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Tabulated Guide to Hazardous Area Info

Hazardous Area / Classified Location Determination

Jurisdiction Source of Hazard Continuous Hazard Intermittent Hazard Accidental Hazard Standard
IEC / EC Gas Zone 0 Zone 1 Zone 2 IEC 60079
USA – NEC 505 Gas Zone 0 Zone 1 Zone 2 NEC 505
Canada Gas Zone 0 Zone 1 Zone 2 CEC 18
IEC / EC Dust Zone 20 Zone 21 Zone 22 IEC 61241
USA – NEC 506 Dust Zone 20 Zone 21 Zone 22 NEC 506
USA – NEC 500 Gas, Dust, Division 1 Division 1 Division 2 NEC 500
Canada Fibres & Flyings Division 1 Division 1 Division 2 CEC 18

Gas Hazard Classifications

Representative Gas IEC / EC USA NEC 505 / Canada CEC 18 USA NEC 500 / Canada CEC Annex J
Acetylene Group IIC Group IIC Class I, Group A
Hydrogen Group IIB+H2 Group IIB+H2 Class I, Group B
Ethylene Group IIB Group IIB Class I, Group C
Propane Group IIA Group IIA Class I, Group D
Methane Group I* Mining* Mining*
*Not within the scope of NEC 500 & 505—under jurisdiction of MSHA. Not within the scope of CEC 18.

Dust Hazard Classifications

Material IEC / EC 60079 IEC / EC 61241 USA NEC 506 USA NEC 500 / Canda CEC 18
Metal Dusts Group IIIC Group D Class II, Group E
Carbonaceous Dusts Group IIIB Group D Group D Class II, Group F
Non-Conductive Dusts Group IIIB Group D Group D Class II, Group G
Fibers & Flyings Group IIIA Group D Group D Class III

Protection Methods – USA Under NEC 500

Method Basis Standard Division 1 Division 2
Intrinsic Safety Energy limiting FM 3610 / ISA12.02.01 Yes Yes
Non-Incendive Energy limiting, mechanical seal FM 3611 No Yes
Exlosion Proof Containment FM 3615 Yes Yes
Pressurization ‘X’ Exclusion FM3620 Yes Yes
Pressurization ‘Y’ Exclusion FM3620 Yes Yes
Pressurization ‘Z’ Exclusion FM3620 No Yes

Protection Methods, Gas Hazards – USA Under NEC 505 / IEC / EU

Method Symbol Basis Standard Zone 0 Zone 1 Zone 2
Intrinsic Safety ia Limit spark energy and surface temperatures 60079-11 Yes Yes Yes
Intrinsic Safety ib Limit spark energy and surface temperatures 60079-11 No Yes Yes
Intrinsic Safety ic Limit spark energy and surface temperatures 60079-11 No No Yes
Energy Limitation nL Limit spark energy and surface temperatures 60079-15 No No Yes
Increased Safety e No arcs, sparks, or hot surfaces 60079-7 No Yes Yes
Non Sparking nA No arcs, sparks, or hot surfaces 60079-15 No No Yes
Flameproof d Contain the explosion, quench the flame 60079-1 No Yes Yes
Enclosed Break nC Contain the explosion, quench the flame 60079-15 No No Yes
Sand Filling q Quench the flame 60079-5 No Yes Yes
Pressurization px Exclude the flammable gas 60079-2 No Yes Yes
Pressurization py Exclude the flammable gas 60079-2 No Yes Yes
Pressurization pz Exclude the flammable gas 60079-2 No No Yes
Simple Pressurization nZ Exclude the flammable gas 60079-15 No No Yes
Sealing nC Exclude the flammable gas 60079-15 No No Yes
Restricted Breathing nR Exclude the flammable gas 60079-15 No No Yes
Encapsulation ma Exclude the flammable gas 60079-18 Yes Yes Yes
Encapsulation mb Exclude the flammable gas 60079-18 No Yes Yes
Oil Immersion o Exclude the flammable gas 60079-6 No Yes Yes

Ingress Protection Codes to IEC 60529

First Numeral: Second Numeral:
Protection against solid objects Protection against liquids
0 No special protection 0 No special protection
1 Objects >50mm diameter, e.g. hand 1 Vertically dripping water
2 Objects >12.5mm diameter, e.g. finger 2 Dripping water when tilted up to 15°
3 Objects >2.5mm diameter, e.g. tool 3 Sprayed water up to 60° from vertical
4 Objects >1.0mm diameter, e.g. wire 4 Splashed water from any direction
5 Dust protected. Ingress insufficient to prevent satisfactory operation 5 Water projected by 6.3mm nozzle from any direction: 12.5 L/min, 100kPa, 3 min.
6 Dust tight, no ingress permitted 6 Water projected by 12.5mm nozzle from any direction: 100 L/min, 100kPa, 3 min.
7 Temporary submersion up to 1 meter
8 Continuous submersion to a stated depth