What is a Combustible Dust?
Combustible dust can be found in most solid organic materials (such as sugar, flour, grain, wood, etc.), many metals, and some nonmetallic inorganic materials. Below are some of the materials that are known to pose a combustible dust hazard in one form or another. Some items on this list are present more often than others; still, all of them should be properly handled to prevent any combustible dust explosion.
What is the technical definition for Combustible Dust?
Combustible dust is defined as finely divided solid material (or particles) which, when suspended in air and exposed to an ignition source, can propagate a rapid combustion reaction. Typically, combustible dust is limited to particles with a nominal diameter of less than 500-microns. Materials may be sampled
and tested for explosibility using a number of laboratory test methods which generally involve dispersing the sample into a cloud using compressed air and exposing the dust-air mixture to a high-intensity ignition source to see if
observable flame or pressure develops.
What is a Combustible Dust Hazard?
Combustible dust hazard refers to the risk of ignition and explosion due to particles suspended in air, usually as a result of mechanical processing or
handling of materials. Some examples of materials that can be a combustible dust hazard include flour, sugar, welding dust, pulverized coal, metal powders
and grain dusts like corn and soybean dusts. Combustible dust is any finely divided solid material in powder, granular, or particulate form which, when
dispersed in air in sufficient quantities as determined by testing according to NFPA 654 and standard industry practices, is capable of igniting and continuing
to burn. Examples include: Wheat flour – Metal Powders