Guide for hazardous areas
Hazardous areas definitions:
Hazardous areas according to ATEX and IECEx zones
Zones - define the type of explosive atmosphere as well as the likelihood of an explosive atmosphere being present:
| 0 |
|
Explosive gas atmosphere present continuously or for long periods |
| 1 |
|
Explosive gas atmosphere likely to occur in normal operation |
| 2 |
|
Explosive gas atmosphere not likely to occur in normal operation but may be present for short periods |
| 20 |
|
Explosive dust atmosphere present continuously or for long periods |
| 21 |
|
Explosive dust atmosphere likely to occur in normal operation |
| 22 |
|
Explosive dust atmosphere not likely to occur in normal operation but may be present for short periods |
Hazardous locations according to North American classes and divisions
Classes - define the type of explosive atmosphere:
| I |
|
A location made hazardous by the presence of flammable gas or vapor that may be present in the air in quantities sufficient to produce an explosive or ignitable mixture |
| II |
|
A location made hazardous by the presence of combustible or electrically conductive dust |
| III |
|
A location made hazardous by the presence of easily ignitable fibers or flyings in the air, but not likely to be in suspension in quantities sufficient to produce ignitable mixtures |
Divisions - define the likelihood of an explosive atmosphere being present:
| 1 |
|
A location where a classified hazard exists or is likely to exist under normal conditions |
| 2 |
|
A location where a classified hazard does not normally exist but is possible to appear under abnormal conditions |
In Canada, new installations must now use the ATEX / IECEx system of Zones instead of Divisions. Existing installations may use either system.
In the USA, all installations can use either the Class / Zone or the Class / Division system.
ATEX
equipment
group |
ATEX equipment
category and
environment type |
Zone
classification
ATEX / IECEx |
Required
equipment
protection
level (EPL) |
Class / Zone
classification
US / Canada |
Class / Division
classification
US / Canada |
| I |
|
|
|
|
|
| I |
|
|
|
|
|
| II |
|
|
|
|
|
| II |
|
|
|
|
|
| II |
|
|
|
|
|
| II |
|
|
|
|
|
| II |
|
|
|
|
|
| II |
|
|
|
|
|
Guide for hazardous areas in PDF