scope:

IEC 60079-31:2013 is applicable to electrical equipmentprotected by enclosure and surface temperature limitation for usein explosive dust atmospheres. It specifies requirements fordesign, construction and testing of electrical equipment and ExComponents. This standard supplements and modifies the generalrequirements of IEC 60079-0. Where a requirement of this standardconflicts with a requirement of IEC 60079-0, the requirement ofthis standard takes precedence. This standard does not apply todusts of explosives, which do not require atmospheric oxygen forcombustion, or to pyrophoric substances. This standard does notapply to electrical equipment or Ex Components intended for use inunderground parts of mines as well as those parts of surfaceinstallations of such mines endangered by firedamp and/orcombustible dust. This standard does not take account of any riskdue to an emission of flammable or toxic gas from the dust.Consideration of additional protective measures is required wherethe application of electrical equipment is in atmospheres, whichcan contain combustible dust as well as explosive gas, whethersimultaneously or separately. Where the electrical equipment has tomeet other environmental conditions, for example, protectionagainst ingress of water and resistance to corrosion, additionalmeasures can be necessary. The measures used should not adverselyaffect the integrity of the enclosure. This second edition cancelsand replaces the first edition published in 2008. This editionconstitutes a technical revision. The major technical changesinclude: - The marked maximum surface temperature shall be measuredon the external surfaces of the enclosure and the surfaces of theinternal components for equipment with types of protection 'ta'; -Additional protection for arcing and sparking parts for 'ta'; -Test for internal enclosure for level 'ta' added. Keywords:explosive dust atmospheres