18/08/2026
What Are ATEX Zones? Zone 0, 1, 2, 20, 21 and 22 Explained.
Before selecting an ATEX explosion-proof light or junction box, you need to know which zone it will be installed in. The zone determines the required equipment category and certification.
An explosion needs three elements: flammable substance, oxygen and an ignition source. ATEX aims to eliminate the ignition source. Zone classification is done by a certified specialist and recorded in an Explosion Protection Document (EPD).
Gas zones
Zone 0: Explosive atmosphere continuously present (e.g. inside storage tanks). Requires Category 1G (EPL Ga).
Zone 1: Explosive atmosphere occurs regularly in normal operation (e.g. around pump seals). Requires Category 2G (EPL Gb).
Zone 2: Explosive atmosphere only under abnormal conditions (e.g. leaks). Requires Category 3G (EPL Gc). Most common zone (over 80%).
Dust zones
Zone 20: Combustible dust cloud continuously present (e.g. inside silos). Requires Category 1D (EPL Da).
Zone 21: Dust cloud occurs regularly in normal operation. Requires Category 2D (EPL Db).
Zone 22: Dust cloud only in fault conditions. Requires Category 3D (EPL Dc).
Rule of thumb
During normal operation, would lighting a lighter cause an explosion here?
Zone 0 / 20: Yes, always
Zone 1 / 21: Sometimes
Zone 2 / 22: Only if something goes wrong
A higher category is always allowed; a lower one is never allowed.
SeekingLED manufactures a full range of ATEX and IECEx certified explosion-proof LED lights and junction boxes covering Zone 1, 2, 21 and 22. Our products include:
LO Series and Bay51 Series pendant lights (Zone 1/2 & 21/22)
FL7 / FL8 Series flood lights (Zone 1/2 or Zone 2/22)
BAJ Series emergency and exit lights
BT8 Series LED T8 tubes
BHD51 Series explosion-proof junction boxes
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