This was originally posted by John Astad at dustexplosions.blogspot.com
Combustible dust should be a major source of concern in process industry, and especially in the new bio-fuels industries that do not have historical experience with fire and explosion prevention. When you are drying, grinding, pulverizing, conveying, and compressing wood flour (or other organic material), you are creating the perfect storm for a combustible dust fire or deflagration. Every time you move or manipulate product in the process you are creating combustible dust. Then all you need is an ignition source for combustion. Ignition sources are plentiful in the drying, grinding and pellitizing stages. And it is very easy to convey a spark or ember into a combustible dust cloud within the pellet cooler, dust collector, and storage bin. These small fires they are currently experiencing in the bio-fuels industries are warning signs, simply precursors to potential larger events.
OSHA requires these plants to provide a safe working environment. Dust control and ignition control are vital for fire prevention. To reduce this risk you must control the probability and severity of possible events. Spark detection and extinguishing systems as required by the NFPA are the most cost effective way to reduce fires in these processes. Along with deluge, sprinkler systems, and explosion venting, these are minimum requirements for preventing most fires and deflagrations. Additional layers of protection may also be added by means of explosion suppression and isolation. Along with these prevention and protection systems, proper design and controls, housekeeping, maintenance, lockout-tagout, and hotwork procedures must be in place.
OSHA General Duty Clause, and National Emphasis Program.
NFPA: 654, 664, 61, 68, 69