S05 HSSRME 3 2020 Burner safety Emerson_Layout 1 03/08/2020 12:16 Page 18
industrial safety
Image Credit: Adobe Stock
The hidden dangers of
combustible dust Combustible dusts are present in many workplaces and industrial facilities, but the hazards are often underestimated. Louise Waters reports. “There are many kinds of products and materials from which combustible dust explosions could occur.”
Combustible dust explosions have occurred in many different types of workplaces and industries.
18
M
ANY WORKPLACES HANDLE combustible particulate material which poses fire and explosion hazards. Combustible dusts are fine particles that can catch fire and present an explosion hazard when disturbed and released into the air in a confined area where there is an ignition source, such as a welding spark or static electricity. This can cause catastrophic loss of life, injuries, and destruction of property. The five elements of a dust explosion are typically referred to as the ‘Dust Explosion Pentagon’. They are: ■ A fuel, which is the combustible dust.
An oxidant, which is typically the oxygen in the air. ■ An ignition source capable of igniting materials when they are dispersed as a cloud. ■ Dispersion, which is when the accumulated dust is spread out and creates a dust cloud. ■ Confinement, which leads to pressure rise and potentially vessel rupture, facility obstruction, or structural collapse. Sometimes a primary explosion will shake loose other accumulated dust, or damage a containment system. When this becomes airborne, it can ignite, causing a secondary explosion, which is often more powerful ■
than the first one. There are many kinds of products and materials from which combustible dust explosions could occur if they are processed in powdered form. According to the USA’ s OHSA, types of dusts include, but are not limited to, metal dust, such as aluminium and magnesium; wood dust; plastic or rubber dust; biosolids; coal dust; organic dust, such as flour, sugar, paper, soap, and dusts from certain textiles. Dusts are created by processes such as abrasive blasting, cutting, grinding, crushing, mixing, sifting, polishing or screening dry materials. The build-up of dried residues from the processing of
ISSUE 3 2020 | www.hssreview.me
