Heinrichs Messtechnik GmbH
Page 6 of 12
Ex-Supplement operating manual V31
3.
Basic technical principles of explosion protection
Ac
c.
Di
rec
tiv
e 2
01
4/3
4/E
U
(A
TEX
)
Example designation
0158
II 2G
Ex
h
IIC
T6 Gb
Equipment groups
I
Equipment group I applies to equipment intended for use in underground
parts of mines as well as those parts of surface installations of such mines
endangered by firedamp and/or combustible dust.
II
Equipment group II applies to equipment intended for use in other places
liable to be endangered by explosive atmospheres. This group is subdivided
into three categories.
Equipment category
Gas
Dust
Definition
1G
(0)
1 D
(20)
Equipment in this category is intended for use in areas in which
explosive atmospheres caused by mixtures of air and gases,
vapours or mists or by air/dust mixtures are present continuously, for
long periods or frequently.
2 G
(1)
2 D
(21)
Equipment in this category is intended for use in areas in which
explosive atmospheres caused by gases, vapours, mists or air/dust
mixtures are likely to occur.
3G
(2)
3D
(22)
Equipment in this category is intended for use in areas in which
explosive atmospheres caused by gases, vapours, mists, or air/dust
mixtures are unlikely to occur or, if they do occur, are likely to do so
only infrequently and for a short period only.
(The numbers in round brackets correspond to the IEC Zones.)
Ac
c. E
N 60
07
9-
0
ff
Ex = Explosion-proof equipment
Examples of electrical types of protection
General requirements
EN DIN 60079-0
„d“
Flameproof enclosure (db, dc)
EN DIN 60079-1
„e“
Increased safety (eb, ec)
EN DIN 60079-7
„i“
Intrinsic safety (ia, ib, ic)
EN DIN 60079-11
„t"
Equipment dust ignition protection by
enclosure "t" (ta, tb, tc)
EN DIN 60079-31
Non-electrical types of protection
„h“
Basic Method and requirements
DIN EN ISO 80079-36
Explosion groups
Gases and vapours
IIA
Acetone, benzene, fuel oil, ethanoic acid
IIB
City gas, ethylene, isoprene
IIC
Acetylene, hydrogen, carbon bisulphide
Dust Atmospheres
IIIA
Fibers and flyings
IIIB
Non-conductive dusts
IIIC
Metal dusts
Temperature classes
Maximum surface temperature
Temperature class
450 °C
842 °F
T1
300 °C
572 °F
T2
200 °C
392 °F
T3
135 °C
275 °F
T4
100 °C
212 °F
T5
85 °C
185 °F
T6
Equipment protection level,
EPL
Gases: Ga, Gb oder Gc
Dust: Da, Db or Dc
Explosion protection designations [square brackets]
refer to “Related electrical equipment or circuits.”
