ISO 15500-8:2015

Road vehicles - Compressed natural gas (CNG) fuel system components - Part 8: Pressure indicator

This part of ISO 15500 specifies tests and requirements for the pressure indicator, a compressed natural gas fuel system component intended for use on the types of motor vehicles defined in ISO 3833. This part of ISO 15500 is applicable to vehicles using natural gas in accordance with ISO 15403-1 (monofuel, bi-fuel, or dual-fuel applications). It is not applicable to the following: liquefied natural gas (LNG) fuel system components located upstream of, and including, the vaporizer; fuel containers; stationary gas engines; container mounting hardware; electronic fuel management; refuelling receptacles. NOTE 1 It is recognized that miscellaneous components not specifically covered herein can be examined to meet the criteria of this part of ISO 15500 and tested according to the appropriate functional tests. NOTE 2 All references to pressure in this part of ISO 15500 are to be considered gauge pressures unless otherwise specified. NOTE 3 This part of ISO 15500 is based upon a service pressure for natural gas as a fuel of 20 MPa [200 bar1)] settled at 15 °C. Other service pressures can be accommodated by adjusting the pressure by the appropriate factor (ratio). For example, a 25 MPa (250 bar) service pressure system will require pressures to be multiplied by 1,25.

Véhicules routiers — Composants des systèmes de combustible gaz naturel comprimé (GNC) — Partie 8: Indicateur de pression

General Information

• Status: Published
• Publication Date: 29-Nov-2015
• 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 15500-8:2001 - Road vehicles - Compressed natural gas (CNG) fuel system components - Part 8: Pressure indicator
• Effective Date: 20-Aug-2011

Overview - ISO 15500-8:2015 (Pressure indicator)

ISO 15500-8:2015 is the international standard that specifies tests and requirements for pressure indicators used in compressed natural gas (CNG) fuel system components for road vehicles. It applies to CNG systems for vehicle types defined in ISO 3833 and to vehicles using natural gas per ISO 15403-1 (monofuel, bi‑fuel, dual‑fuel). The standard clarifies marking, construction, assembly and specific functional tests for CNG pressure indicators (gauges and transducers). It excludes LNG components upstream of the vaporizer, fuel containers, stationary gas engines, certain mounting hardware, electronic fuel-management and refuelling receptacles.

Key topics and technical requirements

• Scope & applicability
  • For CNG vehicular fuel systems; pressures are gauge pressures unless stated otherwise.
  • Based on a reference service pressure of 20 MPa (200 bar) at 15 °C; other service pressures scaled by ratio (e.g., 25 MPa ×1.25).
• Marking
  • Must include manufacturer/agent ID, model/part number, and working pressure or pressure/temperature range. Additional recommended markings include flow direction, fuel type and electrical ratings.
• Construction
  • Pressure indicators must display at least 1.5× service pressure.
  • Gauges require shatter‑proof lens and an external pressure-relief path not directed to the front.
• Mechanical and functional tests
  • Hydrostatic strength: test at 2.5× working pressure per ISO 15500-2 procedures.
  • Leakage: tested across specified temperatures and pressure conditions.
  • Continued operation: 20 000 cycles (pressurize to WP, depressurize to <0.5×WP) followed by leakage verification.
• Electrical tests (if applicable)
  • Insulation resistance: 1 000 V DC between connector pin and housing for ≥2 s; minimum 240 kΩ.
  • Minimum operating voltage: ≤8 V for 12 V systems and ≤16 V for 24 V systems; component pressurized at 0.75× WP during test and reading must meet manufacturer tolerance.

Applications - Who uses ISO 15500-8:2015

• CNG pressure indicator and transducer manufacturers (design, type approval, QA).
• Vehicle OEMs and system integrators specifying compliant CNG components.
• Test laboratories and certification bodies performing hydrostatic, leakage and electrical tests.
• Fleet operators and maintenance teams referencing safe component criteria for CNG vehicles.

Related standards

• ISO 15500 series (Parts 1–20) - CNG fuel system components
• ISO 15500-1 (general requirements) and ISO 15500-2 (test methods)
• ISO 3833 (vehicle types and definitions)
• ISO 15403-1 (natural gas quality for vehicle fuel)

Keywords: ISO 15500-8:2015, CNG pressure indicator, compressed natural gas, pressure gauge tests, hydrostatic strength, insulation resistance, vehicle CNG components.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 15500-8
Second edition
2015-12-01
Road vehicles — Compressed natural
gas (CNG) fuel system components —
Part 8:
Pressure indicator
Véhicules routiers — Composants des systèmes de combustible gaz
naturel comprimé (GNC) —
Partie 8: Indicateur de pression
Reference number
©
ISO 2015
© ISO 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2015 – 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 . 2
6 Tests . 2
6.1 Applicability . 2
6.2 Hydrostatic strength . 3
6.3 Leakage . 3
6.4 Continued operation . 3
6.5 Insulation resistance . 4
6.6 Minimum operating voltage . 4
Bibliography . 5
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 meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 22, Road vehicles, Subcommittee SC 41, Specific
aspects for gaseous fuels.
This second edition cancels and replaces the first edition (ISO 15500-8:2001), which has been
technically revised.
ISO 15500 consists of the following parts, under the general title Road vehicles — Compressed natural
gas (CNG) fuel system components:
— Part 1: General requirements and definitions
— Part 2: Performance and general test methods
— Part 3: Check valve
— Part 4: Manual valve
— Part 5: Manual cylinder valve
— Part 6: Automatic valve
— Part 7: Gas injector
— Part 8: Pressure indicator
— Part 9: Pressure regulator
— Part 10: Gas-flow adjuster
— Part 11: Gas/air mixer
— Part 12: Pressure relief valve (PRV)
— Part 13: Pressure relief device (PRD)
iv © ISO 2015 – All rights reserved

— Part 14: Excess flow valve
— Part 15: Gas-tight housing
...