ISO 15500-5:2020

Overview

ISO 15500-5:2020 specifies the tests and requirements for manual cylinder valves used in compressed natural gas (CNG) fuel systems for road vehicles. This third edition, published by ISO, focuses on valves intended for mono-fuel, bi-fuel, or dual-fuel vehicles using natural gas per ISO 15403-1. The standard ensures reliability, safety, and performance of manual cylinder valves, a critical component in CNG vehicle fuel systems, by defining construction criteria, marking rules, and rigorous testing methods. It excludes components related to liquefied natural gas (LNG), fuel containers, stationary engines, mounting hardware, electronic management, and refuelling receptacles.

Key Topics

• Scope & Applicability: Defines use cases for manual cylinder valves on motor vehicles per ISO 3833, specifying natural gas as the fuel type. Excludes LNG upstream components and other unrelated parts.
• Marking Requirements: Mandates clear component marking including manufacturer identification, model number, working pressure/temperature range, and serial number or date code for traceability. Recommended markings cover flow direction, fuel type, certifications, and reference to the standard.
• Construction and Assembly: Specifies design features such as secure valve handles, 90° quarter-turn operation with rigid stops, clockwise closing rotation, and handling of valves incorporating internal excess flow valves with safe venting instructions.
• Testing Procedures: Extensive test regimen detailed in Clause 6 covers:
  • Hydrostatic strength testing at 2.5 times working pressure
  • Leakage tests under various temperature and pressure conditions
  • Continued operation verification over 2,000 operational cycles
  • Torque testing ensuring valves operate within specified torque limits at ambient and low temperatures
  • Valve stem retention test requiring resistance to torque above 16.5 N·m under pressure
• Performance Standards: Incorporates provisions from ISO 15500-1 and ISO 15500-2 for material tolerances, aging resistance, vibration endurance, and corrosion tests.

Applications

ISO 15500-5:2020 is essential for manufacturers and suppliers of CNG fuel system components, particularly those producing manual cylinder valves for natural gas vehicles. Its application ensures:

• Enhanced Safety: By verifying valve integrity and leakage prevention in a high-pressure CNG environment.
• Reliability in Various Conditions: Including temperature extremes from −40 °C to +85 °C, critical for global vehicle use.
• Regulatory Compliance: Facilitates adherence to international safety and performance standards, enabling smoother market access and certification.
• Quality Assurance: Manufacturers can systematically test valve components against defined criteria, improving durability and customer confidence.
• Compatibility: Supports use in multiple fuel system configurations (mono, bi, dual fuel) using natural gas fuel quality according to ISO 15403-1.

Related Standards

Understanding and compliance with related ISO standards enhance the effective application of ISO 15500-5:2020:

• ISO 15500-1:2015 – General requirements and definitions for CNG fuel system components, establishing baseline terminology and performance criteria.
• ISO 15500-2 – Performance and general test methods used as the basis for many testing procedures in Part 5, including hydrostatic strength and leakage tests.
• ISO 3833 – Defines motor vehicle types and terms relevant for applying Part 5 to correct vehicle classes.
• ISO 15403-1 – Specifies natural gas fuel quality requirements ensuring that valves are designed for appropriate gas composition.

Conclusion

ISO 15500-5:2020 provides a comprehensive framework ensuring the safety, performance, and traceability of manual cylinder valves within CNG vehicle fuel systems. By following its rigorous construction and testing requirements, manufacturers can deliver reliable components that meet international safety standards and endure real-world operating conditions. This standard is a vital reference for automotive engineers, component designers, and regulatory professionals involved in the compressed natural gas vehicle industry.