Pilot Benchmarking Study of Polyether Foams for Acoustical Applications

This paper describes a pilot benchmarking study of polyether foams for acoustical applications. The study investigates the differences in sound absorption performance that result from two different foam manufacturing methods: thin sheet casting and bun manufacturing. A basic conjecture that is examined in this work is that thin sheet cast foams have the following advantages over bun stock manufacturing: higher sound absorption performance and lower variability of the physical properties that determine acoustical performance. It is shown that the sound absorption performance of thin sheet cast urethane foam is 40% and 67% higher than the best performance of bun stock foam when evaluated by the Average Normal Sound Absorption Coefficient (ANSAC) and the noise reduction coefficient (NRC) respectively. In general, the computed variabilities for the properties of thin sheet cast urethane foam are lower than those for the bun stock foams.

In addition, an analysis of variance (ANOVA), suggests that bun stock foam has properties that vary with statistical significance according to the location along the rise direction. This non-uniformity can be found on the noise reduction coefficient, average normal sound absorption coefficient, and density.