“ATEX” is an abbreviation for the ATEX Directive and is short for “Atmospheres Explosibles”. It is a set of European Union regulations that are designed to ensure the safety of products being used in explosive environments. Explosive atmospheres are work areas that contain flammable gases, mists or vapours or by combustible dusts. All it needs is a source of ignition to cause an explosion.
ATEX uses Zone numbers to distinguish between environments with different levels of danger. It is an employer’s responsibility to correctly classify the workplaces for which they are responsible. The classification given to a zone depends on the likelihood of an explosive atmosphere occurring and its persistence if it does. ATEX distinguishes between explosive atmospheres that arise because of gases, vapours and mists and those that arise from dust.
ATEX Zone 0 is the most hazardous workplace type where gases, vapours and mists are present.
The zone classifications for gases, vapours and mists are directly relevant to oil and gas platforms, drilling rigs and storage facilities.
Gases, vapours and mists
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.
The zone classifications for dusts are pertinent to underground mines.
Dusts
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 in normal operation occasionally.
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 in normal operation but, if it does occur, will persist for a short period only.