Use

Determine the insertion loss due to a duct elbow.

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User Inputs

  1. Elbow Type: Select appropriate elbow type, lined, with or without turning vanes.

  2. Bend Plane Width (mm): – refer to “w” in the following diagram (Figure 20 from ASHRAE 2019 HVAC Applications Chapter 49)

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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 Tables 22, 23, and 24 ( Beranek 1960; Ver 1983b).

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Note that the insertion loss includes for a 2w length of lining on both sides of bend measured from the inside of the bend – to be included on the diagram.

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