1.1 This European Standard specifies the constructional requirements for fans constructed to Group II G (of explosion groups IIA, IIB and hydrogen) categories 1, 2 and 3, and Group II D categories 2 and 3, intended for use in explosive atmospheres. NOTE 1 Operation conditions for the different categories of fans used in this European Standard are defined in Clause 4.NOTE 2 Technical requirements for category 1 D fans are not given in this document. Where explosive dust atmospheres are regularly conveyed, explosion protection measures as described in EN 1127–1 are required if this specific us is needed. 1.2 This European Standard does not apply to group I fans (fans for mining), cooling fans or impellers on rotating electrical machines, cooling fans or impellers on internal combustion engines. NOTE 1 Requirements for group I fans are given in EN 1710. NOTE 2 The requirements for electrical parts are covered by references to electrical equipment standards. 1.3 This European Standard specifies requirements for design, construction, testing and marking of complete fan units intended for use in potentially explosive atmospheres in air containing gas, vapour, mist and/or dusts. Such atmospheres may exist inside (the conveyed atmosphere (flammable or not)), outside, or inside and outside of the fan. 1.4 This European Standard is applicable to fans working in ambient atmospheres and with normal atmospheric conditions at the inlet, having - absolute pressures ranging from 0,8 bar to 1,1 bar, - and temperatures ranging from -20 °C to +60 °C, - and maximum volume fraction of 21 % oxygen content, - and an aerodynamic energy increase of less than 25 kJ/kg.