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ASA/ANSI S12.68-2007 (R2025)
Methods of Estimating Effective A-Weighted Sound Pressure Levels When Hearing Protectors are Worn
This standard outlines three methods—ranging from simple to complex—for estimating effective sound pressure levels when hearing protectors are worn. Each method requires estimates of real-ear attenuation and user noise exposure. The NRSA method allows a simple subtraction from A-weighted levels. The NRSG method uses A- and C-weighted levels with graphical data. The most precise method uses octave-band attenuation and measurement data. NRSA and NRSG values are provided at the 80th and 20th percentiles to account for attenuation variability.
Acoustical Society of America [asa]