Comparison of ASTM and ISO sound absorption test methods

A series of planned experiments has been conducted in which the differences between ASTM C423 and ISO 354 have been compared. These experiments focused on the differences in the two test methods, with the goal of identifying and understanding differences in the ultimate test results. A variety of acoustical ceiling tiles were tested in the same NVLAP-certified facility, generating data that cover a broad range of acoustical performance. The factors examined were: the effect of sample size on absorption; the effect of plenum depth on measured absorption; and the differences between the SAA and αw curves resulting from the two test methods. The results of these experiments will then be used to identify areas in which additional research is needed if harmonization of the two standards is to occur.