A layer of dust that can be very thin can be responsible for an explosion. According to the National Fire Prevention Association, combustible dust is a finely divided combustible particulate solid that presents a flash fire hazard or a explosion hazard when suspended in air or the process- specific oxidizing medium over a range of concentration. A dust explosion will exist when five elements are present. Fuel, oxygen, confinement, dispersion and heat will make a dust explosion to occur. Combustible dust is very dangerous and many NADCA members who work in areas where combustion dust may exist should be cautious, because dust does not only burn but it explodes. Several materials that have the potential to form combustible dust are as shown:
Many fires and explosions have triggered by combustible dust and OSHA took action to initiate the Combustible Dust National Emphasis Program (NEP) to protect workers from hazards and monitor safety standards that need to be kept in the workplace. An article by Duct Tales, A Serious Safety Hazard states, “The potential for hazards in such a situation is high, especially if technicians and workers do not realize the danger posed by combustible dust.” In this article, citations issued by OSHA were listed and summarize. It is a great example to have because NADCA members have been found to perform duties and have worked around or on top of potentially dangerous combustible dust. For example, one citation issued by OSHA was Compressed air was periodically used to clean up the combustible dust accumulation in the presence of ignition sources. That citation was issued because compressed air should not be used for cleaning. Here are some examples of safe “housekeeping” guidelines by WMMA.com:
- Work area must be kept clean for dust accumulation
- Machinery should be equipped with engineered dust collection hoods
- Dust accumulation must be kept below minimum layer thickness
- Remove dust from up-facing surfaces i.e. beams, piping and ductwork, machine enclosures etc
- Watch out for hot surfaces and or potential ignition sources
Dust may not seem like it is something that can cause an explosion and it can be overlooked as well. Follow the safety procedures while working in any environment. If you ever have any doubts, ask your on-site safety supervisor. It is better to be safe than to receive a citation and worse a hazard that can affect all those in the workplace.