LN = 40 + 10 log(Q)+ 20 log(p) (1b)
LN = 94 + 20 log(S) - 10 log(Q) (1c)
LN = sound power level from fan (dB)
S = rated motor power (kW)
p = fan static pressure (Pa, N/m2)
Q = volume discharged (m3/s)
Download and print Fan - Generated Sound Power vs. Volume Flow and Static Pressure chart
Sound power level in the octaves can be calculated by adding the values below to the sound power level calculated in the expressions or diagram above.
|Fan Type|| |
|Centrifugal fan, backward-curved blades||-4||-6||-9||-11||-13||-16||-19||-22|
|Centrifugal fan, forward-curved blades||-2||-6||-13||-18||-19||-22||-25||-30|
|Centrifugal fan, straight radial blades||-3||-5||-7||-7||-8||-11||-16||-18|
LN = 90 + 10 log(s) + 10 log(h) (2a)
LN = 55 + 10 log(q) + 20 log(h) (2b)
LN = 125 + 20 log(s) - 10 log(q) (2c)
s = rated motor power (hp)
h = fan static head (inch water gauge)
q = volume discharged (ft3/min)
The discharge velocity from fans should be kept within certain limits to avoid noisy operations.
|Sound studios, churches, libraries||4 - 5||5 - 7|
|Cinemas, theaters, ballrooms||5 - 7||6 - 8|
|Restaurants, offices, hotels, shops||6 - 8||7 - 9|
|Octave Band (Hz)||Fan 1||Fan 2||Fan 3||Fan 4|
Room acoustics and acoustic properties, decibel A, B and C, Noise Rating (NR) curves, sound transmission, sound pressure, sound intensity and sound attenuation.
Noise is usually defined as unwanted sound - noise, noise generation, silencers and attenuation in HVAC systems.
Fan classification established by AMCA.
Power consumption and typical efficiencies of fans
Barriers and enclosures to reduce noise sound pressure levels from machines.
TheBlade Pass Frequency noise generated by a fan can be very intense and varies with the number of blades and the rotation velocity.
Estimate noise generated by air flow in ducts.
Sound power noise generated by blade dampers in ventilation systems.
The octave and the 1/3 octave band frequencies.
The EPA Sound Exposure Level - Ls - describes the noise from a variable source.
Sound power from sources like fans, jet engines, cars, humans and more.
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!
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.