Sch 1 para 10 Dust deposits
(1) Equipment and protective systems which are intended to be used in areas exposed to dust must be so designed that deposit dust on their surfaces is not ignited. (2) In general, dust deposits must be limited where possible. Equipment and protective systems must be easily cleanable. (3) The surface temperatures of equipment parts must be kept well below the glow temperature of the deposit dust. (4) The thickness of deposit dust must be taken into consideration and, if appropriate, means must be taken to limit the temperature in order to prevent a heat build up.