Acoustic louvres are designed to allow airflow through an opening while reducing the amount of unwanted noise.
Sound Transmission Loss (STL), describes the reduced sound energy as sound passes through. For acoustic louvres, the performance varies depending on frequency, which is why acoustic testing is important across a range of frequencies.
Ventuer acoustic louvres use perforated aluminium blades filled with Rockwool, to allow sound energy to enter the blade, absorbing part of the energy, reducing the overall sound transmitted through the louvre.
The performance is measured through acoustic testing. Acoustic data sheets include Sound Reduction Index results across one third octave frequency bands. This shows the sound reduction achieved at various frequencies. These results contribute to an overall acoustic rating, such as Rw or STC, depending on the test method.
But what does transmission loss actually represent, and how is it calculated?
Siemens has created this useful webinar explaining the general concept of Sound Transmission Loss, including how sound is reflected, absorbed and transmitted through a material or assembly.
