Although most people have heard that dust can burn or explode, too few understand the message. Surely it doesn’t mean “ordinary” dust? After all, it doesn’t happen every day.
Unfortunately, the kind of dust that ignites or explodes is often very “ordinary”, and sadly it does happen somewhere almost every day. Be sure you understand the risks.
What Dust Is Combustible?
Even ordinary household dust can burn. Many of the worst accidents have been attributed to flour, paper dust, fine sugar, sawdust, linen fibers, metal filings, plastic packaging dust, perished rubber, and even sewage sludge. Substances you would struggle to ignite with a box of matches can ignite without warning when turned to dust.
Terrible explosions have been caused by chemicals considered completely non-combustible – until they exploded. Unpredictability is part of the problem, and that’s why dust should always be controlled.
Do You See a Dust Problem?
Unseen dust is another problem. Whether or not you notice it in the air, dust accumulates – over months, years or decades – above suspended ceilings, on joists and rafters, behind pipes and (in particular) inside equipment that is supposed to deal with it, like extractors and ducts. Sooner or later that dust will be disturbed and become airborne, encounter heat or cause a blockage.
Static dust is a fire hazard, but it only takes a small amount to lift to initiate an explosion. A small primary ignition creates an air disturbance, and the air disturbance lifts more dust. In this way entire industrial plants have been leveled by a sequence of bigger and bigger explosions – a chain reaction. It only takes a small local accumulation and a chance event and things can go very wrong very quickly (see https://industrialfireprevention.blogspot.com/2013/10/combustible-dust-explosions-common-to.html).
Consider alternative processes that pose a smaller dust risk. Abrasive cleaning, cutting, grinding, sieving, and buffing are all high risk. Addressing the problem by sweeping or with fans and air hoses only add to the danger, so use proper dust collection systems and vacuums. Modern air-con solutions from https://www.dustspares.co.uk/ductwork-parts/galvanised-ducting/galvanised-steel-spiral-duct.html based on spiral duct are highly cost-effective.
Also, maintain your equipment so it doesn’t get hot enough to initiate combustion, and design your environment so there are fewer places for dust to settle.
Finally, develop a detailed control program – recording dust inspections, equipment maintenance, and employee training.