This document describes the basic requirements for the design and application of explosion suppression systems. This document also specifies a method for evaluating the effectiveness and the scale up of explosion suppression systems against defined explosions. It gives the criteria for alternative test apparatus used to undertake explosion suppression efficacy tests and criteria to be applied in defining the safe operating regime of an explosion suppression system. It covers: general requirements for explosion suppression components; evaluating the effectiveness of an explosion suppression system; evaluating the scale up of an explosion suppression system; evaluation and development of design tools for explosion suppression systems; instructions for installation of an explosion suppression system; maintenance instructions for an explosion suppression system. This document is applicable only to explosion suppression systems intended for the protection of closed, or essentially closed, enclosures in which an explosion may result as a consequence of ignition of an explosible mixtures, e. g. dust-air mixtures, gas(vapour)-air mixtures, dust-gas(vapour)-air mixtures and mists. This document is not applicable for explosions of materials listed below, or for mixtures containing some of those materials: unstable materials that are liable to dissociate; explosive materials; pyrotechnic materials; pyrophoric materials. NOTE For the listed materials expert advice is required.