What is ATEX?
ATEX refers to two European directives on explosion safety in environments where flammable gases, vapours, mists or dust are present. The name comes from the French ATmosphères EXplosibles.
ATEX = explosion-safe design, installation and working in hazardous Zones.
ATEX is mandatory in the EU for both employers and manufacturers of equipment in explosive atmospheres.
📜 The two ATEX directives
| Directive | Description |
|---|---|
| ATEX 114 (2014/34/EU) | For manufacturers of equipment used in explosive atmospheres |
| ATEX 153 (1999/92/EC) | For employers — covers the safety of employees in explosive atmospheres |
🧯 What is an explosive atmosphere?
An explosive atmosphere arises when three elements come together:
- Combustible substance (gas, vapour, dust)
- Oxygen (air)
- Ignition source (sparks, heat, static electricity, friction, etc.)
The goal of ATEX is to prevent explosions by controlling this combination.
🧭 ATEX zones (classification of risk areas)
| Zone | Type | Example |
|---|---|---|
| Zone 0 | Continuous gas/vapour | Inside a tank or pipe with volatile solvents |
| Zone 1 | Frequent gas/vapour | Around filling stations, pumps with leak potential |
| Zone 2 | Rare gas/vapour | Plant rooms where vapour appears only incidentally |
| Zone 20 | Continuous dust | Inside a silo with flour, sugar or plastic powder |
| Zone 21 | Frequent dust | Around a packaging line for powders |
| Zone 22 | Rare dust | Areas adjacent to a filling line for dry bulk materials |
⚙️ ATEX equipment and marking
Equipment in ATEX zones must be specially designed, with clear markings:
Example label: II 2G Ex d IIC T4 Gb
| Code element | Meaning |
|---|---|
| II | Non-mining environment |
| 2G | Category 2 (high risk), gas environment |
| Ex d | Explosion-proof enclosure (flameproof housing) |
| IIC | Gas group (hydrogen, acetone, etc.) |
| T4 | Temperature class (max. surface temp. 135 °C) |
| Gb | Equipment protection level (high safety) |
🏭 ATEX in OT environments
| Application | ATEX measure |
|---|---|
| PLC cabinet in zone 1 | Pressurised enclosure or intrinsically safe Ex components |
| Sensor in zone 0 | ATEX-certified version, often with galvanic isolation or Ex-i interface |
| Maintenance on a motor in zone 2 | Only with a work permit, spark-free tools and earthing |
| SCADA monitoring | Ex data logging, temperature monitoring, alarm on gas detection |
⚠️ Risks without ATEX
- Explosion with potential injury, fatalities or severe damage
- Legal liability following an incident
- Breach of the European directive (and national working conditions legislation)
📌 In summary
ATEX is the legal framework for safe working and design in environments with explosion risk. It requires employers and manufacturers to adapt equipment, installations and work processes to the hazard.