This standard applies to machines for surface cleaning and pre-treatment in the following called "cleaning machines" of industrial items using liquids or vapours, i.e. stationary machines and related equipment for automated and manual cleaning and pre-treatment processes. NOTE Cleaning machines are operated with or without heating, for example as dipping or spraying or vapour condensation process, where additional using of ultrasound is possible. These cleaning machines could be designed as single-zone or multi-zone machine, chamber machines, drum cleaning machine, low lift truck machines, round time machines or tunnel (continuous) machines. To the extent of this document, cleaning machines for industrial items are considered as an assembly of the following equipment: - pump(s) and/or other mechanical system of agitation, recirculation and spraying of cleaning liquid; - forced ventilation system; - heating system with temperature control; - condensation system; - filtration and separation system and/or solid particles extraction from the liquid; - conveyor and/or handling system for the items to be processed; - product handling systems and reciprocators which are part of the cleaning machine; - control and/or monitoring systems; - liquid handling system. 1.2 This European Standard deals with the common significant hazards, hazardous situations and events relevant to cleaning machines for industrial items using liquids or vapours when they are used as intended and under the conditions foreseen by the manufacturer (see clause 4). This part of the standard defines the common safety requirements for all kinds of cleaning machines for industrial items using liquids or vapours and related common devices and should be used in connection with other parts of the EN 12921-series. The specific requirements specified in part 2 and following parts of EN 12921 take precedence over the respective requirements in EN 12921.