8 Measurable range ................................................................................................................................................................................. 4

5.9 Data processing and reporting .................................................................................................................................................. 4

5.10 Compensation for variation of cargo temperatures ................................................................................................ 5

5.11 Sealing, security and unsealing ................................................................................................................................................. 5

5.12 Redundancy ............................................................................................................................................................................................... 5

5.13 Data communication .......................................................................................................................................................................... 5

6 Calibration and accuracy verification ............................................................................................................................................ 5

6.1 General ........................................................................................................................................................................................................... 5

6.2 Calibration reference ......................................................................................................................................................................... 6

6.3 Calibration and accuracy verification at factory ........................................................................................................ 6

6.4 Calibration and accuracy verification after installation ...................................................................................... 6

6.5 Periodic accuracy verification .................................................................................................................................................... 9

7 Accuracy requirement .................................................................................................................................................................................... 9

7.1 Overall error .............................................................................................................................................................................................. 9

7.2 Resolution ................................................................................................................................................................................................10

8 ATT calibration records .............................................................................................................................................................................10

Annex A (informative) Information on platinum resistance thermometers ...........................................................11

Bibliography .............................................................................................................................................................................................................................12

© ISO 2012 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 8310:2012(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International

Standards adopted by the technical committees are circulated to the member bodies for voting.

Publication as an International Standard requires approval by at least 75 % of the member bodies

casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 8310 was prepared by Technical Committee ISO/TC 28, Petroleum products and lubricants,

Subcommittee SC 5, Measurement of refrigerated hydrocarbon and non-petroleum based liquefied gaseous fuels.

This second edition cancels and replaces the first edition (ISO 8310:1991), which has been technically revised.

iv © ISO 2012 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 8310:2012(E)
Introduction

Large quantities of liquefied natural gas (LNG), liquefied petroleum gas (LPG) and other liquefied

gases are usually transported by marine carriers dedicated for these applications and traded based on

static measurement on board by automatic tank measurement. Such an automatic tank measurement

may be a part of the custody transfer measurement system (CTMS) which involves determination of

liquid/vapour interface, i.e. liquid level, average temperatures of liquid and vapour, and vapour pressure.

The volumetric quantity of the liquid and gas is then computed with the tank capacity table based on

which the delivered quantity in terms of energy content or mass is calculated.

In most cases, shore tank measurement is not used due to the active and dynamic conditions of the

shore tank operations. In the absence of other means of acceptable measurement, custody transfer

measurement usually takes place on board the carrier or floating production storage offshore (FPSO)

and floating storage offshore (FSO). Liquid cargo density is very sensitive to temperature; therefore,

obtaining accurate temperature readings is extremely important. For example, a change of 0,2 °C for

liquid methane cargo results in a change in density of approximately 0,07 %.

This International Standard also discusses use of automatic tank thermometers on board marine vessels for

other volatile, non-petroleum liquids in fully refrigerated conditions. Many of these non-petroleum liquids,

such as di-methyl ether (DME) are measured in a similar manner to that used for fully refrigerated LPGs.

Values of temperature in this International Standard are in terms of the International Temperature

Scale of 1990, ITS-90. Temperatures in degrees Celsius are denoted by the symbol t.

© ISO 2012 – All rights reserved v
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 8310:2012(E)
Refrigerated hydrocarbon and non-petroleum based
liquefied gaseous fuels — General requirements for
automatic tank thermometers on board marine carriers
and floating storage
1 Scope

This International Standard specifies the essential requirements and verification procedures for

automatic tank thermometers (ATTs) consisting of platinum resistance thermometers (PRT) and an

indicating device used for custody transfer measurement of liquefied natural gas, liquefied petroleum

and chemical gases on board ships. Temperature detectors other than PRT are considered acceptable for

use in the custody transfer service of liquefied gases if they meet the performance requirements of this

International Standard and are approved by national regulations.
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

IEC 60751, Industrial platinum resistance thermometers and platinum temperature sensors

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
automatic tank gauge
ATG
automatic level gauge
ALG

instrument that automatically measures and displays liquid levels or ullages in one or more tanks, either

continuously, periodically or on demand
3.2
automatic tank gauging system
ATG system

system that includes ATGs at the cargo tanks and control/display unit that processes and displays

output signals from the ATG along with any other parameters required to determine the liquid level, i.e.

liquid/vapour interface
3.3
automatic tank thermometer
ATT
automatic tank temperature system
instrument that continuously measures temperature in cargo tanks

NOTE 1 An ATT typically includes temperature sensors, such as PRTs, field-mounted transmitters for electronic

signal transmission, and indicating device(s).

NOTE 2 ATTs on liquefied gas carriers are usually multiple-point ATTs which consist of three or more

temperature sensors, such as PRTs, to measure the temperatures at selected heights in the cargo tank.

© ISO 2012 – All rights reserved 1
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ISO 8310:2012(E)
3.4
custody transfer measurement system
CTMS

system that processes inputs from an ATG system, an ATT, pressure gauges, etc. and provides custody

transfer measurement information on board, generating documents with regard to custody transfer of

liquefied gases
NOTE An ATT can be incorporated as part of a CTMS.
3.5
gas dangerous space or zone

space or zone defined by the International Code for the Construction and Equipment of Ships Carrying

Liquefied Gases in Bulk (IGC Code)
3.6
indicating device
displaying device

set of components of a measuring instrument intended to indicate the measured value

3.7
inherent error
intrinsic error

error of a gauge when it is tested against a reference standard under controlled conditions as specified

by the manufacturer
3.8
nominal resistance

expected resistance R of a PRT at 0 °C, declared by the manufacturer and shown in the thermometer

marking, usually rounded to the nearest ohm
3.9
nominal temperature/resistance relationship
relationship between temperature and resistance of a nominal PRT
3.10
platinum resistance thermometer
PRT
resistance temperature detector
RTD

temperature-responsive device consisting of one or more sensing platinum resistors within a

protective sheath, internal connecting wires and external terminals to permit connection of electrical

measurement instruments
3.11
uncertainty

non-negative parameter characterizing the dispersion of the quantity values being attributed to a

measurand, based on the information used
4 Safety precautions
4.1 General

Nothing contained in this International Standard is intended to supersede any regulatory requirements

or recommended operating practices issued by organizations such as the International Maritime

Organization (IMO), International Chamber of Shipping (ICS), Oil Companies International Marine

Forum (OCIMF), International Association of Classification Societies (IACS) and individual operating

companies, nor is this International Standard intended to conflict with any safety or environmental

considerations, local regulations, or the specific provisions of any contract.
2 © ISO 2012 – All rights reserved
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ISO 8310:2012(E)
4.2 Equipment precautions
4.2.1 General

All electric components of an ATT for use in electrically classified areas shall meet the electrical area

classification. They shall conform to applicable sections of the national and/or international electrical

safety standards. All ATTs shall be maintained in a safe operating condition and manufacturers’

maintenance instructions should be complied with.
4.2.2 Mechanical rigidity

All ATTs shall be capable of withstanding the pressure, temperature, dynamic loads generated from

rolling/pitching, and sloshing from environmental conditions likely to be encountered in the service.

Where a PRT is installed near a submerged pump or the end of a loading/unloading line in a cargo

tank, appropriate measures shall be applied to prevent the ATT from being affected by the vortex or

vaporization, i.e. boiling, of cargo caused by cargo loading or cargo unloading operations. In addition, all

PRTs shall be mounted such that they are not affected by the spray of liquefied gas whenever the spray

nozzles are in operation.
4.2.3 Gastight design

All parts of ATTs exposed to a gas dangerous space or zone shall be of gastight construction.

4.2.4 Compatibility with cargo

All parts of the ATT in contact with liquefied gases or their vapour shall be chemically compatible with

the product, to avoid both product contamination and corrosion of the ATT.
4.2.5 Tolerance against low temperatures

ATTs shall be designed to measure the low temperatures encountered in refrigerated liquefied gas

service. They shall also be designed to withstand the low-temperature thermal contraction of their

components and of the tanks. Additionally, change in the height of PRT in the tanks by such thermal

contraction shall be compensated for in an appropriate manner.
4.2.6 Type approval

The design and installation of ATTs shall be subject to the approval of a national metrology institute (NMI)

[10]

or class society. For electrical considerations, refer to IACS Unified Requirements E10 . Type approval

is normally issued after an ATT has been subjected to a s
...

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