ATEX

What exactly does ATEX mean?

The term ATEX refers to the directive of the European Union related to explosion protection and is derived from the French abbreviation for „atmosphères explosibles“.

 

The new ATEX directives regulate throughout the EU the placing on the market and the proper use of electrical and mechanical/non-electrical equipment, protective systems and components in explosion-hazard areas for manufacturers (2014/34/EU) as well as for the operators (1999/92/EG).

 

The former directive 94/9/EG – ATEX 95 on explosion protection serves as a legal basis, it has been embedded in German law since March 1st, 1996 and regulates the use of explosion-proof equipment, protective systems and components in mining and other industries with potentially explosive atmospheres. A hazardous explosive atmosphere is created by a mixture of air and combustible gases, vapours, mists or dusts.

 

After a seven-year transition phase, the application of the explosion protection directives became obligatory from July 1st, 2003. The ATEX directive of the European Union standardised the legislation in force at the time in all EU member states and was taken as a reference until the mandatory application date on April 20th, 2016.

 

The products are subdivided into two groups: group 1 is applicable for mining, group 2 refers to all other sectors where potentially explosive atmospheres can form. Depending on the individual degree of hazard, the product is assigned to a zone. Also the frequency and duration of the formation of explosive atmospheres are evaluated and are an aspect to allocate the product according to safety criteria.

 

Ignition temperature and temperature class

temperature class
T1

>450 °C

T2

>300 °C up

to ≤ 450 °C

T3

>200 °C up

to ≤ 300 °C

T4

>135 °C up

to ≤ 200 °C

T5

>100 °C up

to ≤ 135 °C

T6

>85 °C up

to ≤ 100 °C

explosion class
II A acetone

(540 °C)

 

propane

(470 °C)

n-butane

(365 °C)

 

Dichlorethan

(440°C)

petrol

(220 - 330 °C)

acetaldehyde

(140 °C)

   
II B city gas

(560 °C)

ethylene

(425 °C)

hydrogen sulphide

(270 °C)

ethyl ether

(180 °C)

   
II C hydrogen

(560 °C)

acethylene

(305 °C)

      carbon disulphide

(95 °C)

 

TypenschildImplementation of the temperature classes

»

for ex. EX II2G IIB TX -10 ºC < Ta < 80 ºC

 

»

TX – temprature class

The max. surface temperature of the valve mainly depends on the temperature of the operating medium. The valve has a max. self-heating of 20 K

 

» Ta – ambient temperature range

 

The ignition temperature of the explosive gases should therefore be above TX +20°C internally and externally

Selection criteria for equipments and protective systems

In all places, in which explosive atmospheres may occur, the equipment and protective systems must be selected on the basis of the categories set out in the  ATEX Directive 2014/34/EU.

 

 

explosive atmosphere zone division explosive atmosphere present Equipment requirements (category)
gas zone 0 continuously, for long periods, frequently 1G
zone 1 occasionally 2G or 1G
zone 2 not, rarely or for a short time 3G, 2G or 1G
Staub zone 20 continuously, for long periods, frequently 1D
zone 21 occasionally 2D or 1D
zone 22 - conductive dust not, rarely or for a short time 2D or 1D
zone 22 - non-conductive dust not, rarely or for a short time 3D, 2D or 1D
 

Weiterführende Informationen

Widely used products

 
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