ISO 15500-1:2015

Overview

ISO 15500-1:2015 defines general requirements and terms for compressed natural gas (CNG) fuel system components used on road vehicles (as defined in ISO 3833). It establishes design principles, marking and instruction requirements, and material and construction expectations for components used in mono-fuel, bi-fuel and dual-fuel natural gas vehicles (NGVs). The standard is based on a reference service pressure of 20 MPa (200 bar) at 15 °C and treats all pressures as gauge pressures unless stated otherwise.

Key topics and requirements

• Scope and applicability
  • Applies to CNG fuel system components for vehicle use (natural gas per ISO 15403‑1).
  • Explicitly excludes LNG upstream components (to and including the vaporizer), fuel containers, stationary gas engines, container mounting hardware, electronic fuel management, and refuelling receptacles.
• Materials and construction
  • Components must be made of materials suitable for CNG; galvanic corrosion between dissimilar materials must be considered.
  • Joints must be gas-tight; disassemblable tapered thread fittings are recommended to be replaced after disassembly.
  • Threads for cylinder-attached components shall conform to cylinder neck thread standards.
  • Temperature service ranges are specified for engine compartments and on-board locations (moderate and cold ranges).
• Non‑metallic materials and corrosion
  • Seals, diaphragms and other non-metallic materials must pass oxygen ageing and immersion tests per ISO 15500-2.
  • Components exposed to weather must meet corrosion resistance tests in ISO 15500-2.
• Electrical and wiring
  • Wiring and electrical parts must meet automotive quality standards (ISO 6722-1 and ISO 6722-2) and be protected against chafing.
• Operation and safety features
  • Automatic fuel shut-off valves shall be closed when de‑energized.
  • Multifunctional components are addressed and should be verified against the relevant parts of the ISO 15500 series.
• Instructions and marking
  • Manufacturers must provide clear, country-appropriate installation, maintenance and safety instructions.
  • Required markings include manufacturer, part/model number, working pressure and temperature range, fuel type, flow direction, electrical ratings, certification symbol, type approval number, and serial/date code.

Applications and users

ISO 15500-1 is essential for:

• CNG component manufacturers (valves, regulators, fittings, lines, filters)
• Vehicle OEMs and system integrators designing NGV fuel systems
• Test laboratories and conformity assessment bodies
• Certification agencies, regulators and aftermarket installers It helps ensure safety, interchangeability and compliance of vehicle CNG components across markets.

Related standards

• ISO 15500 series (Parts 2–20 covering tests and component-specific requirements)
• ISO 15501-1 (CNG fuel system safety requirements)
• ISO 15403-1 (Natural gas quality for vehicle fuel)
• ISO 6722-1 / ISO 6722-2 (automotive wiring)
• ISO 3833 (vehicle types and definitions)

Keywords: ISO 15500-1, CNG fuel system components, compressed natural gas, NGV, CNG standards, service pressure 20 MPa, vehicle CNG components.