ISO 15500-4:2020

Overview

ISO 15500-4:2020 specifies tests and requirements for the manual valve used in compressed natural gas (CNG) fuel system components for road vehicles (as defined in ISO 3833). The standard applies to mono‑fuel, bi‑fuel and dual‑fuel vehicles using natural gas in accordance with ISO 15403‑1. It defines essential marking, construction and performance criteria and references general requirements and test methods in ISO 15500‑1 and ISO 15500‑2.

Key topics and technical requirements

• Scope and exclusions: Applies to CNG manual valves for vehicle use; excludes LNG components upstream of the vaporizer, fuel containers, stationary engines, container‑mounting hardware, electronic fuel management and refuelling receptacles.
• Marking: Components must be traceable with manufacturer/agent name or trademark, model/part number, working pressure (and temperature range), and serial number or date code. Additional recommended markings include flow direction, fuel type and certification symbols.
• Construction and assembly: Requirements follow ISO 15500‑1 and ISO 15500‑2. Handles must be securely attached; 90° (quarter‑turn) valves require rigid stops and specific handle orientation; valves shall close when turned clockwise unless otherwise specified.
• Performance tests (referenced procedures in ISO 15500‑2 and described limits in ISO 15500‑4):
  • Hydrostatic strength: Test pressure = 2.5 × working pressure.
  • Leakage: Leakage testing at specified temperature/pressure combinations (e.g., fractions and multiples of working pressure across –40/–20 °C, 20 °C, 85/120 °C conditions).
  • Continued operation: Cycle testing for 10 000 cycles (or 50 cycles for service valves) with downstream pressure adjustments and post‑cycle leakage verification; valves must operate within maximum torque limits in Table 3 (e.g., 1.7–2.8 N·m at max temperature depending on inlet size).
  • Valve stem retention: Must withstand >16.5 N·m counter‑clockwise torque while pressurized at 125% WP (upstream of first‑stage reducer) or 100% WP (downstream) and remain functional.
• Other applicable tests: Excess torque, bending moment, corrosion, ageing (oxygen/ozone/heat), automotive fluids, vibration, brass compatibility and non‑metallic immersion (as indicated in ISO 15500‑2).

Applications and who uses it

ISO 15500-4:2020 is used by:

• CNG valve and component manufacturers for design validation and product certification.
• Automotive OEMs and system integrators specifying compliant CNG fuel systems.
• Testing laboratories and conformity assessment bodies performing performance and safety tests.
• Regulatory agencies, procurement teams and fleet operators requiring standardized safety and traceability for vehicle CNG systems. Practical uses include ensuring safe shut‑off performance, leak tightness, durability under cycling and suitability for vehicle installation and service operations.

Related standards

• ISO 15500‑1: General requirements and definitions for CNG fuel system components
• ISO 15500‑2: Performance and general test methods
• ISO 15403‑1: Natural gas quality for vehicle fuel
• ISO 3833: Vehicle types - terms and definitions

Keywords: ISO 15500-4:2020, CNG manual valve, compressed natural gas, CNG fuel system components, hydrostatic strength, leakage testing, valve stem retention, continued operation.