Videotec EXH Bedienungsanleitung Seite 19

12.3 GOST-R Mark
Protection
level
1 Ex d
Fig. 11
12.4 Gas group classification
The table below shows the classification of some gases and vapours, according to the explosion-proof
protection group and the temperature class. For a complete list see IEC/EN 60079-12 and IEC/EN 60079-20.
T1
IIA Acetone
Ethanol
Ethyl acetate
Ammonia
Pure benzene
Acetic acid
Carbon monoxide
Methanol
Propane
Toluene
IIB
IIC Hydrogen
Tab. 01 The above temperature classes automatically cover the lower classes (T6 is better than T1).
Class IIB also covers class IIA. Class IIC also covers classes IIB and IIA.
TEMPERATURE CLASS
Maximum allowed surface temperature (°C) for the
housing* in the corresponding class
Tab. 02 * Normally refers to the maximum ambient temperature of the installation. The lower the ignition temperature of the
related explosive atmosphere, the higher should be the maximum allowed surface temperature of the housing.
The maximum surface temperature is determined for a 5mm-thick layer of powder and
the installation regulations require a margin of 75K between the surface temperature
and the ignition temperature of the powder under consideration.
Explosion-proof housing for potentially
explosive environments
Gas
group
Gas temperature
classification
T6 и
eeC
T2 T3
N-Butane Petrol
N-Butyl Diesel fuel
Avgas
Heating oil
N-Hexane
Ethylene
Acetylene
Dust ignition protection
for zone types 21-22
DIP A21 Т
A
T4
Acetaldehyde
Ether
T1 T2 T3
450 300 200
Maximum surface
temperature for dusts
Т6
T5 T6
Ethyl nitrate
Carbon
disulphide
T4 T5
135 100
T6
85
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