A study of the influence of mounting conditions on the measured sound absorption in laboratory tests of suspended ceilings (L)

This letter presents the results of an investigation into the influence of mounting conditions on the measured sound absorption coefficients of a suspended ceiling, specimen. A series of measurements and analyses were carried out using a fixed standard sample,. varying independently different mounting parameters and introducing controlled leaks. A correction of room volume in the calculation of the sound absorption coefficients was also examined. The tests were carried out in accordance with the ISO 354:2003 standard (International Organisation for Standardisation, Geneva, 2003), using the type E mounting. The test specimen consisted of fiberglass wool panels covered with a plastic film. Some of the experiments resulted in no statistically significant alteration. This included, unexpectedly, the sealing requirements of E type mountings. (c) 2006 Acoustical Society of America.