This document specifies requirements for flow control devices that can be connected by the user either directly, by means of a probe or a gas-specific connector, or indirectly by means of a low-pressure hose assembly conforming with ISO 5359 to: a) a terminal unit conforming with ISO 9170-1 of a medical gas pipeline system conforming with ISO 7396-1:2016; b) the pressure outlet of a regulator conforming with ISO 10524-1:2018; or c) to the pressure outlet of a valve integrated pressure regulator (VIPR) conforming with ISO 10524-3 (see 5.2 gas inlets). This document applies to the following types of flow control devices (FCDs): a) flowmeters; b) flowgauge FCDs; and c) fixed orifice FCDs. NOTE Flow control devices that are classed as medical electrical equipment can be subject to additional requirements of IEC 60601-1. This document applies to flow control devices for the following gases: oxygen; oxygen 93 %; nitrous oxide; medical air; carbon dioxide; oxygen/nitrous oxide mixture 50/50 (% volume fraction); oxygen-enriched air; helium; xenon; and specified mixtures of the gases listed above. NOTE Flow control devices can be available for other gases. This document does not apply to flow control devices that are: a) for use with gases for driving surgical tools; b) an integral part of a regulator (see ISO 10524-1:2018); or c) an integral part of a valve with integrated pressure regulator (VIPR) (see ISO 10524-3).