What is an Ex-zone?
An Ex-Zone is a specific area within an installation or workplace where there is a risk of explosion due to gas, vapour or dust. The Zone indicates how often and for how long an explosive atmosphere may be present. This classification is part of the European ATEX directives.
Ex-Zones help determine which equipment and measures are needed to prevent explosions.
🧭 Gas and dust zones: overview
💨 Gas and vapour zones
| Zone | Description | Example |
|---|---|---|
| Zone 0 | Explosive atmosphere permanently or for long periods present | Inside a storage tank with solvent |
| Zone 1 | Explosive atmosphere regularly present during normal operation | Around a filling station or sealed pump |
| Zone 2 | Explosive atmosphere rarely or briefly present | Technical area with occasional leakage |
🌫️ Dust zones
| Zone | Description | Example |
|---|---|---|
| Zone 20 | Explosive dust atmosphere permanently or for long periods present | Inside silos containing flour, powder, sugar |
| Zone 21 | Explosive dust atmosphere regularly present | Around a packaging line for bulk powders |
| Zone 22 | Explosive dust atmosphere rarely or briefly present | Dust separator or conveying system |
⚙️ What determines the Ex-zone?
The Ex-zone is determined based on:
- Type of explosive material (gas, vapour, mist, dust)
- Frequency and duration of the explosive atmosphere
- Ventilation level and area design
- Type of process or installation (open vs. closed systems)
🔧 Ex-zone determines installation requirements
Depending on the zone, requirements apply for:
| Aspect | Zone 0 / 20 | Zone 1 / 21 | Zone 2 / 22 |
|---|---|---|---|
| Equipment category | 1G (gas) / 1D (dust) | 2G / 2D | 3G / 3D |
| Protection level | High | Medium | Basic |
| Examples | Ex-i Sensor, Ex-d motor | Ex-e terminal box, Ex-n lighting | IP54 enclosure with fuses |
🏭 Examples of Ex-zones in practice
| Location | Zone classification |
|---|---|
| Inside an ethanol tank | Zone 0 |
| Around a gas distribution station | Zone 1 |
| In a packaging area for sugar | Zone 21 |
| Electrical room next to a silo | Zone 22 |
📌 In summary
An Ex-Zone indicates the level of explosion risk in a given area. This classification determines which equipment, protective measures and working practices are permitted.