Classification for dusts-an update

What do we mean by combustible dust? By definition dust comprises small solid particles in the atmosphere that settle under their own weight or may remain suspended in air for a time. Generally fibres and flyings present in textile processing are considered as dusts. For a dust to be combustible it must demonstrate that it can burn or glow in air and could form explosive mixtures with air at atmospheric pressures and normal temperatures. The IEC has developed and published a series of test methods that can be used to establish the properties of dusts so that the aspects of their behaviour important to the selection of electrical apparatus can be identified.