Understanding Fan Static Pressure

What is Fan Static Pressure and Why Does It Matter?

When you’re defining the specifications for your industrial fan application, one of the measurements you’ll need is fan static pressure, calculated as the difference between the pressure required at the discharge of the fan and the pressure at the inlet of the fan plus velocity pressure.
(fan static pressure = fan discharge pressure – fan inlet pressure + velocity pressure)

Static pressure is measured by a Water Gauge (WG) and is an indication of the air flow resistance inside your fan. Higher resistance takes energy away from the process. It’s affected by things like the size and state of the ductwork surrounding your fan, as well as air temperature, altitude and whether or not the fan is material-handling.

The Impact of Pressure

Fan static pressure is important to understand for two reasons:

  1. It’s critical to selecting the right industrial fan for your application
  2. It affects your fan and overall system performance

Specifying the Correct Fan Static Pressure

When you are creating the specifications for a new fan application, as always, you will need to know where the air (and in many cases other materials) is coming from and where it’s going. This will allow you to calculate the approximate inlet and outlet pressure expected/needed for optimal system operation. Be sure to specify high-enough to serve your process requirements and handle potential changes in the environment surrounding the fan, so that you can optimize performance and longevity in your overall system.

Spotting Pressure-Related Performance Issues

Once your fan is installed and operating, measuring and monitoring fan static pressure can help you spot problems that might compromise fan and/or system performance, for example:

  • Unstable fan operation
  • Fan surge
  • Incorrect or blocked filters
  • Blockages or poor sizing in the ductwork
  • Poor return flow
  • Changes or discomfort in the surrounding environment (e.g. excess noise, running hot)

Specifying fan static pressure correctly in the first place and catching air flow issues early can help avoid costly fan and system repairs in the long run.

Hear it from the Application Engineer

Senior Application Engineer Chet White covers the basics of calculating fan static pressure in this 1-minute video.

When you’re ready to start your project, reach out and connect with one of our application engineers to discuss the details of your specification.

Related Content: High-Pressure Fans for Your Application

To see what kind of fans are designed for low air flow at high static pressure, take a quick look at our High-Pressure Radial Open and High-Pressure Radial Shrouded fans, both specified up to 140’wg:

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