This standard specifies the requirements for flame arresters which prevent flame transmission when explosive gas/air- or vapour/air-mixtures are present. It establishes uniform principles for the classification, basic construction and information for use including marking of flame arresters and specifies test methods to verify the safety requirements and determine safe limits of use. This draft standard is valid for pressures ranging from 80 kPa to 160 kPa and temperatures ranging from -20 degree C to +150 degree C This draft standard does not cover the following: - External safety-related measurement and control equipment which may be required to keep the operational conditions within the established safe limits. - Flame arresters used for explosive mixtures of vapours and gases, which tend to self-decompose (e.g. acetylene) or which are chemically unstable. - Flame arresters used for carbon disulphide due to its special properties. - Flame arresters with intended use for mixtures other than gas-air or vapour-air mixtures (e.g. higher or lower oxygen-nitrogen ratio, chlorine as oxidant, etc.). - Flame arrester test procedures for internal combustion, compression ignition engines. - Fast acting valves, extinguishing systems and other explosion isolating systems. - Flame arresters for mining application. - Flame arresters integrated or combined with explosion protected equipment like blowers, fans, compressors and pumps.