Experimental verification of a short method for the determination of the acoustical insulation index of party walls

Abstract

The results are presented of experimental work, still in progress at the University of Bologna, aiming to verify the feasibility and reproducibility of a short test method for estimating the sound reduction index of a party wall, according to the ISO proposal (ISO TC 43/SC2/WG10). The method is intended as a quick test to be carried out with reduced instrumentation, during building construction. It is based upon the determination of the A-weighted sound level difference between adjacent rooms, D A . This difference is compared here with the more usual indices (see ISO 140 and 717), and empirical correlations are found that are well correlated to experimental data and so permit forecasting which is more than satisfactory for a survey check method. The empirical correlation equations are in good agreement with the proposed ISO table, which is therefore confirmed, notwithstanding the differences between British and Italian data. A deeper insight into the measured data suggests that receiving room reverberation time measurement is one of the main causes of variance; in order to solve this problem work hypotheses are put forward which do not require the use of absorbing packs.