Classification for dusts - an update

When do we mean by combustible dust? By definition dust comprises small sol id particles in the atmosphere that settle under their own weight or may re main suspended in air for a time. Generally fibres and flyings present in t extile 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 m ixtures with nir at atmospheric pressures and normal temperatures. The IEC has developed and published a series of test methods that can be used to es tablish the properties of dusts so that the aspects of their behaviour impo rtant to the selection of electrical apparatus call be identified.