ISO 22548:2021

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 22548
ISO/TC 8
Ships and marine technology —
Secretariat: SAC
Performance test procedures for LNG
Voting begins on:
fuel gas supply systems (FGSS) for ships
2021­03­04
Voting terminates on:
Navires et technologie maritime — Procédures d'essais de
2021­04­29
performance des systèmes d'alimentation en gaz combustible GNL
(FGSS) pour navires
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 22548:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2021

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ISO/FDIS 22548:2021(E)

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© ISO 2021
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ii © ISO 2021 – All rights reserved

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ISO/FDIS 22548:2021(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test arrangement . 2
4.1 Test preparation . 2
4.2 Test fluid . 3
4.3 Test parameters . 3
5 Test procedure . 4
5.1 Safety test . 4
5.1.1 Test of e.g. alarm and safety devices . 4
5.1.2 Cryogenic function tests . 4
5.1.3 ESD and blow down test . . 4
5.2 Performance test . 4
6 Additional tests . 5
6.1 Unit production test. 5
6.2 Type test . 6
6.3 Endurance test . 6
7 Test report . 6
Annex A (informative) LNG fuel gas supply systems (FGSS) test report — Example .7
Annex B (informative) Typical examples of LNG FGSS within the scope of the test .9
Bibliography .12
© ISO 2021 – All rights reserved iii

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ISO/FDIS 22548:2021(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 non­governmental, 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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2. www .iso .org/ directives
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received. www .iso .org/ patents
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
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iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 8, Ships and marine technology.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
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ISO/FDIS 22548:2021(E)

Introduction
In response to an increased number of ships using LNG fuel, the International Maritime Organization
(IMO) adopted the IGF code that specifies mandatory requirements of the LNG fuel tank, LNG fuel engine,
fuel gas supply system (FGSS), bunkering, control of safety system, monitoring, and fire extinguishing
systems, etc. to ensure the safety of gas-fuelled ships.
The requirements of the IGF and IGC Codes apply to the design and manufacture of LNG FGSS. However,
no widely recognized standards in terms of the performance testing of FGSS has yet been established;
thus, FGSS is tested according to a case-by-case agreement between the buyer and the supplier. For this
reason, there have been needs to develop a standard for performance test methods of FGSS commonly
acceptable to all stakeholders (e.g. shipowners, classification societies, engine makers, shipyards, etc.).
In this context, this document sets up a performance test procedure for the LNG FGSS, which consists
of equipment such as pumps, heat exchangers, valves, piping, etc. With this document, it is expected
that i) the performance of LNG FGSS be identified from an objective point of view, ii) useful information
be provided to all stakeholders, and iii) development of more reliable LNG FGSS be facilitated, thus
contributing to the growth of relevant industries and benefiting all stakeholders.
In addition, as specific requirements from classification societies and/or administrations can apply to
the LNG FGSS concerned, the buyer is expected to identify those before placing a purchase order. The
supplier and the buyer are further expected to agree on any additional applicable requirements.
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 22548:2021(E)
Ships and marine technology — Performance test
procedures for LNG fuel gas supply systems (FGSS) for ships
1 Scope
This document specifies evaluation methods of characteristics such as pressure, flow rate, temperature
and system stability of fuel gas supply systems (FGSS), which are manufactured to use vaporized
liquefied natural gas (LNG) or boil-off gas as fuel gas supply to the vessel's gas consumers. It is applicable
to evaluate the performance of the LNG FGSS: (1) prior to delivery or after installation on board a ship,
and (2) to assure the system characteristics are taken into account for the entire gas consumers during
ship’s gas trial or sea trial.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
IMO, International Code for the Construction and Equipment of Ships carrying Liquefied Gases in Bulk
(IGC Code)
IMO, International Code of Safety for Ships using Gases or other Low-flashpoint Fuels (IGF Code)
3 Terms and definitions
For the purpose of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
LNG fuel gas supply system
LNG FGSS
system that supplies gas fuel at the temperature, pressure and flow conditions required by the gas
consumer, from the fuel tank(s) to the gas consumer, excluding the fuel tank(s), in-tank pump(s), tank
ESD valve(s) and the master gas fuel valve(s) used to control the gas supply
3.2
maximum pressure
maximum operating pressure (MPa) measured during the test period
3.3
minimum pressure
minimum operating pressure (MPa) measured during the test period
3.4
pressure pulsation
pressure variation (MPa) during the test period, defined as the difference between the maximum
pressure (3.2) and the minimum pressure (3.3)
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ISO/FDIS 22548:2021(E)

3.5
flow rate
arithmetic mean of the mass flow rate (kg/h) measured
...