Morclean Ltd : ATEX Models

What does ATEX stand for? ATEX is named after the French ATmosphere EXplosible, which mean explosive atmosphere.

In which countries is ATEX in force? All the 24 member countries (incl. Norway, Iceland and Liechtenstein) of the European Union are subject to the directives. Manufacturers, who comply with its provisions and affix the CE and EX marking, are able to sell their equipment anywhere in the European Union.

In which areas is ATEX in force? ATEX is in force in all areas where explosive atmosphere is present. An explosive atmosphere for the purposes of directive 94/9/EC is defined as a mixture
i) of flammable substances in the form of gases, vapours, mists or dusts;
ii) with air;
iii) under atmospheric conditions;
iv) in which, after ignition, the combustion spreads to the entire unburned mixture (it has to be noted that in the presence of dust not always the whole quantity of dust is consumed by the combustion).

Which equipment must comply with ATEX? In very broad terms, there are three pre-conditions for the Directive to apply: the equipment
i) must have its own source of ignition;
ii) be intended for use in a potentially explosive atmosphere (air mixtures); and
iii) be under normal atmospheric conditions.

How does ATEX classify hazardous areas?
The hazardous places are classified into zones based on the frequency and duration of a hazardous explosive atmosphere:

Gas, Mists or Vapours
Zone 0 - An atmosphere where a mixture of air and flammable substances in the form of gas, vapour or mist is present frequently, continuously or for long periods.
Only Category I equipment can be used in Zone 0

Zone 1 - An atmosphere where a mixture of air and flammable substances in the form of gas, vapour or mist is likely to occur in normal operation occasionally.
Only Category I and II equipment can be used in Zone 1

Zone 2 - An atmosphere where a mixture of air and 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 only a short period.
Category I, II and III can be used in Zone 2

Dusts
Zone 20 - An atmosphere where a cloud of combustible dust in the air is present frequently, continuously or for long periods.
Zone 21 - An atmosphere where a cloud of combustible dust in the air is likely to occur in normal operation occasionally.
Zone 22 - An atmosphere where a cloud of combustible dust in the air is not likely to occur in normal operation but, if it does occur, will persist for only a short period.

Category I equipment - equipment with a very high level of protection
Category II equipment - equipment with a high level of protection
Category III equipment - equipment with a normal level of protection