UL 60079-0

Explosive atmospheres - Part 0: Equipment - General requirements

UL 60079-0

1 Scope

This part of IEC 60079 specifies the general requirements for construction, testing and marking of electrical equipment and Ex components intended for use in explosive atmospheres. 1DV.1 Modification of Clause 1 first paragraph to replace with the following:

1DV.1.1 This standard specifies the general requirements for construction, testing and marking of electrical equipment and Ex components to use in explosive atmospheres. Explosive atmospheres are identified by the National Electrical Code, NFPA 70 as hazardous (classified) locations and include the following specified locations. Class I, Zone 0; Class I, Zone 1; Class I, Zone 2; Zone 20; Zone 21; and Zone 22.

Unless modified by one of the standards supplementing this standard, electrical equipment complying with this standard is intended for use in hazardous areas in which explosive atmospheres exist under normal atmospheric 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 equipment in atmospheric conditions outside this range requires special consideration and may require additional assessment and testing.NOTE 1 Although the normal atmospheric conditions above give a temperature range for the atmosphere of -20 C to +60 C, the normal ambient temperature range for the equipment is -20C to +40 C, unless otherwise specified and marked. See 5.1.1.NOTE 2 In designing equipment for operation in explosive atmospheres under conditions other than the atmospheric conditions given above, this standard may be used for guidance. However, additional testing related specifically to the intended conditions of use is recommended. This is particularly important when the types of protection 'flameproof enclosure "d" ( IEC 60079-1) and 'intrinsic safety "i" ( IEC 60079-11 or IEC 61241-11) are applied.

1DV.2 Modification of Clause 1 Note 2 as follows:

1DV.2.1 Delete "( IEC 60079-1) " and "( IEC 60079-11 or IEC 61241-11)". NOTE 3 Requirements given in this standard result from an ignition hazard assessment made on electrical equipment. The ignition sources taken into account are those found associated with this type of equipment, such as hot surfaces, mechanically generated sparks, thermite reactions, electrical arcing and static electric discharge in normal industrial environments.NOTE 4 It is acknowledged that, with developments in technology, it may be possible to achieve the objectives of the IEC 60079 series of standards in respect of explosion prevention by methods that are not yet fully defined. Where a manufacturer wishes to take advantage of such developments, this International Standard, as well as other standards in the IEC 60079 series, may be applied in part. It is intended that the manufacturer prepare documentation that clearly defines how the IEC 60079 series of standards has been applied, together with a full explanation of the additional techniques employed. The designation "Ex s" has been reserved to indicate a type of protection that is not defined by the IEC 60079 series of standards, but may be referenced in national requirements.

1DV.3 Delete Clause 1 Note 4.

1DV.3.1 This Note does not apply.NOTE 5 Where an explosive gas atmosphere and a combustible dust atmosphere are, or may be, present at the same time, the simultaneous presence of both should be considered and may require additional protective measures.

This standard does not specify requirements for safety, other than those directly related to the explosion risk. Ignition sources like adiabatic compression, shock waves, exothermic chemical reaction, self ignition of dust, naked flames and hot gases/liquids, are not addressed by this standard.NOTE 6 Such equipment should be subjected to a hazard analysis that identifies and lists all of the potential sources of ignition by the electrical equipment and the measures to be applied to prevent them becoming effective.

This standard is supplemented or modified by the following standards concerning specific types of protection:- IEC 60079-1: Gas - Flameproof enclosures "d";- IEC 60079-2: Gas - Pressurized enclosures "p";- IEC 60079-5: Gas - Powder filling "q";- IEC 60079-6: Gas - Oil immersion "o";- IEC 60079-7: Gas - Increased safety "e";- IEC 60079-11: Gas - Intrinsic safety "i";- IEC 60079-15: Gas - Type of protection "n";- IEC 60079-18: Gas and Dust - Encapsulation "m";- IEC 61241-1: Dust - Protection by enclosures "tD";- IEC 61241-2 (IEC 61241-4): Dust - Pressurization "pD";- IEC 61241-11: Dust - Intrinsic safety "iD".

1DV.4 Modification of Clause 1 fifth paragraph to replace with the following dashed items:

1DV.4.1 - ISA 60079-2 (12.04.01): Gas - Pressurized enclosures "p";- ISA 61241-1 (12.10.03): Dust - Protection by enclosures "tD";- ISA 61241-2 (12.10.06): Dust - Pressurization "pD";- ISA 61241-11 (12.10.04): Dust - Intrinsic safety "iD".- ISA 61241-18 (12.10.07): Dust - Encapsulation "mD".- UL 60079-1: Gas - Flameproof enclosures "d";- UL 60079-5: Gas - Powder filling "q";- UL 60079-6: Gas - Oil immersion "o";- UL 60079-7: Gas - Increased safety "e";- UL 60079-11: Gas - Intrinsic safety "i";- UL 60079-15: Gas - Type of protection "n";- UL 60079-18: Gas and Dust - Encapsulation "m".

NOTE 7 The former requirements of IEC 61241-18, Encapsulation "mD", have been incorporated in IEC 60079-18. 1DV.5 Delete Clause 1 Note 7.

1DV.5.1 This Note does not apply.

This standard is supplemented or modified by the following equipment standards: IEC 60079-25: Electrical apparatus for explosive gas atmospheres - Part 25: Intrinsically safe systems IEC 60079-26: Explosive atmospheres - Part 26: Equipment with equipment protection level (EPL) Ga IEC 60079-28: Explosive atmospheres - Part 28: Protection of equipment and transmission systems using optical radiation IEC 62013-1: Caplights for use in mines susceptible to firedamp - Part 1: General requirements - Construction and testing in relation to the risk of explosion IEC 60079-30-1: Explosive atmospheres - Part 30-1: Electrical resistance trace heating - General and testing requirements.

1DV.6 Modification of Clause 1 sixth paragraph to replace with the following and addition of Note.

1DV.6.1 ANSI/ISA 60079-26 (12.00.03): Electrical equipment for use in Class I, Zone 0 hazardous (classified) locations ANSI/IEEE 515: Standard for Testing, Design, Installation, and Maintenance of Electrical Heat Tracing for Industrial ApplicationsNOTE Components such as power connections, splices, end terminations, as well as cable entries, fittings, and seals, are to be evaluated according to the type of protection employed.

This standard with the additional standards mentioned above, are not applicable to the construction of electromedical apparatus, shot-firing exploders, test devices for exploders, and shot-firing circuits.

1DV.7 Addition of 7DV:

1DV.7.1 The U.S. version of IEC 60079-0 does not include requirements for Group I electrical apparatus. Requirements for Group I electrical apparatus included in this document are to be considered omitted in all instances where they appear.

1DV.8 Addition of 8DV:

1DV.8.1 Where references are made to other IEC 60079 standards, the referenced requirements found in these standards shall apply as modified by any applicable U.S. National Differences.