Application of the direct method of ISO 10848 to flanking Transmission through double leaf gypsum board walls

ISO 10848 describes two methods to measure flanking transmission between two adjacent rooms. The first is the indirect method and is based on the measurement of sound pressure level difference between the two rooms. The second is the direct method and uses the surface velocity level difference of coupled elements. In framed constructions, where each element coupled at the junction typically has two leaves, there can be multiple paths across a junction. The indirect method provides an estimate of the sum of all paths. Because, ISO 10848 does not provide guidance on application of the direct method, the indirect method is used almost exclusively. In this paper, statistical energy analysis (SEA) is used as a framework to evaluate how the direct method of ISO 10848 should be applied to quantify the various flanking paths in framed structures. The SEA model is also used to evaluate the suitability of EN 12354 to predict flanking transmission in these structures. Measurements made in the IRC/NRC flanking facility are used to compare the results of the different approaches to determine which one is most consistent with the SEA-model and the indirect method.