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Enter flow rate (CFM) and duct diameter (inch) to begin sizing



  1. Select the duct material from the drop-down list (most duct sizing tools are typically based on galvanised steel ducting by default)

  2. Enter the air flowrate in cubic feet per minute (CFM)

  3. Enter an internal duct size in inches (this must be limited to a maximum aspect ratio of 5:1 for the results to be valid)

  4. The resulting velocity and pressure drop per unit length are displayed in the blue box.

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