Lined Sheet-Metal Ducts - Sound Attenuation
Noise attenuation in rectangular straight, lined, sheet metal ducts.
Attenuation in ducts with 25 mm lining are indicated below:
Attenuation in ducts with 50 mm lining are indicated below:
- 1 in = 25.4 mm
- 1 ft = 0.3 m
- sound attenuation in unlined duct
Example - Sound Attenuation in Lined Duct
The sound attenuation in 610 x 610 mm lined duct is approximately 2.5 dB/m at frequency 250 Hz. The sound attenuation in 10 m duct can be calculated as
(10 m) (2.5 dB/m) = 25 dB
