basis string | category string | derived_fields list | id string | iec_designation string | north_american_designation string | source string | source_quote string | url string | verified_fields list | iec_standard string | disagreements list | also_reported list | max_surface_temperature_c string |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Risk gradation | system attribute | [
"category"
] | 3-levels-zone-0-1-2-system-attribute-2-levels-div-1-div-2 | 3 levels (Zone 0, 1, 2) | 2 levels (Div 1, Div 2) | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | Risk gradation | 2 levels (Div 1, Div 2) | 3 levels (Zone 0, 1, 2) | 3 levels (Zone 0, 1, 2) | https://referencesource.org/ex-classification-system-crosswalk/3-levels-zone-0-1-2-system-attribute-2-levels-div-1-div-2/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Ignitable fibers | area classification | [
"category"
] | area-classification-class-iii | null | Class III | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | Class III | Ignitable fibers | https://referencesource.org/ex-classification-system-crosswalk/area-classification-class-iii/ | [
"basis",
"north_american_designation"
] | null | null | null | null |
Geographic use: USA, Canada vs EU, UK, most of the world | system attribute | [
"category"
] | atex-iecex-zone-system-attribute-nec-500-class-division | ATEX / IECEx (Zone) | NEC 500 (Class/Division) | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | Geographic use | USA, Canada | USA, Canada | EU, UK, most of the world | https://referencesource.org/ex-classification-system-crosswalk/atex-iecex-zone-system-attribute-nec-500-class-division/ | [
"basis"
] | null | null | null | null |
Grain, flour, plastic dusts | dust group | [
"category"
] | dust-group-class-ii-group-g | null | Class II, Group G | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | Class II, Group G | https://referencesource.org/ex-classification-system-crosswalk/dust-group-class-ii-group-g/ | [
"north_american_designation"
] | null | null | null | null |
Legal framework | system attribute | [
"category"
] | eu-directive-2014-34-eu-iecex-scheme-system-attribute-nfpa-70-adopted-by-ahjs | EU Directive 2014/34/EU / IECEx scheme | NFPA 70 (adopted by AHJs) | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | Legal framework | NFPA 70 (adopted by AHJs) | NFPA 70 (adopted by AHJs) | EU Directive 2014/34/EU / IECEx scheme | https://referencesource.org/ex-classification-system-crosswalk/eu-directive-2014-34-eu-iecex-scheme-system-attribute-nfpa-70-adopted-by-ahjs/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Contain the explosion inside the enclosure | protection concept | [
"category"
] | ex-d-flameproof-protection-concept-explosion-proof-xp | Ex d (Flameproof) | Explosion-proof (XP) | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | Explosion-proof (XP) | Ex d (Flameproof) | IEC 60079-1 | Contain the explosion inside the enclosure | https://referencesource.org/ex-classification-system-crosswalk/ex-d-flameproof-protection-concept-explosion-proof-xp/ | [
"basis",
"iec_designation",
"iec_standard",
"north_american_designation"
] | IEC 60079-1 | null | null | null |
Flameproof enclosure | protection concept | [
"category"
] | ex-d-protection-concept-flameproof-enclosure | Ex d | Flameproof enclosure | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | Ex d | Flameproof enclosure | https://referencesource.org/ex-classification-system-crosswalk/ex-d-protection-concept-flameproof-enclosure/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Increased safety | protection concept | [
"category"
] | ex-e-protection-concept-increased-safety | Ex e | Increased safety | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | Ex e | Increased safety | https://referencesource.org/ex-classification-system-crosswalk/ex-e-protection-concept-increased-safety/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Limit energy below ignition threshold | protection concept | [
"category"
] | ex-i-ex-ia-ex-ib-protection-concept-intrinsically-safe-is | Ex i (Ex ia, Ex ib) | Intrinsically Safe (IS) | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | Intrinsically Safe (IS) | Ex i (Ex ia, Ex ib) | IEC 60079-11 | Limit energy below ignition threshold | https://referencesource.org/ex-classification-system-crosswalk/ex-i-ex-ia-ex-ib-protection-concept-intrinsically-safe-is/ | [
"basis",
"iec_designation",
"iec_standard",
"north_american_designation"
] | IEC 60079-11 | null | null | null |
Intrinsic safety | protection concept | [
"category"
] | ex-i-protection-concept-intrinsically-safe | Ex i | Intrinsically Safe | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | Ex i | Intrinsic safety | https://referencesource.org/ex-classification-system-crosswalk/ex-i-protection-concept-intrinsically-safe/ | [
"basis",
"iec_designation"
] | null | null | null | null |
Encapsulation | protection concept | [
"category"
] | ex-m-protection-concept-encapsulation | Ex m | Encapsulation | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | Ex m | Encapsulation | https://referencesource.org/ex-classification-system-crosswalk/ex-m-protection-concept-encapsulation/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Normal operation cannot cause ignition | protection concept | [
"category"
] | ex-na-ex-ec-protection-concept-non-incendive | Ex nA / Ex ec | Non-incendive | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | Non-incendive | Ex nA / Ex ec | IEC 60079-15 / -7 | Normal operation cannot cause ignition | https://referencesource.org/ex-classification-system-crosswalk/ex-na-ex-ec-protection-concept-non-incendive/ | [
"basis",
"iec_designation",
"iec_standard",
"north_american_designation"
] | IEC 60079-15 / -7 | null | null | null |
Seal ignition source from atmosphere | protection concept | [
"category"
] | ex-nc-ex-m-protection-concept-hermetically-sealed | Ex nC / Ex m | Hermetically sealed | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | Hermetically sealed | Ex nC / Ex m | IEC 60079-15 / -18 | Seal ignition source from atmosphere | https://referencesource.org/ex-classification-system-crosswalk/ex-nc-ex-m-protection-concept-hermetically-sealed/ | [
"basis",
"iec_designation",
"iec_standard",
"north_american_designation"
] | IEC 60079-15 / -18 | null | null | null |
Maintain positive pressure with inert gas | protection concept | [
"category"
] | ex-p-ex-px-ex-py-ex-pz-protection-concept-purged-pressurized | Ex p (Ex px, Ex py, Ex pz) | Purged/Pressurized | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | Purged/Pressurized | Ex p (Ex px, Ex py, Ex pz) | IEC 60079-2 | Maintain positive pressure with inert gas | https://referencesource.org/ex-classification-system-crosswalk/ex-p-ex-px-ex-py-ex-pz-protection-concept-purged-pressurized/ | [
"basis",
"iec_designation",
"iec_standard",
"north_american_designation"
] | IEC 60079-2 | null | null | null |
Pressurization | protection concept | [
"category"
] | ex-p-protection-concept-pressurization | Ex p | Pressurization | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | Ex p | Pressurization | https://referencesource.org/ex-classification-system-crosswalk/ex-p-protection-concept-pressurization/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Prevent dust ingress and limit surface temperature | protection concept | [
"category"
] | ex-t-dust-protection-by-enclosure-protection-concept-dust-ignition-proof | Ex t (Dust protection by enclosure) | Dust-ignition-proof | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | Dust-ignition-proof | Ex t (Dust protection by enclosure) | IEC 60079-31 | Prevent dust ingress and limit surface temperature | https://referencesource.org/ex-classification-system-crosswalk/ex-t-dust-protection-by-enclosure-protection-concept-dust-ignition-proof/ | [
"basis",
"iec_designation",
"iec_standard",
"north_american_designation"
] | IEC 60079-31 | null | null | null |
Metal dust | gas group | [
"category"
] | gas-group-group-e | null | Group E | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | E | Metal dust | https://referencesource.org/ex-classification-system-crosswalk/gas-group-group-e/ | [
"basis"
] | null | null | null | null |
Carbon dust | gas group | [
"category"
] | gas-group-group-f | null | Group F | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | F | Carbon dust | https://referencesource.org/ex-classification-system-crosswalk/gas-group-group-f/ | [
"basis"
] | null | null | null | null |
Grain / flour dust | gas group | [
"category"
] | gas-group-group-g | null | Group G | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | G | Grain / flour dust | https://referencesource.org/ex-classification-system-crosswalk/gas-group-group-g/ | [
"basis"
] | null | null | null | null |
Gas classification | system attribute | [
"category"
] | groups-iic-iib-iia-system-attribute-groups-a-b-c-d | Groups IIC, IIB, IIA | Groups A, B, C, D | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | Gas classification | Groups A, B, C, D | Groups IIC, IIB, IIA | Groups IIC, IIB, IIA | https://referencesource.org/ex-classification-system-crosswalk/groups-iic-iib-iia-system-attribute-groups-a-b-c-d/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Protection concept | system attribute | [
"category"
] | iec-aligned-types-ex-d-ex-i-ex-e-etc-system-attribute-explosion-proof-xp-intrinsically-safe-is | IEC-aligned types (Ex d, Ex i, Ex e, etc.) | Explosion-proof (XP), intrinsically safe (IS) | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | Protection concept | Explosion-proof (XP), intrinsically safe (IS) | IEC-aligned types (Ex d, Ex i, etc.) | IEC-aligned types (Ex d, Ex i, Ex e, etc.) | https://referencesource.org/ex-classification-system-crosswalk/iec-aligned-types-ex-d-ex-i-ex-e-etc-system-attribute-explosion-proof-xp-intrinsically-safe-is/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Propane | gas group | [
"category"
] | iia-gas-group-class-i-group-d | IIA | Class I, Group D | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | IIA | Propane | Class I, Group D | | https://referencesource.org/ex-classification-system-crosswalk/iia-gas-group-class-i-group-d/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
MESG >0.90 mm | gas group | [
"category"
] | iia-gas-group-group-d | IIA | Group D | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | D | IIA | Methane, propane, gasoline | >0.90 mm | https://referencesource.org/ex-classification-system-crosswalk/iia-gas-group-group-d/ | [
"iec_designation"
] | null | [
{
"field": "basis",
"versions": [
{
"as_of": "2026-08-06T00:00:00",
"source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html",
"source_quote": "D | IIA | Methane, propane, gasoline | >0.90 mm",
"value": "MESG >0.90 mm"
},
{
"as_of": "2026-08... | null | null |
Ethylene | gas group | [
"category"
] | iib-gas-group-class-i-group-c | IIB | Class I, Group C | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | IIB | Ethylene | Class I, Group C | Ethylene | https://referencesource.org/ex-classification-system-crosswalk/iib-gas-group-class-i-group-c/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
MESG 0.50–0.90 mm | gas group | [
"category"
] | iib-gas-group-group-c | IIB | Group C | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | C | IIB | Ethylene, ethyl ether | 0.50–0.90 mm | https://referencesource.org/ex-classification-system-crosswalk/iib-gas-group-group-c/ | [
"iec_designation"
] | null | [
{
"field": "basis",
"versions": [
{
"as_of": "2026-08-06T00:00:00",
"source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html",
"source_quote": "C | IIB | Ethylene, ethyl ether | 0.50–0.90 mm",
"value": "MESG 0.50–0.90 mm"
},
{
"as_of": "2026... | null | null |
Hydrogen | gas group | [
"category"
] | iib-h2-gas-group-class-i-group-b | IIB + H2 | Class I, Group B | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | IIB + H 2 | Hydrogen | Class I, Group B | Hydrogen | https://referencesource.org/ex-classification-system-crosswalk/iib-h2-gas-group-class-i-group-b/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Acetylene | gas group | [
"category"
] | iic-gas-group-class-i-group-a | IIC | Class I, Group A | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | IIC | Acetylene | Class I, Group A | Acetylene | https://referencesource.org/ex-classification-system-crosswalk/iic-gas-group-class-i-group-a/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
MESG <0.50 mm | gas group | [
"category"
] | iic-gas-group-group-a | IIC | Group A | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | A | IIC | Acetylene | <0.50 mm | https://referencesource.org/ex-classification-system-crosswalk/iic-gas-group-group-a/ | [
"iec_designation"
] | null | [
{
"field": "basis",
"versions": [
{
"as_of": "2026-08-06T00:00:00",
"source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html",
"source_quote": "A | IIC | Acetylene | <0.50 mm",
"value": "MESG <0.50 mm"
},
{
"as_of": "2026-08-06T00:00:00",
... | null | null |
Hydrogen | gas group | [
"category"
] | iic-gas-group-group-b | IIC | Group B | https://ldpi-inc.com/resources/classification-codes/class-1-locations/ | Hydrogen | B | 520 | 968 | 6,000 PSI | IIC | https://referencesource.org/ex-classification-system-crosswalk/iic-gas-group-group-b/ | [
"basis",
"iec_designation"
] | null | null | null | null |
MESG <0.50 mm | gas group | [
"category"
] | iic-partially-iib-h-gas-group-group-b | IIC (partially IIB+H₂) | Group B | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | B | IIC (partially IIB+H₂) | Hydrogen, butadiene | <0.50 mm | https://referencesource.org/ex-classification-system-crosswalk/iic-partially-iib-h-gas-group-group-b/ | [
"iec_designation"
] | null | null | null | null |
Fibers and flyings | dust group | [
"category"
] | iiia-dust-group-class-iii | IIIA | Class III | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | Gas / dust group | Typical Substances | IIC | Acetylene | Class I, Group A | Acetylene | IIB + H 2 | Hydrogen | Class I, Group B | Hydrogen | IIB | Ethylene | Class I, Group C | Ethylene | IIA | Propane | Class I, Group D | Propane | IIIC | Conductive dust | Class II, Group E | Combustible metal dust | IIIB | Non-condu... | https://referencesource.org/ex-classification-system-crosswalk/iiia-dust-group-class-iii/ | [
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Carbon dusts | dust group | [
"category"
] | iiib-dust-group-class-ii-group-f | IIIB | Class II, Group F | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | Gas / dust group | Typical Substances | IIC | Acetylene | Class I, Group A | Acetylene | IIB + H 2 | Hydrogen | Class I, Group B | Hydrogen | IIB | Ethylene | Class I, Group C | Ethylene | IIA | Propane | Class I, Group D | Propane | IIIC | Conductive dust | Class II, Group E | Combustible metal dust | IIIB | Non-condu... | https://referencesource.org/ex-classification-system-crosswalk/iiib-dust-group-class-ii-group-f/ | [
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Metal dusts | dust group | [
"category"
] | iiic-dust-group-class-ii-group-e | IIIC | Class II, Group E | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | Gas / dust group | Typical Substances | IIC | Acetylene | Class I, Group A | Acetylene | IIB + H 2 | Hydrogen | Class I, Group B | Hydrogen | IIB | Ethylene | Class I, Group C | Ethylene | IIA | Propane | Class I, Group D | Propane | IIIC | Conductive dust | Class II, Group E | | https://referencesource.org/ex-classification-system-crosswalk/iiic-dust-group-class-ii-group-e/ | [
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Certification body | system attribute | [
"category"
] | notified-bodies-atex-excbs-iecex-system-attribute-nrtls-ul-fm-csa | Notified Bodies (ATEX) / ExCBs (IECEx) | NRTLs (UL, FM, CSA) | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | Certification body | NRTLs (UL, FM, CSA) | NRTLs | Notified Bodies (ATEX) / ExCBs (IECEx) | https://referencesource.org/ex-classification-system-crosswalk/notified-bodies-atex-excbs-iecex-system-attribute-nrtls-ul-fm-csa/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Ignition temperature of gas / dust >450 | temperature code | [
"category"
] | t1-temperature-code-t1 | T1 | T1 | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | 450 | T1 | >450 | https://referencesource.org/ex-classification-system-crosswalk/t1-temperature-code-t1/ | [
"iec_designation",
"max_surface_temperature_c",
"north_american_designation"
] | null | [] | [
{
"as_of": "2026-08-06T00:00:00",
"field": "max_surface_temperature_f",
"source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/",
"source_quote": "T1 | T1 | 450 | 842",
"value": "842"
}
] | 450 |
Ignition temperature of gas / dust >300-450 | temperature code | [
"category"
] | t2-temperature-code-t2 | T2 | T2 | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | 300 | T2 | >300-450 | https://referencesource.org/ex-classification-system-crosswalk/t2-temperature-code-t2/ | [
"iec_designation",
"max_surface_temperature_c",
"north_american_designation"
] | null | [] | [
{
"as_of": "2026-08-06T00:00:00",
"field": "max_surface_temperature_f",
"source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/",
"source_quote": "T2 | T2 | 300 | 572",
"value": "572"
}
] | 300 |
Ignition temperature of gas / dust >200-300 | temperature code | [
"category"
] | t3-temperature-code-t3 | T3 | T3 | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | 200 | T3 | >200-300 | https://referencesource.org/ex-classification-system-crosswalk/t3-temperature-code-t3/ | [
"iec_designation",
"max_surface_temperature_c",
"north_american_designation"
] | null | [] | [
{
"as_of": "2026-08-06T00:00:00",
"field": "max_surface_temperature_f",
"source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/",
"source_quote": "T3 | T3 | 200 | 392",
"value": "392"
}
] | 200 |
Ignition temperature of gas / dust >135-200 | temperature code | [
"category"
] | t4-temperature-code-t4 | T4 | T4 | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | 135 | T4 | >135-200 | https://referencesource.org/ex-classification-system-crosswalk/t4-temperature-code-t4/ | [
"iec_designation",
"max_surface_temperature_c",
"north_american_designation"
] | null | [] | [
{
"as_of": "2026-08-06T00:00:00",
"field": "max_surface_temperature_f",
"source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/",
"source_quote": "T4 | T4 | 135 | 275",
"value": "275"
}
] | 135 |
Ignition temperature of gas / dust >100-135 | temperature code | [
"category"
] | t5-temperature-code-t5 | T5 | T5 | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | 100 | T5 | >100-135 | https://referencesource.org/ex-classification-system-crosswalk/t5-temperature-code-t5/ | [
"iec_designation",
"max_surface_temperature_c",
"north_american_designation"
] | null | [] | [
{
"as_of": "2026-08-06T00:00:00",
"field": "max_surface_temperature_f",
"source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/",
"source_quote": "T5 | T5 | 100 | 212",
"value": "212"
}
] | 100 |
Ignition temperature of gas / dust >85-100 | temperature code | [
"category"
] | t6-temperature-code-t6 | T6 | T6 | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | 85 | T6 | >85-100 | https://referencesource.org/ex-classification-system-crosswalk/t6-temperature-code-t6/ | [
"iec_designation",
"max_surface_temperature_c",
"north_american_designation"
] | null | [] | [
{
"as_of": "2026-08-06T00:00:00",
"field": "max_surface_temperature_f",
"source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/",
"source_quote": "T6 | T6 | 85 | 185",
"value": "185"
}
] | 85 |
Ignition temperature of gas / dust >280-300 | temperature code | [
"category"
] | temperature-code-t2a | null | T2A | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | 280 | T2A | >280-300 | https://referencesource.org/ex-classification-system-crosswalk/temperature-code-t2a/ | [
"max_surface_temperature_c",
"north_american_designation"
] | null | [] | [
{
"as_of": "2026-08-06T00:00:00",
"field": "max_surface_temperature_f",
"source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/",
"source_quote": "T2A | | 280 | 536",
"value": "536"
}
] | 280 |
Ignition temperature of gas / dust >260-280 | temperature code | [
"category"
] | temperature-code-t2b | null | T2B | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | 260 | T2B | >260-280 | https://referencesource.org/ex-classification-system-crosswalk/temperature-code-t2b/ | [
"max_surface_temperature_c",
"north_american_designation"
] | null | [] | [
{
"as_of": "2026-08-06T00:00:00",
"field": "max_surface_temperature_f",
"source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/",
"source_quote": "T2B | | 260 | 500",
"value": "500"
}
] | 260 |
Ignition temperature of gas / dust >230-260 | temperature code | [
"category"
] | temperature-code-t2c | null | T2C | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | 230 | T2C | >230-260 | https://referencesource.org/ex-classification-system-crosswalk/temperature-code-t2c/ | [
"max_surface_temperature_c",
"north_american_designation"
] | null | [] | [
{
"as_of": "2026-08-06T00:00:00",
"field": "max_surface_temperature_f",
"source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/",
"source_quote": "T2C | | 230 | 446",
"value": "446"
}
] | 230 |
Ignition temperature of gas / dust >215-230 | temperature code | [
"category"
] | temperature-code-t2d | null | T2D | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | 215 | T2D | >215-230 | https://referencesource.org/ex-classification-system-crosswalk/temperature-code-t2d/ | [
"max_surface_temperature_c",
"north_american_designation"
] | null | [] | [
{
"as_of": "2026-08-06T00:00:00",
"field": "max_surface_temperature_f",
"source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/",
"source_quote": "T2D | | 215 | 419",
"value": "419"
}
] | 215 |
Ignition temperature of gas / dust >180-200 | temperature code | [
"category"
] | temperature-code-t3a | null | T3A | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | 180 | T3A | >180-200 | https://referencesource.org/ex-classification-system-crosswalk/temperature-code-t3a/ | [
"max_surface_temperature_c",
"north_american_designation"
] | null | [] | [
{
"as_of": "2026-08-06T00:00:00",
"field": "max_surface_temperature_f",
"source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/",
"source_quote": "T3A | | 180 | 356",
"value": "356"
}
] | 180 |
Ignition temperature of gas / dust >165-180 | temperature code | [
"category"
] | temperature-code-t3b | null | T3B | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | 165 | T3B | >165-180 | https://referencesource.org/ex-classification-system-crosswalk/temperature-code-t3b/ | [
"max_surface_temperature_c",
"north_american_designation"
] | null | [] | [
{
"as_of": "2026-08-06T00:00:00",
"field": "max_surface_temperature_f",
"source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/",
"source_quote": "T3B | | 165 | 329",
"value": "329"
}
] | 165 |
Ignition temperature of gas / dust >160-165 | temperature code | [
"category"
] | temperature-code-t3c | null | T3C | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | 160 | T3C | >160-165 | https://referencesource.org/ex-classification-system-crosswalk/temperature-code-t3c/ | [
"max_surface_temperature_c",
"north_american_designation"
] | null | [] | [
{
"as_of": "2026-08-06T00:00:00",
"field": "max_surface_temperature_f",
"source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/",
"source_quote": "T3C | | 160 | 320",
"value": "320"
}
] | 160 |
Ignition temperature of gas / dust >120-135 | temperature code | [
"category"
] | temperature-code-t4a | null | T4A | https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups | 120 | T4A | >120-135 | https://referencesource.org/ex-classification-system-crosswalk/temperature-code-t4a/ | [
"max_surface_temperature_c",
"north_american_designation"
] | null | [] | [
{
"as_of": "2026-08-06T00:00:00",
"field": "max_surface_temperature_f",
"source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/",
"source_quote": "T4A | | 120 | 248",
"value": "248"
}
] | 120 |
Flammable gases and vapors | area classification | [
"category"
] | zone-0-1-2-gas-area-classification-class-i | Zone 0, 1, 2 (gas) | Class I | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | Class I | Flammable gases and vapors | https://referencesource.org/ex-classification-system-crosswalk/zone-0-1-2-gas-area-classification-class-i/ | [
"basis",
"north_american_designation"
] | null | null | null | null |
Hazard basis | system attribute | [
"category"
] | zone-0-1-2-gas-zone-20-21-22-dust-system-attribute-class-i-gas-ii-dust-iii-fibers | Zone 0, 1, 2 (gas); Zone 20, 21, 22 (dust) | Class I (gas), II (dust), III (fibers) | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | Hazard basis | Class I (gas), II (dust), III (fibers) | Zone 0, 1, 2 (gas only) | Zone 0, 1, 2 (gas); Zone 20, 21, 22 (dust) | https://referencesource.org/ex-classification-system-crosswalk/zone-0-1-2-gas-zone-20-21-22-dust-system-attribute-class-i-gas-ii-dust-iii-fibers/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Continuous hazard | area classification | [
"category"
] | zone-0-area-classification-class-i-division-1 | Zone 0 | Class I Division 1 | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | Continuous hazard | Class I Division 1 | Zone 0 | https://referencesource.org/ex-classification-system-crosswalk/zone-0-area-classification-class-i-division-1/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Explosive atmosphere continuously or for long periods (>1000 hrs/yr) | area classification | [
"category"
] | zone-0-area-classification-no-nec-500-equivalent | Zone 0 | (no NEC 500 equivalent) | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | Zone 0 | Explosive atmosphere continuously or for long periods (>1000 hrs/yr) | https://referencesource.org/ex-classification-system-crosswalk/zone-0-area-classification-no-nec-500-equivalent/ | [
"basis",
"iec_designation"
] | null | null | null | null |
Explosive atmosphere present continuously or for long periods | area classification | [
"category"
] | zone-0-area-classification-no-nec-equivalent | Zone 0 | (no NEC equivalent) | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | Zone 0 | Explosive atmosphere present continuously or for long periods | https://referencesource.org/ex-classification-system-crosswalk/zone-0-area-classification-no-nec-equivalent/ | [
"basis",
"iec_designation"
] | null | null | null | null |
Hazard present during normal operation | area classification | [
"category"
] | zone-0-zone-1-area-classification-division-1 | Zone 0 / Zone 1 | Division 1 | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | Division 1 | Hazard present during normal operation | https://referencesource.org/ex-classification-system-crosswalk/zone-0-zone-1-area-classification-division-1/ | [
"basis",
"north_american_designation"
] | null | null | null | null |
Frequent hazard | area classification | [
"category"
] | zone-1-area-classification-class-i-division-1 | Zone 1 | Class I Division 1 | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | Frequent hazard | Class I Division 1 | Zone 1 | https://referencesource.org/ex-classification-system-crosswalk/zone-1-area-classification-class-i-division-1/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Explosive atmosphere likely during normal operation | area classification | [
"category"
] | zone-1-area-classification-no-nec-equivalent | Zone 1 | (no NEC equivalent) | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | Zone 1 | Explosive atmosphere likely during normal operation | https://referencesource.org/ex-classification-system-crosswalk/zone-1-area-classification-no-nec-equivalent/ | [
"basis",
"iec_designation"
] | null | null | null | null |
Explosive atmosphere likely during normal operation (10–1000 hrs/yr) | area classification | [
"category"
] | zone-1-zone-0-area-classification-division-1 | Zone 1 (+ Zone 0) | Division 1 | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | Division 1 | Zone 1 (+ Zone 0) | Explosive atmosphere likely during normal operation (10–1000 hrs/yr) | https://referencesource.org/ex-classification-system-crosswalk/zone-1-zone-0-area-classification-division-1/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Occasional hazard | area classification | [
"category"
] | zone-2-area-classification-class-i-division-2 | Zone 2 | Class I Division 2 | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | Occasional hazard | Class I Division 2 | Zone 2 | https://referencesource.org/ex-classification-system-crosswalk/zone-2-area-classification-class-i-division-2/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Explosive atmosphere not likely; only abnormal conditions (<10 hrs/yr) | area classification | [
"category"
] | zone-2-area-classification-division-2 | Zone 2 | Division 2 | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | Division 2 | Zone 2 | Explosive atmosphere not likely; only abnormal conditions (<10 hrs/yr) | https://referencesource.org/ex-classification-system-crosswalk/zone-2-area-classification-division-2/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | [
{
"field": "basis",
"versions": [
{
"as_of": "2026-08-06T00:00:00",
"source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html",
"source_quote": "Division 2 | Zone 2 | Explosive atmosphere not likely; only abnormal conditions (<10 hrs/yr)",
"value": "Explosive at... | null | null |
Explosive atmosphere unlikely in normal operation, only short duration eg. accidental leakage | area classification | [
"category"
] | zone-2-area-classification-no-nec-equivalent | Zone 2 | (no NEC equivalent) | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | Zone 2 | Explosive atmosphere unlikely in normal operation, only short duration eg. accidental leakage | https://referencesource.org/ex-classification-system-crosswalk/zone-2-area-classification-no-nec-equivalent/ | [
"basis",
"iec_designation"
] | null | null | null | null |
Combustible dust | area classification | [
"category"
] | zone-20-21-22-dust-area-classification-class-ii | Zone 20, 21, 22 (dust) | Class II | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | Class II | Combustible dust | https://referencesource.org/ex-classification-system-crosswalk/zone-20-21-22-dust-area-classification-class-ii/ | [
"basis",
"north_american_designation"
] | null | null | null | null |
Dust classification | system attribute | [
"category"
] | zone-20-21-22-iiia-iiib-iiic-system-attribute-class-ii-groups-e-f-g | Zone 20, 21, 22 (IIIA, IIIB, IIIC) | Class II Groups E, F, G | https://exknowledge.com/pages/nec-500-vs-atex-iec.html | Dust classification | Class II Groups E, F, G | Not covered | Zone 20, 21, 22 (IIIA, IIIB, IIIC) | https://referencesource.org/ex-classification-system-crosswalk/zone-20-21-22-iiia-iiib-iiic-system-attribute-class-ii-groups-e-f-g/ | [
"basis",
"iec_designation",
"north_american_designation"
] | null | null | null | null |
Combustible dust present continuously | area classification | [
"category"
] | zone-20-area-classification-no-nec-equivalent | Zone 20 | (no NEC equivalent) | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | Zone 20 | Combustible dust present continuously | https://referencesource.org/ex-classification-system-crosswalk/zone-20-area-classification-no-nec-equivalent/ | [
"basis",
"iec_designation"
] | null | null | null | null |
Dust likely during normal operation | area classification | [
"category"
] | zone-21-area-classification-no-nec-equivalent | Zone 21 | (no NEC equivalent) | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | Zone 21 | Dust likely during normal operation | https://referencesource.org/ex-classification-system-crosswalk/zone-21-area-classification-no-nec-equivalent/ | [
"basis",
"iec_designation"
] | null | null | null | null |
Dust unlikely except briefly | area classification | [
"category"
] | zone-22-area-classification-no-nec-equivalent | Zone 22 | (no NEC equivalent) | https://www.inframena.com/hazardous-area-classification-equivalency-guide/ | Zone 22 | Dust unlikely except briefly | https://referencesource.org/ex-classification-system-crosswalk/zone-22-area-classification-no-nec-equivalent/ | [
"basis",
"iec_designation"
] | null | null | null | null |
North American vs IEC/ATEX explosion protection designations
Canonical, always-current version: https://referencesource.org/ex-classification-system-crosswalk/ Machine-readable: https://referencesource.org/ex-classification-system-crosswalk/data.json — this mirror is a point-in-time copy.
- Last verified: 2026-08-06
- Stale after: 2028-08-05 (past this date, prefer the canonical copy — it re-verifies on a cadence this snapshot does not)
- Records: 65
Crosswalk between the two concurrent hazardous-area classification systems: the North American Class / Division system of NEC Articles 500 and 505 (NFPA 70) and the CSA code, against the Zone system of IEC 60079, ATEX and IECEx. Each record is one designation in one system with its stated counterpart in the other, covering area classification (Division 1 and 2 against Zone 0, 1, 2, 20, 21, 22), gas groups (A, B, C, D against IIA, IIB, IIC, IIB+H2), dust groups (E, F, G against IIIA, IIIB, IIIC), protection concepts (explosion-proof against Ex d, intrinsically safe against Ex i, purged/pressurized against Ex p, dust-ignition-proof against Ex t, non-incendive against Ex nA/Ex ec) with the IEC standard number for each, and temperature codes T1 to T6 with their maximum surface temperatures. Answers 'is ATEX Ex d IIB T4 the same as Class I Div 1 Group C', 'what does T2D mean and is there an IEC equivalent', 'Division 1 or Zone 1 which is stricter', 'NEC Group B IEC equivalent', and 'can I install Zone 1 equipment in a Division 1 area'. Three things the mapping gets wrong when stated as a simple table: NEC 500 has no Zone 0 equivalent so Division 1 spans Zone 0 and Zone 1 and is under-specified for Zone 0; the North American temperature codes T2A, T2B, T2C, T2D, T3A, T3B, T3C and T4A have no IEC counterpart at all; and publishers disagree on NEC Group B, giving it as IIC or as IIB+H2, which changes the required flameproof gap. Every counterpart is quoted from the page that stated it and attributed, so the disagreement is visible.
Provenance — what every record carries
Every record carries source (the URL the value was read from) and
source_quote (a verbatim quote from that page stating it). A value you
cannot check against its page is indistinguishable from an invented one;
these can all be checked. Each record is also individually addressable on
the canonical site at its url.
Licence position
Facts extracted from freely published manufacturer and industry reference pages. Designation crosswalks are safety facts, not copyrightable expression. NFPA 70 and the IEC 60079 series are not reproduced and were not opened -- the fact is taken, never the document. Four separate publishers, no bulk take from any one.
Facts are not copyrightable; what this dataset takes from each source is a fact plus a short attributed quote linking back to the page that states it.
Sources
- https://exknowledge.com/pages/nec-500-vs-atex-iec.html
- https://www.inframena.com/hazardous-area-classification-equivalency-guide/
- https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups
- https://ldpi-inc.com/resources/classification-codes/class-1-locations/
Fields
See any record in data/records.jsonl — field names are self-describing,
and the canonical page for each record renders them with labels:
https://referencesource.org/ex-classification-system-crosswalk/
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