Measurement and estimation of the flanking impact sound transmission in timber frame building constructions

Abstract

The Kij vibration reduction index is the essential parameter for characterizing the flanking transmission of impact sound in buildings. The calculation method according to EN ISO 12354-2 based on Kij has been established for many years for heavy homogenous constructions. For timber frame constructions, the determination of the vibration reduction index is not, with sufficient accuracy, possible. The parameter used for characterizing the flanking sound transmission in timber frame constructions to estimate the normalized flanking impact sound pressure level Ln,f is the direction-averaged vibration level difference Dv,i,j. The paper discusses the applicability of this method for timber frame constructions by comparing the measured and the predicted normalized flanking impact sound pressure level Ln,f of a timber frame T-joint. The direction-averaged vibration level difference Dv,i,j was measured in a test facility in one T-joint configuration under different loads on the joint. The measurement result was used to calculate Ln,f. The results are compared with the measurement of the normalized flanking impact sound pressure level by shielding the direct transmission path. The results show that with minor modifications of the measurement procedure, a satisfactory agreement between the prediction model of the EN ISO 12354-2 and the measurement result can be achieved.