3
Zone
Description
Supported?
Gas
0
Explosive gas air mixture continuously present.
1
Explosive gas air mixture likely to occur in normal
operation.
2
Explosive gas air mixture not likely to occur, and if it does
it will only exist for a short time.
Dust
20
Explosive atmosphere in the form of a cloud of
combustible dust in air is continuously present, or for long
periods or frequently.
21
Explosive atmosphere in the form of a cloud of
combustible dust in air is likely to occur occasionally in
normal operation.
22
Explosive atmosphere in the form of a cloud of
combustible dust in air is not likely to occur in normal
operation, but if it does occur, will only persist for a short
period.
Group
Definition
Supported?
Gas
IIA
e.g. Propane
IIB
e.g. Ethylene
IIC
e.g. Hydrogen
Dust
IIIA
Combustible flyings
IIIB
Non-conductive dusts
IIIC
Conductive dusts
Table 1:
Gas and Dust Zones in which the ExTemp may be used
Table 2:
Gas and Dust Groups in which the ExTemp is suitable for use
Table 3:
Gas ignition temperature classifications to which the ExTemp conforms
Gas Ignition Temperature
Classification
Supported?
450 °C
T1
300 °C
T2
200 °C
T3
135 °C
T4
100 °C
T5
NO
85 °C
T6
NO