Places in the presence of flammable vapors or gases .
These possible formation of explosive atmospheres at any time , for example, the areas of transfer of liquid explosives, paint booths , storage of solvents , etc. .
Are subdivided according to the probability of the presence of explosive atmosphere :
- Zone 0 : permanent presence or for extended periods of time.
- Zone 1 : capable of forming in normal working conditions .
- Zone 2 : presence unlikely and short periods .
Security principles to consider are:
- Explosion risk areas should be as small as possible.
- The presence of electrical equipment will be minimized and will be protected in accordance with the area.
Places in the presence of combustible dust .
As an example we can mention grain silos , mills , coal processing plants , fertilizer plants , etc. .
Within this class are distinguished :
- Area 20 : It is one in which there is or may have combustible dust operations during normal operation , start-up or cleaning , in sufficient quantity to produce an explosive atmosphere . Example: in mills sprayers .
- Area 21 Is that where the cloud or dust layer is likely to form in normal working conditions .
- Area 22 : presence unlikely and short periods .