The most efficient fan size may not fit the physical space available. Inlet size and location, fan weight and ease of maintenance also must be considered.

Fan size should be determined by performance requirements.

However, the following general information may be helpful: You may also not know the amount of resistance in the exhaust system that the fan has to overcome and what is the fan efficiency. You may or may not know how much air has to be moved by the fan.

If the exhaust air contains corrosive contaminants, a fan with a protective coating or made of special materials (stainless, fibreglass, etc.) may have to be used.įans that handle high temperature exhaust air must be made from materials and parts resistant to high temperatures.

If the exhaust air contains explosive or flammable material, spark resistant construction (explosion proof motor if the motor is in the air stream) should be selected to conform to the standards of the National Fire Protection Association and provincial governmental regulations.

If the particulate load in the exhaust air is high or when material is handled, the normal selection would be a radial centrifugal fan.

If the exhaust air contains light dust, fume or moisture, a backward inclined or radial centrifugal fan would be preferred.

If the exhaust air contains a small amount of smoke or dust, a backward inclined centrifugal or axial fan should be selected.

However, you can make the following observations to determine if the fan selected is appropriate: Material handled through the fan Selection of the proper fan can be complicated and should be done by a ventilation or fan expert. How do you know if the correct type of fan has been selected? The rugged radial blade centrifugal fans are the best type for exhausting heavy amounts of dust because they are less likely to become clogged or abraded by the dust. They can operate against a high resistance and are typically used in local exhaust ventilation systems. The fans in your home furnace, vacuum cleaner and hair dryer are examples of centrifugal fans. There are three types of centrifugal fans determined by the type of fan blades: They are usually limited to 'clean air' applications such as exhaust ducts going through the roof. Tubeaxial and vaneaxial fans are essentially propeller fans made to fit in a duct.

are not suited for local exhaust ventilation because they do not provide enough suction to draw air through the system.

can move large amounts of air if there is little resistance, and.

The basic characteristics of these fans include that they: Common examples are your automobile radiator fan or a free standing room fan. These fans are often mounted in a wall or ceiling. Propeller fans are most commonly used for dilution ventilation or cooling. There are three basic types of axial fans: propeller, tubeaxial, and vaneaxial. Figure 1 Types of fans Axial or propeller fans

How are pc fan sizes determined