Overview
EN ISO 5171:2019 - Gas welding equipment: pressure gauges used in welding, cutting and allied processes - specifies requirements for Bourdon-tube pressure gauges used with compressed gas systems up to 30 MPa (300 bar). The standard covers use with dissolved acetylene and liquefied gases under pressure, but explicitly excludes gauges used in acetylene-manufacturing plants. EN ISO 5171:2019 is the CEN-endorsed version of ISO 5171:2019.
Key topics and technical requirements
- Scope and units: All pressures are gauge (effective) pressures expressed in MPa and bar.
- Maximum scale reading: Values are selected from specified series (Table 1 / preferred numbers); the maximum operating pressure mark must not exceed 3/4 of the maximum scale reading.
- Manufacturing requirements: Material selection rules (including special provisions for oxygen pressure gauges) and general construction requirements.
- Design and dimensions: Requirements for case, flange, dial, pointer, pointer stop and window to ensure reliable indication and safe mounting.
- Safety features: Venting/blowout design to safely dissipate internal pressure in the event of tube leakage or burst.
- Marking: Mandatory marking elements for identification, maximum pressure, accuracy class and traceability.
- Tests and conformity: Defined test program including accuracy, torsion, bend, case vent, overpressure and leakage (Test A and Test B) and flammability tests to validate performance and safety.
- Normative references: Linked standards such as ISO 14114 (acetylene manifolds), ISO 15296 (vocabulary) and pipe thread standards are referenced for consistent implementation.
Applications and users
EN ISO 5171:2019 is intended for:
- Manufacturers of gas welding and cutting equipment and Bourdon-tube pressure gauges
- Equipment designers and OEMs specifying gauges for oxygen, acetylene (dissolved), and other compressed or liquefied gases
- Procurement, quality, and compliance teams verifying equipment selection against international requirements
- Testing laboratories and conformity assessors performing the specified mechanical, leakage and flammability tests
- Safety officers and maintenance personnel applying safe selection and marking practices for gas welding systems
Practical benefits include improved safety, consistent performance across welding and cutting installations, and easier regulatory compliance when specifying gauges for high-pressure gas systems.
Related standards
- ISO 14114 - Acetylene manifold systems for welding/cutting
- ISO 15296 - Vocabulary for gas welding equipment
- ISO pipe-thread standards (e.g., ISO 7-1, ISO 228-1)
- ISO 4589-2 - Plastics burning behaviour (referenced for flammability testing)
Keywords: EN ISO 5171:2019, pressure gauges, Bourdon-tube, gas welding equipment, welding cutting, acetylene, oxygen, 30 MPa, safety testing.