The National Fire Protection Association (NFPA) sets standards and codes to protect buildings against fire and explosion risks, and the Occupational Safety & Health Administration (OSHA) is applying these standards with increasing vigilance. When it comes to combustible dust, several standards must be considered. This white paper reviews the current status of the OSHA National Emphasis Program for combustible dust, the NFPA standards that address how to prevent or limit explosion hazards, how to identify these hazards, and the types of equipment used to eliminate or control explosion hazards. We will also examine the most common shortfalls to compliance and how to avoid them.
The last decade: a look back
In January 2003, an explosion at the West Pharmaceutical facility in Kingston, North Carolina killed six workers and injured 38 others, including two firefighters. The culprit: inadequate control of dust hazards at the plant. Only a month later, in February 2003, another explosion and fire damaged the CTA Acoustics manufacturing plant in Corbin, Kentucky, fatally injuring seven workers. Investigators found that resin dust, accumulated in a production area, was likely ignited by flames from a malfunctioning oven, triggering the explosion.The most famous combustible dust explosion in the past decade – and the one responsible for re-focusing the national spotlight on this issue – was the February 2008 accident at the Imperial Sugar Company’s Wentworth, Georgia refinery. A dust cloud explosion triggered a fatal blast and fire that killed 13 workers and injured 42 others, generating a storm of media attention and government scrutiny.
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| These dust collectors are equipped with passive and active controls. Passive controls are an explosion vent and ducting that control the pressure and flame direction, and a rotary valve that contains the flame in the hopper. The active control is a chemical isolation system mounted on the inlet duct. Triggered by a pressure/flame detector, it will extinguish a flame front passing through the inlet pipe before it goes back into the plant. |
These are by no means the only fatal explosions to occur in U.S. manufacturing plants, though they are the three deadliest to be investigated. More recently, in December 2010, two brothers lost their lives in a chemical explosion at the New Cumberland, West Virginia plant of AL Solutions. And during 2011, three deadly fires and explosions occurred at a Hoeganaes Corp. plant in Gallatin, Tennessee. Investigators found that accumulations of fine iron powder in the facility led to the explosions.
In the U.S. alone in the 25 years between 1980 and 2005, the Chemical Safety Board reported 281 explosions caused by ignited combustible dust. These explosions resulted in 199 fatalities and 718 injuries. Combustible dust explosions over the past decade in U.S. plants are blamed for well over 100 fatalities and hundreds more injuries. Sadly, experts believe these accidents could have been prevented if the companies involved had followed best practices for fire and explosion protection such as the methodologies described in this white paper.
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