ISO 19723-2:2018

INTERNATIONAL ISO
STANDARD 19723-2
First edition
2018-07
Road vehicles — Liquefied natural gas
(LNG) fuel systems —
Part 2:
Test methods
Véhicules routiers — Systèmes à carburant gaz naturel liquéfié
(GNL) —
Partie 2: Méthodes de test
Reference number
ISO 19723-2:2018(E)
©
ISO 2018

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ISO 19723-2:2018(E)

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ISO 19723-2:2018(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test methods . 2
4.1 Tank mounting strenght tests . 2
4.1.1 General. 2
4.1.2 Inertia test . 2
4.1.3 Static test . 2
4.1.4 Acceptance criteria . 3
4.2 Leak test . 3
4.3 Functional LNG/CNG automatic valve test. 4
4.4 Receptacle . 4
4.4.1 General. 4
4.4.2 Receptacle clearance test . 4
4.4.3 Receptacle mounting tests . 4
4.5 Hold time test . 4
4.6 Acceptable test results . 5
4.7 Venting system check . 5
4.8 LNG accumulation system check . 5
4.9 Bonfire test . 5
5 Marking . 5
Annex A (informative) Engineering experience for the mounting of LNG tanks .7
Bibliography .11
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ISO 19723-2:2018(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.
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 (see 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 (see 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 on 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
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: www .iso .org/iso/foreword .html.
This document was prepared by ISO/TC 22, Road vehicles, Subcommittee SC 41, Specific aspects for
gaseous fuels.
A list of all the parts in the ISO 19723 series, can be found on the ISO website.
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ISO 19723-2:2018(E)

Introduction
For the purposes of this document, all fuel system components in contact with liquid natural gas have
been considered suitable for natural gas as defined in the ISO 15403 series.
When applying this document, it is understood that a safety device to prevent overfilling the vehicle's
fuel system is part of the refueling station. The pressure gauge has not been considered as a safety
component.
When necessary, technical solutions regarding functional requirements are given in Annex A.
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INTERNATIONAL STANDARD ISO 19723-2:2018(E)
Road vehicles — Liquefied natural gas (LNG) fuel
systems —
Part 2:
Test methods
1 Scope
This document specifies performance and general test methods for liquefied natural gas fuel system
components intended for use on the types of motor vehicles defined in ISO 3833.
This document is applicable to vehicles (mono-fuel, bi-fuel or dual-fuel applications) using liquefied gas
in accordance with the ISO 15403 series. It is not applicable to the following: original-production and
converted vehicles.
This document is only applicable on the components in the "LNG system" meaning an assembly of
components (tanks, valves, flexible fuel lines, etc.) and connecting parts (fuel lines, fittings, etc.) fitted
on motor vehicles using LNG in their propulsion system and related components up to and including the
vaporizer. Other parts downstream from the vaporizer are considered as CNG components covered by
ISO 15501.
NOTE All references to pressures, given in megapascals and bar (1 bar = 0,1 MPa = 105 Pa; 1 MPa = 1 N/
2
mm ) are considered gauge pressures, unless otherwise specified.
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.
ISO 898-1, Mechanical properties of fasteners made of carbon steel and alloy steel — Part 1: Bolts, screws
and studs with specified property classes — Coarse thread and fine pitch thread
ISO 6487, Road vehicles — Measurement techniques in impact tests — Instrumentation
ISO 12617, Road vehicles — Liquefied natural gas (LNG) refuelling connector — 3,1 MPa connector
ISO 12991:2012, Liquefied natural gas (LNG) — Tanks for on-board storage as a fuel for automotive
vehicles
ISO 19723-1:2018, Road vehicles — Liquefied natural gas (LNG) fuel systems — Part 1: Safety requirements
3 Terms and definitions
No terms and definitions are listed in this document.
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/
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ISO 19723-2:2018(E)

4 Test methods
4.1 Tank mounting strenght tests
4.1.1 General
When a vehicle is equipped with several tanks, they should be tested as a unit.
When a tank or groups of tanks are installed on a vehicle such that they are separately anchored to the
original structure of the vehicle, then each tank or separate group of tank can be tested individually.
When performing these tests, accessories and piping shall not contribute to reinforcing the tank
mounting.
The requirements of ISO 19723-1:2018, 4.4.3, shall be verified by the test specified in 4.1.1, 4.1.2 or 4.1.3.
4.1.2 Inertia test
The tank or group of tanks to be tested shall be mounted on the vehicle body or a part of the vehicle
body, according to the specifications of the original equipment manufacturer (OEM) or after-market
converter.
The vehicle body or part of the vehicle body shall be firmly anchored to the test trolley. The method
used for anchoring the vehicle body to the test trolley shall not result in reinforcement of the tank
anchorages or the part of the vehicle structure participating in anchoring the tank or tanks. Testing
performed with a trolley shall geometrically match original vehicle conditions.
The test shall be carried out using the following procedure.
a) Fill the tank or tanks with an equivalent full weight of liquid nitrogen saturated to one-half the
working pressure.
b) Measure the trolley deceleration with data channels of channel frequency class (CFC) 60
corresponding to the characteristics given in ISO 6487.
c) Maintain the value of the deceleration as defined in ISO 19723-1:2018, 4.4.3, for at least 30 ms.
4.1.3 Static test
This test may be carried out on a vehicle body or on a part of a vehicle body.
The tank or group of ta
...