Comparing low frequency impact insulation measured with the rubber ball versus the tapping machine

The heavy/soft impact source or rubber ball, defined in ISO 10140 and 16283, is used primarily in Japan and Korea to evaluate low-frequency impact insulation from sources such as walking without shoes and children jumping. ASTM test methods currently do not include the heavy/soft source, and low frequency impact noise insulation is currently measured with the tapping machine using ratings such as LIR and LIIC per ASTM E3207. ISO ratings using spectrum adaptation terms from 50 Hz or lower can also be used. The relationship between these ratings and those measured using the heavy/soft source has not been well characterized for assemblies that are common in North America. The authors present field and laboratory data of impact insulation with both sources. Analysis of the data describes the relationship between the sources, the information they provide to the designers of floor assemblies, and implications for classifications of low frequency impact insulation.