Explosive atmospheres - Part 38 : equipment and components in explosive atmospheres in underground mines
ISO/IEC 80079-38:2016 is published as a dual logo standard and specifies the explosion protection requirements for the design, construction, assessment and information for use (maintenance, repair, marking) of equipment that may be an individual item or form an assembly. This includes machinery and components for use in mines susceptible to explosive atmospheres of firedamp and/or combustible
dust. The standard atmospheric conditions (relating to the explosion characteristics of the atmosphere) under which it may be assumed that 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. This part of ISO/IEC 80079 applies for equipment and components according to EPL Mb to be used in explosive atmospheres containing firedamp and/or combustible dust. For equipment and components according to EPL Ma, the requirements of this standard and of ISO 80079-36 and IEC 60079-0 apply. It is necessary to take account of external
conditions to the equipment which may affect the hazard and the resultant protection measures. These measures may include ventilation, gas detection or gas drainage. This part of ISO/IEC 80079 also deals with the prevention of ignitions of explosive atmospheres caused by burning (or smouldering) of combustible material such as fabric fibres, plastic "O"-rings, rubber seals, lubricating oils or greases used in the construction of the equipment if such items could be an ignition source. For example, the mechanical failure of rotating shaft bearings can result in frictional heating that ignites its plastic cage, plastic seal or lubricating grease. Detailed requirements and test procedures for the fire protection of conveyer belts are not part of this part of ISO/IEC 80079. Keywords: explosive atmospheres in underground mines, combustible dust
