Speech privacy in an open office is dependent on many factors (see Guide E 1374 for a discussion on open office acoustical considerations). One of these factors is the masking sound in the office. Without masking sound in the open office, confidential speech privacy is not possible at normal voice levels. The four critical acoustical parameters of masking sound are its spatial uniformity, temporal uniformity, spectrum shape, and level. The measurement and determination of these parameters are addressed in this test method.

The results from this test method can be used to determine if the masking sound meets a particular specification.

1.1 This test method specifies the procedures that can be used to evaluate the spatial and temporal uniformity of masking sound in open offices using A-weighted sound levels. It also specifies the procedure for evaluating the masking sound spectrum and level using one-third octave band sound pressure levels.

1.2 The results of this test method can be used to determine if the masking sound meets a particular specification for spatial and temporal uniformity if that specification is written in terms of A-weighted sound levels and if the masking sound meets a particular spectrum shape and level in the office area.

1.3 This test method must not be used to evaluate the acoustical environment in an office space. It is intended only to evaluate the masking sound in an office. This test method, for instance, does not evaluate the low frequency rumble noise found in some offices.

1.4 This standard does not purport to address all of the safety problems, 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.