Axial fans are suitable for large quantities of air at low pressures. Also available in adjustable impeller blades which make it possible to adapt the fan to the requirement changes. Impellers can be supplied in aluminum , mild steel or stainless steel. Belt driven axial fans are used in situations where it is important. Bifurcated Fans are direct driven axial fans where the motor is encased in a metal box to isolate it from the airflow.