1.1 This test method covers the use of an impedance tube, two microphone locations, and a digital frequency analysis system for the determination of normal incidence sound absorption coefficients and normal specific acoustic impedance ratios of materials.

1.2 Laboratory Accreditation - A procedure for accrediting a laboratory for performing this test method is given in Annex A1.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of the use of this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.