Abstract
For over 50 years, the American Society for Testing and Materials (ASTM International) has promulgated a method for the laboratory testing of random-incidence sound absorption coefficients (Test Method C423). This test method falls under the purview of ASTM Committee E33 (Environmental Acoustics). In 1999, the protocols in this test method became significantly more stringent with the goal of improving inter-laboratory “reproducibility” (i.e., quantitative differences among laboratories when testing the same specimen). ASTM calls such an inter-laboratory test a “round robin”; its outcome is an array of computed precision (i.e., uncertainty) values. This paper presents results from several “round robin” evaluations and discusses some possible causes for the range of values. If time permits, the fine points of the test protocols in C423 will be described and compared to those in ISO 354.
Published Version
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