Is the OSHA grain facility standard working? Luckily workers escaped injury at the Destrehan, Louisiana grain elevator explosion early Thursday morning. Since the beginning of 2008, through media accounts, an alarming tally of 13 grain facility combustible dust related explosions have occurred throughout the United States. Dust explosions and fires have plagued a wide swath of industry whether it be in manufacturing or the grain sectors.
Grain and Manufacturing Sectors
Fast rewind, over two decades ago after a rash of 1977 grain silo explosions that caused dozens of fatalities and resulted in the OSHA Grain Facility Standard , which outlined measures in protecting the workforce from combustible grain dust explosions and fires. But still, fires and explosions continue to occur resulting in numerous fatalities and injuries.
Immediately after the February 7, 2008 catastrophic Imperial Sugar Refinery dust explosion in Port Wentworth, Georgia , congressional leaders drafted a combustible dust bill that outlined provisions in protecting the manufacturing sector workforce from the hazards of combustible dust explosions and fires. The bill currently sits very bored, and stretched out, yawning waiting for action in Senate chambers after passing in the House by a mostly Democrat roll call.
Kick Like a Mule
Why does there have to be two separate OSHA regulations concerning combustible dust explosions and fires ? One for the grain sector and one proposed for the manufacturing sector? An explosion is an explosion just like a mule is a mule. Just different colors and a different sort of swag of the tail but the same powerful kick as any muleskinner can tell you.
The effects of any explosion whether it be a physical or chemical explosion entail damaging effects of overpressure, thermal radiation, and ensuing projectiles. Dust explosions are quite similar to vapor cloud explosions (VCE) that occur when flammable gases or vapors are suspended in air combined with the essential flammable limit (LFL-UFL) and joining their buddy, an ignition source.
Amazingly, the maximum pressures (Pmax) that develop in milliseconds, with the energy release of a dust or vapor cloud explosion in general are quite similar, around 7 Bar (1 bar = 14.5 psi) or 100 psi. Around 3 psi is enough to knock many commercial buildings down such as with aluminum siding
In 2008, through media accounts, the Combustible Dust Policy Institute has noted over 155 combustible dust related explosions and fires in the combined grain and manufacturing sectors. Dust explosions that result in adverse economic impact, fatalities and injuries do not differentiate between a grain elevator or dust collector inside a manufacturing process facility.
Crowl, D. A. (2003). Gases and Vapors. In Understanding Explosions (p. 17). Wiley-AIChE.
Crowl, D. (2003). Appendix E Combustion Data For Dust Clouds. In Understanding Explosions (p.
191). New York, New York: Wiley-AIChE.