Doc. 73/17Use of Non-Metallic Materials in High Pressure Oxygen Breathing Gas Applications

Non-metallic materials such as plastics, elastomers, and lubricants are known to be the most critical materials used in high pressure oxygen and oxygen mixture supply systems. These materials are typically found in valves, regulators, non-return valves and flexible hoses where their uses include seat inserts, O-ring, gaskets, and regulator diaphragms.

High pressure oxygen breathing gas systems with pressures equal to and greater than 30 barg (435 psig) and with an oxygen content above 23.5% by volume are considered by the publication. It applies in particular to non-metallic materials which if they ignite or decompose could contaminate the gas stream with toxic products. The recommendation of this publication can be beneficially applied at pressures lower than 30 barg (435 psig).

This publication is to be applied to high pressure customer breathing installations (for example, hospitals and homecare) where the ignition of non-metallic materials creates an immediate risk of inhalation of toxic products. This includes all elements of that installation from cylinder valve to point of use. This publication is not intended to apply to cylinder filling centres though it is recommended that the toxicity issue is addressed by a risk assessment of the filling system design.

The publication is part of the programme to develop Globally Harmonised publications amongst Regional Gas Associations.