1.1 This practice covers the establishment of uniform procedures for determination of the A-weighted sound level difference between two neighboring (usually adjoining) rooms in a building (see 1.2). For this practice, it does not matter how the sound reaches one room from the other; the measurement procedure is concerned only with evaluating the degree of acoustical isolation between the rooms. The practice does not evaluate any specific acoustic barrier, such as the party wall common to the two rooms, nor is it intended to do so. Rather, it provides a measure of the effective combined insulation along all of the paths by which acoustical energy may be transmitted.

1.2 Sound level difference for the purposes of this practice is the difference in space-averaged, A-weighted sound levels in the source room and the receiving room, respectively, due to the operation of a test sound source in the source room. When suitably corrected to adjust for typically furnished conditions of sound absorption in the receiving room, this normalized sound level difference is a reliable single-number rating of the acoustical isolation between the two rooms.

1.3 This practice is suitable, and intended, for use by building code writers and others concerned with the provision of adequate acoustical isolation between (and within) dwellings. It is recommended that this test procedure be applied only to multifamily dwellings, to single and double patient's rooms in hospitals, to motel or hotel rooms, and to small offices.

1.4 Specifically, the use of this practice should be restricted to rooms with ceiling heights between approximately 2.6 and 2.7 m (8 and 9 ft) and with horizontal dimensions up to about 6 m (20 ft). The requirements on the selection of microphone locations, given in 8.3.1, may make it impractical to perform the test in rooms with length or breadth less than approximately 3.3 m (11 ft).

1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.