period two
Sound Perception and
Rating Methods
notes
A–Weighting
IUsed for outdoor sound ordinances and indoor, hearing-related safety standards (OSHA)
IUse with sound pressure data only, not sound power
IExpress as a single number descriptor only, not as octave-band data
Figure 25
A-weighting is often used to define sound in outdoor environments. For example, local sound ordinances typically regulate dBA levels at property lines.
Hearing-related safety standards, written by organizations such as the Occupational Safety and Health Administration (OSHA), also commonly refer to A-weighted sound-pressure levels when determining whether hearing protection is required in a certain environment.
To avoid confusion, we recommend that A-weighting be applied only to octave- band sound-pressure data, not to sound-power data. Also, A-weighting should be limited to expressing a single-number descriptor. Displaying sound data in all eight octave bands in terms of A-weighted sound pressures should be avoided.
