1. Scope 1.1 This standard specifies the general requirements for construction, testing
and marking of electrical apparatus for explosive gas atmospheres and is
supplemented of modified by the following parts of IEC Publication 79
concerning specific types of protection: - Flameproof Enclosures (Publication 79-1)
- Pressurized Enclosures (Publication 79-2)
- Sand-filled Apparatus (Publication 79-5)
- Oil-immersed Apparatus (Publication 79-6)
- Increased Safety (Publication 79-7)
- Intrinsic Safety (Publication 79-11) Note. - In order to permit new developments it is recommended that
apparatus which does not comply with the requirements of IEc
Publication 79 but is recognized as safe for use in explosive
gas atmospheres by a national or other appropriate authority
should be marked with the symbol 's' (see Clause 25). Such
apparatus may be a part of apparatus that complies with the
requirements of IEC Publication 79. 1.2 This standard is applicable to electrical apparatus for explosive gas
atmospheres where atmospheric conditions for the explosion characteristics of
the explosive gas atmosphere are considered as having pressures in the range 80
kPa (0.8 bar) to 110 kPa (1.1 bar) at a temperature in the range -20 °C to +60
°C. Atmospheric conditions outside this range may need special consideration. 1.3 This standard is not applicable to devices whose electrical parameters,
according to the manufacturer's specifications, do not exceed any of the values
1.2 V, 0.1 A, 20 µJ or 25 mW, which need not be certified or marked as required
by IEC Publication 79. However, such devices are subject to the requirements
of the various parts of IEC Publication 79 if they are connected to a device
which contains a source or a storage element of electrical energy which could
cause the circuit to exceed these parameters.