Fans - Noise Power Generation

Calculate Sound Power Level generated by fans using empirical equations. Select between SI or Imperial units and choose the appropriate formula based on available parameters (motor power, static pressure/head, or volume discharged).

Sound Power Level Calculator

Select the unit system and formula to calculate the Sound Power Level (LN) generated by fans.

SI Units:

Formula 1a: LN = 67 + 10 log(S) + 10 log(p)
Formula 1b: LN = 40 + 10 log(Q) + 20 log(p)
Formula 1c: LN = 94 + 20 log(S) - 10 log(Q)

Imperial Units:

Formula 2a: LN = 90 + 10 log(s) + 10 log(h)
Formula 2b: LN = 55 + 10 log(q) + 20 log(h)
Formula 2c: LN = 125 + 20 log(s) - 10 log(q)

Calculator

Inputs

Unit System

Formula Choice

Rated Motor Power (kW or hp) (kW / hp)

Fan Static Pressure (Pa or inch H₂O) (Pa / in H₂O)

Volume Discharged (m³/s or ft³/min) (m³/s / ft³/min)

Results

Sound Power Level (LN)-- dB

Octave (Hz)	Centrifugal - Backward-Curved	Centrifugal - Forward-Curved	Centrifugal - Straight Radial	Axial Fan
63	-4	-2	-3	-7
125	-6	-6	-5	-9
250	-9	-13	-7	-7
500	-11	-18	-7	-7
1000	-13	-19	-8	-8
2000	-16	-22	-11	-11
4000	-19	-25	-16	-16
8000	-22	-30	-18	-18

Application	Supply System (m/s)	Exhaust System (m/s)
Sound studios, churches, libraries	4 - 5	5 - 7
Cinemas, theaters, ballrooms	5 - 7	6 - 8
Restaurants, offices, hotels, shops	6 - 8	7 - 9