Hazardous Area / Classified Location Determination

JurisdictionSource of HazardContinuous HazardIntermittent HazardAccidental HazardStandard
IEC / ECGasZone 0Zone 1Zone 2IEC 60079
USA – NEC 505GasZone 0Zone 1Zone 2NEC 505
CanadaGasZone 0Zone 1Zone 2CEC 18
IEC / ECDustZone 20Zone 21Zone 22IEC 61241
USA – NEC 506DustZone 20Zone 21Zone 22NEC 506
USA – NEC 500Gas, Dust,Division 1Division 1Division 2NEC 500
CanadaFibres & FlyingsDivision 1Division 1Division 2CEC 18

Gas Hazard Classifications

Representative GasIEC / ECUSA NEC 505 / Canada CEC 18USA NEC 500 / Canada CEC Annex J
AcetyleneGroup IICGroup IICClass I, Group A
HydrogenGroup IIB+H2Group IIB+H2Class I, Group B
EthyleneGroup IIBGroup IIBClass I, Group C
PropaneGroup IIAGroup IIAClass I, Group D
MethaneGroup 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

MaterialIEC / EC 60079IEC / EC 61241USA NEC 506USA NEC 500 / Canda CEC 18
Metal DustsGroup IIICGroup DClass II, Group E
Carbonaceous DustsGroup IIIBGroup DGroup DClass II, Group F
Non-Conductive DustsGroup IIIBGroup DGroup DClass II, Group G
Fibers & FlyingsGroup IIIAGroup DGroup DClass III

Protection Methods – USA Under NEC 500

MethodBasisStandardDivision 1Division 2
Intrinsic SafetyEnergy limitingFM 3610 / ISA12.02.01YesYes
Non-IncendiveEnergy limiting, mechanical sealFM 3611NoYes
Exlosion ProofContainmentFM 3615YesYes
Pressurization ‘X’ExclusionFM3620YesYes
Pressurization ‘Y’ExclusionFM3620YesYes
Pressurization ‘Z’ExclusionFM3620NoYes

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

MethodSymbolBasisStandardZone 0Zone 1Zone 2
Intrinsic SafetyiaLimit spark energy and surface temperatures60079-11YesYesYes
Intrinsic SafetyibLimit spark energy and surface temperatures60079-11NoYesYes
Intrinsic SafetyicLimit spark energy and surface temperatures60079-11NoNoYes
Energy LimitationnLLimit spark energy and surface temperatures60079-15NoNoYes
Increased SafetyeNo arcs, sparks, or hot surfaces60079-7NoYesYes
Non SparkingnANo arcs, sparks, or hot surfaces60079-15NoNoYes
FlameproofdContain the explosion, quench the flame60079-1NoYesYes
Enclosed BreaknCContain the explosion, quench the flame60079-15NoNoYes
Sand FillingqQuench the flame60079-5NoYesYes
PressurizationpxExclude the flammable gas60079-2NoYesYes
PressurizationpyExclude the flammable gas60079-2NoYesYes
PressurizationpzExclude the flammable gas60079-2NoNoYes
Simple PressurizationnZExclude the flammable gas60079-15NoNoYes
SealingnCExclude the flammable gas60079-15NoNoYes
Restricted BreathingnRExclude the flammable gas60079-15NoNoYes
EncapsulationmaExclude the flammable gas60079-18YesYesYes
EncapsulationmbExclude the flammable gas60079-18NoYesYes
Oil ImmersionoExclude the flammable gas60079-6NoYesYes

Ingress Protection Codes to IEC 60529

First Numeral:Second Numeral:
Protection against solid objectsProtection against liquids
0No special protection0No special protection
1Objects >50mm diameter, e.g. hand1Vertically dripping water
2Objects >12.5mm diameter, e.g. finger2Dripping water when tilted up to 15°
3Objects >2.5mm diameter, e.g. tool3Sprayed water up to 60° from vertical
4Objects >1.0mm diameter, e.g. wire4Splashed water from any direction
5Dust protected. Ingress insufficient to prevent satisfactory operation5Water projected by 6.3mm nozzle from any direction: 12.5 L/min, 100kPa, 3 min.
6Dust tight, no ingress permitted6Water projected by 12.5mm nozzle from any direction: 100 L/min, 100kPa, 3 min.
7Temporary submersion up to 1 meter
8Continuous submersion to a stated depth