The term ATEX (Atmosphères Explosibles) refers to two distinct European Directives sharing a common objective: regulating environments where an explosion hazard may be present, known as ATEX areas or environments.
When working in an ATEX environment, the possibility of mitigating an explosion once it occurs is extremely limited, often with severe consequences. Therefore, it is essential to adopt all necessary preventive measures (technical prevention and/or protection actions, appropriate product selection, operating procedures, etc.) to prevent the occurrence of an explosion.
An explosion occurs when the following three conditions are present simultaneously:
Presence of an oxidising agent, i.e. a substance that enables combustion (e.g. oxygen in the air);
Presence of a fuel, i.e. a substance that participates in combustion (such as gases, vapours, mists or dusts);
Presence of an ignition source, which may derive from electrical factors (sparks, electrostatic discharges) or thermal factors (excessive temperatures, flames, hot gases).
The main regulatory framework consists of two European Directives:
Directive 99/92/EC (ATEX 137) – Workplace Directive
This directive concerns workplaces, focusing on workers’ health and safety, and establishes the classification of hazardous zones, the selection of equipment and operational instructions.
Explosive areas are identified by a warning sign: a yellow triangle with a black border and the marking “Ex”.
Directive 2014/34/EU (ATEX 114) – Product Directive
This directive applies to equipment and protective systems intended for use in potentially explosive atmospheres. Such products must meet Essential Safety Requirements (ESR) and are addressed to manufacturers, distributors, importers and certification bodies.
Compliance is indicated by the hexagonal Ex symbol on the product marking.
Both ATEX directives are referenced in Legislative Decree 81/08 – Title XI and Ministerial Decree 03/08/2015.
According to Article 293 of Legislative Decree 81/08 – Title XI, employers are required to classify workplaces into zones based on the frequency and duration of the presence of explosive atmospheres.
Reference is made to harmonised technical standards, including:
EN 60079-10-1 – Classification of hazardous areas due to the presence of gases;
EN 60079-10-2 – Classification of hazardous areas due to the presence of combustible dusts.
| Gas zones | Dust zones | Description |
|---|---|---|
| Zone 0 | Zone 20 | Continuous or frequent presence of explosive atmosphere (>1000 h/year) |
| Zone 1 | Zone 21 | Likely occurrence during normal operation (10–1000 h/year) |
| Zone 2 | Zone 22 | Unlikely or short-duration occurrence (<10 h/year) |
Based on classification, employers must ensure compliance with minimum safety requirements set out in Annex L of Legislative Decree 81/08.
All products used (including clothing), equipment and electrical installations within ATEX zones must be ATEX-compliant, in accordance with Directive 2014/34/EU, to prevent ignition.
