Glossary · Existing plants and retrofit
Hazardous area classification (Ex zones)
Also known as: Ex zones, Zone classification, ATEX zones
German: Zoneneinteilung
Under Directive 1999/92/EC, hazardous area classification divides places where explosive atmospheres may occur into zones by the frequency and duration of their occurrence: Zones 0, 1 and 2 for gas, vapor and mist, Zones 20, 21 and 22 for dust. The zone determines which equipment categories may be used there.
- Compliance
- EU
- German source term
In one sentence
Hazardous area classification divides areas into Ex zones 0–2 (gas) and 20–22 (dust); the zones decide which equipment may be used where.
Example
After a spray booth is moved six meters, the Zone 1 around its exhaust now overlaps a cable route with standard junction boxes — a change only visible if the zone drawing is updated.
Explained in context
Context cards connect this term with others to answer one question. Also in British English and German.
How it applies
- Zones: Zone 0 / 20 — explosive atmosphere present continuously, for long periods or frequently; Zone 1 / 21 — likely to occur occasionally in normal operation; Zone 2 / 22 — not likely in normal operation and, if it occurs, only for a short time. Equipment category 1 is required for Zone 0/20, category 2 for Zone 1/21, category 3 for Zone 2/22.
- Germany: The zone criteria are in Annex I No. 1.7 of the GefStoffV; the classification is recorded in the explosion protection document.
- Changes: Zones follow sources of release, ventilation and building geometry. Extensions, moved equipment or changed ventilation can shift them, so every conversion needs a check of the zone drawing.
Ex zones vs. hazardous zones in machine safety
An Ex zone is an area of a workplace classified by the likelihood of an explosive atmosphere. A hazardous zone in machine safety is the space around a machine where a person can be exposed to a hazard. The words sound alike; the concepts and the laws behind them are different.