Use

Determine the insertion loss due to a branch.

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User Inputs

  1. Main Duct: Rectangular or Circular
  2. Main Duct dimensions (mm) (depending on cross section)
  3. Branch Duct: Rectangular or Circular
  4. Branch Duct dimensions (mm) (depending on cross section)

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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 26.

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Refer to the full text of ASHRAE 2019 HVAC Applications Chapter 49 Noise and Vibration Control for full description of application.

Output

Attenuation (dB) from the duct branch applied to the input Sound Power Level, with attenuated Sound Power Level (red node) output octave bands in dB(A), dB(Z) and dB(C). Output being the sound power level at the upstream side of the main duct less the attenuation through the branch. Therefore, the output is for the branch duct path.

Click on ‘Z’ of the Sound Power Output to see dB(A) and dB(C) weightings.

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