ISO 12614-8:2021

Road vehicles - Liquefied natural gas (LNG) fuel system components - Part 8: Excess flow valve

This document specifies tests and requirements for the excess flow valve, a liquefied natural gas fuel system component intended for use on the types of motor vehicles defined in ISO 3833. This document is applicable to vehicles using natural gas in accordance with ISO 15403-1 (mono-fuel, bi-fuel, or dual-fuel applications). It is not applicable to the following: a) fuel containers; b) stationary gas engines; c) container mounting hardware; d) electronic fuel management; e) refuelling 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 a 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 8: Valve de limitation de débit

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

• Revises: ISO 12614-8:2014 - Road vehicles - Liquefied natural gas (LNG) fuel system components - Part 8: Excess flow valve
• Effective Date: 23-Apr-2020

Overview - ISO 12614-8:2021 (Excess flow valve for LNG vehicles)

ISO 12614-8:2021 specifies tests and requirements for the excess flow valve used in liquefied natural gas (LNG) fuel systems for road vehicles (types defined in ISO 3833). It is part of the ISO 12614 series covering LNG fuel system components and applies to mono‑fuel, bi‑fuel, and dual‑fuel vehicles that use natural gas in accordance with ISO 15403-1. The document defines design classes, marking, construction conformity with ISO 12614‑1 and ISO 12614‑2, and the functional and environmental tests required to verify safety and performance.

Key topics and technical requirements

• Valve types covered
  • Internal (installed inside cylinder/cylinder valve) and external excess flow valves
  • Shut‑off (stops flow) and flow‑limiter (limits flow; auto‑resets) designs
• Marking and traceability
  • Must include manufacturer/agent, model/part number, operating specs (working pressure, temperature range, valve type, activation flow or ΔP, maximum flow when activated), and flow direction where needed.
• Pressure basis
  • All pressures are gauge pressures. The standard is based on a nominal working pressure of 1.6 MPa (16 bar); other working pressures are accommodated by proportional scaling (e.g., 2.0 MPa → multiply pressures by 1.25).
• Mandatory tests
  • Hydrostatic strength - test at 2.5 × working pressure (per ISO 12614‑2 procedure)
  • Leakage - for shut‑off valves; internal leakage limit stated in the standard (see document)
  • Continued operation - cycle 20 times at working differential pressure, then re‑test leakage and hydrostatic strength
  • Operation - verify activation flow and minimum activation pressure using manufacturer’s conditions; flows corrected to 15 °C
  • Tests specific to external valves: excess torque resistance and bending moment
• Environmental and material tests
  • Corrosion, vibration, ageing, electrical overvoltage and material compatibility tests referenced in ISO 12614‑2 as applicable

Applications and users

ISO 12614-8 is intended for:

• LNG fuel system manufacturers and component suppliers designing excess flow valves
• Vehicle OEMs and integrators specifying certified components for LNG vehicles
• Testing laboratories and conformity assessment bodies performing performance and safety testing
• Regulators and certification agencies assessing compliance with LNG vehicle safety requirements

Practical benefits include improved safety in refuelling and crash scenarios, consistent product marking and traceability, and a clear test regime for verifying valve integrity under pressure and environmental stress.

Related standards

• ISO 12614-1 - General requirements and definitions (LNG fuel system components)
• ISO 12614-2 - Performance and general test methods
• ISO 3833 - Road vehicle types - terms and definitions
• ISO 15403-1 - Natural gas quality for vehicle fuels

Keywords: ISO 12614-8:2021, excess flow valve, LNG fuel system, liquefied natural gas, road vehicles, hydrostatic strength, leakage test, activation flow, working pressure.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 12614-8
Second edition
2021-06
Road vehicles — Liquefied natural gas
(LNG) fuel system components —
Part 8:
Excess flow valve
Véhicules routiers — Équipements pour véhicules utilisant le gaz
naturel liquéfié (GNL) comme combustible —
Partie 8: Valve de limitation de débit
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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Phone: [phone]
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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 Marking . 2
5 Construction and assembly . 3
6 Test . 3
6.1 Applicability . 3
6.2 Hydrostatic strength . 3
6.3 Leakage . 3
6.4 Excess torque resistance . 4
6.5 Bending moment . 4
6.6 Continued operation . 4
6.7 Operation . 4
Bibliography . 5
Foreword
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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 12614-8:2014), 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 12614-8:2021(E)
Road vehicles — Liquefied natural gas (LNG) fuel system
components —
Part 8:
Excess flow valve
1 Scope
This document specifies tests and requirements for the excess flow valve, a liquefied natural gas fuel
system component intended for use on the types
...