Akustisk mätning av U-värde

Sammanfattning: This pre-study investigates the possibility of U-value measurements through an acoustic method. A hypothesis about an acoustic model built on acoustic theories combined with U-value theories is presented to answer the questions:•Can U-value theory be combined with acoustic theories?•Can the coefficient of heat be affirmed trough an acoustic measurement?The idea for this dissertation begun with a logical idea in mathematical similarity, between the coefficient of heat transmission units and sound intensity units. The U-value theory is based on assumptions such as initial resistance for inner walls and initial resistance for outer walls. The resistance in the material is interpreted through sound intensity theory.The argument is built upon mass law theory, which means if the frequency or thickness of the material layer doubles it implies an increase of sound reduction by 6 dB. Six different materials; foam, glas fiber insulation, MDF, gypsum, concrete and glass are being investigated through Insul 7 simulations. A practical lab assessment with two glass fiber insulation boards with different density is presented. These fiberboards were received from Saint-Gobain Isover, with alredy measured density and lambda value.The conclusions are drawn from simulations, practical lab testing and different theories. This dissertation confirms that it´s possible to use an acoustic model for U-value measurements, but the hypothesis need a further investigation. That means that the hypothesis is based on mass law theory only and the second degree effects are not calculated in this model. In other words, the model will most probably work better for materials with low density and will be less reliable on materials with high density.