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| Hazardous Area Equipment
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Zones
| Zones |
|
Definitions |
Category
Atex |
Equipment Integrity |
| Gases and Vapours |
Dusts |
|
G Gas
D Dust |
|
|
0
|
20
|
Explosive atmosphere is present continuously, frequently or for long periods
|
1G
1D
|
Safe under normal operation or rare malfunction
|
|
1
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21
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Explosive atmosphere is likely to occur under normal operation
|
2G
2D
|
Safe under normal operation or rare malfunction
|
|
2
|
22
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Explosive atmosphere may occur under abnormal operation and persist for a short period
|
3G
3D
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Equipment must be safe under normal operation
|
Protection Concepts
| Electrical |
Symbol |
Zones |
Standard |
Concept |
| |
|
|
|
|
| Flameproof |
d |
1 and 2 |
IEC BS EN 60079-1 |
Contains explosion and flame quenched |
| Increased safety |
e |
1 and 2 |
IEC BS EN 60079-7 |
No arcs, sparks or hot surfaces |
| Non-Sparking |
nA |
2 |
IEC BS EN 60079-15 |
No arcs, sparks or hot surfaces |
| Pressurised |
p |
1 and 2 |
IEC BS EN 60079-2 |
Keep flammable gas out |
| Oil immersed |
o |
1 and 2 |
IEC BS EN 60079-6 |
Keep flammable gas out |
| Restrictive breathing |
nR |
2 |
IEC BS EN 60079-15 |
Keep flammable gas out |
| Simple pressurised |
nZ |
2 |
IEC BS EN 60079-15 |
Keep flammable gas out |
| Quartz or sand filled |
q |
1 and 2 |
IEC BS EN 60079-5 |
Contains explosion and flame quenched |
| Encapsulation |
ma |
0,1 and 2 |
IEC BS EN 60079-18 |
Keep flammable gas out |
| Encapsulation |
mb |
1 and 2 |
IEC BS EN 60079-18 |
Keep flammable gas out |
| Enclosed break |
nC |
2 |
IEC BS EN 60079-15 |
Contains explosion and flame quenched |
| Energy limiting |
nL |
2 |
IEC BS EN 60079-15 |
Limit spark energy and surface temperatures |
| Intrinsic safety |
ia |
0,1 and 2 |
IEC BS EN 60079-11 |
Limit spark energy and surface temperatures |
| Intrinsic safety |
ib |
1 and 2 |
IEC BS EN 60079-11 |
Limit spark energy and surface temperatures |
| Intrinsic safety |
ic |
2 |
IEC BS EN 60079-11 |
Limit spark energy and surface temperatures |
| |
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| Dust |
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| |
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| Enclosure |
tD |
20,21 and 22 |
IEC BS EN 61241-1 |
|
| Pressurisation |
pD |
21 and 22 |
IEC BS EN 61241-2 |
|
| Encapsulation |
maD |
20,21 and 22 |
IEC BS EN 61241-18 |
|
| Encapsulation |
mbD |
21 and 22 |
IEC BS EN 61241-18 |
|
| Intrinsic safety |
iaD |
20,21 and 22 |
IEC BS EN 61241-11 |
|
| Intrinsic safety |
ibD |
21 and 22 |
IEC BS EN 61241-11 |
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| Mechanical |
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| |
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| Constructional safety |
c |
0,1,2,20,21 and 22 |
BS EN 13463-5 |
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| Liquid immersion |
k |
0,1,2,20,21 and 22 |
BS EN 13463-8 |
|
| Pressurisation |
p |
1,2,21 and 22 |
BS EN 13463-7 |
|
| Ignition source control |
b |
0,1,2,20,21 and 22 |
BS EN 13463-6 |
|
| Inherent safety |
g |
0,1,2,20,21 and 22 |
BS EN 13463-4 |
|
| Flow restricting enclosure |
fr |
2 and 22 |
BS EN 13463-2 |
|
| Flameproof enclosure |
d |
1,2,21 and 22 |
BS EN 13463-3 |
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Gas Groups
| Gas Group |
Typical Gases |
| I |
Methane |
| IIA |
Benzene
Propane
|
| IIB |
Ethylene
Hydrogen Sulphide
|
| IIC |
Hydrogen |
Full list of classification can be found in BS EN IEC 60079-20
Temperature Class
|
Group II
Surface
|
|
Group I
Mining
|
| Maximum surface temperature °C |
Temperature Class |
Maximum surface temperature °C |
| 450 |
T1 |
450°C without coal dust layer |
| 300 |
T2 |
150°C with coal dust layer |
| 200 |
T3 |
|
| 135 |
T4 |
|
| 100 |
T5 |
|
| 85 |
T6 |
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