This part of ISO/IEC 80079 describes the test methods for the identification of combustible dust and combustible dust layers in order to permit classification of areas where such materials exist for the purpose of the proper selection and installation of electrical and mechanical equipment for use in the presence of combustible dust. The standard atmospheric conditions for determination of characteristics of combustible dusts are: ? temperature –20 °C to +60 °C, ? pressure 80 kPa (0,8 bar) to 110 kPa (1,1 bar) and ? air with normal oxygen content, typically 21 % v/v. The test methods defined do not apply to: ? recognized explosives, propellants (e.g. gunpowder, dynamite), or substances or mixtures of substances which may, under some circumstances, behave in a similar manner or ? dusts of explosives and propellants that do not require atmospheric oxygen for combustion, or to pyrophoric substances.