This standard was prepared by the Association’s Committee on Architectural Acoustics as one of a series dealing with the evaluation of sound-attenuating properties of building elements. It provides a classification system based on single number indices which are primarily intended for the initial comparison of the sound reduction properties of partitions, including walls and floor-ceiling assemblies, used to divide spaces in domestic and commercial buildings. Such single indices are in no way intended to supplant the detailed sound transmission loss and noise reduction values obtained by measurement for each frequency band.

In addition to the use of this classification system for the determination of sound transmission class (STC), which applies to partitions whose transmission losses have been measured in the laboratory, this system can be used to determine the field sound transmission class (FSTC) for partitions and noise isolation class (NIC) between spaces in buildings.

This standard is based on ASTM 413, Standard Classification for Determination of Sound Transmission Class; it differs from it in its presentation but not in any essential. Also, some use has been made in Australia of another classification system, the single number rating of airborne sound insulation index (I a). The procedure for the determination of this index is given in ISO R 717—1968, Rating of Sound Insulation for Dwellings. Some information about this method is provided in the appendix to this standard.

This standard may require reference to the following Australian and international
Standards:

AS 1191 Method for Laboratory Measurement of Airborne Sound
Transmission Loss of Building Partitions
AS 1633 Glossary of Acoustic Terms
AS 2253 Methods of Field Measurement of the Reduction of Airborne
Sound Transmission in Buildings
ISO R 717 Rating of Sound Insulation for Dwellings

First published 1979.