This European Standard deals with the significant hazards of machines for surface cleaning and pre-treatment - in the following called "cleaning machines" - of industrial items using flammable cleaning liquids or a mixture of cleaning liquids, even in emulsion form, which can potentially create, even temporarily, a condition of flammability. This European Standard applies in combination with EN 12921-1. Both parts together cover all significant hazards relevant for cleaning machines of industrial items using liquids or vapours, when they are used as intended and under the conditions foreseen by the manufacturer (see Clause 4). The specific requirements specified in this European Standard take precedence over the respective requirements of EN 12921-1. To the extent of this document the terms combustible materials and flammable substance and explosive are equivalently used. NOTE 1 The condition of flammability can be generated only when molecules of the fluid are in intimate contact with oxygen from the air. Ignition is possible when: the fluid generates a concentration of vapour in air, or: the flammable fluid is present as a suspension of fine droplets in air (aerosol). NOTE 2 In practice, fires and explosions differ by the size and intensity of the reaction, and by the instantaneous effects on the environment. This European Standard does not apply to machinery and related equipment excluded from the scope of EN 12921-1. This European Standard is not applicable to cleaning machines of industrial items using flammable cleaning liquids which are manufactured before the publication of this European Standard by CEN.