Instruction Manual ZHK
V07-19.0
119/129
Unit category
Selection for type of ex-
plosive atmosphere
Avoidance sources
of ignition
Degree of
security
Use in
zone
1 G
Gas / gas-mixture or
steam / gas-mixture or fog
Even in rare mal-
functions
very high
0
2 G
Gas / gas-mixture or
steam / gas-mixture or fog
Even with the
usual malfunctions
high
1
3 G
Gas / gas-mixture or
steam / gas-mixture or fog
In normal operation
normal
2
1 D
Dust / gas-mixture
Even in rare mal-
functions
very high
20
2 D
Dust / gas-mixture
Even with the
usual malfunctions
high
21
3 D
Dust / gas-mixture
In normal operation
normal
22
Table 18:
AHU categories
Classification according to surface temperature for devices of group II G:
Temperature class
Max. surface temperature (°C)
T1
450
T2
300
T3
200
T4
135
T5
100
T6
85
Table 19:
Temperature classes of AHU category 2 G
For devices of group II D, the maximum surface temperature is specified.
The maximum allowable surface temperature must always be lower than
the ignition temperature of the explosive atmosphere.
Summary of Contents for ZHK Series
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