mirror of https://referencesource.org/ex-classification-system-crosswalk/

README.md

@@ -23,7 +23,7 @@ Machine-readable: https://referencesource.org/ex-classification-system-crosswalk
 - **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:** 128
+- **Records:** 122
 
 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. It also carries the equipment marking codes themselves -- the NEC 500 bracket codes (XP), (IS), (NI), (DIP), (PX), (PY), (PZ) and the NFPA 496 purge Types X, Y and Z, against the NEC 505 and CEC Ex / AEx codes -- each with the country whose column printed it, the hazard class and division or zone it is approved for, and the ISA, UL, FM, NFPA or CSA standard behind it, because the same code means different standards either side of the border: (IS) is UL 913 / FM 3610 in the US and C22.2 No. 157 in Canada. 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.
 
@@ -48,6 +48,7 @@ fact plus a short attributed quote linking back to the page that states it.
 - https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf
 - https://www.inframena.com/hazardous-area-classification-equivalency-guide/
 - https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups
+- https://exknowledge.com/pages/gas-groups.html
 - https://ldpi-inc.com/resources/classification-codes/class-1-locations/
 
 ## Fields

data/records.jsonl

@@ -30,13 +30,13 @@
 {"basis": "Ethylene", "category": "gas group", "derived_fields": ["category"], "id": "iib-gas-group-class-i-group-c", "iec_designation": "IIB", "north_american_designation": "Class I, Group C", "source": "https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups", "source_quote": "IIB | Ethylene | Class I, Group C | Ethylene", "url": "https://referencesource.org/ex-classification-system-crosswalk/iib-gas-group-class-i-group-c/", "verified_fields": ["basis", "iec_designation", "north_american_designation"]}
 {"basis": "Propane", "category": "gas group", "derived_fields": ["category"], "id": "iia-gas-group-class-i-group-d", "iec_designation": "IIA", "north_american_designation": "Class I, Group D", "source": "https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups", "source_quote": "IIA | Propane | Class I, Group D |", "url": "https://referencesource.org/ex-classification-system-crosswalk/iia-gas-group-class-i-group-d/", "verified_fields": ["basis", "iec_designation", "north_american_designation"]}
 {"basis": "Combustible dust", "category": "area classification", "derived_fields": ["category"], "id": "zone-20-21-22-dust-area-classification-class-ii", "iec_designation": "Zone 20, 21, 22 (dust)", "north_american_designation": "Class II", "source": "https://www.inframena.com/hazardous-area-classification-equivalency-guide/", "source_quote": "Class II | Combustible dust", "url": "https://referencesource.org/ex-classification-system-crosswalk/zone-20-21-22-dust-area-classification-class-ii/", "verified_fields": ["basis", "north_american_designation"]}
-{"basis": "Metal dusts", "category": "dust group", "derived_fields": ["category"], "id": "iiic-dust-group-class-ii-group-e", "iec_designation": "IIIC", "north_american_designation": "Class II, Group E", "source": "https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups", "source_quote": "Gas / dust group | Typical Substances | IIC | Acetylene | Class I, Group A | Acetylene | IIB + H2 | 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 |", "url": "https://referencesource.org/ex-classification-system-crosswalk/iiic-dust-group-class-ii-group-e/", "verified_fields": ["iec_designation", "north_american_designation"]}
-{"basis": "Carbon dusts", "category": "dust group", "derived_fields": ["category"], "id": "iiib-dust-group-class-ii-group-f", "iec_designation": "IIIB", "north_american_designation": "Class II, Group F", "source": "https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups", "source_quote": "Gas / dust group | Typical Substances | IIC | Acetylene | Class I, Group A | Acetylene | IIB + H2 | 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-conductive dust | Class II, Group F |", "url": "https://referencesource.org/ex-classification-system-crosswalk/iiib-dust-group-class-ii-group-f/", "verified_fields": ["iec_designation", "north_american_designation"]}
-{"basis": "Grain, flour, plastic dusts", "category": "dust group", "derived_fields": ["category"], "id": "dust-group-class-ii-group-g", "north_american_designation": "Class II, Group G", "source": "https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups", "source_quote": "Class II, Group G", "url": "https://referencesource.org/ex-classification-system-crosswalk/dust-group-class-ii-group-g/", "verified_fields": ["north_american_designation"]}
+{"basis": "Combustible metal dust", "category": "dust group", "derived_fields": ["category"], "id": "iiic-dust-group-class-ii-group-e", "iec_designation": "IIIC", "north_american_designation": "Class II, Group E", "source": "https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups", "source_quote": "IIIC | Conductive dust | Class II, Group E | Combustible metal dust", "url": "https://referencesource.org/ex-classification-system-crosswalk/iiic-dust-group-class-ii-group-e/", "verified_fields": ["basis", "iec_designation", "north_american_designation"]}
+{"basis": "Combustible carbonaceous dust", "category": "dust group", "derived_fields": ["category"], "id": "iiib-dust-group-class-ii-group-f", "iec_designation": "IIIB", "north_american_designation": "Class II, Group F", "source": "https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups", "source_quote": "IIIB | Non-conductive dust | Class II, Group F | Combustible carbonaceous dust", "url": "https://referencesource.org/ex-classification-system-crosswalk/iiib-dust-group-class-ii-group-f/", "verified_fields": ["basis", "iec_designation", "north_american_designation"]}
+{"basis": "Combustible dusts not in group E or F", "category": "dust group", "derived_fields": ["category"], "id": "dust-group-class-ii-group-g", "north_american_designation": "Class II, Group G", "source": "https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups", "source_quote": "Class II, Group G | Combustible dusts not in group E or F", "url": "https://referencesource.org/ex-classification-system-crosswalk/dust-group-class-ii-group-g/", "verified_fields": ["basis", "north_american_designation"]}
 {"basis": "Dust classification", "category": "system attribute", "derived_fields": ["category"], "id": "zone-20-21-22-iiia-iiib-iiic-system-attribute-class-ii-groups-e-f-g", "iec_designation": "Zone 20, 21, 22 (IIIA, IIIB, IIIC)", "north_american_designation": "Class II Groups E, F, G", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "Dust classification | Class II Groups E, F, G | Not covered | Zone 20, 21, 22 (IIIA, IIIB, IIIC)", "url": "https://referencesource.org/ex-classification-system-crosswalk/zone-20-21-22-iiia-iiib-iiic-system-attribute-class-ii-groups-e-f-g/", "verified_fields": ["basis", "iec_designation", "north_american_designation"]}
 {"basis": "Ignitable fibers", "category": "area classification", "derived_fields": ["category"], "id": "area-classification-class-iii", "north_american_designation": "Class III", "source": "https://www.inframena.com/hazardous-area-classification-equivalency-guide/", "source_quote": "Class III | Ignitable fibers", "url": "https://referencesource.org/ex-classification-system-crosswalk/area-classification-class-iii/", "verified_fields": ["basis", "north_american_designation"]}
 {"basis": "IEC considers fibers within the dust framework", "category": "dust group", "derived_fields": ["category"], "id": "dust-group-class-iii", "north_american_designation": "Class III", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "Fiber hazards: NEC Class III (fibers/flyings) has no IEC equivalent. IEC considers fibers within the dust framework.", "url": "https://referencesource.org/ex-classification-system-crosswalk/dust-group-class-iii/", "verified_fields": ["basis", "north_american_designation"]}
-{"basis": "Fibers and flyings", "category": "dust group", "derived_fields": ["category"], "id": "iiia-dust-group-class-iii", "iec_designation": "IIIA", "north_american_designation": "Class III", "source": "https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups", "source_quote": "Gas / dust group | Typical Substances | IIC | Acetylene | Class I, Group A | Acetylene | IIB + H2 | 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-conductive dust | Class II, Group F | Combustible carbonaceous dust | Class II, Group G | Combustible dusts not in group E or F | IIIA | Combustible flyings | Class III |", "url": "https://referencesource.org/ex-classification-system-crosswalk/iiia-dust-group-class-iii/", "verified_fields": ["iec_designation", "north_american_designation"]}
+{"basis": "Combustible fibres and flyings", "category": "dust group", "derived_fields": ["category"], "id": "iiia-dust-group-class-iii", "iec_designation": "IIIA", "north_american_designation": "Class III", "source": "https://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups", "source_quote": "IIIA | Combustible flyings | Class III | Combustible fibres and flyings", "url": "https://referencesource.org/ex-classification-system-crosswalk/iiia-dust-group-class-iii/", "verified_fields": ["basis", "iec_designation", "north_american_designation"]}
 {"category": "protection concept", "country": "US", "derived_fields": ["category"], "division_or_zone": "Division 1", "hazard_class": "Class II", "id": "class-ii-us-protection-concept-dip", "iec_standard": "UL 1203", "north_american_designation": "(DIP)", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "(DIP) US Class II Division 1 UL 1203", "url": "https://referencesource.org/ex-classification-system-crosswalk/class-ii-us-protection-concept-dip/", "verified_fields": ["country", "division_or_zone", "hazard_class", "iec_standard", "north_american_designation"]}
 {"category": "protection concept", "country": "CA", "derived_fields": ["category"], "division_or_zone": "Division 1", "hazard_class": "Class II", "id": "class-ii-ca-protection-concept-dip-a21", "iec_standard": "CSA E61241-1-1", "north_american_designation": "(DIP) A21", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "(DIP) A21 CA Class II Division 1 CSA E61241-1-1", "url": "https://referencesource.org/ex-classification-system-crosswalk/class-ii-ca-protection-concept-dip-a21/", "verified_fields": ["country", "division_or_zone", "hazard_class", "iec_standard", "north_american_designation"]}
 {"category": "protection concept", "derived_fields": ["category"], "division_or_zone": "Division 2", "id": "protection-concept-dip-a22", "iec_standard": "CSA E61241-1-1", "north_american_designation": "(DIP) A22", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "(DIP) A22 Division 2 CSA E61241-1-1", "url": "https://referencesource.org/ex-classification-system-crosswalk/protection-concept-dip-a22/", "verified_fields": ["division_or_zone", "iec_standard", "north_american_designation"]}
@@ -49,7 +49,6 @@
 {"basis": "Explosive atmosphere not likely; only abnormal conditions (<10 hrs/yr)", "category": "area classification", "derived_fields": ["category"], "disagreements": [{"field": "basis", "versions": [{"as_of": "2026-08-06", "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 atmosphere not likely; only abnormal conditions (<10 hrs/yr)"}, {"as_of": "2026-08-06", "source": "https://www.inframena.com/hazardous-area-classification-equivalency-guide/", "source_quote": "Division 2 | Hazard present only under abnormal conditions", "value": "Hazard present only under abnormal conditions"}]}], "id": "zone-2-area-classification-division-2", "iec_designation": "Zone 2", "north_american_designation": "Division 2", "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)", "url": "https://referencesource.org/ex-classification-system-crosswalk/zone-2-area-classification-division-2/", "verified_fields": ["basis", "iec_designation", "north_american_designation"]}
 {"category": "area classification", "derived_fields": ["category"], "id": "zone-2-zone-22-area-classification-division-2", "iec_designation": "Zone 2 / Zone 22", "north_american_designation": "Division 2", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "Division 2 Zone 2 / Zone 22", "url": "https://referencesource.org/ex-classification-system-crosswalk/zone-2-zone-22-area-classification-division-2/", "verified_fields": ["iec_designation", "north_american_designation"]}
 {"basis": "Prevent dust ingress and limit surface temperature", "category": "protection concept", "derived_fields": ["category"], "id": "ex-t-dust-protection-by-enclosure-protection-concept-dust-ignition-proof", "iec_designation": "Ex t (Dust protection by enclosure)", "iec_standard": "IEC 60079-31", "north_american_designation": "Dust-ignition-proof", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "Dust-ignition-proof | Ex t (Dust protection by enclosure) | IEC 60079-31 | Prevent dust ingress and limit surface temperature", "url": "https://referencesource.org/ex-classification-system-crosswalk/ex-t-dust-protection-by-enclosure-protection-concept-dust-ignition-proof/", "verified_fields": ["basis", "iec_designation", "iec_standard", "north_american_designation"]}
-{"basis": "Encapsulation", "category": "protection concept", "derived_fields": ["category"], "id": "ex-m-protection-concept-encapsulation", "iec_designation": "Ex m", "north_american_designation": "Encapsulation", "source": "https://www.inframena.com/hazardous-area-classification-equivalency-guide/", "source_quote": "Ex m | Encapsulation", "url": "https://referencesource.org/ex-classification-system-crosswalk/ex-m-protection-concept-encapsulation/", "verified_fields": ["basis", "iec_designation", "north_american_designation"]}
 {"category": "protection concept", "country": "CA", "derived_fields": ["category"], "division_or_zone": "Division 1 & 2", "hazard_class": "Class I", "id": "class-i-ca-protection-concept-ex", "iec_standard": "CSA 60079-0", "north_american_designation": "Ex", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "Ex CA Class I Division 1 & 2 CSA 60079-0", "url": "https://referencesource.org/ex-classification-system-crosswalk/class-i-ca-protection-concept-ex/", "verified_fields": ["country", "division_or_zone", "hazard_class", "iec_standard", "north_american_designation"]}
 {"category": "protection concept", "country": "US", "derived_fields": ["category"], "division_or_zone": "Zone 20, 21, 22", "id": "us-protection-concept-ex", "iec_standard": "ISA 60079-0", "north_american_designation": "Ex", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "Ex US Zone 20, 21, 22 ISA 60079-0", "url": "https://referencesource.org/ex-classification-system-crosswalk/us-protection-concept-ex/", "verified_fields": ["country", "division_or_zone", "iec_standard", "north_american_designation"]}
 {"category": "protection concept", "country": "CA", "derived_fields": ["category"], "division_or_zone": "Zone 1", "hazard_class": "Class I", "id": "class-i-ca-protection-concept-ex-d", "iec_standard": "CSA 60079-1", "north_american_designation": "Ex d", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "Ex d CA Class I Zone 1 CSA 60079-1", "url": "https://referencesource.org/ex-classification-system-crosswalk/class-i-ca-protection-concept-ex-d/", "verified_fields": ["country", "division_or_zone", "hazard_class", "iec_standard", "north_american_designation"]}
@@ -68,20 +67,17 @@
 {"category": "protection concept", "country": "CA", "derived_fields": ["category"], "division_or_zone": "Zone 1", "hazard_class": "Class I", "id": "class-i-ca-protection-concept-ex-q", "iec_standard": "CSA E60079-5", "north_american_designation": "Ex q", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "Ex q CA Class I Zone 1 CSA E60079-5", "url": "https://referencesource.org/ex-classification-system-crosswalk/class-i-ca-protection-concept-ex-q/", "verified_fields": ["country", "division_or_zone", "hazard_class", "iec_standard", "north_american_designation"]}
 {"basis": "Contain the explosion inside the enclosure", "category": "protection concept", "derived_fields": ["category"], "id": "ex-d-flameproof-protection-concept-explosion-proof-xp", "iec_designation": "Ex d (Flameproof)", "iec_standard": "IEC 60079-1", "north_american_designation": "Explosion-proof (XP)", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "Explosion-proof (XP) | Ex d (Flameproof) | IEC 60079-1 | Contain the explosion inside the enclosure", "url": "https://referencesource.org/ex-classification-system-crosswalk/ex-d-flameproof-protection-concept-explosion-proof-xp/", "verified_fields": ["basis", "iec_designation", "iec_standard", "north_american_designation"]}
 {"basis": "Protection concept", "category": "system attribute", "derived_fields": ["category"], "id": "iec-aligned-types-ex-d-ex-i-ex-e-etc-system-attribute-explosion-proof-xp-intrinsically-safe-is", "iec_designation": "IEC-aligned types (Ex d, Ex i, Ex e, etc.)", "north_american_designation": "Explosion-proof (XP), intrinsically safe (IS)", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "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.)", "url": "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/", "verified_fields": ["basis", "iec_designation", "north_american_designation"]}
-{"basis": "Flameproof enclosure", "category": "protection concept", "derived_fields": ["category"], "id": "ex-d-protection-concept-flameproof-enclosure", "iec_designation": "Ex d", "north_american_designation": "Flameproof enclosure", "source": "https://www.inframena.com/hazardous-area-classification-equivalency-guide/", "source_quote": "Ex d | Flameproof enclosure", "url": "https://referencesource.org/ex-classification-system-crosswalk/ex-d-protection-concept-flameproof-enclosure/", "verified_fields": ["basis", "iec_designation", "north_american_designation"]}
-{"basis": "MESG <0.50 mm", "category": "gas group", "derived_fields": ["category"], "disagreements": [{"field": "basis", "versions": [{"as_of": "2026-08-06", "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": "2026-08-06", "source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/", "source_quote": "Acetylene | A | 305 | 581 | 6,000 PSI | IIC", "value": "Acetylene"}]}], "id": "iic-gas-group-group-a", "iec_designation": "IIC", "north_american_designation": "Group A", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "A | IIC | Acetylene | <0.50 mm", "url": "https://referencesource.org/ex-classification-system-crosswalk/iic-gas-group-group-a/", "verified_fields": ["iec_designation"]}
-{"basis": "Hydrogen", "category": "gas group", "derived_fields": ["category"], "id": "iic-gas-group-group-b", "iec_designation": "IIC", "north_american_designation": "Group B", "source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/", "source_quote": "Hydrogen | B | 520 | 968 | 6,000 PSI | IIC", "url": "https://referencesource.org/ex-classification-system-crosswalk/iic-gas-group-group-b/", "verified_fields": ["basis", "iec_designation"]}
-{"basis": "MESG <0.50 mm", "category": "gas group", "derived_fields": ["category"], "id": "iic-partially-iib-h-gas-group-group-b", "iec_designation": "IIC (partially IIB+H₂)", "north_american_designation": "Group B", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "B | IIC (partially IIB+H₂) | Hydrogen, butadiene | <0.50 mm", "url": "https://referencesource.org/ex-classification-system-crosswalk/iic-partially-iib-h-gas-group-group-b/", "verified_fields": ["iec_designation"]}
-{"basis": "MESG 0.50–0.90 mm", "category": "gas group", "derived_fields": ["category"], "disagreements": [{"field": "basis", "versions": [{"as_of": "2026-08-06", "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": "2026-08-06", "source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/", "source_quote": "Ethylene | C | 450 | 842 | 1,200 PSI | IIB", "value": "Ethylene"}]}], "id": "iib-gas-group-group-c", "iec_designation": "IIB", "north_american_designation": "Group C", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "C | IIB | Ethylene, ethyl ether | 0.50–0.90 mm", "url": "https://referencesource.org/ex-classification-system-crosswalk/iib-gas-group-group-c/", "verified_fields": ["iec_designation"]}
+{"basis": "MESG <0.50 mm", "category": "gas group", "derived_fields": ["category"], "disagreements": [{"field": "basis", "versions": [{"as_of": "2026-08-06", "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": "2026-08-06", "source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/", "source_quote": "Acetylene | A | 305 | 581 | 6,000 PSI | IIC", "value": "Acetylene"}]}], "id": "iic-gas-group-group-a", "iec_designation": "IIC", "north_american_designation": "Group A", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "A | IIC | Acetylene | <0.50 mm", "url": "https://referencesource.org/ex-classification-system-crosswalk/iic-gas-group-group-a/", "verified_fields": ["iec_designation", "north_american_designation"]}
+{"basis": "Hydrogen", "category": "gas group", "derived_fields": ["category"], "id": "iic-gas-group-group-b", "iec_designation": "IIC", "north_american_designation": "Group B", "source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/", "source_quote": "Hydrogen | B | 520 | 968 | 6,000 PSI | IIC", "url": "https://referencesource.org/ex-classification-system-crosswalk/iic-gas-group-group-b/", "verified_fields": ["basis", "iec_designation", "north_american_designation"]}
+{"basis": "MESG <0.50 mm", "category": "gas group", "derived_fields": ["category"], "id": "iic-partially-iib-h-gas-group-group-b", "iec_designation": "IIC (partially IIB+H₂)", "north_american_designation": "Group B", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "B | IIC (partially IIB+H₂) | Hydrogen, butadiene | <0.50 mm", "url": "https://referencesource.org/ex-classification-system-crosswalk/iic-partially-iib-h-gas-group-group-b/", "verified_fields": ["iec_designation", "north_american_designation"]}
+{"basis": "MESG 0.50–0.90 mm", "category": "gas group", "derived_fields": ["category"], "disagreements": [{"field": "basis", "versions": [{"as_of": "2026-08-06", "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": "2026-08-06", "source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/", "source_quote": "Ethylene | C | 450 | 842 | 1,200 PSI | IIB", "value": "Ethylene"}]}], "id": "iib-gas-group-group-c", "iec_designation": "IIB", "north_american_designation": "Group C", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "C | IIB | Ethylene, ethyl ether | 0.50–0.90 mm", "url": "https://referencesource.org/ex-classification-system-crosswalk/iib-gas-group-group-c/", "verified_fields": ["iec_designation", "north_american_designation"]}
 {"basis": "Methane (mining)", "category": "gas group", "derived_fields": ["category"], "id": "gas-group-group-d", "north_american_designation": "Group D", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "Methane (mining) Group D", "url": "https://referencesource.org/ex-classification-system-crosswalk/gas-group-group-d/", "verified_fields": ["basis", "north_american_designation"]}
-{"basis": "MESG >0.90 mm", "category": "gas group", "derived_fields": ["category"], "disagreements": [{"field": "basis", "versions": [{"as_of": "2026-08-06", "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": "2026-08-06", "source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/", "source_quote": "Gasoline | D | 280 | 536 | 600 PSI | IIA", "value": "Gasoline"}, {"as_of": "2026-08-06", "source": "https://www.inframena.com/hazardous-area-classification-equivalency-guide/", "source_quote": "D (Propane) | IIA", "value": "Propane"}]}], "id": "iia-gas-group-group-d", "iec_designation": "IIA", "north_american_designation": "Group D", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "D | IIA | Methane, propane, gasoline | >0.90 mm", "url": "https://referencesource.org/ex-classification-system-crosswalk/iia-gas-group-group-d/", "verified_fields": ["iec_designation"]}
+{"basis": "MESG >0.90 mm", "category": "gas group", "derived_fields": ["category"], "disagreements": [{"field": "basis", "versions": [{"as_of": "2026-08-06", "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": "2026-08-06", "source": "https://ldpi-inc.com/resources/classification-codes/class-1-locations/", "source_quote": "Gasoline | D | 280 | 536 | 600 PSI | IIA", "value": "Gasoline"}, {"as_of": "2026-08-06", "source": "https://www.inframena.com/hazardous-area-classification-equivalency-guide/", "source_quote": "D (Propane) | IIA", "value": "Propane"}]}], "id": "iia-gas-group-group-d", "iec_designation": "IIA", "north_american_designation": "Group D", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "D | IIA | Methane, propane, gasoline | >0.90 mm", "url": "https://referencesource.org/ex-classification-system-crosswalk/iia-gas-group-group-d/", "verified_fields": ["iec_designation", "north_american_designation"]}
 {"basis": "Combustible Metal Dusts", "category": "dust group", "derived_fields": ["category"], "disagreements": [{"field": "basis", "versions": [{"as_of": "2026-10-06", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "Combustible Metal Dusts Group E", "value": "Combustible Metal Dusts"}, {"as_of": "2026-10-06", "source": "https://www.inframena.com/hazardous-area-classification-equivalency-guide/", "source_quote": "E | Metal dust", "value": "Metal dust"}]}], "id": "dust-group-group-e", "north_american_designation": "Group E", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "Combustible Metal Dusts Group E", "url": "https://referencesource.org/ex-classification-system-crosswalk/dust-group-group-e/", "verified_fields": ["basis", "north_american_designation"]}
 {"basis": "Carbon dust", "category": "dust group", "derived_fields": ["category"], "disagreements": [], "id": "dust-group-group-f", "north_american_designation": "Group F", "source": "https://www.inframena.com/hazardous-area-classification-equivalency-guide/", "source_quote": "F | Carbon dust", "url": "https://referencesource.org/ex-classification-system-crosswalk/dust-group-group-f/", "verified_fields": ["basis"]}
 {"basis": "Grain / flour dust", "category": "dust group", "derived_fields": ["category"], "id": "dust-group-group-g", "north_american_designation": "Group G", "source": "https://www.inframena.com/hazardous-area-classification-equivalency-guide/", "source_quote": "G | Grain / flour dust", "url": "https://referencesource.org/ex-classification-system-crosswalk/dust-group-group-g/", "verified_fields": ["basis"]}
 {"basis": "Gas classification", "category": "system attribute", "derived_fields": ["category"], "id": "groups-iic-iib-iia-system-attribute-groups-a-b-c-d", "iec_designation": "Groups IIC, IIB, IIA", "north_american_designation": "Groups A, B, C, D", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "Gas classification | Groups A, B, C, D | Groups IIC, IIB, IIA | Groups IIC, IIB, IIA", "url": "https://referencesource.org/ex-classification-system-crosswalk/groups-iic-iib-iia-system-attribute-groups-a-b-c-d/", "verified_fields": ["basis", "iec_designation", "north_american_designation"]}
 {"basis": "Seal ignition source from atmosphere", "category": "protection concept", "derived_fields": ["category"], "id": "ex-nc-ex-m-protection-concept-hermetically-sealed", "iec_designation": "Ex nC / Ex m", "iec_standard": "IEC 60079-15 / -18", "north_american_designation": "Hermetically sealed", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "Hermetically sealed | Ex nC / Ex m | IEC 60079-15 / -18 | Seal ignition source from atmosphere", "url": "https://referencesource.org/ex-classification-system-crosswalk/ex-nc-ex-m-protection-concept-hermetically-sealed/", "verified_fields": ["basis", "iec_designation", "iec_standard", "north_american_designation"]}
-{"basis": "Increased safety", "category": "protection concept", "derived_fields": ["category"], "id": "ex-e-protection-concept-increased-safety", "iec_designation": "Ex e", "north_american_designation": "Increased safety", "source": "https://www.inframena.com/hazardous-area-classification-equivalency-guide/", "source_quote": "Ex e | Increased safety", "url": "https://referencesource.org/ex-classification-system-crosswalk/ex-e-protection-concept-increased-safety/", "verified_fields": ["basis", "iec_designation", "north_american_designation"]}
-{"basis": "Intrinsic safety", "category": "protection concept", "derived_fields": ["category"], "id": "ex-i-protection-concept-intrinsically-safe", "iec_designation": "Ex i", "north_american_designation": "Intrinsically Safe", "source": "https://www.inframena.com/hazardous-area-classification-equivalency-guide/", "source_quote": "Ex i | Intrinsic safety", "url": "https://referencesource.org/ex-classification-system-crosswalk/ex-i-protection-concept-intrinsically-safe/", "verified_fields": ["basis", "iec_designation"]}
 {"basis": "Limit energy below ignition threshold", "category": "protection concept", "derived_fields": ["category"], "id": "ex-i-ex-ia-ex-ib-protection-concept-intrinsically-safe-is", "iec_designation": "Ex i (Ex ia, Ex ib)", "iec_standard": "IEC 60079-11", "north_american_designation": "Intrinsically Safe (IS)", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "Intrinsically Safe (IS) | Ex i (Ex ia, Ex ib) | IEC 60079-11 | Limit energy below ignition threshold", "url": "https://referencesource.org/ex-classification-system-crosswalk/ex-i-ex-ia-ex-ib-protection-concept-intrinsically-safe-is/", "verified_fields": ["basis", "iec_designation", "iec_standard", "north_american_designation"]}
 {"category": "protection concept", "country": "CA", "derived_fields": ["category"], "division_or_zone": "Division 1", "hazard_class": "Class I", "id": "class-i-ca-protection-concept-is", "iec_standard": "C22.2 No. 157", "north_american_designation": "(IS)", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "(IS) CA Class I Division 1 C22.2 No. 157", "url": "https://referencesource.org/ex-classification-system-crosswalk/class-i-ca-protection-concept-is/", "verified_fields": ["country", "division_or_zone", "hazard_class", "iec_standard", "north_american_designation"]}
 {"category": "protection concept", "country": "US", "derived_fields": ["category"], "division_or_zone": "Division 1", "hazard_class": "Class I", "id": "class-i-us-protection-concept-is", "iec_standard": "UL 913 / FM 3610", "north_american_designation": "(IS)", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "(IS) US Class I Division 1 UL 913 / FM 3610", "url": "https://referencesource.org/ex-classification-system-crosswalk/class-i-us-protection-concept-is/", "verified_fields": ["country", "division_or_zone", "hazard_class", "iec_standard", "north_american_designation"]}
@@ -89,14 +85,12 @@
 {"category": "protection concept", "country": "US", "derived_fields": ["category"], "division_or_zone": "Division 1", "hazard_class": "Class II", "id": "class-ii-us-protection-concept-is", "iec_standard": "UL 913 / FM 3610", "north_american_designation": "(IS)", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "(IS) US Class II Division 1 UL 913 / FM 3610", "url": "https://referencesource.org/ex-classification-system-crosswalk/class-ii-us-protection-concept-is/", "verified_fields": ["country", "division_or_zone", "hazard_class", "iec_standard", "north_american_designation"]}
 {"category": "protection concept", "country": "CA", "derived_fields": ["category"], "division_or_zone": "Division 1", "hazard_class": "Class III", "id": "class-iii-ca-protection-concept-is", "iec_standard": "CSA C22.2 No. 157", "north_american_designation": "(IS)", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "(IS) CA Class III Division 1 CSA C22.2 No. 157", "url": "https://referencesource.org/ex-classification-system-crosswalk/class-iii-ca-protection-concept-is/", "verified_fields": ["country", "division_or_zone", "hazard_class", "iec_standard", "north_american_designation"]}
 {"category": "protection concept", "country": "US", "derived_fields": ["category"], "division_or_zone": "Division 1", "hazard_class": "Class III", "id": "class-iii-us-protection-concept-is", "iec_standard": "UL 913 / FM 3610", "north_american_designation": "(IS)", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "(IS) US Class III Division 1 UL 913 / FM 3610", "url": "https://referencesource.org/ex-classification-system-crosswalk/class-iii-us-protection-concept-is/", "verified_fields": ["country", "division_or_zone", "hazard_class", "iec_standard", "north_american_designation"]}
-{"basis": "Geographic use: USA, Canada vs EU, UK, most of the world", "category": "system attribute", "derived_fields": ["category"], "id": "atex-iecex-zone-system-attribute-nec-500-class-division", "iec_designation": "ATEX / IECEx (Zone)", "north_american_designation": "NEC 500 (Class/Division)", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "Geographic use | USA, Canada | USA, Canada | EU, UK, most of the world", "url": "https://referencesource.org/ex-classification-system-crosswalk/atex-iecex-zone-system-attribute-nec-500-class-division/"}
 {"basis": "Legal framework", "category": "system attribute", "derived_fields": ["category"], "id": "eu-directive-2014-34-eu-iecex-scheme-system-attribute-nfpa-70-adopted-by-ahjs", "iec_designation": "EU Directive 2014/34/EU / IECEx scheme", "north_american_designation": "NFPA 70 (adopted by AHJs)", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "Legal framework | NFPA 70 (adopted by AHJs) | NFPA 70 (adopted by AHJs) | EU Directive 2014/34/EU / IECEx scheme", "url": "https://referencesource.org/ex-classification-system-crosswalk/eu-directive-2014-34-eu-iecex-scheme-system-attribute-nfpa-70-adopted-by-ahjs/", "verified_fields": ["basis", "iec_designation", "north_american_designation"]}
 {"category": "protection concept", "country": "CA", "derived_fields": ["category"], "division_or_zone": "Division 2", "hazard_class": "Class I", "id": "class-i-ca-protection-concept-ni", "iec_standard": "C22.2 No. 213", "north_american_designation": "(NI)", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "(NI) CA Class I Division 2 C22.2 No. 213", "url": "https://referencesource.org/ex-classification-system-crosswalk/class-i-ca-protection-concept-ni/", "verified_fields": ["country", "division_or_zone", "hazard_class", "iec_standard", "north_american_designation"]}
 {"basis": "Non-Incendive", "category": "protection concept", "country": "US", "derived_fields": ["category"], "division_or_zone": "Division 2", "hazard_class": "Class I", "id": "class-i-us-protection-concept-ni", "iec_standard": "ISA 12.12.01/FM 3611", "north_american_designation": "(NI)", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "Non-Incendive (NI) US Class I Division 2 ISA 12.12.01/FM 3611", "url": "https://referencesource.org/ex-classification-system-crosswalk/class-i-us-protection-concept-ni/", "verified_fields": ["basis", "country", "division_or_zone", "hazard_class", "iec_standard", "north_american_designation"]}
 {"basis": "Dust Protected", "category": "protection concept", "country": "US", "derived_fields": ["category"], "division_or_zone": "Division 2", "hazard_class": "Class II", "id": "class-ii-us-protection-concept-ni", "iec_standard": "ISA 12.12.01 / FM 3611", "north_american_designation": "(NI)", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "Dust Protected (NI) US Class II Division 2 ISA 12.12.01 / FM 3611", "url": "https://referencesource.org/ex-classification-system-crosswalk/class-ii-us-protection-concept-ni/", "verified_fields": ["basis", "country", "division_or_zone", "hazard_class", "iec_standard", "north_american_designation"]}
 {"basis": "Normal operation cannot cause ignition", "category": "protection concept", "derived_fields": ["category"], "id": "ex-na-ex-ec-protection-concept-non-incendive", "iec_designation": "Ex nA / Ex ec", "iec_standard": "IEC 60079-15 / -7", "north_american_designation": "Non-incendive", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "Non-incendive | Ex nA / Ex ec | IEC 60079-15 / -7 | Normal operation cannot cause ignition", "url": "https://referencesource.org/ex-classification-system-crosswalk/ex-na-ex-ec-protection-concept-non-incendive/", "verified_fields": ["basis", "iec_designation", "iec_standard", "north_american_designation"]}
 {"basis": "Certification body", "category": "system attribute", "derived_fields": ["category"], "id": "notified-bodies-atex-excbs-iecex-system-attribute-nrtls-ul-fm-csa", "iec_designation": "Notified Bodies (ATEX) / ExCBs (IECEx)", "north_american_designation": "NRTLs (UL, FM, CSA)", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "Certification body | NRTLs (UL, FM, CSA) | NRTLs | Notified Bodies (ATEX) / ExCBs (IECEx)", "url": "https://referencesource.org/ex-classification-system-crosswalk/notified-bodies-atex-excbs-iecex-system-attribute-nrtls-ul-fm-csa/", "verified_fields": ["basis", "iec_designation", "north_american_designation"]}
-{"basis": "Pressurization", "category": "protection concept", "derived_fields": ["category"], "id": "ex-p-protection-concept-pressurization", "iec_designation": "Ex p", "north_american_designation": "Pressurization", "source": "https://www.inframena.com/hazardous-area-classification-equivalency-guide/", "source_quote": "Ex p | Pressurization", "url": "https://referencesource.org/ex-classification-system-crosswalk/ex-p-protection-concept-pressurization/", "verified_fields": ["basis", "iec_designation", "north_american_designation"]}
 {"basis": "Maintain positive pressure with inert gas", "category": "protection concept", "derived_fields": ["category"], "id": "ex-p-ex-px-ex-py-ex-pz-protection-concept-purged-pressurized", "iec_designation": "Ex p (Ex px, Ex py, Ex pz)", "iec_standard": "IEC 60079-2", "north_american_designation": "Purged/Pressurized", "source": "https://exknowledge.com/pages/nec-500-vs-atex-iec.html", "source_quote": "Purged/Pressurized | Ex p (Ex px, Ex py, Ex pz) | IEC 60079-2 | Maintain positive pressure with inert gas", "url": "https://referencesource.org/ex-classification-system-crosswalk/ex-p-ex-px-ex-py-ex-pz-protection-concept-purged-pressurized/", "verified_fields": ["basis", "iec_designation", "iec_standard", "north_american_designation"]}
 {"category": "protection concept", "country": "CA", "derived_fields": ["category"], "division_or_zone": "Division 1", "hazard_class": "Class II", "id": "class-ii-ca-protection-concept-px", "iec_standard": "NFPA 496", "north_american_designation": "(PX)", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "(PX) CA Class II Division 1 NFPA 496", "url": "https://referencesource.org/ex-classification-system-crosswalk/class-ii-ca-protection-concept-px/", "verified_fields": ["country", "division_or_zone", "hazard_class", "iec_standard", "north_american_designation"]}
 {"category": "protection concept", "country": "US", "derived_fields": ["category"], "division_or_zone": "Division 1", "hazard_class": "Class II", "id": "class-ii-us-protection-concept-px", "iec_standard": "NFPA 496 (FM 3620)", "north_american_designation": "(PX)", "source": "https://www.euroswitch.com/wp-content/uploads/euroswitch-hazardous-area-guide_V6.pdf", "source_quote": "(PX) US Class II Division 1 NFPA 496 (FM 3620)", "url": "https://referencesource.org/ex-classification-system-crosswalk/class-ii-us-protection-concept-px/", "verified_fields": ["country", "division_or_zone", "hazard_class", "iec_standard", "north_american_designation"]}