ISO 20766-15:2023

Overview

ISO 20766-15:2023 - "Road vehicles - Liquefied petroleum gas (LPG) fuel system components - Part 15: Excess flow valve" specifies general requirements, design principles, marking and testing for LPG excess flow valves used on motor vehicles (mono‑fuel, bi‑fuel and dual‑fuel) as defined in ISO 3833. The standard applies to valves with service pressures in the range of 110 kPa to 840 kPa (gauge) and complements other parts of the ISO 20766 series and ISO 9162 for gaseous fuels.

Key Topics

• Scope & applicability
  • Intended for automotive LPG fuel system excess flow valves; excludes fuel containers, stationary gas engines, container mounting hardware and refuelling receptacles.
  • Pressure references are gauge pressures unless stated otherwise.
• Marking requirements
  • Manufacturer name/trademark, model/part number, operating specs (working pressure, temperature range, valve type, activation flow or ΔP, maximum flow), and flow direction where needed.
  • Recommended: fuel type, electrical ratings (if applicable), certification symbol, approval number, serial/date code and reference to ISO 20766.
• Construction & assembly
  • Valves must withstand maximum working pressure and the temperature range defined in ISO 20766‑1.
  • Flow rating must not exceed the capacity of the piping/tubing/hose it protects.
  • Design must include pressure equalization (bypass hole ≤ No.60 drill / 1.02 mm diameter).
• Testing & performance
  • Applicable tests include hydrostatic strength, external leakage, operation test, non‑metallic material immersion (LPG compatibility), corrosion resistance, temperature cycling (room, high, low), vibration, brass compatibility, automotive fluids exposure, electrical overvoltages and insulation resistance (some tests conditional).
  • Operation test criteria: valve operation must be within −20% to +10% of the manufacturer’s rated closing flow and must close automatically at a pressure differential no greater than 105 kPa. Tests are averaged over vertical, horizontal and inverted flow orientations. Three samples per size/style are required; tests use air and water as specified.

Applications

• Manufacturers of LPG excess flow valves and automotive fuel-system components use ISO 20766-15 for design validation, marking and type approval.
• OEMs and vehicle integrators apply the standard when selecting and installing safety valves in LPG-powered vehicles (mono/bi/dual‑fuel).
• Test laboratories and certification bodies use the specified tests and acceptance criteria for conformity assessment and type approval.
• Regulators and safety engineers reference the standard when defining national regulations or fleet safety requirements for LPG vehicles.

Related Standards

• ISO 20766 series (other parts covering LPG fuel system components)
• ISO 20766‑1 (terms, temperature ranges)
• ISO 3833 (vehicle categories)
• ISO 9162 (gaseous fuels - vehicle applications)

Keywords: ISO 20766-15, LPG excess flow valve, automotive LPG safety, excess flow valve testing, LPG fuel system standard.