Direct and flanking sound transmission of solid gypsum walls ‐ practical experience and numerical prediction

Abstract

In modern multi storey buildings gypsum blocks are often used for solid inner walls without static requirements. However, these relatively light walls with a mass per unit area of about 90 kg/m2 are not connected rigidly to the adjacent building elements. They are decoupled with elastic interlayers made of bitumen, cork or polyethylene foam. These elastic interlayers have a significant influence on the direct and the flanking sound transmission of the gypsum walls. For this reason the decoupled walls have to be considered different to rigidly connected walls. Within a recent research project there was an extensive investigation into the direct and the flanking sound transmission of gypsum walls in different test facilities in the laboratory. For several kinds of elastic interlayers the sound reduction index of gypsum walls was measured in the test stand for direct sound transmission. The vibration reduction index was investigated in a test facility for flanking transmission as well as in different building situations. The measured values are used as input data for the prediction model according EN 12354‐1. The overall sound reduction index calculated with this prediction model is compared with the results measured in the buildings.