Improvement of sound insulation of doors or windows by absorption treatment inside the peripheral gaps

Abstract

Slit-shaped gaps included in such building elements as doors and windows are apt to deteriorate sound insulation performance of the wall system. In order to reduce sound transmission through these parts, sound absorption layer is often put inside the gaps. In this study, the effect of such a sound absorption treatment was examined by numerical and experimental studies. In the numerical study, the effect of sound absorption treatment on the gaps existing around doors/windows was examined by applying the FDTD method. To examine the results of the numerical study, a full-scale model experiment was performed using the sound intensity measurement method. A considerably good agreement was found between the results of the numerical study and those of the experimental study. As a result, it has been indicated that the sound insulation defect caused by the sound transmission through the gaps can be much improved by sound absorption treatment inside the gaps. Narrow gaps which exist around the door panel or window sash are apt to deteriorate sound insulation performance of the total wall system. The influence of the acoustical transmission through the gaps or apertures has been theoretically investigated [1-6]. More practical case studies on sound insulation performance of such real building elements with gaps as doors and windows has also been investigated [7-11]. However, prevention of sound transmission through such peripheral gaps has not been reported. In this study, therefore, we examined the effect of sound absorption treatment in narrow gaps with various shapes in cross section. As a case study, in-situ measurement of sound insulation performance of a door panel in an office building was performed under the conditions of with and without absorption treatment.