Acoustic properties of commercial thermal insulators

Abstract

Material manufacturers give very limited or no information of the acoustic properties of thermal insulators in broad perspective. The purpose of our study was to compare the acoustic performance of commercially available thermal insulators. Thirteen insulator types produced by several manufacturers were studied. The acoustic performance was determined holistically by measuring six acoustic quantities: sound reduction index of bare insulator, sound reduction index of encapsulated insulator (insulator between two boards), normal incidence sound absorption coefficient, airflow resistivity, dynamic stiffness per unit area, and reduction of impact sound pressure level in a floating floor. All measurements were conducted according to prevailing ISO standards in an experienced test laboratory. The acoustic performance differed significantly between insulator types for each acoustic quantity. The ranges were 1027 dB, 3352 dB, 0.200.78, 3.02700 kPas/m2, 1.5730 MN/m3, and 1536 dB, when the thickness of the insulator was 100 mm. Closed-pore insulator types usually carried worse acoustic properties than open-pore insulator types. Lower thermal conductivity was associated with worse acoustic performance of two acoustic quantities. Insulator manufacturers should consider to better declare the acoustic properties of insulator products, because this knowledge is needed in the acoustic design of building constructions and other applications.