ISO 20766-24:2022

Overview

ISO 20766-24:2022 defines requirements for gas tubes used in liquefied petroleum gas (LPG) fuel systems for road vehicles. Part of the ISO 20766 series, this standard covers general definitions, design principles, marking and instruction requirements, material and construction guidance, and mandatory test methods for rigid gas tubing intended for mono‑fuel, bi‑fuel and dual‑fuel vehicles as defined in ISO 3833.

Key facts:

• Scope: gas tubes for vehicle LPG systems (service pressure range nominally between 110 kPa and 840 kPa; other pressures accommodated by proportional adjustment).
• Not applicable to: fuel containers, stationary gas engines, container mounting hardware, electronic fuel management or refuelling receptacles.
• Emphasis on corrosion resistance, secure mounting, protection against vibration/abrasion and galvanic corrosion.

Key Topics and Requirements

• Definitions and component scope: Gas tube defined as a rigid metallic or non‑metallic fuel line designed not to flex in normal operation.
• Marking: Must include manufacturer, model/part number, working pressure (or pressure/temperature range), serial/date code and flow direction when needed. Recommended: fuel type, electrical ratings, certification symbol and reference to ISO 20766-24.
• Materials and construction:
  • Use corrosion‑resistant materials (e.g., copper, stainless steel) or protective coatings/sleeves.
  • Secure routing to avoid vibration and jacking points; protective material at fixings and passages; compatibility between couplings and tubes to minimize galvanic corrosion.
  • Only longitudinal welding permitted on non‑seamless tubing.
• Mandatory tests (per ISO 20766-2 procedures referenced):
  • Hydrostatic strength: test pressure = 2.25 × working pressure.
  • Leakage: allowed limit as specified (document lists a maximum of 15 cm/hour under specified conditions).
  • High/low temperature conditioning: leakage test at max operating temps (65 °C, 85 °C or 120 °C) and min operating temps (−40 °C or −20 °C) with pressure at 150% working pressure after ≥8 h conditioning.
  • Continued operation durability: 100 000 cycles.
  • Bending test: mandrel diameters (≤8 mm → 3× tube OD; >8 mm → 5× tube OD), followed by hydrostatic and leakage tests.

Applications - Who Uses This Standard

• Vehicle OEMs and chassis manufacturers integrating LPG systems
• LPG system component manufacturers and tubing suppliers
• Certification bodies and test laboratories performing conformity and type approval
• Aftermarket installers, maintenance engineers and fleet operators specifying safe LPG tubing and installation practices
• Regulators referencing vehicle gas system safety requirements

Related Standards

• ISO 20766-1 - General requirements and definitions
• ISO 20766-2 - Performance and general test methods (test procedures referenced)
• ISO 3833 - Vehicle types, terms and definitions
• ISO 9162 - LPG fuel specifications

Keywords: ISO 20766-24:2022, LPG gas tubes, road vehicles, liquefied petroleum gas, hydrostatic strength, leakage test, corrosion resistance, gas tube testing, vehicle LPG systems.