To put noise levels into perspective....
Noise levels in excess of 90 DB, for an excess of 8 hours, will result in permanent hearing loss. It is for that reason that hearing protection is required (OSHA) in industrial facilities where a noise survey has concluded that personnel could be exposed to noise levels in excess of 84 db. A peak, one time exposure to a noise level of 140 DB will also result in permanent hearing loss. Exposure to noise in excess of 100 DB for a duration of 2 hours will also result in permanent hearing loss. Double hearing protection is required when employees may be exposed to 140 db peak and / or 100 db over 15 minutes duration (OSHA).
