WOK/Ex fans have been developed for use in areas of explosion hazard, where explosive atmosphere (i.e. mixture of flammable compounds in the form of gas and vapour with the air) can occur. WOK/Ex fans are meant for conveying the air and explosive atmospheres. They can be applied for general ventilation of production halls, workshops, store houses, according to the explosiveness group. The fans are marked II 2 G c Ex e IIB T1, T2, T3. They are installed directly in the wall openings or in windows, as air supply- or extraction application.