1.1 This International Standard is applicable to: – flow-metering devices that are connected, either directly or by means of flexible connecting assemblies, and disconnected by the operator at terminal units of a medical gas pipeline system for flow adjustment, measurement and delivery of medical gases; – flow-metering devices that are connected and disconnected by the operator at gas-specific connection points of devices such as pressure regulators. 1.2 This International Standard applies to: a) flow-metering devices intended to be used with the following medical gases: – oxygen; – nitrous oxide; – medical air; – carbon dioxide; – oxygen/nitrous oxide mixture [50 %/50 % (by volume)]; – specified mixtures of the gases listed above; b) flow-metering devices intended to be used with the following gases: – oxygen-enriched air; – helium; – xenon. NOTE – Regional or national regulations might permit use of oxygen-specific connection points for oxygen-enriched air. 1.3 This International Standard does not apply to electrical or electronic flow-metering devices. 1.4 This International Standard does not apply to gases used for driving surgical tools.