The relationship between zones, categories and protection levels (EPL) in ATEX and IECEx

To navigate ATEX and IECEx standards, it is necessary to understand the relationship between installation zones, device categories and EPL (Equipment Protection Level) protection levels.

Installation zones: classify rooms according to the frequency and duration of the presence of an explosive atmosphere.

Gas zones:

Zone 0: permanent or long-term presence of an explosive atmosphere

Zone 1: occasional presence

Zone 2: short-term presence

Dust zones:

Zone 20: permanent presence

Zone 21: occasional presence

Zone 22: short-term presence

ATEX categories: determine the level of protection of a device depending on its intended use in a specific zone.

1G / 1D: zones 0 and 20 (maximum safety level)

2G / 2D: zones 1 and 21

3G / 3D: zones 2 and 22

EPL protection levels (IECEx): use abbreviations to indicate the degree of protection of the device.

Ga / Da: very high level, suitable for zones 0 / 20

Gb / Db: high level, zones 1 / 21

Gc / Dc: normal level, zones 2 / 22

In practice, ATEX categories and EPL levels make it easier to select the most suitable equipment for each zone. For example, a device with 1G or EPL Ga certification can be installed even in less hazardous areas, such as zone 1 or 2, while ensuring maximum safety.