Sch 1 para 32 Explosive atmospheres caused by gases, vapours or mists
(1) Equipment must be so designed and constructed that sources of ignition do not become active, even in the event of rare incidents relating to equipment. (2) It must be equipped with means of protection such that— (a) either, in the event of failure of one means of protection, at least an independent second means provides the requisite level of protection; or (b) the requisite level of protection is ensured in the event of two faults occurring independently of each other. (3) For equipment with surfaces which may heat up, measures must be taken to ensure that the stated maximum surface temperatures are not exceeded even in the most unfavourable circumstances. (4) Temperature rises caused by heat build-ups and chemical reactions must also be taken into account. (5) Equipment must be so designed that the opening of equipment parts which might be sources of ignition is possible only under non-active or intrinsically safe conditions. Where it is not possible to render equipment non-active, the manufacturer must affix a warning label to the opening part of the equipment. (6) If necessary, equipment must be fitted with appropriate additional interlocking systems.