Specifies 3 methods, in ascending order of complexity of use and potential accuracy, for estimation of sound pressure levels that are effective when a hearing protector is worn: 1) Noise Level Reduction Statistic for use with A-weighting (NRSA), 2) Noise level Reduction Statistic, Graphical (NRSG), and 3) the octave-band method. Also specifies, in the case of NRSA and NRSG, that values will be presented for both 80th and 20th percentiles to reflect the range of attenuation that can be anticipated.
ANSI/ASA S12.68-2007 history
2007ANSI/ASA S12.68-2007 Methods of Estimating Effective A-Weighted Sound Pressure Levels when Hearing Protectors Are Worn