A.3 Gas Group Classification - Stahl EC-940-PTZ-HF Série Manuel D'instructions

A.3 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/EN60079-12 and IEC/EN60079-20.
GAS GROUP CLASSIFICATION
Temperature class (Maximum surface temperature of the housing) 1
Class T1
450°C (842°F)
I Methane
IIA Acetone
Ethanol
Ethyl acetate
Ammonia
Pure benzene
Acetic acid
Carbon monoxide
Methanol
Propane
Toluene
IIB
IIC Hydrogen
Tab. 10
1 A higher temperature class automatically covers a lower one (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 corre-
sponding class
Tab. 11
Normally referred to the maximum ambient temperature of installation. The lowest ignition temperature of the explosive
atmospheres must be higher than the maximum surface temperature of the housings.
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.
44
T2 T3
300°C (572°F) 200°C (392°F)
N-Butane Petrol
N-Butyl Diesel fuel
Avgas
Heating oil
N-Hexane
Ethylene
Acetylene
T4 T5
135°C (270°F) 100°C
Acetaldehyde
Ether
T1 T2 T3
450 300 200
T6
85°C (185°F)
Ethyl nitrate
Carbon disulphide
T4 T5 T6
135 100 85
MNTCMPXHDB_1824_EN