Technical Information
ATEX ATmospheres EXplosible
ATEX, an acronym derived from “Atmospheres Explosible,” refers to the European Parliament Directive 94/9/EC, updated under the ATEX 2014/34/EU Guidelines. This directive primarily establishes manufacturing standards to ensure the quality and safety of protective systems designed for use in potentially explosive atmospheres.
In industrial environments, during manufacturing, transport, storage, or even when at rest, air pollutants can create explosive atmospheres. These pollutants can be in the form of dust, gases, mists, or vapors; sometimes, they may combine to form hybrid mixtures, such as dust and gas.
To initiate a fire, the Fire Triangle principle states that fuel, heat, and a minimum of 16% oxygen are required. A similar concept applies to explosions, known as the Explosion Pentagon, which includes the additional factors of confinement and dispersion. The explosivity of a mixture is influenced by the particle size and concentration, with smaller particles providing more surface area for oxygen contact, thereby increasing explosivity. Conversely, excessive density can block oxygen access, and higher humidity levels generally reduce explosivity risk.
Explosion Risk
Defining the explosion risk involves the facility’s Health, Safety, and Environment (HSE) team, particularly in selecting zone criteria according to ATEX 137 99/92/CE. Once the specific zone criteria are determined, selecting the appropriate product according to the ATEX 2014/34/EU guidelines becomes straightforward.
Zones | ATmosphere – EXplosive | Equipment | Applications | ||
Gases | Dusts | Group | Category | ||
0 |
| Continuously / Long Periods / Frequently | II | 1G | Other Areas – Gas |
| 20 | (over 1000 hours per year or >10% of the time) | II | 1D | Other Areas – Dust |
1 |
| Occasionally | II | 2G | Other Areas – Gas |
| 21 | (10 – 1000 hours per year or 0.1 to 10% of the time) | II | 2D | Other Areas – Dust |
2 |
| For a Short Period Only | II | 3G | Other Areas – Gas |
| 22 | (under 10 hours per year or 0 to 0.1% of the time) | II | 3D | Other Areas – Dust |
ATEX 137 99/92/CE | I | M1 | Mines | ||
I | M2 | Mines | |||
ATEX 2014/34/EU |