Gas and dust zones describe atmosphere presence
- Hazardous areaThis term
An explosive atmosphere can be present in a quantity requiring special precautions. Classification considers substance, release and ventilation conditions.
- Zone 0 / 20
Gas Zone 0 and dust Zone 20 describe continuous, long or frequent presence. The gas and dust systems remain separate classifications.
- Zone 1 / 21
Gas Zone 1 and dust Zone 21 describe occasional presence in normal operation. Determine the actual extent through the relevant classification method.
- Zone 2 / 22
Gas Zone 2 and dust Zone 22 describe unlikely, brief presence under the stated conditions. They do not mean an area has no ignition risk.
Gas zones and dust zones use separate number series. Their descriptions concern the expected presence of an explosive atmosphere, rather than an enclosure rating or a physical distance alone.
Illustrative presence bands with no probability or duration scale. Area classification is a three-dimensional engineering assessment; these sketches do not set zone boundaries or select equipment.