This European Standard specifies basic methodology used in achieving safety of equipment for intended use in potentially explosive atmospheres. The provisions specified in this European Standard are intended for the designer. It also specifies a strategy for standard makers. This European Standard specifies the procedure and information required to allow ignition risk assessment to be carried out for the design of equipment or component. This European Standard provides advice for a decision to be made for the categorisation of equipment but does not provide means to prove the conformity of equipment categories. In this procedure the following information is to be taken into account: a) Possible occurrence of an explosive atmosphere inside the equipment or component or penetrating the equipment or component from the outside (in normal operation or during malfunctions) and the amount of explosive atmosphere involved leading to possible explosion impact inside of the equipment or component; b) equipment or components surrounded by an explosive atmosphere (in normal operation or during malfunctions); c) equipment or components wholly or partly surrounded by an explosive atmosphere considering also any explosive atmosphere in connection (in normal operation or during malfunctions); d) presence and likelihood (effectiveness) of ignition sources. The final objective is designing and manufacturing equipment or components intended for use in potentially explosive atmospheres. For this purpose equipment or components if necessary shall be designed with adequate preventive and/or protective measures. This European Standard specifies neither specific methods of analysis associated with ignition risk assessment, nor specific requirements for a category of equipment. It describes the methodology of ignition risk assessment. (continued)