Industrial Fan Selection Guide

Factors For Consideration When Selecting a Fan

Knowing if your application requires high volumes of airflow but low pressure or high pressure and low volumes is just one of the questions that need to be answered in order to determine the correct industrial fan selection.

It is important to also take into consideration factors such as:

• Density of the air to be moved.
• Air temperature.
• Humidity.

When determining the pressure required it is important to consider system restrictions. For example, additional pressure may be required to achieve flow across a filter, or to compensate a pressure drop due to length, size and complexity of ducting.

All ducting will have an effect on the air passing through a system and this will nearly always take the form of a restriction to the flow and therefore have an influence on pressure requirements.

At the earliest stage in the design process the ducting should be carefully evaluated and made as efficient as possible. This will reflect beneficially on the final design in the overall cost, the compactness of the fan and the running costs.

In reality, there are many factors that impact upon fan specification and applications that demand particular air movement characteristics for cooling, exhausting, aerating, ventilating and drying should undergo a ‘system resistance’ assessment. Only by evaluating all the impacting factors (flow resistance, power units, size, space envelope) is it possible to ensure maximum efficiency and reliability of both the fan and the equipment involved.

Many factors are involved in selecting the right industrial fan for your process. Your decision depends on much more than price alone. Does your application require high or low airflow? What will the pressure level be? Are there an environmental challenges that will need to be addressed? Keep in mind that an industrial fan that is selected to meet your specific application needs will be the most cost-effective option for your bottom line.

When it comes to fan specification, the proper choice is influenced by the type of air movement needed, whether for cooling, exhausting, aerating, ventilating or drying. As all of the factors are assessed, maximum efficiency and reliability of both the fan and the equipment involved can be achieved.

Based on our experience as an experienced industrial fan specialist, we have identified 10 basic fan selection steps to guide you in choosing the best fan for your application needs:

1. Type of Fan
   All fans do not operate in the same way. Axial fans draw air in using a propeller, and discharge air in the same direction. Centrifugal fans have a wheel that draws air into the housing and discharges it out at 90°. Your first step should be to determine the type of air movement and fan type you need.
2. Ducting
   Earlier in the design process, ducting should be considered for performance and efficiency. This will influence the final design in terms of overall cost, the compactness of the fan, and the operational costs.
3. Total Airflow
   Airflow is rated in cubic feet of air per minute (CFM). When conveying material, make sure there is adequate CFM for the duct pipe or hose size.
4. Static Pressure
   The resistance to the airflow, or static pressure, is caused by air moving through the pipe, hose, duct, filter, and other factors. Static pressure is rated in inches of water gauge (SPWG).
5. Density
   Density changes resulting from temperature and/or barometric pressure variations should be corrected to standard conditions.
6. Air Temperature
   The temperature of the air going through the fan or blower will affect the performance of the fan or blower.
7. Altitude
   The altitude at which the fan or blower will be operating also impacts the performance of the fan or blower.
8. Material Handling
   If material will be conveyed through the fan or blower, the material characteristics should be considered.
9. Ambient Temperature
   The temperature of the air outside the fan or blower, or ambient temperature, can affect the operation of fan or blower.
10. Safety Conditions
    Special accommodations may be required if any material going through the blower is flammable or combustible.

If you are in need of guidance in the industrial fan selection process, we would be happy to assist. Contact the specialists at Air Solutions to discuss your fan selection questions.