Protection principles |
||||
|
The protection principles can be equally applied to electrical and non-electrical equipment and for gases and dust. The principles allow for design in various safety categories in accordance with the Directive 94/9/EC. |
||||
 |
||||
| category 1 |
with maximum scope of protection and thus a very high degree of safety |
|||
| category 2 |
with increased scope of protection and therefore a high degree of safety |
|||
| category 3 |
with conventional scope of protection and therefore a conventional degree of safety |
|||
 |
 |
|||
| Zone 0 |
A place in which an explosive atmosphere consisting of a mixture with air of flammable substances in the form of gas, vapour or mist is present continuously or for long periods or frequently. |
|||
| Zone 1 |
A place in which an explosive atmosphere consisting of a mixture with air of flammable substances in the form of gas, vapour or mist is likely to occur occasionally during normal operation. |
|||
| Zone 2 |
A place in which an explosive atmosphere consisting of a mixture with air of flammable substances in the form of gas, vapour or mist is not likely to occur in normal operation but, if it does occur, will persist for a short period only. |
|||
| Zone 20 |
A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is present continuously, or for long periods or frequently. |
|||
| Zone 21 |
A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is likely to occur occasionally during normal operation. |
|||
| Zone 22 |
A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is not likely to occur during normal operation but, if it does occur, will persist for a short period only. |
|||