ISO 15500-12:2015
(Main)Road vehicles - Compressed natural gas (CNG) fuel system components - Part 12: Pressure relief valve (PRV)
Road vehicles - Compressed natural gas (CNG) fuel system components - Part 12: Pressure relief valve (PRV)
ISO 15500-12:2015 specifies tests and requirements for the pressure relief valve (PRV), a compressed natural gas fuel system component intended for use on the types of motor vehicles defined in ISO 3833. ISO 15500-12:2015 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) 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. 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 bar[1]] 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. [1] 1 bar = 0,1 MPa = 105 Pa; 1 MPa = 1 N/mm2.
Véhicules routiers — Composants des systèmes de combustible gaz naturel comprimé (GNC) — Partie 12: Soupapes de sécurité à la pression
General Information
- Status
- Published
- Publication Date
- 29-Nov-2015
- Technical Committee
- ISO/TC 22/SC 41 - Specific aspects for gaseous fuels
- Current Stage
- 9092 - International Standard to be revised
- Start Date
- 14-Feb-2023
- Completion Date
- 13-Dec-2025
Relations
- Effective Date
- 20-Aug-2011
Overview
ISO 15500-12:2015 specifies tests and requirements for the pressure relief valve (PRV) used in compressed natural gas (CNG) fuel systems for road vehicles defined in ISO 3833. It applies to vehicles using natural gas in accordance with ISO 15403-1 (mono‑fuel, bi‑fuel or dual‑fuel applications) and focuses on ensuring safe, reliable operation and traceability of PRVs. References to pressure are gauge pressures unless otherwise stated, and the part is based on a nominal service pressure of 20 MPa (200 bar) at 15 °C.
Key Topics
Scope and applicability
- PRVs for CNG vehicle fuel systems; not applicable to LNG components upstream of the vaporizer, fuel containers, stationary gas engines, container mounting hardware, electronic fuel management or refuelling receptacles.
Marking and traceability
- Components shall be marked to allow tracing to the manufacturer, model designation, working pressure and temperature range. Recommended additional markings include flow direction, fuel type, certification symbol, type approval number and serial/date code.
Construction and assembly
- PRVs must comply with the general provisions in ISO 15500-1 and ISO 15500-2. Tolerances follow ISO 15500-2 specifications.
Required tests (as specified in Clause 6):
- Hydrostatic strength - test to at least 2,5 times the working pressure; mechanism removed and orifice blocked for the test.
- Leakage - tested at working pressure and across temperature conditions (e.g. −40 °C or −20 °C, room temperature, and 85 °C or 120 °C as applicable).
- Continued operation - PRV must withstand 600 cycles; cycle defined by pressurizing to set pressure to open and vent, then reducing pressure until re‑seating. After cycling, leakage test at 20 °C ± 5 °C.
- Operational test - verify opening and re‑seating pressures. At 20 °C opening pressure must be ±5 % of set pressure; re‑seating ≥ 90 % of set pressure (with wider tolerances at extreme temperatures).
- Additional tests include corrosion, ageing, vibration, compatibility and automotive fluids as required.
Test media
- Air, nitrogen or natural gas may be used; if not natural gas, flow values must be corrected to natural gas.
Applications
This part of ISO 15500 is targeted at manufacturers, test laboratories, vehicle OEMs and certification bodies working with CNG vehicle fuel systems. Implementing these requirements supports:
- Safer venting under overpressure conditions
- Consistent operational performance across temperatures
- Regulatory and type‑approval compliance
- Clear component identification for service and recalls
Related Standards
- ISO 15500-1: General requirements and definitions
- ISO 15500-2: Performance and general test methods
- ISO 3833: Road vehicle types and definitions
- ISO 15403-1 and ISO/TR 15403-2: Natural gas quality for vehicles
For detailed procedural steps and acceptance criteria, consult ISO 15500-12:2015 and the referenced parts of the ISO 15500 series.
Frequently Asked Questions
ISO 15500-12:2015 is a standard published by the International Organization for Standardization (ISO). Its full title is "Road vehicles - Compressed natural gas (CNG) fuel system components - Part 12: Pressure relief valve (PRV)". This standard covers: ISO 15500-12:2015 specifies tests and requirements for the pressure relief valve (PRV), a compressed natural gas fuel system component intended for use on the types of motor vehicles defined in ISO 3833. ISO 15500-12:2015 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) 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. 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 bar[1]] 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. [1] 1 bar = 0,1 MPa = 105 Pa; 1 MPa = 1 N/mm2.
ISO 15500-12:2015 specifies tests and requirements for the pressure relief valve (PRV), a compressed natural gas fuel system component intended for use on the types of motor vehicles defined in ISO 3833. ISO 15500-12:2015 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) 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. 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 bar[1]] 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. [1] 1 bar = 0,1 MPa = 105 Pa; 1 MPa = 1 N/mm2.
ISO 15500-12:2015 is classified under the following ICS (International Classification for Standards) categories: 43.060.40 - Fuel systems. The ICS classification helps identify the subject area and facilitates finding related standards.
ISO 15500-12:2015 has the following relationships with other standards: It is inter standard links to ISO 15500-12:2001. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
You can purchase ISO 15500-12:2015 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of ISO standards.
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 15500-12
Second edition
2015-12-01
Road vehicles — Compressed natural
gas (CNG) fuel system components —
Part 12:
Pressure relief valve (PRV)
Véhicules routiers — Composants des systèmes de combustible gaz
naturel comprimé (GNC) —
Partie 12: Soupapes de sécurité à la 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
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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 Operational test . 3
6.5.1 General. 3
6.5.2 Test procedure . 3
Bibliography . 5
Foreword
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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 15500-12:2001), 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 and ventilation hose
— Part 16: Rigid fuel line in stainless steel
— Part 17: Flexible fuel line
— Part 18: Filter
— Part 19: Fittings
— Part 20: Rigid fuel line in material other than stainless steel
...
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