The adjustment ensures that the errors arising from this approach are more likely to underestimate rather than overestimate the protection that would be predicted using the more precise Octave-Band Method. The 7 dB adjustment has nothing to do with the differences between laboratory and real world performance. It is not to be confused with any constant decibel or percentage deratings of the NRR that have been proposed to account for such discrepancies 6 . Alternative to the Adjusted NRR Due to the poor accuracy of the Adjusted NRR Method it is advisable to use the Octave-Band or NRR Methods. However, the method of noise monitoring that is preferred by OSHA is personal dosimetry, and no commercially available dosimeters currently provide C-weighted dose assessments.
Resultant values are A-weighted and summed to yield estimated dBA exposure.
Three alternative names for the same technique. Although this procedure is not explicitly presented in the Amendment, it is scientifically acceptable and has been implemented elsewhere 8 . Obtain an A-weighted noise dose. The confusion arose since EPA chose to accommodate those users whom it feared would lack C-weighted measurement capabilities. It did this by effectively developing a two-number rating system, without ever explicitly stating that fact 9 .