Class I, Division 1 :
Where ignitable concentration can
exist under normal operating
conditions; may exist frequently
because of repair, maintenance or
leakage; or may exist due to
breakdown of equipment in
conjunction with an electrical
failure.
Class I, Division 2 :
Where volatile flammable liquids
are stored, etc., in closed
containers; where ignitable
concentrations are normally
prevented by positive pressure
ventilation; or adjacent to Class I,
Division 1 locations.
Locations in which flammable
gases or vapors are or may be
present in the air in quantities
sufficient to produce explosive
atmospheres.
|
Class I, Zone 0 :
Where ignitable concentration are present continuously or for long periods of time.
Class I, Zone 1 :
Where ignitable concentrations are likely to exist under normal operations; may exist frequently
because of repair, maintenance or leakage; may exist due to breakdown of equipment in
conjunction with an electrical failure; or adjacent to Class I, Zone 1 locations.
Class I, Zone 2 :
Where ignitable concentrations are not likely to exist in normal operations or may exist for a short
time only; where volatile liquids are stored, etc., in closed containers; where ignitable
concentrations are normally prevented by positive pressure ventilation; or adjacent to Class I, Zone
1 locations.
Area Classification Division versus Zone and Gases and
Vapours Classification
Description |
NEC & CEC (North American) |
IEC |
Continuous Hazard |
Division 1 or Zone 0 |
Zone 0 |
Intermittent Hazard |
Division 1 or Zone 1 |
Zone 1 |
Hazard Under Abnormal conditions |
Division 2 or Zone 2 |
Zone 2 |
GAS
Acetylene |
Group IIC
|
Group A
|
Hydrogen |
Group IIB + H2 |
Group B |
Ethylene |
Group IIB |
Group C |
Propane |
Group IIA |
Group D |
Coal Mines |
Group I |
Gaseous Mines |
|
