IEC 60974-8-2021 pdf Arc welding equipment – Part 8: Gas consoles for welding and plasma cutting systems

7.3 Limits of temperature rise As specified in 7.3 of IEC 60974-1:2017. Additionally, the temperature of surfaces exposed to combustible gases shall be at least 20 % cooler than the ignition temperature of any combustible gas intended to be used in the GAS CONSOLE . Conformity shall be checked by operating the GAS CONSOLE at the maximum specified ambient temperature and system duty cycle, while monitoring the inside of the gas console with an IR camera for temperatures exceeding the 20 % margin of the ignition temperature of any combustible gas intended to be used in the GAS CONSOLE . a) with the combinations of gas(es) and flow rates which creates the worst-case condition, as specified by the manufacturer; b) with the cooling liquid as specified by the manufacturer. 8 Connections for plasma cutting torches As specified in 11.4.6 of IEC 60974-1:2017, where the torch connects to the GAS CONSOLE . 9 Mechanical provisions General 9.1 As specified in Clause 14 of IEC 60974-1:2017, with the following additions. 9.2 Protection against fire or explosion The GAS CONSOLE shall be designed to prevent fire or explosion under normal operating conditions and under a SINGLE – FAULT CONDITION (for example, defective valve, hose, etc.). Where a GAS CONSOLE uses a combustible gas, any circuit, subassembly, or component shall not be capable of creating temperatures or a spark with sufficient energy to cause an ignition. A GAS CONSOLE using combustible gas in a mixture shall not allow the concentration of mixture to be between the LFL and UFL. Conformity shall be checked by: a) design evaluation and calculations of the circuits, subassembly, or component verification; or b) applying a fault (for example, open circuit, short circuit, and/or restriction of movement) to the circuits, subassembly, or component until an event occurs (for example, a spark which does not cause ignition, fuse opens, unit shuts down, etc.) or a steady-state temperature is achieved.