ISO 15500-19:2020

Road vehicles - Compressed natural gas (CNG) fuel system components - Part 19: Fittings

This document specifies tests and requirements for fittings, compressed natural gas (CNG) 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 natural gas in accordance with the ISO 15403 series. It is not applicable to the following: a) liquefied natural gas (LNG) fuel system components located upstream of, and including, the vaporizer; b) fuel containers; c) stationary gas engines; d) container-mounting hardware; e) electronic fuel management; f) refuelling receptacles.

Véhicules routiers — Composants des systèmes de combustible gaz naturel comprimé (GNC) — Partie 19: Raccords

General Information

• Status: Published
• Publication Date: 02-Aug-2020
• 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 3 - Fuel system components and refuelling connector for vehicles propelled by gaseous fuel
• Current Stage: 9092 - International Standard to be revised
• Start Date: 14-Feb-2023
• Completion Date: 13-Dec-2025

Relations

• Revises: ISO 15500-19:2012/Amd 1:2016 - Road vehicles - Compressed natural gas (CNG) fuel system components - Part 19: Fittings - Amendment 1
• Effective Date: 09-Jun-2018
• Revises: ISO 15500-19:2012 - Road vehicles - Compressed natural gas (CNG) fuel system components - Part 19: Fittings
• Effective Date: 09-Jun-2018

Overview

ISO 15500-19:2020 specifies tests and requirements for fittings used in compressed natural gas (CNG) vehicle fuel systems. It applies to CNG systems on motor vehicles defined in ISO 3833 (mono-fuel, bi-fuel and dual-fuel) using natural gas per the ISO 15403 series. The standard excludes LNG components upstream of the vaporizer, fuel containers, stationary engines, container-mounting hardware, electronic fuel management and refuelling receptacles.

Keywords: ISO 15500-19, CNG fittings, compressed natural gas fittings, vehicle fuel system components, CNG standard

Key topics and requirements

• Scope and applicability
  • Targets fittings for CNG vehicle fuel systems; compatible with natural gas quality defined by ISO 15403.
• Marking
  • Mandatory marking to allow traceability: manufacturer/agent name or symbol, model/part number, working pressure (or pressure‑temperature range), and serial number/date code.
  • Recommended additional markings: flow direction, fuel type, electrical ratings, certification symbol, type approval number, reference to the standard.
• Construction and compatibility
  • Fittings must meet ISO 15500-1 and ISO 15500-2 provisions.
  • Rigid fuel line compatibility is required; stainless-steel lines must use stainless-steel fittings.
  • Prevention of galvanic corrosion is mandatory.
• Performance tests
  • Hydrostatic strength: tested per ISO 15500-2 at four times the working pressure.
  • Continued operation: cycling test of 100 000 cycles while fitted to a rigid fuel line; followed by leakage and hydrostatic tests.
  • Pull-off: fittings are tested attached to rigid line and mating parts; tensile load applied (max 250 N/min) until separation. The measured pull-off force must exceed a calculated threshold based on internal diameter and working pressure (the requirement already embeds a safety factor of 4).
  • Repeated assembly: fittings must withstand 25 assembly/disassembly cycles representative of field use and still meet leakage requirements.
  • Other referenced tests in ISO 15500-2 include leakage, excess torque, bending moment, corrosion and material ageing tests.

Applications and who uses it

• Fitting and component manufacturers designing CNG connectors, adapters and inline fittings.
• OEMs and vehicle integrators specifying compliant fuel-system components.
• Test laboratories and certification bodies performing hydrostatic, endurance and pull-off testing.
• Regulatory authorities and fleet managers ensuring safety and traceability for CNG vehicle installations. Practical value: ensures mechanical integrity, leak resistance, material compatibility and traceability of CNG fittings in high‑pressure vehicle fuel systems.

Related standards

• ISO 15500-1 - General requirements and definitions (CNG components)
• ISO 15500-2 - Performance and general test methods (referenced test procedures)
• ISO 3833 - Road vehicle types, terms and definitions
• ISO 15403 series - Natural gas quality for vehicle fuels

For designers, manufacturers and test labs working on CNG fuel systems, ISO 15500-19 is the authoritative reference for fitting performance, marking and test criteria.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 15500-19
Third edition
2020-08
Road vehicles — Compressed natural
gas (CNG) fuel system components —
Part 19:
Fittings
Véhicules routiers — Composants des systèmes de combustible gaz
naturel comprimé (GNC) —
Partie 19: Raccords
Reference number
©
ISO 2020
© ISO 2020
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
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below or ISO’s member body in the country of the requester.
ISO copyright office
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Published in Switzerland
ii © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Marking . 2
5 Construction and assembly . 2
6 Tests . 2
6.1 Applicability . 2
6.2 Hydrostatic strength . 3
6.3 Continued operation . 3
6.4 Pull off . 3
6.5 Repeated assembly . 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 for gaseous fuels.
This third edition cancels and replaces the second edition (ISO 15500-19:2012), which has been
technically revised. It also incorporates the Amendment ISO 15500-19:2012/Amd.1:2016. The main
changes compared to the previous edition are as follows:
— serial number or data code became mandatory in marking;
— removed vibration resistance test clause and added reference to ISO 15500-2.
A list of all parts in the ISO 15500 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 2020 – All rights reserved

Introduction
For the purposes of this document, all fuel system components in contact with
...