1.1The purpose of this classification is to provide a method to calculate single-number ratings that can be used for assesing the isolation for the outdoor sound provided by a building or comparing building facade specimens including walls, doors, windows, and combinations thereof, including complete structures. These ratings are designed to correlate with subjective impressions of the ability of building elements to reduce the penetration of outdoor ground and air transportation noise that contains strong low-frequency sound.2 These ratings provide an evaluation and rank ordering of the performance of test specimens based on their effectiveness at controlling the sound of a specific outdoor sound spectrum called the reference source spectrum.

1.2In addition to the calculation method, this classification defines some ratings not defined in other standards. Other standards may define additional ratings based on the method of this classification.

1.3The rating does not necessarily relate to the perceived aesthetic quality of the transmitted sound. Different facade elements with similar ratings may differ significantly in the proportion of low and high frequency sound that they transmit and the spectra of sources can vary significantly. It is best to use specific sound transmission loss values, in conjunction with actual spectra of outdoor and indoor sound levels, for making final selections of facade elements.

1.4Excluded from the scope of this classification are applications involving noise spectra differing markedly from that shown in Table 1. Thus excluded, for example, would be certain industrial noises with high levels at frequencies below the 80 Hz one-third octave band, relative to levels at higher frequencies, and any source, including some transportation sources, that does not have a spectrum similar to that in Table 1. However, for any source with a spectrum similar to that in Table 1, this classification provides a more reliable ranking of the performance of partitions and facade elements than do other classifications such as Classification E413.

1.5The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.