Overview
ISO 14114:2017 - Gas welding equipment - Acetylene manifold systems sets general requirements for the design, materials and testing of acetylene cylinder manifold systems used in welding, cutting and allied processes. The standard covers manifold systems extending from the cylinder valve or bundle outlet connections to the outlet connection of the main shut-off valve. It applies to single acetylene cylinders and cylinder bundles coupled for collective withdrawal and includes a test procedure for decomposition blockers. National regulations limiting the number of cylinders or bundles at a location can also apply.
Key topics and technical requirements
- Scope and definitions: terms for manifold components (high/low pressure, change-over units, decomposition blocker, flame arrestor) are defined in accordance with ISO 15296.
- Mandatory components:
- High-pressure non-return valves immediately downstream of cylinder/bundle outlets.
- High-pressure pipework/coiled metal pipes or high-pressure hoses (wall thickness per ISO 10961 / ISO 14113).
- Automatic quick-acting shut-off devices upstream of the regulator.
- High-pressure stop valves or three-way valves for one- and two-sided systems.
- Pressure regulators and change-over units per ISO 7291.
- Pressure-relief valves or automatic pressure-actuated shut-off devices per ISO 5175 / ISO 15615.
- Low-pressure safety devices: non-return valves, flame arrestors, temperature- or pressure-sensitive cut-off valves.
- Main shut-off valve and appropriate gauges (per ISO 15615 or device-specific standards).
- Materials: components must resist acetylene, acetone and dimethylformamide (DMF) and mechanical/thermal loads per ISO 9539.
- Testing requirements:
- High-pressure strength test: hydraulic test at 315 bar (31.5 MPa) for 5 minutes (no visible permanent deformation).
- Low-pressure strength test: pneumatic test of minimum 24 bar (2.4 MPa) unless other standards require higher pressures.
- External gas tightness: on-site commissioning leak tests at 1 bar (0.1 MPa) (low) and at least 18 bar (1.8 MPa) (high); low-pressure downstream tested at regulator maximum outlet pressure.
- Decomposition blocker: tested per Annex B; must stop acetylene decomposition, show no visible deformation or part ejection at initial gauge pressure 1.5 bar (0.15 MPa), and flame detectors must not detect flame.
Applications and users
ISO 14114:2017 is essential for:
- Manufacturers of acetylene manifold systems and components
- System designers and OEMs supplying gas welding equipment
- Installers and commissioning technicians performing leak and strength tests
- Safety officers, facility managers and inspectors responsible for workshop or warehouse gas safety
- Certification bodies and regulators assessing conformity with gas welding safety requirements
Keywords: ISO 14114:2017, acetylene manifold systems, gas welding equipment, decomposition blocker, manifold design, pressure testing, safety devices.
Related standards
Relevant referenced standards include:
For configuration examples and the decomposition blocker test procedure, see Annex A and Annex B of ISO 14114:2017.
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