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ASA/ANSI ASA S1.26-2014 (R2024)
Methods for Calculation of the Absorption of Sound by the Atmosphere
This Standard provides the means to calculate atmospheric absorption losses of sound from any source, moving or stationary, for a wide range of meteorological conditions. The atmosphere is assumed to bestill, homogeneous moist air of normal composition. Non-homogeneous atmospheres can be divided into horizontal layers within which homogeneous conditions can be assumed. Attenuation coefficients for pure-tone sounds are calculated by means of equations (or a table) over ranges of frequency, and the humidity, pressure, and temperature of the atmosphere. For sounds analyzed by fractional-octave-band filters (e.g., one-third-octave-band filters), alternative methods are provided in annexes to calculate the attenuation caused by atmospheric absorption from that specified for pure-tone sounds.
Acoustical Society of America [asa]