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.

Unlined Sheet-Metal Ducts - Sound Attenuation

Sponsored Links

Attenuation of sound in unlined sheet metal ducts at different frequencies are indicated below:

Unlined Sheet-Metal Ducts - Sound Attenuation
DuctAttenuation (dB/m duct)
Octave band center frequency (Hz)
63.512525050010002000
and higher
Round 100 - 300 mm 0.1 0.1 0.1 0 0 0
Round > 300 mm 0 0 0 0 0 0
Rectangular 150 x 150 mm 0.65 0.65 0.5 0.35 0.35 0.35
Rectangular 600 x 600 mm 0.65 0.65 0.35 0.15 0.15 0.15
Rectangular 1800 x 1800 mm 0.35 0.35 0.15 0.03 0.03 0.03

Example - Sound Attenuation in an Unlined Duct

The sound attenuation in a rectangular 600 x 600 mm unlined duct is 0.35 dB/m for frequency 250 Hz. The sound attenuation in 10 m duct is 

(10 m) (0.35 dB/m) = 3.5 dB

Sponsored Links

Related Topics

• Acoustics

Room acoustics and acoustic properties, decibel A, B and C, Noise Rating (NR) curves, sound transmission, 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

Lined Sheet-Metal Ducts - Sound Attenuation

Noise attenuation in rectangular straight, lined, sheet metal ducts.

Sound Attenuation - Duct split to Terminals

Estimating sound attenuation where ducts splits to terminals.

Sound Attenuation in Duct Elbows

Noise attenuation in duct elbows by reflected sound.

Sound Attenuation in Ducts due to End Reflection

Low frequency noise transferred from main duct to end terminals is reflected back to main duct.

Sound Transmission through Duct Walls

Sound transmission from ducts to surrounding rooms.

Sound Transmission through Flanking Paths

Sound transmitted through duct walls, floors and ceilings.

Ventilation Systems - Acoustic Calculation Procedure

Acoustic noise calculation procedure HVAC systems.

Ventilation Systems - Classification of Noise Reduction Silencers

Noise in a ventilation system can be reduced by reactive, diffuser type, active and/or dissipative silencers.

Sponsored Links

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.