Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

Sound Transmission through Duct Walls

Sound transmission from ducts to surrounding rooms.

Sponsored Links

Sound transmission through duct walls

Sound or noise transmitted from the inside of a duct to the surrounding room can be expressed as:

Lp = LN - TL - 10 log (A F / 4 Ad)                                 (1)

where

Lp = sound pressure in room (dB)

LN = sound power level in the duct (dB)

TL = transmission loss through duct wall (dB)

A = room absorption (m2 sabine)

F = cross section area of duct (m2)

Ad = surface area of duct (m2)

Typical sound transmission loss through duct walls are indicated in the table below:

Sound Transmission through Duct Walls - Attenuation - TL - (dB)
Duct sheet
thickness
(mm)
Frequency (Hz)
1252505001000
1.25 17 22 25 29
1.0 15 20 23 27
0.75 14 19 22 26
0.65 12 17 20 24

The acoustic performance of round and oval ducts is superior to rectangular ducts since their curved surfaces allow less breakout noise. Low-frequency sound is better contained in round ducts.

Ducts - sound transmission through walls

Sponsored Links

Related Topics

  • Acoustics

    Room acoustics and acoustic properties. decibel A, B and C calculations. Noise Rating (NR) curves. Sound transmission through walls. Calculate sound pressure, sound intensity and sound attenuation.
  • Noise and Attenuation

    Noise is usually defined as unwanted sound - noise, noise generation, silencers and attenuation in HVAC systems.

Related Documents

Sponsored Links

Search

Search is the most efficient way to navigate the Engineering ToolBox.

Engineering ToolBox - SketchUp Extension - Online 3D modeling!

3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with older versions of the amazing SketchUp Make and the newer "up to date" SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp Make/Pro from the Extension Warehouse !

Translate this Page

Translate this page to Your Own Language .

About the Engineering ToolBox!

Privacy Policy

We don't collect information from our users. More about

Citation

This page can be cited as

  • The Engineering ToolBox (2003). Sound Transmission through Duct Walls. [online] Available at: https://www.engineeringtoolbox.com/sound-attenuation-ducts-walls-d_79.html [Accessed Day Month Year].

Modify the access date according your visit.

3D Engineering ToolBox - draw and model technical applications! 2D Engineering ToolBox - create and share online diagram drawing templates! Engineering ToolBox Apps - mobile online and offline engineering applications!

Unit Converter

















































3.15.9

Sponsored Links
.