Euroclima ZHK, Руководство пользователя

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Instruction Manual ZHK
V07-21.0 129/140
The device-specific explosion protection measures of this category (outside) must provide the nec-
essary security at disturbances and error states, which usually must be considered.
11.3 Supplementary notes on AHU design
Unit cate-
gory
Designed for kind
of explosive at-
mosphere
Usage in
zone
Explanation
EPL: Equipment protec-
tion level
1 G
gas / air mixture or
steam air mixture or
fog
0
Explosive atmo-
sphere perman-
ently present
Ga:
Safety in normal operation
usual and rare operation
disturbances / in case of 2
independent failures
2 G
gas / air mixture or
steam air mixture or
fog
1
Explosive atmo-
sphere occasio-
nally present
Gb:
Safety during normal oper-
ation and usual operation
disturbances
3 G
gas / air mixture or
steam air mixture or
fog
2
Explosive atmos-
phere rarely and
only for a short
time
Gc:
Safety in normal operation
1 D Dust air mixture 20
Explosive atmo-
sphere perman-
ently present
Da:
Safety in normal operation
usual and rare operation
disturbances / in case of 2
independent failures
2 D Dust air mixture 21
Explosive atmo-
sphere occasio-
nally present
Db:
Safety during normal oper-
ation and usual operation
disturbances
3 D Dust air mixture 22
Explosive atmos-
phere rarely and
only for a short
time
Dc:
Safety in normal operation
Table 22:
AHU categories
11.4 Ignition temperature and temperature classes
The ignition temperature of a flammable gas, vapor or dust is the lowest temperature of a heated
surface at which the ignition of the gas/air mixture or vapor/air mixture occurs. It is practically the
lowest temperature value at which a hot surface can ignite the corresponding volatile atmosphere
and lead to explosion.