According to ATEX ARBO legislation and regulations directive 1999/92 / EG (ATEX 153, ATEX 137), every employer who is dealing with potentially explosive environments where employees are at a potential risk is obliged to take organizational measures and record it in a so-called Explosion Safety Document (ESD).
ESD also presents the risk inventory in which the zone layout is determined and the documentation inventory of all possible – both electrical and non-electrical – sources of ignition.
Explosion-hazardous area must be clearly marked for employees with a warning triangle which contains the text “Ex” in black on a yellow background. According to the ATEX directive, explosion-proof material that has been made suitable for use in potentially explosive areas is marked with the ‘Ex’ logo in a hexagon. With the latter characteristics, there is no duty to yellow background.
A potentially explosive area can be classified in the following danger zones:
| Zone | Description |
|---|---|
| 0 | A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapour or mist is present continuously or for long periods or frequently. |
| 1 | A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapour or mist is likely to occur in normal operation occasionally. |
| 2 | A place in which an explosive atmosphere consisting of a mixture with air of dangerous 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. |
| 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. |
| 21 | A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is likely to occur in normal operation occasionally. |
| 22 | A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is not likely to occur in normal operation but, if it does occur, will persist for a short period only. |
The classification of the danger zone for gas explosion hazard is standardised in EN-IEC 60079-10-1.
EN-IEC 60079-10-2 is a separate section for dust explosion hazard.