ATEX and process equipment: the two directives worth distinguishing

Directive 2014/34/EU regulates equipment and protective systems intended for use in potentially explosive atmospheres. Its main responsible party is the equipment manufacturer: it defines equipment categories, essential requirements and the corresponding marking.

Directive 1999/92/EC regulates the protection of the health and safety of workers exposed to risks from explosive atmospheres. Its responsible party is the employer or site operator: it includes risk assessment, zone classification and organisational and technical measures at the workplace.

Classification divides areas according to the frequency and duration of the presence of explosive atmospheres: zones 0, 1 and 2 for gases and vapours, and zones 20, 21 and 22 for combustible dusts. This classification is not decided by the equipment manufacturer or the buyer in isolation: it is part of the site risk assessment, which must be carried out by expert persons in accordance with the applicable local legislation.

For the buyer, the practical consequence is clear: if the installation already has a documented zone classification, that document is the reference that should accompany the equipment enquiry. If it does not exist or is outdated, the prudent approach is to state so explicitly rather than assume a zone by analogy with another plant.

The equipment directive establishes equipment categories (1, 2 and 3) related to the level of protection, and equipment groups according to the environment of use. An item's marking reflects the category and the conditions for which it has been assessed. The correspondence between the classified zone of the installation and the equipment category must be verified in each case: no equipment is generically suitable for any explosive atmosphere.

It is also worth remembering that a complete process equipment item can combine elements with different considerations: the vessel's internal chamber, motors and drives, instrumentation and electrical connections may require differentiated assessments. That is why the useful question is not «is this equipment ATEX?», but «which parts of the equipment have been assessed, for which conditions and with what documentation?».

• The zone classification of the area where the equipment will be installed, if it already exists, or the fact that it is pending assessment.
• The generic nature of the substances present: gases, vapours or dusts, without disclosing formulations.
• Which parts of the equipment would be inside and outside the classified area, including motors, sensors and connections.
• The documentation the installation will require: declarations, instructions and marking under the equipment directive.
• Who is responsible for the risk assessment and final verification in the country of installation.

With this information, the conversation with the manufacturer starts from verifiable data rather than assumptions. The specific suitability of equipment for a given zone is always confirmed by the competent assessment.

Some common cases require additional attention: second-hand equipment whose original documentation is unavailable, modifications to existing equipment, motors or instrumentation added in the field, and installations where the zone classification is old or was never documented. In all of them, the prudent path is a review by expert persons in accordance with local legislation before assuming the suitability of the whole.

From the purchasing perspective, it is worth putting in writing who provides the zone classification, who verifies the correspondence between zone and equipment category, and what documentation will be delivered with the equipment. These three questions, resolved in writing at the quotation stage, prevent most later disputes and allow proposals to be compared on a homogeneous, verifiable basis.