This document specifies the requirements for flame arresters that 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 the marking of flame arresters, and specifies test methods to verify the safety requirements and determine safe limits of use. This document is valid for pressures ranging from 80 kPa to 160 kPa and temperatures ranging from "20 °C to +200 °C. NOTE 1 For flame arresters with operational conditions inside the scope, but outside atmospheric conditions, see Annex E. NOTE 2 In designing and testing flame arresters for operation under conditions other than those specified above, this Document can be used as a guide. This Document can also be used to design any additional testing related to the specific conditions of use. This is particularly important when high temperatures and pressures are applied. The test mixtures might need to be modified in these cases. This document is not applicable to the following: " external safety-related measurement and control equipment that might be required to keep the operational conditions within the established safe limits; NOTE 3 Integrated measurement and control equipment, such as integrated temperature and flame sensors as well as parts which, for example, intentionally melt (retaining pin), burn away (weather hoods) or bend (bimetallic strips), are within the scope of this Document. " flame arresters used for explosive mixtures of vapours and gases, which tend to self - decompose (for example, acetylene) or which are chemically unstable; " flame arresters used for carbon disulfide, due to its special properties; " flame arresters whose intended use is for mixtures other than gas-air or vapour-air mixtures (for example, higher oxygen-nitrogen ratio, chlorine as oxidant, etc.); " flame arrester test procedures for reciprocating internal combustion engines; NOTE 4 This includes the design requirements but excludes as installed testing; " fast acting valves, extinguishing systems and other explosion isolating systems; " Flame arresters used in gas detectors (those being covered for example, by IEC 60079-29- 1 and IEC 62990-1).