ATEX Explained
The ATEX regulations and labelling rules have evolved over many years and are complicated, our UK-based team are happy to help with specialist advice to ensure sustained performance.
The ATEX Explosion Protection regulations
When mechanical or electrical equipment is to be situated in a hazardous area it must be ATEX certified as required by the EU directive 94/9/EC. This directive is more commonly known as the ATEX directive.
Hazardous areas are those where a potentially explosive mix of air and flammable gasses or air and dust or air, dust and gasses may occur.
Outside of the European Union similar regulations apply under the IECEX certification system. In North America products must be listed by UL as suitable for use in hazardous atmospheres. Please note that while the ATEX and IECEX certification system are similar, the North American approach is different; see area classification below.
Scope of ATEX
ATEX certification of products for use in potentially hazardous atmospheres is compulsory.
Classification of ATEX equipment
The ATEX directive classifies equipment into groups and categories which are defined by the marking on the equipment – see “Product marking” below.
Classification of an ATEX area
Hazardous areas are divided into Zones (European and IECEX method) or Classes and Divisions (North American method) according to the likelihood of a potentially explosive atmosphere being present.
| Equipment Group |
Equipment Category (ATEX) |
Equipment Protection Level |
Atmosphere Type |
Level of Ignition Protection |
Required Protection Performance & Operation | |
| Gas | Dust | |||||
| I | MI | Ma | Ma | Methane & Dust | Very High | Two faults, remain energised & functioning |
| I | M2 | Mb | Mb | Methane & Dust | High | Severe normal operation, de-energise in explosive atmosphere |
| II | 1 | Ga | Da | Gas, Vapour, Mist, Dust | Very High | Two faults |
| II | 2 | Gb | Db | Gas, Vapour, Mist, Dust | High | One fault |
| II | 3 | Gc | Dc | Gas, Vapour, Mist, Dust | Low | Normal operation |
The ATEX directive requires the product to be marked with the CE mark, the ‘EX’ mark and the equipment coding as per table below.
|
Heading |
Mark |
Use |
|
Explosion proof |
|
in accordance with the ATEX directive |
|
Equipment Group |
I |
For use in underground mines |
|
II |
For use in all other places |
|
|
Category |
1 |
Equipment that is intended for use in areas where an explosive atmosphere is present continuously, for long periods or frequently |
|
2 |
Equipment that is intended for use in areas where an explosive atmosphere is likely to occur in normal operation and must ensure a high level of protection. |
|
|
3 |
Equipment that is intended for use in areas where an explosive atmosphere is unlikely to occur in normal operation and must ensure a normal level of protection. |
|
|
Gas / Dust |
G |
Equipment certified for use in flammable gases |
|
D |
Equipment certified for use where dust is present in the atmosphere |
|
|
Type of Protection* |
d |
Flameproof |
|
Ia |
Intrinsically Safe |
|
|
e |
Increased safety |
|
|
Gas Group |
I |
Mines |
|
II |
Surface above ground industries |
|
|
Gas Sub Group |
A |
Less easily ignited gases e.g. propane |
|
B |
Easily ignited gases e.g ethylene |
|
|
C |
Most easily ignited e.g. hydrogen or acetylene |
|
|
Temperature Classification |
T1 |
450ºC |
|
T2 |
300ºC |
|
|
T3 |
200ºC |
|
|
T4 |
135ºC |
|
|
T5 |
100ºC |
|
|
T6 |
85ºC |
* There are 8 methods of protection, for simplicity we have listed the 3 most commonly used.
ATEX Product marking example
An ATEX approved electrical product is marked with the following code:
|
II 2G Eexd IIB T4 |
From the breakdown of the code below it can be seen that the product is flameproof, suitable for use in zone 1 surface applications where gas group B gases may be present and the surface temperature of the product under fault conditions will not exceed 135 ºC.
|
|
Explosion proof in accordance with ATEX |
|
II |
Equipment group: II surface industries. |
|
2 |
Category: 2 equipment ( suitable for use in Zone 1) |
|
G |
Gas / Dust: Suitable for atmospheres containing gas |
|
E |
European certificate in accordance with harmonised standards |
|
Ex |
Explosion-proof electrical equipment |
|
d |
Type of protection is ‘Flameproof enclosure’ |
|
II |
Gas Group II – surface industries |
|
B |
Gas sub group = B |
|
T4 |
Temperature class T4 |
UK ATEX Making
In the UK from the 1st January 2023 the UK CA mark along with the registration of a UK based notifying body must also be incorporated onto ATEX product labelling
