ISA 60079-0

This standard specifies the general requirements forconstruction, testing and marking of electrical apparatus and Excomponents intended for use in Class I, Zone 0, 1, or 2hazardous (classified) locations as defined by the NationalElectrical Code, ANSI/NFPA 70.

Unless modified by one of the parts of this standard,electrical apparatus complying with this standard is intended foruse in hazardous areas in which explosive gas atmospheres, causedby mixtures of air and gases, vapours or mists, exist under normalatmospheric conditions of

• temperature –20 °C to +60 °C;

• pressure 80 kPa (0.8 bar) to 110 kPa (1.1 bar); and

• air with normal oxygen content, typically 21 % v/v.

The application of electrical apparatus in atmosphericconditions outside this range may need special consideration.

NOTE 1 The determination of the maximum surface temperature isbased on an operational ambient temperature of –20 °C to +40 °C, ifnot otherwise specified by the manufacturer. See also 5.1.1.

NOTE 2 In designing apparatus for operation in explosive gasatmospheres under conditions other than the atmospheric conditionsgiven above, this standard may be used as a guide. However,additional testing related specifically to the intended conditionsof use is recommended. This is particularly important when thetypes of protection ‘flameproof enclosures “d”‘  and‘intrinsic safety “i”‘ are applied.

NOTE 3 Requirements given in this standard result from anignition hazard assessment made on electrical equipment. Theignition sources taken into account are those found associated withthis type of equipment, such as hot surfaces, mechanicallygenerated sparks, thermite reactions, electrical arcing and staticelectric discharge in normal industrial environments. For otherignition sources like adiabatic compression, shock waves,exothermic chemical reaction, self ignition of dust, naked flames,hot gases/liquids the apparatus are subjected to a hazard analysisthat identifies and lists all of the potential sources of ignitionby the electrical apparatus and the measures to be applied toprevent them becoming effective.

This standard is supplemented or modified by the followingstandards concerning specific types of protection:

– Flameproof enclosures “d”;

– Pressurized enclosures “p”;

–  Powder filling “q”;

– Oil immersion “o”;

– Increased safety “e”;

– Intrinsic safety “i”;

– Type of protection “n”;

– Encapsulation “m”.

This standard is supplemented or modified by the followingapparatus standards:

– ANSI/IEEE 515: Standard for Testing, Design,Installation, and Maintenance of Electrical Heat Tracing forIndustrial Applications.

NOTE Components such as power connections, splices, endterminations, as well as cable entries, fittings, and seals are tobe evaluated according to the type of protection employed.

This standard along with the additional standardsmentioned above are not applicable to the construction ofelectromedical apparatus, shot-firing exploders, test devices forexploders and for shot-firing circuits.

Edition:

05

Published:

08/15/2005

ANSI:

ANSI Approved

Number of Pages:

124

File Size:

1 file , 640 KB