ISA 60079-10-1

This standard is concerned with the classificationof areas where flammable gas or vapor or mist hazards (see Notes 1,2 and 3) may arise and may then be used as a basis to support theproper selection and installation of equipment for use in ahazardous area.

It is intended to be applied where there may be an ignitionhazard due to the presence of flammable gas or vapor, mixed withair under normal atmospheric conditions (see Note 4), but it doesnot apply to

a) mines susceptible to firedamp;

b) the processing and manufacture of explosives;

c) areas where a hazard may arise due to the presence ofcombustible dusts or fibres (refer to ANSI/ISA-60079-10-2);

d) catastrophic failures which are beyond the concept ofabnormality d ealt with in this standard (see Note 5);

e) rooms used for medical purposes;

f) domestic premises. This standard does not take into accountthe effects of consequential damage.

Definitions and explanations of terms are given together withthe main principl es and procedures relating to hazardous areaclassification.

For detailed recommendations regarding the extent of thehazardous areas in specific industries or applications, referencemay be made to national or industry codes relating to thoseapplications.

NOTE 1 Flammable mists may form or be present at the same timeas flammable vapors. Liquids not considered to be hazardous interms of this standard (due to the flash point), when releasedunder pressure may also generate flammable mists. In such cases,the strict application of area classification for gases and vaporsmay not be appropriate as the basis for selection of equipment.

Information on flammable mists is provided in Annex D.

NOTE 2 The use of IEC 60079-14 for selection of equipment andinstallations is not required for mist hazards. IEC 60079-14 hasnot been adopted for use in the US.

NOTE 3 For the purpose of this standard, an area is a three-dimensional region or space.

NOTE 4 Atmospheric conditions include variations above and belowreference levels of 101,3 kPa (1 013 mbar) and 20 °C (293 K),provided that the variations have a negligible effect on theexplosion properties of the flammable materials.

NOTE 5 Catastrophic failure in this context is applied, forexample, to the rupture of a pr ocess vessel or pipeline and eventsthat are not predictable.

NOTE 6 In any process facility, irrespective ofsize, there may be numerous sources of ignition apart from thoseassociated with equipment. Appropriate precautions will benecessary to ensure safety in this context. This standard may beused with judgement for other ignition sources.

Edition:

14

Published:

08/15/2014

ANSI:

ANSI Approved

Number of Pages:

80

File Size:

1 file , 1.5 MB