This is a general information page.

The European Directive "ATmosphère EXplosible", said ATEX, is a legal requirement in all European Union Member States since 1st July 2003.

Manufacturers that design, manufacture or sell any equipment or protective system intended for use in potentially explosive atmospheres must comply with the ATEX Directive 94/9/EC and the CE Marking Directive.

With the introduction of the ATEX Directive manufacturers now have an opportunity to introduce more innovative products than was possible under the old Explosive Atmospheres Directive. The ATEX Directive sets a number of technical and quality objectives that must be complied with to the satisfaction of a notified body, but once these have been met, a manufacturer is entitled to display the distinctive European Mark which is recognized throughout the European Union.

Equipment Categories Associated with the ATEX Directive 

Equipment is classified into two groups, each group is divided into several categories:

• Group I comprises equipment intended for use in mines. It is divided into categories M1 and M2.
• M1 identifies equipment that must continue to operate when a potentially explosive atmosphere is present.
• M2 identifies equipment that does not operate when a potentially explosive atmosphere is present.
• Group II comprises equipment intended for use on other sites possibly exposed to danger by explosive atmospheres. This group is divided into categories 1, 2 and 3. The choice of category depends on the location (zone) where the product is intended to be used. (See table)
• Category 1 equipment is intended for use in Zone 0 situations.
• Category 2 equipment is intended for use in Zone 1 situations.
• Category 3 equipment is intended for use in Zone 2 situations.

Relationship between Zones and Categories for Group II Equipment
(Gas Zone "G")

To validate compliance with ATEX, several standards are used, primarily the EN 50-014, describing the "general rules" for construction and testing of electrical equipment for use in hazardous areas to ensure this equipment can not cause explosion of the surrounding atmosphere. This standard provides definitions of atmospheres, mixtures, and temperatures. It is completed by the following European Standards, specific to each of the types of standards of protection. The most common for natural gas are:

• EN 50 018: Flameproof "d"
• EN 50 019: Increased safety "e"
• EN 50 020: Intrinsic safety "i"

Quality Assurance under the ATEX Directive

Depending on the category of equipment involved, manufacturers are also required to install a quality system that ensures that a product that has been type examined will be faithfully replicated. There are 5 annexes in the ATEX Directive which identify different quality systems for this purpose. Broadly speaking these annexes require manufacturers to have in place either an ISO 9000 quality management system or a notified body must be involved in the inspection of product in some capacity. In either case a notified body is responsible for ensuring that a manufacturer produces products which fully accord with the design which was the subject of the original EC Type Examination Certificate. Quality management systems must either be audited by the notified body, if that body holds accreditation to EN 45012 or another organization that has this qualification and is accepted by the notified body. The latter provides manufacturers greater freedom of choice.

CE Marking Directive

All equipment with CE Marking will carry the following: 

• Marking according to Directive 94/9/EC
• "CE" symbol (and the number of notified body if applicable)
• Hexagon specific symbol for protection against the risk of explosion
• Group (I or II), category (1, 2, 3 ,...) and type of risk (gas (G) or dust (D))
• Any additional marking according to standards under which the machine complies (e.g. "EEx d IIC" according to EN 50 014)
• The ATEX certificate number

Example of Marking of Shutoff Device Type OS2 Position Detector 

All information above is indicative and not exhaustive.