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ASA/ANSI S12.9-2021/Part 4

Quantities and procedures for description and measurement of environmental sound - Part 4: noise assessment and prediction of long-term community response

This Standard specifies methods to assess environmental sounds and to predict the annoyance response of communities to long-term noise from any and all types of environmental sounds produced by one or more distinct or distributed sound sources.  The sound sources may be separate or in various combinations.  Application of the method of the Standard is limited to areas where people reside and related long-term land uses.  This Standard does not address the effects of intrusive sound on people in areas of short-term use such as parks and wilderness areas, nor does it address other effects of noise such as sleep disturbance or health effects.  This Standard does not provide a method to predict the community response to short-term, infrequent, non-repetitive sources of sound.

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Acoustical Society of America [ASA]


As the voice of the U.S. standards and conformity assessment system, the American National Standards Institute (ANSI) empowers its members and constituents to strengthen the U.S. marketplace position in the global economy while helping to assure the safety and health of consumers and the protection of the environment.