ATEX Approval & Standards

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).

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:

1. Likelihood that explosive atmospheres will occur: classification of zones,
2. Likelihood that ignition sources will be present: equipment categories,
3. 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.

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.

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.