Acoustic Louvres

Similar to silencers, acoustic louvres are also commercially available devices that allow the passage of air while restricting the passage of sound generated from noisy spaces. They act much the same as ordinary louvres but consist of hollow acoustic vanes instead of flat sheet vanes. The acoustic vanes, with the underside (the side facing the noise source) formed from perforated sheet, are filled with sound absorptive material. A typical construction of an acoustic louvre is shown in Figure 56. The acoustic performance of an acoustic louvre is specified by the transmission loss in decibels (dB) in each octave band. This enables a direct comparison to be made between the performance of the louvre and a solid wall/structure which it probably replaces. Since an acoustic louvre is a very short attenuator, it is appropriate only where the length of space is restricted and the noise reduction requirement is low. Acoustic louvres are frequently installed in the facades of buildings where they are architecturally acceptable and provide a requisite amount of noise attenuation to prevent creating unacceptably high noise levels outside.

Figure 56: Acoustic Louvres