ISO 12614-1:2021

Road vehicles - Liquefied natural gas (LNG) fuel system components - Part 1: General requirements and definitions

This document specifies general requirements and definitions of liquefied natural gas fuel system components, intended for use on the types of motor vehicles as defined in ISO 3833. It also provides general design principles and specifies requirements for instructions and marking. This document is not applicable to the following: a) fuel containers; b) stationary gas engines; c) container mounting hardware; d) electronic fuel management; e) fuelling receptacles. It is recognized that miscellaneous components, not specifically covered herein can be examined to meet the criteria of this document and tested according to the appropriate functional tests. All references to pressure in this document are to be considered gauge pressures unless otherwise specified. This document is based upon a working pressure for natural gas as fuel of 1,6 MPa [16 bar1]. Other working pressures can be accommodated by adjusting the pressure by the appropriate factor (ratio). For example, a 2 MPa (20 bar) working pressure system will require pressures to be multiplied by 1,25. 1 1 bar = 0,1 MPa = 105 Pa; 1 MPa = 1 N/mm2.

Véhicules routiers — Équipements pour véhicules utilisant le gaz naturel liquéfié (GNL) comme combustible — Partie 1: Exigences générales et définitions

General Information

• Status: Published
• Publication Date: 03-Jun-2021
• ICS: 43.060.40 - Fuel systems
• Technical Committee: ISO/TC 22/SC 41 - Specific aspects for gaseous fuels
• Drafting Committee: ISO/TC 22/SC 41/WG 4 - Fuel system components and refuelling connector for vehicles propelled by Liquefied Natural Gas (LNG)
• Current Stage: 6060 - International Standard published
• Start Date: 04-Jun-2021
• Due Date: 08-Jan-2022
• Completion Date: 04-Jun-2021

Relations

• Consolidated By: ISO 18119:2018/Amd 2:2024 - Gas cylinders - Seamless steel and seamless aluminium-alloy gas cylinders and tubes - Periodic inspection and testing - Amendment 2
• Effective Date: 28-Feb-2023
• Revises: ISO 12614-1:2014 - Road vehicles - Liquefied natural gas (LNG) fuel system components - Part 1: General requirements and definitions
• Effective Date: 23-Apr-2020

Overview

ISO 12614-1:2021 defines general requirements and definitions for liquefied natural gas (LNG) fuel system components used on road vehicles (as defined in ISO 3833). It establishes basic design principles, materials and temperature considerations, electrical and wiring expectations, requirements for instructions and marking, and terminology for LNG vehicle components. All pressures in the standard are gauge pressures. The document is part of the ISO 12614 series and addresses component-level safety and interoperability rather than fuel containers, fuelling receptacles or electronic fuel management.

Key topics and technical requirements

• Scope and exclusions: Applies to LNG fuel system components for motor vehicles; not applicable to fuel containers, stationary gas engines, container mounting hardware, electronic fuel management, or fuelling receptacles.
• Terminology: Defines terms such as LNG, LNG vehicle, vaporizer (heat exchanger), pressure relief valve (PRV), excess flow valve, tank pressure regulator, gas temperature sensor, fuel content gauges, etc.
• Materials & construction:
  • Components in contact with LNG/vapor must use suitable materials and corrosion-resistant construction.
  • Non-metallic materials must pass oxygen ageing and immersion tests per ISO 12614-2.
  • Joints must be gas-tight; replace tapered thread fittings if disassembled.
• Temperature ratings:
  • Components not intended below −40 °C follow ISO 15500 series.
  • Components intended for cryogenic use must be suitable from −162 °C to 85 °C (or up to 120 °C if installed in engine compartment).
• Pressure basis:
  • Based on a working pressure of 1.6 MPa (16 bar); other working pressures are accommodated by multiplying pressures by the appropriate ratio (example: 2.0 MPa → multiply by 1.25).
• Electrical requirements:
  • Wiring and electrical equipment must be automotive quality and comply with ISO 6722 (mechanical strength, insulation, current capacity).
• Instructions & marking:
  • Manufacturers must provide clear installation, maintenance and safety instructions in the destination language.
  • Required marking includes manufacturer, part number, working pressure/temperature range, flow direction, fuel type, electrical ratings, certification symbol/approval number, serial/date code, and reference to ISO 12614-1.

Applications and users

ISO 12614-1 is intended for:

• Vehicle OEMs and system integrators designing LNG vehicles
• Component manufacturers (valves, vaporizers, sensors, regulators, hoses)
• Test laboratories and conformity assessment bodies verifying component compliance
• Fleet operators and maintenance personnel using LNG vehicle components
• Regulators and type-approval authorities referencing safety and marking requirements

Practical applications include design validation, supplier specifications, installation guidance, routine maintenance instructions, and component marking for traceability and compliance.

Related standards

• ISO 12614 (all parts) - LNG fuel system component series
• ISO 12614-2 - non-metallic materials tests referenced
• ISO 15500 (CNG series) - referenced for certain design principles
• ISO 6722 - road-vehicle single-core cables (60 V / 600 V)
• ISO 3833 - vehicle type definitions

Keywords: ISO 12614-1, LNG fuel system components, liquefied natural gas, LNG vehicle, pressure 1.6 MPa, vehicle standards, LNG component marking, cryogenic fuel system.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 12614-1
Second edition
2021-06
Road vehicles — Liquefied natural gas
(LNG) fuel system components —
Part 1:
General requirements and definitions
Véhicules routiers — Équipements pour véhicules utilisant le gaz
naturel liquéfié (GNL) comme combustible —
Partie 1: Exigences générales et définitions
Reference number
©
ISO 2021
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested 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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CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Construction and assembly . 4
5 Electrical equipment and wiring . 4
6 Instructions . 5
7 Marking . 5
Annex A (informative) Construction and assembly . 6
Bibliography . 8
Foreword
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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
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on the ISO list of patent declarations received (see www .iso .org/ patents).
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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 22, Road vehicles, Subcommittee SC 41,
Specific aspects of gaseous fuels.
This second edition cancels and replaces the first edition (ISO 12614-1:2014), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— editorial changes.
A list of all parts in the ISO 12614 series can be found on the ISO website.
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.
iv © ISO 2021 – All rights reserved

INTERNATIONAL STANDARD ISO 12614-1:2021(E)
Road vehicles — Liquefied natural gas (LNG) fuel system
components —
Part 1:
General requirements and definitions
1 Scope
This document specifies general requirements and definitions of liquefied natural gas fuel system
components, intended for use on the types of motor vehicles as defined in ISO 3833. It also provides
general design principles and specifies requirements for instructions and marking.
This document is not applicable to the following:
a) fuel containers;
b) stationary gas engines;
c) container mounting hardware;
d) electronic fuel management;
e) fuelling receptacles.
It is recognized that miscellaneous components, not specifically covered herein can be examined to
meet the criteria of this document and tested according to the appropriate functional tests.
All references to pressure in this document are to be considered gauge pressures unless otherwise
specified.
1)
This document is based upon a working pressure for natural gas as fuel of 1,6 MPa [16 bar ]. Other
working pressures can be accommodated by adjusting the pressure by the appropriate factor (ratio).
For example, a 2 MPa (20 bar) working pressure system will require pressures to be multiplied by 1,25.
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 6722 (all parts), Road vehicles — 60 V and 600 V single-core cables
ISO 12614 (all parts), Road vehicles — Liquefied natural gas (LNG) fuel system components
ISO 15500 (all parts), Road vehicles — Compressed natural gas (CNG) fuel system components
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
1) 1 bar = 0,1 MPa = 105 Pa; 1 MPa = 1 N/mm2.
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 https:// www .electropedia .org/
3.1
burst pressure
static pressure which causes failure and consequential fluid loss through the component envelope
Note 1 to entry: It is the highest pressure during a burst test.
3.2
electronic control unit
ECU
device for control of the engine
3.3
fitting
connector used in joining a piping, tubing, or hose system
3.4
flexible fuel line
flexible tubing or hose through which natural gas flows
3.5
fuel content gauge
system that measures the level of the liquid in the fuel tank
3.6
differential pressure fuel content gauge
fuel content gauge (3.5) based on the difference of the pressure at the top and bottom parts of the fuel
tank (the system measures the weight of the liquid)
3.7
capacitance fuel content gauge
device that measures changes in fuel level through indirect or direct capacitive sensing techniques
3.8
gas temperature sensor
device for gas temperature measurement, which is placed downstream of the vaporizer (3.10)
3.9
gas tight housing
device which vents gas leakage to
...