ISO 20766-12:2019

Overview

ISO 20766-12:2019 specifies requirements for the non‑return valve used in liquefied petroleum gas (LPG) fuel systems for road vehicles. It covers general design principles, marking and instruction requirements, and defined test procedures to verify safety and functional performance. The standard applies to mono‑fuel, bi‑fuel and dual‑fuel vehicles as defined in ISO 3833 and for gaseous fuels per ISO 9162. It is focused on vehicle components (not fuel containers, stationary engines, refuelling receptacles, electronic fuel management, or container mounting hardware).

Keywords: ISO 20766-12:2019, non-return valve, LPG fuel systems, liquefied petroleum gas, road vehicles

Key Topics

• Scope & applicability

  • Intended for non‑return valves in vehicle LPG systems; pressures are gauge pressures.
  • Service pressure range covered: about 110 kPa (butane‑rich @20 °C) to 840 kPa (propane @20 °C); other pressures accommodated by proportional adjustment.

• Marking & identification

  • Required markings to enable traceability: manufacturer/agent name or logo, model/part number, working pressure (or pressure/temperature range).
  • Recommended markings include flow direction, flow capacity, fuel type, electrical ratings (if applicable), certification symbol, approval number and serial/date code.

• Construction & assembly

  • Components must comply with ISO 20766‑1 (general requirements) and ISO 20766‑2 (performance/test methods).

• Test requirements

  • Hydrostatic strength: tested at 2.25 × working pressure.
  • Leakage: verified at multiple temperatures and at pressures expressed as factors of the working pressure (including very low leak checks and higher pressure checks).
  • Continued operation: endurance of 50,000 cycles plus 24 hours of chatter flow under specified conditions; subsequent re‑testing for leakage and hydrostatic strength is required.
  • Additional applicable tests (where relevant) include corrosion, vibration, material compatibility, ageing and flow capacity per ISO 20766‑2.

Applications

• Manufacturers and designers of LPG non‑return valves use the standard to guide safe product design and labelling.
• OEM vehicle integrators and system suppliers rely on it for component selection, type approval and system safety verification.
• Test laboratories and regulatory bodies apply the specified procedures for conformity assessment, certification and quality control.
• Fleet operators and installers use the standard’s marking and documentation requirements for maintenance traceability.

Related Standards

• ISO 20766‑1 - General requirements and definitions for LPG fuel system components
• ISO 20766‑2 - Performance and general test methods (referenced for test procedures)
• ISO 3833 - Road vehicle types, terms and definitions
• ISO 9162 - Specifications for liquefied petroleum gases

ISO 20766‑12:2019 helps ensure robust, traceable and tested non‑return valves for safer LPG vehicle fuel systems.