Influence of the type of fastening of multi-layered closing panels on the estimate of the sound transmission loss.

Abstract

Industrialized closing systems appear as rational solutions in steel-structured construction. These closing systems, consisting of multi-layered panels, have been applied in projects where it is intended to obtain a high sound transmission loss without raising the cost and without using a lot of mass. However, acoustic isolation depends on several factors, including the type of connection between the panels, requiring a preliminary study of the acoustic performance of the closing system to prevent future interventions. This paper uses a simplified graphical method to evaluate the influence of the type of connection (line-line, line-punctual or punctual-punctual) of industrialized closing panels on the estimation of the sound transmission loss that occurs across the wall constituted by these panels. The panels are combined, forming multi-layered closings interleaved by a layer of air, either without or with a sound-absorbing material between them. The results show that it is necessary to check the effectiveness of each type of fastening of the closing systems because, for example, for the frequency range between 500 and 2,000 Hz, the sound transmission loss of a closing system consisting of cementitious plate with glass wool and line-punctual and punctual-punctual connections exceeds in 6.25% the sound transmission loss of the same system with line-line fastening. For a system composed of expanded polystyrene with glass wool, the sound transmission loss provided by line-line fastening exceeds in 7.0% the sound transmission loss of the same closing system with line-punctual and punctual-punctual fastenings.