The ATEX Directive requires equipment and protective systems intended for both explosive and potentially explosive atmospheres to be designed and manufactured to minimize the occurrence and limit the severity of accidental explosions.
It applies to:
1. New ‘equipment’ intended for use in ‘explosive atmospheres’, such as electrical components and apparatus and machinery.
2. Separately supplied protective systems for controlling unavoidable explosions in explosive atmospheres, such as explosion vents, suppression systems, etc.
An ‘explosive atmosphere’ is a mixture of flammable substances (gases, vapours, mists or dusts) with air, under atmospheric conditions capable of causing a hazardous explosion if ignited. ‘Equipment’ is equipment capable of igniting the explosive atmosphere under normal or fault conditions. It is divided into electrical and non-electrical equipment. The Essential Requirements define technical measures for the assessment and reduction of explosion risks. The articles and other annexes define the certification procedures that manufacturers have to apply. These procedures get stricter with more Notified Body involvement as the likelihood of an explosive atmosphere increases (that is, according to their category.) They also give requirements for governments to implement and enforce the directive. Equipment and protective systems that comply with the Directive can bear the CE and Ex markings; components do not bear the CE marking. Further markings form a code defining the category and suitability for different types of explosive atmospheres. A Declaration of Conformity is required. The ATEX equipment directive is linked to the ATEX Worker Directive 99/92/EC on employers' obligations to protect workers from explosive atmospheres in work places.