Hot work has been the cause of numerous fires and grain dust explosions. Hot work includes, but is not limited to, brazing, cutting, grinding, soldering, and welding.
The heat generated from these activities can ignite combustible dust on surfaces and in suspension easily, resulting in smoldering fires, flash fires, and combustible dust explosions.
Grain dust ignition temperatures vary by commodity, but generally fall within the range of 700 degrees and 900 degrees F. The heat generated by hot work can ignite grain dust easily.
Consider the heat produced by the following hot work activities:
Arc welding - 10,000 degrees F.
Oxy-acetylene cutting - 5,000 degrees F.
Grinding (metal) - 1,200 degrees F.
Bucket elevator leg explosion caused by hot work.
The required precautions listed on hot work permits reflect the requirements of OSHA's Welding, Cutting and Brazing Standard 1910.252 (a). This section also is referenced in the Grain Handling Standard 1910.272.
Ensure that the following precautions (if applicable) are taken prior to hot work activities:
Ensure that sprinklers and host streams are in service and operable.
Ensure that hot work equipment is in good condition (welding leads, torches, etc.).
Ensure that fire extinguishers, hose streams, etc. are operable.
Ensure that the removal of dust, lint, debris, flammable liquids, and oily deposits.
Ensure that explosive atmospheres in the area are eliminated.
Wet down or cover combustible floors with damp sand or fire blankets.
Remove flammable or combustible materials, or protect them with fire blankets, guards, or metal shields.
Cover all floor and wall openings (hatches, lids, etc.).
Install fire blankets and curtains under and around work.
Protect, close, or shut down ducts, spouts, conveyors, bucket elevators, etc. that may carry sparks to distant combustible materials or suspended dust.
Clean all enclosed equipment of combustible materials (i.e., grain dust).
Hot work presents unique hazards to the grain industry. Do not play with fire!
