Relationship between the normalized impact sound pressure level (NISPL) and the transmission loss (TL) of a floor ceiling assembly

Abstract

The relationship between the normalized impact sound pressure level (NISPL) and the sound transmission loss (TL) of a floor ceiling assembly has been understood since 1963 (Heckl, and Rathe) and confirmed in 1971 (Ver), both for concrete based buildings. This concept has even made its way into ISO 12354-2. This paper will analyze approximately eight hundred floor/ceiling assemblies that Pliteq has measured in the lab to see if this relationship holds for other types of assemblies and where it might fall short. In a related topic, there has been discussion at ISO to create a delta sound reduction index (R) and normalized impact sound level (Ln) for added ceilings similar to the Delta IIC for floor coverings. The Ln/R are similar to the TL and NISPL in ASTM. The same data set will be queried to see if this is a valid approach for real world constructions in North America.