The ATEX regulation consists of two European directives describing manufacturers and users requirements on equipment and work space in explosive atmospheres.
ATEX ZONES DESCRIPTION
ATEX zone category | Description | Gas & Vapor | Dust |
1 | Area containing explosive gas/air (or dust) mixture permanently or for a long time | 0 | (20) |
2 | Area in which an explosive gas/air (or dust) mixture is likely to occur in normal plant operation (occasional risk) | 1 | (21) |
3 | Area in which an explosive gas/air (or dust) mixture is not likely to occur in normal plant operation (equipment malfunction) | 2 | (22) |
ATEX EQUIPMENT MARKING
Since July 1st 2003, any new device installed must meet requirements from ATEX regulation. This directive is about installation compliance of a new device in an industrial environment. The marking indicates the equipment compliance and is made of several parts:
Reference code | (1) | (2) | (3) | (4) | (5) | (6) | (7) |
Example | II | 1 | G | EEx | d | IIB | T6 |
- First figure (1) indicates location: I for mines, II for surface industries like chemistry and petrochemistry
- Second figure (2) indicates ATEX zone category: 1 for zones 0 and 20, 2 for zones 1 and 21, 3 for zones 2 and 22
- Third figure (3) indicates zone type: G for gas or vapor zone, D for dust zone
- Fourth figure (4) indicates the equipment standard: E for CENELEC, Ex for CEI (international)
- Fifth figure (5) indicates safety type: d for explosion-proof, e for enhanced safety, ia or ib for intrinsic safety
- Sixth figure (6) indicates indicate reference gas (for gas zones): I for methane, IIA for propane, IIB for ethylene, IIC for hydrogen and acethylene
- Seventh figure (7) indicates surface maximum temperature: T1 = 450 °C, T2 = 300 °C, T3 = 200 °C, T4 = 135 °C, T5 = 100 °C, T6 = 85 °C
Above marking example (table) thus corresponds to an equipment dedicated to surface industry, for zone 0 (gas) that meets CENELEC and CEI standards, explosion-proof, with ethylene as reference gas for a minimum surface temperature of 85°C.
In ATEX zones postable gas detectors, fixed gas detection systems and sirens & signals have to be ATEX compliant to guarantee safety.