Explosion hazards

Abstract

Many bulk solids, when dispersed in air to form a cloud or suspension and ignited, rapidly propagate a flame through the suspension, with a subsequent sudden increase of pressure as a result of the release of heat and gaseous products from the burning dust. This is commonly called a ‘dust explosion’, in contrast to a ‘fire’ which would be said to occur if the burning dust were in a pile or layer. In fact, dust will generally smoulder or burn with a flame: some, especially plastics, tend to melt or flame or give off noxious vapours which are readily detected, but others may glow and smoulder, remaining an undetected hazard which could persist for days. Although only a minority of dust fires actually result in an explosion, the potential danger is a very real one. Typical examples would be the explosions of airborne dust following the sudden disturbance of a smouldering layer during cleaning or the collapse of a burning pile of material.