An inter-comparison of laboratory measurements of airborne sound insulation of lightweight plasterboard walls.

This paper describes the results of the European Inter-Laboratory Test (ILT) program, conducted for the determination of repeatability and reproducibility values for the laboratory measurements of airborne sound insulation of walls. A total of 24 laboratories took part in this ILT, 21 belonging to the European Community. Two test structures were constructed; a double lightweight wall and a single lightweight wall, both built of plasterboard. The sound reduction index values were measured. The main result of the ILT was the significant difference obtained for the reproducibility value, R , for the double lightweight wall with values up to 12 dB at middle-highfrequencies. On the contrary, the reproducibility value for the single wall was very similar to the tentative values indicated in Annex A of ISO 140-2. Good agreement between laboratories was found for both structures in the computed repeatability values, r