An investigation of the sound transmission class rating system using large-volume, high-variability datasets

Abstract

From shortly before, ASTM International introduced the E90-61T classification method in 1961 to the present time, the use of the sound transmission class (STC) rating system in North America expanded arguably more than any other building acoustics metric available today. From building codes to architectural specifications, the STC rating continues to connect acoustical engineers to building designers and occupants as a method for conceptualizing sound isolation in buildings, notwithstanding a valid evidence basis for significant flaws in the STC calculation methodology. Modern innovation in acoustic treatment introduces a far greater variety in achievable sound isolation performance than when the STC was first introduced. PABCO Gypsum has performed thousands of standardized sound transmission loss (STL) testing, providing a large and varied sample from which to observe trends. This paper utilizes this large-volume sample to compare tested assemblies with the same or similar STC ratings. STL data will be observed and compared to probable loudness level differences with the hope that this information will motivate further research and change in sound isolation classification methodology.