SIEMENS
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Siemens D 83.1 · 2016
2
Motors with Explosion Protection
Orientation
■
Overview
(continued)
Temperature classes and groups
Combustible gases and vapors are divided into temperature
classes according to their ignitability and into groups according
to their spark ignition capacity. The marking of a three-phase
motor with the codes for the type of protection, group and tem-
perature class specifies that it can be used without danger
in hazardous areas depending on the zone classification. The
numerical sequence of the codes for the group and temperature
class has been selected so that motors that satisfy the require-
ments for a certain group and temperature class also satisfy the
requirements for lower groups and classes.
Temperature classes
Examples of the assignment of combustible gases and vapors
Temperature class
of electrical
equipment
Maximum surface
temperature of electrical
equipment
Ignition
temperature of
gases or vapors
T1
450 °C
> 450 °C
T2
300 °C
> 300 °C
T3
200 °C
> 200 °C
T4
135 °C
> 135 °C
T5
100 °C
> 100 °C
T6
85 °C
> 85 °C
Group
Temperature classes
T1
T2
T3
T4
T5
T6
Material
designation
Ignition
tem-
perature
°C
Material
designation
Ignition
tem-
perature
°C
Material
designation
Ignition
tem-
perature
°C
Material
designation
Ignition
tem-
perature
°C
Material
designa-
tion
Ignition
tem-
perature
°C
Material
designa-
tion
Ignition
tem-
perature
°C
IIA
1)
Acetone
540
i-amyl acetate
380
Benzine
Acetalde-
hyde
140
Ethane
515
n-butane
365
Gasoline
2)
Ethyl acetate
460
n-butyl
alcohol
340
Special
benzine
2)
Ethyl chloride
510
Cyclohexa-
none
430
Diesel fuel
2)
Ammonia
630
1.2-dichloro-
ethane
440
Heating oils
2)
Benzene
555
Acetic acid
anhydride
330
n-hexane
240
Acetic acid
485
Carbon
monoxide
605
Methane
595
Methanol
455
Methyl
chloride
625
Naphthalene
520
Phenol
595
Propane
470
Toluene
535
IIB
1)
Town gas
(illuminating
gas)
560
Ethyl alcohol
425
Hydrogen
sulfide
270
Ethyl ether
180
Ethylene
425
Ethylene
oxide
440
IIC
1)
Hydrogen
560
Acetylene
305
Carbon
disulfide
95
1)
Subgroups IIA, IIB and IIC must be specified for the Ex nA and Ex de types
of protection described in this list in accordance with EN 60079-0.
2)
The minimum ignition temperature depends on the composition and lies
between 220 and 300 °C, over 300 °C in special cases.
© Siemens AG 2016