For a given fan duty, select the largest possible fan diameter in order to minimize velocity pressure.

Select an appropriate fan diameter that will meet the minimum required tip clearance.

In order to achieve higher static efficiencies, select a fan having a high pressure and low air flow regions as derived from the performance curves.

In applications having high velocity pressure, the use of a velocity recovery cone must be accompanied with the operating environment.

Select a fan having the appropriate tip speed to meet the required noise limitations.

Select a fan having an adequate static pressure margin to avoid stall and minimize noise level.