Considerations When Selecting a Fan

Multiple factors are involved with proper fan specification. Processes require specific air movement characteristics for applications such as cooling, exhausting, aerating, ventilating and drying. Through the evaluation of all impacting factors, you can be assured of maximum efficiency and reliability of the fan as well as the equipment with which it is used.

Factors to consider in fan specification:

Fan Type

  • Centrifugal – blower wheel draws air into the housing and discharges it out at 90°
  • Axial – draws air in using a propeller, and discharges air in the same direction


  • Rated in cubic feet of air per minute (CFM)
  • Adequate CFM for the duct pipe or hose size is required for material conveyance

Air Temperature

  • Temperature of air going through the fan
  • Affects the fan performance

Altitude of Environment

  • Altitude at which the fan will be operating
  • Impacts the performance of the fan

Air Density

  • Temperature and/or barometric pressure causes variations
  • Variations need to be corrected to standard conditions

Static Pressure/ Resistance to Airflow

  • Caused by air moving through system components such as duct, pipe, or filters.
  • Rated in inches of water gauge (SPWG)

Material Handling

  • Characteristics of material to be conveyed through the fan

Ambient Temperature

  • Temperature of the air outside the fan
  • May affect the operation of fan

NOTE: Special safety accommodations are required if flammable or combustible materials are involved.