Introduction and Definition of Hazardous Areas

        What are ATEX Zones?

According to the ATEX Directive there are different areas within explosive atmospheres that need to be classified according to the potential hazardous risk that each area presents, and only appropriate certified equipment can be used in each area. These different areas are divided into three classifications, also known as zones. For explosive atmospheres from gases and vapours, these zones would be Zone 2, Zone 1, and Zone 0. For explosive atmospheres from dust, the zones are Zone 22, Zone 21, and Zone 20. Each zone classification depends on the level of risk with Zone (2)2 being the least risky and Zone (2)0 being the most. With the ATEX Directive, all electrical equipment is classified according to these zones and thus certifies in which areas it can be safely used. More on the how to determine ATEX zones follows.

       How to determine ATEX zones

           The ATEX directive covers explosive atmospheres from gases and vapours as well as solid dust, which contrary to what you might think, can also lead to explosions.

            ATEX ZONES FOR GASES/VAPOURS

• Zone 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.
• Zone 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.
• Zone 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.