Brochure/Catalogue
Glossary
Z
Zone division Hazardous areas are divided into zones. These divisions take into account
the various risks from explosive atmospheres. The corresponding explosion
protection can then be implemented economically and safely in accordance with
the particular conditions of the zone. The zone denitions in the ATEX directive
provide comprehensive regulations for the European Community.
IEC 60079-10 is valid for gases and vapours. A similar classication is used for
facilities in the USA which are covered by the US standard NEC 505.
IEC 61241-3 covers the division into zones according to the dust level.
Explosion risk areas are classied into zones according to likelihood of explosive
atmospheres occurring and their persistence:
Zone 0: this zone has an explosive atmosphere that is a mixture of air and
ammable gases, vapours or mists. The mixture is present frequently or
over long periods.
Zone 1: an explosive atmosphere may occasionally occur in this zone under
normal operating conditions.
Zone 2: an explosive atmosphere is not likely to occur in this zone or may only
occur briey.
Zone 20: this zone has an explosive atmosphere that is a ammable mixture of
air and dust. The mixture is present often or over long periods.
Zone 21: an explosive atmosphere, in the form of a ammable dust/air
mixture, may occasionally occur in this zone under normal operating
conditions.
Zone 22: an explosive atmosphere, in the form of a ammable dust/air mixture,
is not likely to occur in this zone or may only occur briey.
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Technical appendix/Glossary
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