Conditions for Dust Explosions
During powder coating application , the conditions for dust explosions must be paid attention highly to avoid any problem occur .
A number of conditions must exist simultaneously for a dust explosion to occur.
The dust must be combustible (as far as dust clouds are concerned, the terms “combustible”, “flammable” and “explosible” all have the same meaning and could be used interchangeably).
The dust must be dispersed (forming a cloud in air).
The dust concentration must be within the explosible range (above the minimum explosible concentration).
The dust must have a particle size distribution capable of propagating flame.
The atmosphere in which the dust cloud is present must be capable of supporting combustion.
The available ignition source must have sufficient energy to initiate combustion.
The ignition sources that have been found to be the cause of the majority of explosions in dust handling/processing plants include welding and cutting, heating and sparks generated by mechanical equipment failure, sparks generated by mechanical impacts, hot surfaces, open flames and burning materials, self heating, electrostatic discharges, and electrical sparks.
The sensitivity of a dust cloud to ignition by different ignition sources should be determined through appropriate laboratory tests.