This part of IEC 60079 specifies the general requirements for construction, testing and
marking of Ex Equipment and Ex Components intended for use in explosive atmospheres.
The standard atmospheric conditions (relating to the explosion characteristics of the
atmosphere) under which it may be assumed that Ex Equipment can be operated are:
• temperature –20 °C to +60 °C;
• pressure 80 kPa (0,8 bar) to 110 kPa (1,1 bar); and
• air with normal oxygen content, typically 21 % v/v.