ISO 15500-13:2023

Overview

ISO 15500-13:2023 - Road vehicles - Compressed natural gas (CNG) fuel system components - Part 13: Pressure relief device (PRD) defines tests and requirements for PRDs used on motor vehicles (mono‑fuel, bi‑fuel or dual‑fuel) that use natural gas as specified in ISO 15403-1. This third edition (2023) updates the 2012 edition and adds new test requirements such as high‑pressure activation, water‑jet protection and impact due to drop. The standard is intended for vehicle types defined in ISO 3833 and is not applicable to LNG components upstream of the vaporizer, fuel containers, stationary gas engines, container‑mounting hardware, electronic fuel management or refuelling receptacles.

Key topics and technical requirements

ISO 15500-13:2023 covers both functional and environmental requirements for PRDs, including:

• Terms & definitions (activation pressure, activation temperature, fusible material, burst disc, series/parallel combination PRDs, long/remote trigger PRDs, Kv flow coefficient).
• Marking, construction and assembly requirements to ensure traceability and safe installation.
• Comprehensive test program:
  • Hydrostatic strength (housing and fusible material)
  • Leakage and bending moment tests
  • Continued operation and accelerated‑life testing
  • Benchtop activation for thermally‑activated, pressure‑activated, series and parallel combination devices
  • Thermal cycling and condensate‑corrosion resistance
  • Flow capacity and high‑pressure activation & flow‑rate tests
  • Water‑jet protection and impact due to drop (new in 2023 edition)
• Production batch inspection and acceptance testing procedures.
• Annex A: normative method for determining fusible material yield temperature and PRD activation temperature.
• Design is based on a reference service pressure of 20 MPa (200 bar) at 15 °C; other service pressures are accommodated by a proportional factor (e.g., 25 MPa → multiply pressures by 1.25).

Practical applications - who uses this standard

ISO 15500-13:2023 is used by:

• CNG PRD designers and manufacturers for product development and conformity
• Automotive OEMs and system integrators for component selection and vehicle safety design
• Test laboratories and certification bodies performing type approval and acceptance testing
• Fleet operators, safety engineers and regulators assessing CNG vehicle safety and compliance
• Component suppliers and quality managers for production‑batch inspection

Related standards

• ISO 15500 series (general requirements and other CNG component parts)
• ISO 15500-1 (general requirements and definitions)
• ISO 15500-2 (performance and general test methods)
• ISO 15403-1 (natural gas quality for vehicular use)
• ISO 20653 (IP protection degrees for related electrical equipment)

ISO 15500-13:2023 provides the technical backbone for safe, reliable PRD performance in CNG vehicle systems and supports regulatory compliance, product certification and real‑world safety engineering.