Laboratory Study on Flanking Sound Transmission in Cold-Formed Steel-Framed Constructions

In a recent study at the National Research Council Canada, the sound transmission in lightweight steel-framed constructions was investigated. The results of direct sound insulation tests of wall and floor assemblies were reported at EURONOISE 2015 and INTERNOISE 2015. This paper focuses on flanking sound transmission in lightweight steel-framed constructions. A representative mock-up specimen was constructed in NRC's 8-room flanking transmission facility. The specimen consists of four loadbearing walls with 152mm deep steel studs, four non-loadbearing walls with 92mm deep steel studs, and four floor-ceiling assemblies consisting of steel joists and a composite steel deck with gypsum concrete. Measurements were conducted according to the indirect method described in ISO 10848. The individual flanking paths were measured by a sequence of transmission loss measurements in which other transmission paths were suppressed by shielding. For the bare specimen without linings, the sound transmission for horizontally adjacent rooms with continuous subfloors is dominated by the floor-floor flanking paths. Floor coverings or floor toppings are needed to meet the requirements in the National Building Code of Canada. This presentation will present details of the measurements, highlight some of the results and discuss implications.