ISA 60079-10-2

This standard is concerned with the identification andclassification of areas where explosive dust atmospheres andcombustible dust layers are present, in order to permit the properassessment of ignition sources in such areas.

In this standard, explosive dust atmospheres and combustibledust layers are treated separately. In Clause 4, areaclassification for explosive dusts clouds is described, with dust layers acting as one of the possible sources of release. In Clause7, the hazard of dust layer ignition is described.

The examples in this standard are based on a system of effectivehousekeeping being implemented in the plant to prevent dust layersfrom accumulating. Where effective housekeeping is not present, thearea classification includes the possible formation of explosivedust clouds from dust layers.

The principles of this standard can also be followed whencombustible fibres or flyings may cause a hazard.

This standard is intended to be applied where there can be arisk due to the presence of explosive dust atmospheres orcombustible dust layers under normal atmospheric conditions.

It does not apply to

– underground mining areas,

– areas where a risk can arise due to the presence of hybridmixtures,

– dusts of explosives, pyrophoric or pyrotechnic substances,or other dusts that do not require atmospheric oxygen forcombustion,

– catastrophic failures which are beyond the concept ofabnormality dealt with in this standard (see Note 1),

– any risk arising from an emission of flammable or toxic gasfrom the dust.

This standard does not take into account the effects ofconsequential damage following a fire or an explosion.

NOTE 1 Catastrophic failure in this context is applied, forexample, to the rupture of a storage silo or a pneumaticconveyor.

NOTE 2 In any process plant, irrespective of size, there can benumerous sources of ignition apart fr om those associated withequipment. Appropriate precautions will be necessary to ensuresafety in this context, but these are outside the scope of thisstandard.

Edition:

13

Published:

09/13/2013

ANSI:

ANSI Approved

Number of Pages:

48

File Size:

1 file , 810 KB