Overview
ISO 9090:2019 - "Gas tightness of equipment for gas welding and allied processes" specifies acceptable maximum external gas leakage rates and measurement procedures for components used in the gas supply to a blowpipe (from the hose outlet or cylinder valve to the blowpipe). It covers individual components (regulators, blowpipes, safety devices, quick‑action couplings, hose assemblies, etc.) but does not apply to gas supply plants. Individual product standards (for example ISO 9012 for some hand blowpipes) take precedence for test method details.
Key topics and requirements
- Expression of leakage: Leakage is given as total leakage for a complete component in cm3/h, corrected to standard conditions (23 °C, 1.013 bar).
- Permissible leakage rates (selected):
- Regulators: ≤ 10 cm3/h
- Blowpipes: ≤ 8 cm3/h total; ≤ 4 cm3/h per valve
- Safety devices and most other equipment: ≤ 8 cm3/h
- Quick‑action couplings (connected and unconnected female elements): ≤ 10 cm3/h
- Hose assemblies: ≤ 4 cm3/h
- Test gases and corrections:
- Devices for helium and/or hydrogen are tested with helium; other devices with dry oil‑free air or nitrogen. Routine tests can use air or nitrogen. If a different gas is used, apply the Annex A correction factors. (Note: hydrogen is not used directly for leakage testing; helium is used for hydrogen-capable devices.)
- Test pressures:
- Regulators: test pressures as defined in ISO 2503.
- Other devices (type tests): tested at manufacturer’s maximum working pressure and at 10% of that pressure or 0.5 bar, whichever is lower. Routine tests use the more unfavourable of the two.
- Measurement method (type test): Immersion method - device immersed in water, pressurized, and escaping gas collected in a graduated cylinder over 1 hour (after initial 10 min). Results corrected to standard conditions.
Applications and users
- Manufacturers of gas welding and cutting equipment (design validation, quality control)
- Test laboratories performing type and routine leak tests
- Safety and maintenance engineers responsible for workshop and on‑site equipment integrity
- Procurement and compliance teams requiring documented conformity with ISO requirements
- Regulatory and certification bodies assessing product safety for welding/cutting applications
Related standards
- ISO 2503 - pressure regulators for gas welding cylinders (referenced for regulator test pressures)
- ISO 15296 - vocabulary for gas welding equipment terminology
- Individual product standards (e.g., ISO 9012) may define specific test conditions and take precedence where applicable
Keywords: ISO 9090:2019, gas tightness, leak rates, leak testing, immersion method, blowpipes, regulators, hose assembly, quick‑action coupling, welding equipment.