(1) "Harmful industrial noise" means:
(a) sound that results in acoustic trauma such as sudden instantaneous temporary noise or impulsive or impact noise exceeding 140 dB peak sound pressure levels; or
(b) the sound emanating from equipment and machines during employment exceeding the following permissible sound levels, dBA slow response, and corresponding durations per day, in hours:Sound levelDuration90892695497310021021.51051.01100.51150.25 or less
(2) "Loss of hearing" means binaural hearing loss measured in decibels with frequencies of 500, 1,000, 2,000, and 3,000 cycles per second (Hertz). If the average decibel loss at 500, 1,000, 2,000, and 3,000 cycles per second (Hertz) is 25 decibels or less, usually no loss of hearing exists.