Dilemmas in the assessment of the insulating properties of double massive partition according to EN 12354-1

The introduced requirements for thermal insulation between dwellings, as well as some practical reasons, initiated greater use of double walls in building design practice. The standard EN 12354 -1 did not defined a procedures for calculation of the apparent sound reduction index for such constructions. The paper suggests a possible approach for calculation of apparent sound reduction index based on the calculation methodology for the single partition defined by the standard. Some theoretical analyses of the sound energy transmission through direct and flanking paths in a case of double massive partition were presented. Verification of the proposed approach were done by laboratory measurement and by FEM numerical simulation. The analysis included a number of commonly used constructions and types of their junctions.