How much dB must be subtracted to achieve a truer estimate of actual attenuation according to OSHA?

The requirement to subtract a specific amount of decibels to achieve a more accurate representation of actual attenuation is based on standards set by the Occupational Safety and Health Administration (OSHA). According to OSHA guidelines, a subtraction of 7 dB is recommended to correct for the differences between the nominal attenuation values provided by hearing protection devices and the actual attenuation experienced by workers under typical conditions.

This 7 dB adjustment accounts for factors such as the fit of the hearing protection and individual variations in ear anatomy, which can lead to discrepancies between laboratory measurements and real-world performance. As a result, by applying this subtraction, audiology professionals can provide a more realistic estimate of the effectiveness of hearing protection in reducing noise exposure.