What does ATEX mean?
ATEX is an acronym and is derived from “Atmosphère Explosible” (French for explosive atmosphere).
ATEX is the directive 94/9/EC dated 23 March 1994 concerning equipment and protective systems intended for use in potentially explosive atmospheres.
Why explosion protection?
Explosive atmospheres are a constant hazard in the mining, chemical and petrochemical industries
because of the processing techniques used. These explosive atmospheres are caused by escaping gas, vapours and mist, for example. Explosive atmospheres must also be
anticipated in mills, silos and sugar and feed processing plants.
ATEX directive 94/9/EC
Since 1 July 2003, non-electrical equipment in potentially explosive areas has also been subject to a special directive, the ATEX directive 94/9/EC. This directive is also known as the ATEX 95 (unofficial designation).
This directive was transposed into German law on 12 December 1996. This directive has been in force since 1 July 2003, and has replaced the old regulations.
Equipment group/ Category/ Zone
The relationship between equipment group, categories and zones is most easily shown using a graphic.
Equipment group I has been greyed out in the graphic as Festo does not provide components for this area.
What is the difference between category 2 and category 3?
Category 3 (zones 2 and 22):
Normal level of safety
Unexpected explosive atmospheres, rare, short duration
Category 2 (zones 1 and 21):
High degree of safety
Operation with device faults (1 error)
Occasional explosive atmospheres possible.
The temperature classes reflect the permissible surface temperatures of the equipment. Equipment which is approved for a temperature class T6 conforms to stricter requirements than the other temperature classes and can be used in the lower temperature classes T1 to T5.
T1 450 °C
T2 300 °C
T3 200 °C
T4 135 °C
T5 100 °C
T6 85 °C
What does "intrinsically safe" mean?
The voltage and/or current (power) in an intrinsically safe circuit is so low
that a potentially explosive atmosphere cannot be ignited as the result of a short circuit,
interruption or earth fault.
The ignition energy of any possible spark is smaller than the
minimum ignition energy of the potentially explosive atmosphere.
Neither a spark nor a thermal effect will ignite the
potentially explosive atmosphere.
A piece of equipment is defined as intrinsically safe if all
its circuits can be defined as intrinsically safe. The current and voltage in an
intrinsically safe circuit are so low that, on short circuit,
interruption or earth fault, a potentially explosive atmosphere cannot be
ignited. This means that the ignition energy of any possible spark is
smaller than the minimum ignition energy of the potentially explosive atmosphere.
Festo offers components as well as complete solutions such as control cabinets and mounting plates for the explosion protection area. Simply contact our competent specialist staff.