| Zone 0 |
Continuously hazardous (protection technique allowed)
Exia intrinsic safety |
|
|
|
|
Zone 1 |
Frequently hazardous (protection technique allowed)
Exib intrinsic safety
Exd flameproof
Exe increased safety
Exp pressured or purged
Exv ventilation
Exs special protection |
|
|
|
|
Zone 2 |
Infrequently hazardous (protection technique allowed)
Exn Non-sparking |
|
|
|
|
Group II |
Classification (protection technique allowed)
DIP dust - excluding ignition proof:- the new DIP standard will reflect 3 zones for dust areas, zone 20, 21 and 22 |
GROUP II hazardous area zones
Gas/Vapour area zones
|
 |
Dust area zones |
 |
The classification of Zone is a complex problem but the main factors to consider are:
- The probability of the presence of gas
-
The quantity and duration of hazardous vapour
-
The amount of ventilation
-
The nature of gas: lighter or heavier than air
The consequence of an explosion:
The division of plant or parts into zones is generally undertaken by the supervisory authority in that industry in tandem with process engineers / chemists at the design and construction stage.
|
