What Are Zone 0, Zone 1 and Zone 2? Their Impact on Exproof Fan Selection
The first step in selecting an exproof fan for a hazardous area is not the fan model, but the zone classification. Zoning describes how often an explosive atmosphere may occur and directly affects the protection level required from the equipment.
Why are hazardous areas classified into zones?
Areas where explosive atmospheres may occur because of gas, vapour or mist are classified as Zone 0, Zone 1 or Zone 2. The objective is to describe the frequency of the hazard and select equipment with a suitable protection level. Combustible-dust areas use the corresponding Zone 20, 21 and 22 system.
The difference between Zone 0, Zone 1 and Zone 2
- Zone 0: An explosive gas atmosphere is present continuously, for long periods or frequently.
- Zone 1: An explosive atmosphere is likely to occur occasionally during normal operation.
- Zone 2: An explosive atmosphere is not likely in normal operation and, if it occurs, exists only for a short period.
How do ATEX equipment categories correspond?
As a general rule, Zone 0 requires suitable Category 1G equipment; Zone 1 may use suitable 1G or 2G equipment; and Zone 2 may use suitable 1G, 2G or 3G equipment. Category alone is not enough: gas group, temperature class, EPL, ambient temperature and the certification scope must also match the application.
How zoning affects fan selection
A fan may meet the required airflow and pressure but still be unsuitable if its hazardous-area rating does not match the installation zone. The zone plan, properties of the conveyed atmosphere and the fan location should therefore be defined before selection. Fan, motor and associated electrical accessories must follow the same safety concept.
A common selection mistake
An exproof-certified motor does not automatically make the complete fan suitable for a hazardous area. Impeller and casing construction, ignition risks, earthing, accessories and the complete product certification must also be checked. You can review our exproof fan range or share your project data for technical selection support.