ISO 15500-2:2016

Overview

ISO 15500-2:2016 - "Road vehicles - Compressed natural gas (CNG) fuel system components - Part 2: Performance and general test methods" - defines performance criteria and general test methods for CNG fuel system components intended for motor vehicles (as defined in ISO 3833). It applies to mono‑fuel, bi‑fuel and dual‑fuel vehicles that use compressed natural gas in accordance with ISO 15403 (all parts). The standard excludes LNG components upstream of the vaporizer, fuel containers, stationary engines, container‑mounting hardware, electronic fuel management and refuelling receptacles.

Key topics and technical requirements

• Test environment and media
  • Default room temperature: 20 °C ± 5 °C unless otherwise stated.
  • Tests are normally conducted using dry air or nitrogen; natural gas may be used with safety precautions.
• Hydrostatic strength
  • Components are pressure‑tested to failure; pressure increase rate and failure recording are specified. Previously tested samples must not show failure pressure less than 80% of virgin samples.
• Leakage (external and internal)
  • Bubble immersion tests or helium vacuum/global accumulation methods are accepted for detection.
  • Components must meet specified leakage limits (see Clause 6.1.2); conditioning and temperature states are defined.
• Mechanical and durability tests
  • Excess torque resistance: threaded components must withstand at least 150% of rated installation torque without deformation, followed by leakage and hydrostatic checks.
  • Bending moment, vibration resistance, continued operation (temperature cycling: room, high, low), and corrosion resistance.
• Materials and ageing
  • Tests include ozone ageing, oxygen ageing, resistance to dry heat, automotive fluid exposure, non‑metallic material immersion, and brass compatibility.
• Electrical and other tests
  • Electrical over‑voltages and other functional safety checks where applicable.
• Service pressure baseline
  • Service pressure is based on 20 MPa (200 bar) at 15 °C; other pressures can be scaled (e.g., 25 MPa requires a factor of 1.25).

Applications and users

Who uses ISO 15500-2:2016:

• CNG component manufacturers and suppliers (valves, regulators, fittings, lines)
• Automotive OEMs and powertrain engineers integrating CNG systems
• Independent test laboratories and certification bodies performing conformity testing
• Regulatory authorities and fleet operators seeking harmonized safety and performance criteria

Benefits:

• Ensures safety, reliability and interoperability of CNG components
• Facilitates market access through common test methods and acceptance criteria
• Helps designers validate materials and mechanical integrity under real‑world conditions

Related standards

• ISO 15500‑1:2015 (General requirements and definitions)
• Other parts of ISO 15500 (Parts 3–20 covering specific components)
• ISO 3833 (vehicle classification)
• ISO 15403 (natural gas fuel specifications)
• Normative references cited: ISO 188, ISO 1431‑1, ISO 1817, ISO 9227

Keywords: ISO 15500-2:2016, CNG fuel system components, compressed natural gas standard, CNG testing, hydrostatic strength, leakage test, vehicle CNG components.