Evaluation of Test Specimen Perimeter Sealing Material's Impact On Laboratory Testing of Diffuse Field Sound Absorption

Diffuse field sound absorption testing by standard method ASTM C423-17 is one of the most commonly performed laboratory tests in North America used for characterizing material performance for noise control applications. The accompanying standard practice for test specimen mounting, ASTM E795-16, currently provides guidelines for mounting various types of test specimens in a reverberation room but does not specify a standard frame material used for sealing the perimeter of the test specimen. To investigate the impact that the frame material has on measured diffuse field sound absorption, a series of measurements and analyses were conducted by varying the frame used to seal the perimeter of a rigid glass fiber board insulation sample in type A mounting. In this paper, experimental results are shared and suggestions are provided for improving the specimen mounting procedures detailed in standard practice ASTM E795-16.