The EN ISO 80079-36 requirement specifies the basic method and the requirements for the design, construction, testing and marking of Ex appliances, Ex components, protective systems, non-electric equipment and assemblies of these products that have their own potential sources of ignition and that are intended to be used in explosive atmospheres.
The standard does not specify safety requirements, other than those directly referring to the risk of ignition that can lead to an explosion. The standard atmospheric conditions (in relation to the explosion features of the atmosphere) under which it can be assumed that the equipment can operate are:
- temperature from -20 °C to 60 °C;
- pressure from 80 kPa (0.8 bar) to 110 kPa (1.1 bar);
- air with normal oxygen content, typically 21 % v/v.
These atmospheres can also exist inside the equipment. Furthermore, the outside atmosphere can be drawn into the equipment by means of natural breathing produced following fluctuations of the internal operational pressure of the appliance, and/or of the temperature. The standard specifies the requirements for the design and construction of equipment intended for explosive atmospheres in compliance with all the Equipment Protective Levels (EPLs) of Group I, II and III.