A potentially explosive atmosphere is composed by air mixtures of gases, vapours, mists or dusts, which can ignite under certain operating conditions.

Equipment and protective systems intended for use in potentially explosive atmospheres cover a quite large range of products, including equipment used on fixed offshore platforms, in petrochemical plants, mines, flour mills and other areas where a potentially explosive atmosphere may be present.

The Equipment and Protective systems intended for use in Potentially Explosive Atmospheres (ATEX) Directive 94/9/EC provides the technical requirements to be applied and the relevant conformity assessment procedures before placing this equipment on the European market. These requirements are given technical expression by “Harmonised Standards”, developed by the European Standardisation Organisations: CEN (for non-electrical equipment) and CENELEC (for electrical equipment) – develop standards which references are presented to and published by the European Commission in the Official Journal of the European Union (OJEU).

How to apply the Directive
The Directive is implemented in Europe by means of each national authority transposing its provisions into their legislation, and it is these texts which have direct effect in the first instance. As a result Member States and others who apply its requirements are directly responsible for implementation and enforcement, as well as, for example, the management of Notified Bodies. As it is these national provisions which directly apply to manufacturers, it is always recommended as a first step for manufacturers to discuss any issues that they may have concerning the Directive with the relevant national contact points.

As a result of the excellent co-operation between all those involved, the formal ATEX Standing Committee has been able to give a unanimous positive opinion to a set of guidance notes which have been published by the Commission services to assist those who need to apply the Directive. This is not “law” and has no legal weight as such, but has been found to be a very useful document. As with all such documents continuous revision is required, and this is done by means of “Clarification Papers” which are also provided under this heading. These papers are the result of further discussion at the Experts Working Group. It is therefore suggested that the reader considers both sets of advisory texts whilst keeping in mind that the manufacturer or other responsible person continues to have sole responsibility for compliance with the provisions of the Directive. The fourth edition of the Guidelines on the application of Directive 94/9/EC was issued in September 2012.

In parallel to the ATEX Directive 94/9/EC, the Directive 1999/92/EC pdf deals with the minimum requirements for improving the safety and health protection of workers potentially at risk from explosive atmospheres, under the responsibility of the Directorate General for Employment, Social Affairs & Equal Opportunities. This sets out the responsibilities of employers and not manufacturers. For its implementation, see the Non-binding guide to good practice for implementing the European Parliament and Council Directive 1999/92/EC on minimum requirements for improving the safety and health protection of workers potentially at risk from explosive atmospheres.