This part of IEC 60079 is concerned with the identification and classification of areas whereexplosive dust atmospheres and combustible dust layers are present, in order to permit theproper assessment of ignition sources in such areas.In this standard, explosive dust atmospheres and combustible dust layers are treatedseparately. In Clause 4, area classification for explosive dusts clouds is described, with dustlayers acting as one of the possible sources of release. In Clause 7 other generalconsiderations for dust layers are described.The examples in this standard are based on a system of effective housekeeping beingimplemented in the plant to prevent dust layers from accumulating. Where effectivehousekeeping is not present, the area classification includes the possible formation ofexplosive dust clouds from dust layers.The principles of this standard can also be followed when combustible fibres or flyings mightcause a hazard.This standard is intended to be applied where there can be a risk due to the presence ofexplosive dust atmospheres or combustible dust layers under normal atmospheric conditions(see Note 1).