Sound absorption coefficient measurement for various building elements

Abstract

The current sound absorption coefficient testing measurement method, ISO 354, primarily focuses on materials used for surface coverings or equivalent sound absorption objects. However, there are other building elements such as lightweight partition walls and windows that do not have solid structures behind them. These elements may allow sound to transmit to adjacent interior spaces or escape to the outside. On the other hand, the transmitted sound is expected to be rebounded into the measurement room when the test material is placed on a hard and thick surface as described in ISO 354. The test was conducted in a reverberation chamber located at the center of three consecutive acoustic testing chambers: reverberation-reverberation-anechoic. The testing chambers are equipped with test openings between them and are fully isolated from one another. The purpose of the test was to confirm whether the current measurement method reflects the influence of the assumed rebounded sound. The sound absorption coefficients were measured with the specimen installed on the floor, representing the ISO 354 condition, and comparisons were made to the conditions where the specimen was installed in another reverberation chamber opening and in the anechoic chamber opening.