This European Standard describes the general requirements for explosion isolation systems. An explosion isolation system is a protective system, which prevents an explosion pressure wave and a flame or only a flame from propagating via connecting pipes or ducts into other parts of apparatus or plant areas. This European Standard specifies methods for evaluating the efficacy of the various explosion isolation systems, and methods for evaluating design tools for such explosion isolation systems when applying these in practice. This European Standard also sets out the criteria for alternative test methods and interpretation means to validate the efficacy of explosion isolations. It covers e.g.: a) general requirements for the explosion isolation components; b) evaluating the effectiveness of an explosion isolation system; c) evaluating design tools for explosion isolation systems.