Use

Determine the insertion loss due to the end reflection from a duct termination.

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User Inputs

  1. Duct Width (mm)
  2. Duct Height (mm)
  3. End Reflection: Rectangular or circular duct
  4. Termination: Flush with wall or discharging into free space.

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SoundSurfer Input

Sound Power Level (red node) from an upstream source.

Algorithm

Insertion loss is based on ASHRAE 2019 HVAC Applications Chapter 49 Noise and Vibration Control Table 28 as associated formulae.

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end ref2.jpg

A = cross sectional area of the a rectangular duct $m^2$

end ref.jpg

where

$c_o$ = speed of sound (dimensionally consistent with D), m/s