Acoustic approach for building air permeability estimation

Air infiltration represents an essential parameter for the building and for the HVAC design and thus its accurate estimation is very important. The classic approaches to estimate the leakage air flow for an existing building present a series of disadvantages. The mathematical prediction models present errors up to 100%, while the currently used experimental measuring approach is expensive and weather dependent. In this paper we analyzed the leakage air flow using a different approach: an acoustic method for building air permeability measurement. We aim to determine if the air and noise transfer phenomena through window joints are correlated and what is the relation between the two transfer phenomena. In order to analyze this relation we measured both the infiltration air flow transfer and the airborne noise transfer through window joints for the same building façade. Different joinery degradation cases were simulated by different fixed positions of the joinery. For each case, two measurements were performed: the airtightness measurements in order to determine the air change rate and the airborne noise transfer in order to determine the sound transmission loss. Finally, we found that the air change rate is inverse correlated to the sound transmission loss; the higher the sound transmission loss, the smaller the air infiltration rate. This acoustic estimation for the building air permeability presents multiple advantages compared to the two classic approaches: good precision because it is an experimental approach, no expensive measurement devices, free of climate changes and it also represents a fast tool for evaluating building air permeability.