ATEX Approval & Standards
It is important to use ATEX-approved equipment to protect yourself from equipment-related explosions. This equipment must meet the technical requirements for the types of zone you wish to use it in. ATEX standards are regulated by European directives and specific equipment markings. ATEX stands for ATmosphère EXplosive (explosive atmosphere).
"Explosive atmosphere: a mixture with air, under atmospheric conditions, of flammable substances in the form of gases, vapours, mists or dusts in which, after ignition has occurred, combustion spreads to the entire unburned mixture" - Source: European Directive 2014/34/EU of 26 February 2014.
Two European directives form the ATEX regulations. They set out the minimum standards with regard to explosive atmospheres for employers and manufacturers.
Directive 99/92/EC or ATEX 137
– Responsibilities of employers with regard to worker safety
Employers are required to carry out an assessment of explosion risks and take the necessary measures to eliminate or reduce these risks.
- Assess explosion risks on their site,
- Classify hazardous zones and provide signage,
- Keep an explosion protection document,
- Take preventive technical and organisational measures,
- Comply with the criteria for selecting electrical equipment.
Directive 2014/34/EU (recast of 94/9/EC) or ATEX 95
– Responsibilities of manufacturers of equipment intended for use in ATEX zones
The responsibilities of manufacturers include:
- Requirements relating to equipment and protective systems intended for use in explosive atmospheres (such as gas detectors),
- Requirements relating to safety devices and controlling devices intended for use outside potentially explosive atmospheres but required for the proper functioning of equipment and protective systems (for example, controllers),
- The classification of equipment groups into categories,
- Essential health and safety requirements relating to the design and manufacture of equipment or systems.
To comply with the ATEX directive, equipment must:
- Bear the CE marking,
- Have the required certifications for hazardous zones,
- Meet a recognised performance standard, for example EN 60079-29-1:2007 for detectors for flammable gases (specific to each application).
This sign authorises the free movement of the equipment in the European Union.
ATEX equipment marking
Article 137 of ATEX directive 99/92/EC sets out the responsibilities of employers concerning the use of equipment designed for explosive atmospheres:
- Prevent the formation of explosive atmospheres,
- Avoid the ignition of explosive atmospheres,
- Mitigate the effects of explosions.
Click here to consult the directive: Click here
The employer must carry out an assessment of explosion risks:
- Likelihood that explosive atmospheres will occur: classification of zones,
- Likelihood that ignition sources will be present: equipment categories,
- Nature of flammable materials: gas groups, ignition temperature (T index), gas, vapour, mist.
All equipment in explosion hazard zones, whether electrical or otherwise, as well as protective systems, must meet the technical requirements corresponding to the type of zone. There are three categories, corresponding to the requisite equipment safety levels.
In addition, a specific marking is used to identify the equipment and its features.
1 - Equipment groups & Equipment categories
This regulatory marking is usually accompanied by a standard equipment marking, so the compatibility of the equipment can be checked against the physical and chemical characteristics of the constituents of the explosive atmosphere.
2 - Method of protection
The method(s) of protection used to ensure equipment safety level. There are several different methods that are adapted, as appropriate, to gases/vapours, dust, or electrical or non-electrical materials.
3 - Gas/vapour group & temperature group
Les gaz/vapeurs sont classés en fonction de leur sensibilité à l’inflammation en trois familles : IIC étant la plus dangereuse.
NB: Les poussières sont classées, notamment en fonction de leur état de division (taille de particules et de leur conductivité en 3 familles).
La température de surface du matériel à comparer avec les températures d’auto-inflammation des produits. Pour les gaz/vapeurs, la classe est indiqué via un code numérique.
NB: Pour les poussières, la température maximale pouvant être atteinte est directement indiquée.
Gases/vapours are categorised into three groups according to their ignitability, II C being the most dangerous group.
Note: dust is categorised into three groups, according primarily to its state of matter (size of particles) and conductivity.
The surface temperature of the equipment, to be compared with the autoignition temperature of the hazards. For gases/vapours the group is shown as a numerical code.
Note: for dust, the maximum temperature that can be reached is indicated directly.
Gases/vapours and dust group
ATEX zones and IEC equipment group
The International Electrotechnical Commission for Explosive Atmospheres (IECEx) issues standards that are used mainly by countries outside Europe and North America. The IECEx standards relate to the classification of standard equipment and zones. These standards can often be found in the technical equipment specifications, making it interesting to draw a parallel between the IECEx standards and the ATEX standards.
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