Fans are used to move air from one area to another, to provide or to remove cold, hot, dry or damp air. Applications are many and varied but the prime purpose is to move a mass of air.

The amount of air to be moved often defines the size of the fan with due consideration of the space envelope available. The type of fan used is sometimes left to tradition, but should be selected by considering the resistance to flow of air likely to be encountered and the shape of the air path required.

For more advice refer to the 'Get the best from your fan' area in the Information Centre.

Fans can be categorised into four main types defined by the method of air movement they employ.

Fan types
• Axial fans and Compact fans
• Centrifugal fans can be subdivided into forward curved and backward curved, with and without scroll housings
• Mixed flow and Diagonal Flow fans
• Cross flow or Tangential flow fans

Fan controls are available in many technologies, variable voltage, variable frequency and EC control. For more detail description refer to the information centre.