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.