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

This is an AMP page - Open full page! for all features.

Sound Attenuation - Main Duct to Branch Ducts

Sound attenuation from main duct to branch ducts

Sponsored Links

When main ducts are split into branches the sound power level - Lw - is reduced according the size of the branch, or amount of air to the branch.

The sound attenuation from a main duct to a branched duct can be calculated as

dLN = 10 log (Ab / Am)                                  (1)

where

dLN = sound attenuation (dB)

Ab = branch area (m2, ft2)

Am = main duct area (m2, ft2)

The attenuation is indicated in the diagram below:

Example - Sound Attenuation from Main Duct to Branched Duct

In an example 20% of the air goes to the branch duct and 80% of the air goes further on in the main duct. The branch duct area is 20% of the main duct area before the branch and the main duct area after the branch is 80% of the main duct area before the branch.

The sound attenuation from the main duct to the branch duct can be calculated:

dLN_branch = 10 log ((20%) / (100%)) 

     = 7 dB

The sound attenuation in the main duct can be calculated:

dLN_main_duct = 10 log ((80%) / (100%)) 

     = 1 dB

Sponsored Links

Related Topics

Related Documents

Sponsored Links

Share

Search Engineering ToolBox

  • the most efficient way to navigate the Engineering ToolBox!

SketchUp Extension - Online 3D modeling!

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 the amazing, fun and free SketchUp Make and SketchUp Pro .Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

Privacy

We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.

Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.

Google use cookies for serving our ads and handling visitor statistics. Please read Google Privacy & Terms for more information about how you can control adserving and the information collected.

AddThis use cookies for handling links to social media. Please read AddThis Privacy for more information.

Topics

Unit Converters

Temperature

oC
oF


Load Calculator!

Length

m
km
in
ft
yards
miles
naut miles


Load Calculator!

Area

m2
km2
in2
ft2
miles2
acres


Load Calculator!

Volume

m3
liters
in3
ft3
us gal


Load Calculator!

Weight

kgf
N
lbf


Load Calculator!

Velocity

m/s
km/h
ft/min
ft/s
mph
knots


Load Calculator!

Pressure

Pa (N/m2)
bar
mm H2O
kg/cm2
psi
inches H2O


Load Calculator!

Flow

m3/s
m3/h
US gpm
cfm


Load Calculator!

11 8

This website use cookies. By continuing to browse you are agreeing to our use of cookies! Learn more