[AIVC, Air infiltration and ventilation glossary, 1992]:a mechanical device employing rotating aero foil blades or vanes to continuously move air from one place to another.[EN 12792:2003, 148]:rotary bladed machine which receives mechanical energy and utilizes it by means of one or more impellers fitted with blades to maintain a continuous flow of air or other gas passing through it and whose work per unit mass does not normally exceed 25 kJ/kg. The term fan is taken to mean the fan as supplied without any addition to the inlet or outlet, except where such an addition is specified. (See ISO 5801)