In situ measured flanking transmission in light weight timber houses with elastic flanking isolators - part 2

There is a successful trend in Sweden to produce multi-storey lightweight timber based houses under industrialized conditions. This concept lets the houses to be manufactured in a relatively high degree of prefabrication. Common types are volume modules or flat wall and floor modules. When assembling at building site, elastic isolators are used in several constructions to reduce flanking transmission. Sound insulation demands are relatively high and therefore the flanking transmission must be well controlled by the isolators. There is though no verified prediction model of the isolating performance of these isolators, they are only modeled as simple springs operating vertically. In the paper there are analyses of the structure borne vibration level difference of elastic isolators installed in different structures. Comparisons are made that show the performance relative to theoretical spring isolators. An empirically based model of the vibration level difference across the flank coupling is derived. The model is based on measurements from 16 building installations. The simplified measurement method is compared with full scale accelerometer measurements on the flanking walls and the ceiling. A goal is that the data can be implemented in EN prediction models for sound insulation in light weight buildings.