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