_
Your Safety Our Reality
Electrical equipment
ATEX
IEC/CENELEC
NEC 505
II (1)2 G
Ex d [ia Ga]
Ex d [ia Ga]
Class I, Zone 1 AEx d [ia]
IIC
IIC
IIC
T4 Gb*
T4 Gb*
T4
IEC/CENELEC (old)
Ex
d [ia]
IIC
T4
IEC/CENELEC (alternate)
Ex
db [ia]
IIC
T4
IEC/CENELEC (dust)
Ex
tb
IIIC
T90C
Group C,D
T4
NEC 500
Class I, Division 1
Non-electrical equipment
Db*
ATEX
II 2 G
ck IIC T6
* When using the alternate symbols, the EPL can be left out.
Types of protection for electrical equipment in explosive gas atmospheres
Type of protection
Symbol
Zone
Diagram
Equipment category and Equipment protection level (EPL)
Main application
Standard
acc. to EU-directive 94/9/EG
(ATEX)
junction boxes, control stations for installing
Ex-components (with a different type
of protection), squirrel-cage motors, light
fittings
IEC 60079-7
EN 60079-7
ISA 60079 -7
Group
switchgears, control stations, indicating
equipment, control systems, motors,
transformers, heating equipment, light fittings
IEC 60079-1
EN 60079-1
ISA 60079-1
standard alternate
increased
safety
flameproof
enclosures
pressurized
enclosures
intrinsic safety
oil immersion
powder filling
encapsulation
type of protection n
optical radiation
eb
db
px
py
pz
pxb
pyb
pzc
1
1
2
switchgear and control cabinets, analysers,
large motors
ia
ib
ic
ia
ib
ic
0
1
2
instrumentation technology,
fieldbus technology, sensors, actuators
[Ex ib] = associated electrical apparatus
installation in the safe area
ob
qb
ma
mb
mc
0
1
2
nA
nC
nR
nAc
nCc
nRc
2
2
2
all electrical equipment for Zone 2
nA = non-sparking device
nC = sparking devices and components
nR = restricted breathing enclosures
op _
op _
op _
op _ a
op _ b
op _ c
0
1
2
op is = inherently safe optical radiation
op pr = protected optical radiation
op sh = optical radiation interlock
protection by
enclosures
pressurization
ta
tb
tc
ta
tb
tc
pb
pc
20
21
22
21
22
old identification:
tD A21 = under procedure A for Zone 21
tD B21 = under procedure B for Zone 21
switchgear and control cabinets, motors
old identification: pD21, pD22
intrinsic safety
encapsulation
ID 103061
ia
ib
ic
ma
mb
mc
ia
ib
ic
ma
mb
mc
20
21
22
20
21
22
S-PB-Ex-Plakat-elektr.+mech.- 06 v-en-12/2011
M1
Ma
during rare malfunctions
M2
Mb
until de-energizing of the equipment
Explosive gas atmosphere
IEC 60079-2
EN 60079-2
ISA 60079-2
II
2G
Gb
Zone 1
during expected malfunctions
II
3G
Gc
Zone 2
in normal operation
IEC 60079-11
EN 60079-11
ISA 60079-11
Explosive dust atmosphere
IEC 60079-6
EN 60079-6
ISA 60079-6
IEC 60079-5
EN 60079-5
ISA 60079-5
IEC 60079-18
EN 60079-18
ISA 60079-18
IEC 60079-15
EN 60079-15
ISA 60079-15
IEC 60079-28
EN 60079-28
IEC 60079-31
EN 60079-31
IEC 61241-1
EN 61241-1
ISA 61241-1
IEC 61241-4
EN 61241-4
ISA 61241-2
instrumentation technology,
fieldbus technology, sensors, actuators
[Ex ib] = associated electrical apparatus
installation in the safe area
IEC 60079-11
EN 60079-11
old identification:
iaD = for use in Zone 20, 21, 22
ibD = for use in Zone 21, 22
IEC 61241-11
EN 61241-11
ISA 61241-11
switchgear with small capacity, control and
signalling units, display units, sensors
IEC 60079-18
EN 60079-18
ISA 61241-18
old identification:
maD = for use in Zone 20, 21, 22
mbD = for use in Zone 21, 22
Mines susceptible to firedamp
during rare malfunctions
Types of protection for electrical equipment in explosive dust atmospheres
switchgear, control stations, junction boxes,
control boxes, motors, light fittings
Sufficient security
Zone 0
IEC 60079-27
EN 60079-27
ISA 60079-27
ma
mb
mc
EPL
Ga
FISCO: fieldbus intrinsically-safe concept
switchgear with small capacity, control and
signalling units, display units, sensors
Equipment category
IEC/CENELEC/NEC 505
1G
IEC 60079-25
EN 60079-25
sensors, display units, electronic ballasts,
transmitters
acc. to
IEC and CENELEC
II
intrinsically safe systems
transformers, starting resistors
Groups
II
1D
Da
Zone 20
during rare malfunctions
II
2D
Db
Zone 21
during expected malfunctions
II
3D
Dc
Zone 22
in normal operation
(1)G associated apparatus installation in non-hazardous area
Group I
NEC 500
Mines susceptible to firedamp
Methane
Group II
Explosive gas atmosphere
Subdivisions
Class I
Typical gas
Subdivisions
IIA
Propane
Propane
Class I Group D
IIB
Ethylene
Ethylene
Class I Group C
IIC
Hydrogen
Hydrogen
Class I Group B
Acetylene
Acetylene
Class I Group A
Group III *
Explosive dust atmosphere
Subdivisions
Typical dust
Class II/III
Subdivisions
IIIA
combustible flyings
fibers/flyings
Class III
IIIB
non-conductive dust
non-conductive dust
Class II Group G
IIIC
conductive dust
carbonaceous dust
Class II Group F
combustible metal dust
Class II Group E
* acc. to IEC (2007) and CENELEC (2009)
Zones
Dangerous
explosive atmosphere
CENELEC/IEC/NEC 505
Gas
Continously, longterm
or frequently
Occasionally
Not likely to occur and
for short period only
Zone 0
Zone 1
Zone 2
NEC 500 (Class I)
Dust
CENELEC/IEC/NEC 506
Division 1
Zone 20
NEC 500 (Class II, III)
Division 2
Zone 21
Division 1
Zone 22
Division 2
Types of protection for non-electrical equipment in gas and dust atmospheres
Type of protection
constructional
safety
Diagram
c
Main application
Standard
couplings, pumps, gear drives, chain drives,
belt drives
EN 13463-5
Temperature classification
Maximum
surface
temperature
Gas Temperature Classes
Equipment marking
NEC 500
CENELEC/
IEC/NEC 505
450C
T1
T1
300C
T2
T2
280C
brakes, couplings
EN 13463-3
pressurisation
pumps
pumps
EN 60079-2
control of
ignition sources
pumps, beld drives
EN 13463-6
liquid immersion
submerged pumps, gears
EN 13463- 8
flow restricting
enclosure
fr
equipment only for Zone 2 or Zone 22
EN 13463-2
Equipment marking
NEC 500
CENELEC/
IEC/NEC 505
200C
T3
T3
180C
T3 A
T2 A
165C
T3 B
260C
T2 B
160C
T3C
230C
T2 C
135C
T4
215C
T2 D
120C
T4A
100C
T5
T5
85C
T6
T6
Dust: indication of the max. surface
temperature in C
flameproof
enclosures
Maximum
surface
temperature
Gas Temperature Classes
T4
R. STAHL is one of the globally leading suppliers
of explosion protected equipment and systems like:
> Instrumentation > Switching and Distribution
> Installation
> Signalling and Alarming
> Lighting
> Operating and Monitoring
R. STAHL, Am Bahnhof 30, 74638 Waldenburg, Germany
Phone + 49 7942 943 - 0, Fax + 49 7942 943 - 4333, info.ex @ stahl.de
www.stahl.de
