ISO 5172:2006

Overview

ISO 5172:2006 - "Gas welding equipment - Blowpipes for gas welding, heating and cutting - Specifications and tests" sets international specifications and test procedures for blowpipes used in gas welding, heating and cutting of metals. The standard covers manual welding/heating blowpipes with a nominal thermal power up to 32 000 kcal/h and manual and machine cutting blowpipes with a cutting range up to 300 mm. It does not apply to air‑aspirated blowpipes (see ISO 9012).

Key topics and technical requirements

ISO 5172 defines terminology, design, marking, materials and safety/operational requirements for blowpipes. Major technical topics include:

• Mixing systems - classifications and definitions for low‑pressure, high‑pressure injector and equal‑pressure blowpipes.
• Flow rate classification - single flow rate, multiple flow rates (by injector, pressure, attachments or control valves).
• Mixing position - preliminary mixer vs. nozzle mixing.
• Safety incidents & definitions - backfire, sustained backfire, flashback and gas backflow.
• Hose connections and materials - requirements for compatibility and construction.
• Marking - mandatory marking of blowpipes, valves, nozzles and interchangeable parts plus gas symbols.
• Safety and operational requirements - device design and user safety features.
• Test procedures - standardized tests such as leak tests, sustained backfire tests (including alternative procedures and production/field acceptance), valve endurance tests, backflow tests and wind stability tests for fuel gas/compressed air flames.
• Informative annexes - e.g., corresponding flow rates for common fuel gases, terminology and example constructions, mixing ratios, nozzle dimensions and colour codes.

Practical applications and users

ISO 5172 is essential for anyone involved in the design, manufacture, testing, procurement or use of gas welding and cutting blowpipes:

• Manufacturers of blowpipes and cutting attachments - for product design, type testing and certification.
• Testing laboratories and conformity assessors - to perform leak, backfire, valve endurance and other standardized tests.
• Welding engineers and safety officers - to ensure equipment meets operational and safety requirements.
• Procurement teams and quality managers - to specify compliant blowpipes for workshops and production.
• Industrial maintenance and fabrication shops - for correct selection and safe use of blowpipes within rated thermal and cutting ranges.

Related standards

• ISO 9012 - air‑aspirated blowpipes (not covered by ISO 5172)
• ISO 5175 - safety devices for fuel gases and oxygen/compressed air
• ISO 9539 - materials for gas welding equipment
• ISO 15296 - vocabulary for gas welding equipment

ISO 5172 is a practical technical reference that improves safety, interoperability and testing consistency for gas welding and cutting blowpipes. Keywords: ISO 5172, blowpipes, gas welding equipment, specifications and tests, backfire test, nozzle, mixing system, valve endurance.