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Inter-Laboratory Test of Sound Insulation Measurements on Heavy Walls: Part I — Preliminary Test

The intention of sound reduction index (SRI) measurements in transmission suites is to obtain more reliable values of the specific test element's sound insulation properties. Unfortunately, these values are influenced by the mounting of the test element itself and the construction design of the test facility. Both the mounting of the test element and, in part, the design of the test facility can effect the damping of the test element. From previous studies a suggested solution has been to take into account the damping in terms of the test element's loss factor. By incorporation of the loss factor in SRI measurements, of heavy walls, it has been suggested that this could reduce the deviations in SRI values due to laboratory influences. To determine the variance of sound transmission measurements in test facilities for a heavy wall, an inter-laboratory test (ILT) was performed in twelve different institutes. This ILT study included the measurement of sound reduction index, velocity levels and damping. In this first part, of a two part paper, a review concerning the principle previous studies is given. Furthermore, decisions regarding the choice of the test element, principal measurements and participating laboratories are reported.