What Is ATEX?
ATEX refers to two EU directives that outline the essential safety measures that must be implemented in workplaces and equipment in explosive atmospheres.
ATEX stands for “ATmosphères EX”, which is derived from the term in French, Appareils destinés à être utilisés en ATmosphèLorem ipsum dolor sit amet, consectetur adipiscing elit. res EXplosives (“Devices intended for use in explosive atmospheres” in English )
What Is An Explosive Atmosphere?
Explosive atmospheres are the common working environments where oxygen and flammable gases, vapors, or powder exist at the saLorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo.me time, according to DSEAR (Dangerous Substances and Explosive Atmospheres Regulations)
And when an ignition source is added, it can pose an explosion immediately.
ATEX95 and ATEX37 are issued directives by the European Union to prevent this kind of disaster in those hazardous areas
Besides ATEX, IEC Ex Standards (ILorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo.nternational Electrotechnical Commission) is a similar regulation, but unlike ATEX, which is mandatory in EU, IEC Ex is used globally.
NEC Standards (National Electrical Code) are employed in North America (U.S. and Canada)
Compared with ATEX and IECEX, the regulation of North America is quite different, refer to the section below about the classification of an area.
Both ATEX and IECEX are European standards, they both divide hazardous locations into “zone0”, “zone1”, “zone2”.
The main difference between them is: ATEX is applied in the European Union, while IECEX is applied outside of the EU globally;
ATEX certification is the process of giving certificates to products and equipment for importation, sale, installation, and use in the European Union market.
ATEX certification is also known as ATEX approval.
The ATEX Approval process is carried out by a third-party organization, AKA notified body in the Atex certificates label, the notified body has been officially designated by European Union to implement conformity assessment procedures, check the PDF to see where the notified body is listed in the product marking.
The authorized organization will test the equipment to see whether it is functionally and structurally pursuant to the requirements of ATEX Directives.
If they pass the testing, the agency will issue ATEX certificates indicating their type of protection, where it can be used, protection levels, and so on. These information will be listed in the product marking, refer to the following section about product marking.
ATEX certificates are compulsory for products/equipment that are intended to use in explosive atmospheres according to the ATEX equipment directive 2014/34/EU(also known as ATEX95), and the “Ex” logo must be shown on the equipment. The products/equipment includes electrical and non-electrical ones, as well as protective systems.
EN60079 includes a series of standards, such as EN60079-1, EN60079-7, EN60079-11, EN60079-2, EN60079-18, and so on.
Each standard defines a specific protection type and principle for ATEX-certified equipment, for example, EN60079-11 is for the type of protection: intrinsic safety, refer to the PDF file labeling of explosion-proof equipment to learn more.
ATEX Directives control the manufacture, installation, and use of equipment in explosive atmospheres, including electrical and non-electrical items.
Its rating(classification) measure includes two parts:
- Equipment
- Working areas
For products/equipment: Refer to “Product Marking” below
For working areas: ATEX and IECEX divide the hazardous areas into zones.
P.S.: Instead of zones, North American regulation uses “Divisions” to define the classification of an area, refer to the below table to check their relationships.
| ATEX & IECEX classification | Definition of zone or division | North American classification |
| Zone 0 (gases) | An area where the flammable substance is present continuously or for a long period | Class I Division 1 (gases) |
| Zone 20 (dusts) | Class II Division 1 (dusts) | |
| Zone 1 (gases) | An area where the flammable substance is likely to present under correct operation | Class I Division 1 (gases) |
| Zone 21 (dusts) | Class II Division 1 (dusts) | |
| Zone 2 (gases) | An area where the flammable substance is not likely to present under correct operation and if it occurs it will only last for a short time | Class I Division 2 (gases) |
| Zone 22 (dusts) | Class II Division 2 (dusts) |
You can also refer to the picture below about their relationship of both two regulation system.
Besides the CE mark and “Ex” logo, ATEX also requires the equipment to have equipment coding(e.g. Ex II 2G Eexd IIB T4) to show the detailed classification of the products, such as types of protection, temperature classification, and where it can be used.
The equipment codings are explained in the below table
| Mark Type | Mark | Use |
| Explosion proof | Ex | pursuant to the ATEX directives |
| Equipment Group | I | Can be used in underground mines |
| II | Can be used in all other places | |
| Equipment Category | 1 | Equipment that is intended for use in an area where the flammable substance is present continuously or for a long period |
| 2 | Equipment that is intended for use in an area where the flammable substance is likely to present under correct operation | |
| 3 | Equipment that is intended for use in an area where the flammable substance is not likely to present under correct operation and if it occurs it will only last for a short time | |
| Gas / Dust | G | Equipment is approved for use in areas with flammable gases |
| D | Equipment is approved for use in areas with potentially explosive dust | |
| Type of Protection | Ex d | Flameproof enclosure – prevents transmission of the explosion outside |
| Ex e | Increased safety – prevents high temperatures and sparks | |
| Ex i | Intrinsic safety – low current/voltage supply | |
| Ex p | Pressurised apparatus – positive pressure device | |
| Ex m | Moulding – encapsulated | |
| Ex o | Oil immersion – parts immersed in oil to isolate from explosive atmosphere | |
| Ex q | Powder filling – prevents transmission of explosion outside | |
| Ex n | Protection “n” – as agave, but for use in zone2 | |
| Ex t | Protection by enclosure – dust explosion proof | |
| Gas Group | I | Mines |
| II | Surface above ground industries | |
| Gas Sub Group | A | Less easily ignited gases e.g., Ammonia, Methane, Ethane |
| B | Easily ignited gases e.g, Acrylic, Nitrile, Ethylene | |
| C | Most easily ignited e.g., hydrogen or acetylene | |
| Temperature Classification* | T1 | 450 ºC |
| T2 | 300 ºC | |
| T3 | 200 ºC | |
| T4 | 135 ºC | |
| T5 | 100 ºC | |
| T6 | 85 ºC |
* Product use depending on temperatures class (T1 – T6). The temperature class indicates the max. Temperature of the exposed surface of the product. For dust explosion proof, the max. Surface temperature is directly shown (e.g. T80ºC )
If equipment is ATEX approved, it will have mark as the following one
According to the above knowledge we have just learned, we can see that the product is intrinsic safety, designed for use in zone 1 or zone 2 areas, where gas group C may exist and its surface temperature will not exceed 135 ºC
| Ex | Explosion proof pursuant to the ATEX |
| II | Equipment is designed to used above ground (not under ground) |
| 2 | Equipment Category 2 can be used in zone 1 and zone 2 areas |
| G | Gas / Dust: designed for explosive atmosphere with hazardous gases |
| Ex i | Intrinsic safety – low current/voltage supply |
| II | Gas Group: surface (not under mines) |
| C | Gas sub group: C, the gases could be easily ignited |
| T4 | Equipment surface temperature will not exceed 135 ºC |
Refer to the labeling of ex equipment above, intrinsic safety is only a type of protection for equipment in ATEX system. Its production marking is “Ex i” in a certified equipment.
Its protection principle is “Low current/voltage supply” that means this type of protection tries to limit energy output to avoid electrical spark or ignition resources.
There are 9 types of protection in ATEX equipments, such as Exd(flameproof enclosure), Exe(increased safety), Exi(intrinsic safety), Exo(oil immersion), and so on.
