ISO 7291:2010

Overview

ISO 7291:2010 - "Gas welding equipment - Pressure regulators for manifold systems used in welding, cutting and allied processes up to 30 MPa (300 bar)" specifies performance, design and test requirements for pressure regulators used in manifold systems. The standard covers regulators for compressed gases up to 30 MPa (300 bar) and specific gases including dissolved acetylene, LPG, MPS and CO2. It applies to manifold-mounted regulators (linking two or more cylinder sources) and is not applicable to regulators fitted directly to individual gas cylinders (see ISO 2503).

Key topics and technical requirements

• Scope and gases covered: compressed gases ≤ 30 MPa, acetylene, liquefied petroleum gases, methylacetylene‑propadiene mixtures (MPS) and carbon dioxide.
• Materials and manufacturing: materials must conform to ISO 9539; components cleaned/degreased for oxygen service.
• Safety-critical design features:
  • Filter: integral particle filter retaining particles ≥ 0.1 mm, not removable without a tool.
  • Pressure‑adjusting device: designed to prevent the valve being held fully open or compressing the spring to solid length; adjustment must not allow relief device venting.
  • Pressure relief / venting: manifolds must either safely retain or safely vent high‑pressure gas; flammable gases require safe venting paths.
• Leakage limits:
  • External leakage to atmosphere meets ISO 9090; total external leakage < 10 cm3/h.
  • Internal leakage (high‑ to low‑pressure) limited by function of standard discharge Q (e.g., q < 50 cm3/h for Q < 30 m3/h; q < 2 500 cm3/h for Q > 1 500 m3/h).
• Performance and testing:
  • Type tests include functional tests, mechanical resistance (pressure testing), oxygen ignition test, acetylene decomposition tests, gauge durability and marking durability.
  • Pressure gauges supplied with the regulator must comply with ISO 5171 and be resistant to acetylene decomposition.

Practical applications

• Specification and acceptance criteria for manifold pressure regulators in welding and cutting shops, industrial gas supply systems and cylinder-bank installations.
• Guidance for manufacturing, type testing and quality assurance of regulators intended for gas distribution networks in fabrication, shipbuilding, construction and maintenance.
• Basis for procurement specs, conformity assessment and safety audits of gas manifold equipment used in allied processes.

Who should use ISO 7291:2010

• Pressure regulator manufacturers and designers
• Test laboratories and certification bodies
• Safety engineers, maintenance teams and welding workshop managers
• Procurement and compliance officers specifying manifold equipment

Related standards

• ISO 5171 - Pressure gauges for welding and cutting
• ISO 9090 - Gas tightness of welding equipment
• ISO 9539 - Materials for welding equipment
• ISO 15296 - Vocabulary for gas welding equipment
• ISO 2503 - Regulators fitted directly to gas cylinders (not covered by ISO 7291)

Keywords: ISO 7291:2010, pressure regulators, manifold systems, welding cutting, 30 MPa, acetylene, LPG, CO2, leakage limits, type tests, gas welding equipment.