Focus Article - The Hazards of Combustible Dusts and Powders
In the Chemical Process Industries, powdered materials are a common raw material, process intermediate, or final product. It is typical for powders to contain finely divided particles smaller than 500 microns. Small particles by their very nature have a high surface area per unit mass and, if combustible, can propagate a flame through premixed atmospheres. Some 70% of the dusts that are handled in industry can propagate flame. Such flame propagation is called a deflagration and is capable of producing hazardous over-pressures as well as thermal effects.