Exproof Fan Selection Guide: How Do We Choose the Right Fan?
Fans used in environments with an explosion risk do more than circulate air; they form part of plant, personnel and process safety. Selection must therefore consider both aerodynamic performance and hazardous-area classification.
1. Define the hazardous area
First determine whether the environment presents a risk from gas, vapour, mist or combustible dust. The area is then classified as Zone 0, 1, 2 or Zone 20, 21, 22. The fan equipment category must be suitable for this classification.
2. Determine the characteristics of the explosive substance
- Gas group: IIA, IIB or IIC
- Dust group: IIIA, IIIB or IIIC
- Ignition temperature and temperature class
- Ambient temperature and chemical influences
- Required IP protection rating
3. Calculate airflow and pressure
Even with the correct safety certification, a fan cannot perform its duty if it does not meet the required airflow and system pressure. Duct losses, filters, dampers and the operating scenario must be calculated together.
4. Evaluate mechanical risks
The fan casing and impeller materials should be selected to reduce spark risk; earthing and equipotential bonding must be provided for static electricity. The mechanical suitability of the fan must be checked as carefully as the motor certification.
5. Verify the marking and documentation
The ATEX marking, equipment group, category, protection concept, gas or dust group, temperature class and EPL must be mutually compatible. The certificate scope and manufacturer documentation should be reviewed before ordering.