ISO 21969:2009

Overview

ISO 21969:2009 - High-pressure flexible connections for use with medical gas systems - specifies safety, design and test requirements for flexible connections used between medical gas cylinders (or cylinder bundles) and manifolds or equipment. The standard covers connections for nominal filling pressures up to 25 000 kPa at 15 °C and applies to medical gases such as oxygen, nitrous oxide, breathing air, helium, carbon dioxide, xenon, gas mixtures, and gases used to drive surgical tools.

Key topics and technical requirements

• Scope and gases covered: Connections for cylinders, cylinder bundles, manifolds and cylinder-to-equipment inlets (e.g., anaesthetic workstations) - not for cylinder filling or low-pressure hoses.
• Materials and construction: Metallic constructions only; non‑metallic polymer‑lined or rubber‑reinforced hoses are prohibited. Materials must be corrosion‑resistant and oxygen‑compatible (see ISO 15001 for selection guidance).
• Connectors and gas‑specificity: Inlet and outlet connectors must be gas‑specific and conform to ISO 407, ISO 5145 or relevant national standards to prevent misconnection.
• Mechanical performance:
  • Leakage limit: ≤ 0.2 ml/min external leakage at nominal inlet pressure.
  • Mechanical strength: Must withstand 2.25 × nominal inlet pressure (P) without permanent deformation.
  • Bursting pressure: Minimum 3 × P.
• Flow and pressure drop: Maximum allowable pressure drops are specified for cylinder and cylinder‑bundle use (tests at defined flow rates).
• Safety features: Requirements for torsion prevention, restraining devices on corrugated sections, resistance to ignition under oxygen pressure shocks, and cleaning/cleanliness per ISO 15001.
• Testing: Type tests detailed for leakage, mechanical strength, burst, ignition and pressure‑drop using clean, oil‑free air or nitrogen under controlled ambient conditions.

Applications and who uses ISO 21969:2009

• Manufacturers of high‑pressure flexible connections and medical gas fittings use this standard to design and certify products.
• Medical gas system designers and installers ensure compatibility with medical gas pipeline systems (ISO 7396‑1) and safe cylinder connections.
• Hospitals, clinics and biomedical engineers reference the standard when specifying replacement hoses and connections for oxygen, nitrous oxide and other medical gases.
• Testing laboratories and regulators apply the test methods and performance criteria for compliance assessment and safety verification.

Related standards

• ISO 7396‑1 (medical gas pipeline systems)
• ISO 407, ISO 5145 (cylinder valve and connector standards)
• ISO 15001 (oxygen compatibility / cleanliness)
• ISO 14971 (risk management)
• ISO 10524‑1 (integral pressure regulators)
• ISO 5359 (low‑pressure hose assemblies - excluded)

Keywords: ISO 21969:2009, high-pressure flexible connections, medical gas systems, oxygen compatibility, pressure testing, medical gas safety.