Design of Floor-Ceiling Assemblies Using Dual Ratings of Impact Noise Insulation

Abstract

New ratings to evaluate impact noise insulation have recently been published as ASTM standards, which are commonly used to evaluate building acoustics measurements in North America. ASTM E3207 defines new ratings for lowfrequency impact insulation, defined by the 50-80 Hz thirdoctave bands. ASTM E3222 defines new ratings for highfrequency impact insulation, defined by the 400-3150 Hz bands. These ratings are based on the two-rating method of evaluating impact noise isolation proposed by the authors [1] and have been used for many years prior to publication. Some have objected that dual ratings are not necessary to assess code compliance or predict subjective reaction. These points are debatable, but such convenience is not the primary benefit of a dual rating system. The physics of impact noise generation is different in the two frequency domains, and therefore impact insulation in the two frequency domains requires different designs, products, and strategies. Using separate ratings provides value and design information that is obscured with single ratings. Examples illustrating these points are presented.