ISO 20766-3:2018

Overview

ISO 20766-3:2018 specifies requirements for the 80% stop valve used in liquefied petroleum gas (LPG) vehicle fuel systems. It forms Part 3 of the ISO 20766 series and applies to LPG systems for road vehicles defined in ISO 3833, including mono‑fuel, bi‑fuel and dual‑fuel applications (gaseous fuels per ISO 9162). The standard covers definitions, general design principles, required markings and a suite of performance and durability tests for valves that limit container filling to about 80% of capacity.

Key topics and technical requirements

• Scope & applicability
  • For LPG 80% stop valves used on motor vehicles; excludes fuel containers, stationary gas engines, container mounting hardware, electronic fuel management and refuelling receptacles.
• Marking and traceability
  • Components must be marked with manufacturer/agent name or trademark, model/part number and working pressure (or working pressure/temperature range). Additional recommended markings include flow direction, fuel type, certification symbol and serial/date code.
• Design & functional limits
  • Valve closing is intended at the 80% fill level (document specifies the closing volume and associated tolerance). Electrically operated valves must fail-safe (closed on power off) and meet insulation/overvoltage tests.
• Performance tests
  • Hydrostatic strength: tested at 2.25 × working pressure.
  • Leakage: tested across specified temperatures and pressure factors relative to working pressure.
  • Continued operation: valves must withstand 6 000 cycles between empty and the cut‑off position; filling rate at cut‑off (differential pressure 700 kPa) shall not exceed 0.5 L/min (500 cc/min).
  • Float requirements: where applicable, float assemblies must resist deformation and withstand an external pressure of 4 500 kPa; vibration and charging‑speed tests also apply.
• Test matrix
  • Referenced test types include excess torque, bending moment, corrosion, vibration, insulation resistance and material compatibility-many specified in ISO 20766‑2.

Applications and users

This standard is essential for:

• LPG valve and component manufacturers (design, testing, quality control)
• Vehicle OEMs and system integrators specifying safety components for LPG conversions or factory-fitted LPG systems
• Test laboratories and certification bodies performing type approval and conformity testing
• Fleet operators and installers evaluating component safety, marking and performance Use cases include design validation, regulatory compliance, type‑approval testing and supplier quality assurance for LPG vehicle fuel system safety.

Related standards

• ISO 20766 series (Part 1, Part 2)
• ISO 3833 (vehicle categories)
• ISO 9162 (gaseous fuels handling)
• Other referenced documents: ISO 11114‑2, EN 589, EN 13760

Keywords: ISO 20766-3, LPG 80% stop valve, liquefied petroleum gas, LPG fuel systems components, valve testing, hydrostatic strength, leakage test, continued operation cycles, LPG vehicle safety.