OSHA Standards For Exposure

OSHA (the Occupational Safety and Health Administration of the U.S. Federal Government) has determined exposure limits to various Sound Pressure Levels for industrial purposes. The same levels are relevant for music performance, but they represent a level of exposure that I personally can't tolerate. These standards are based on large scale statistical studies of hearing damage in the working population, and they correlate well with the increase in risk that any individual has in regard to hearing damage. Unfortunately, we do not know why hearing damage occurs to some people and not others for a given exposure level, so it is not a given that if you expose your hearing to levels in excess of the OSHA standards you will damage your hearing, just that such exposure will result in an increased likelihood of damage.

The basic level set by OSHA is:

85 dBA Leq for 16 hours per day.

This means that as long as the average level you listen to over a 16 hour day is no greater than 85 dBA Sound Pressure Level, you are not at any statistical risk for noise-induced hearing loss.

Each increase of 5 decibels Sound Pressure Level requires a halving of the exposure time, so that, according to OSHA, you can stand:

90 dBA Leq for eight hours, or

95 dBA Leq for four hours, or

100 dBA Leq for two hours, or

105 dBA Leq for one hour, or

110 dBA Leq for 30 minutes, or

115 dBA Leq for 15 minutes, or

120 dBA Leq for 7 minutes. Not!

For music quality work, I can't imagine subjecting myself to these exposure times. For mixing, (in 2006) I set my levels acording to a film standard of 85 dBC Sound Pressure Level at the mix position for each loudspeaker, which typically yields approximately 90 dBC at the mix position in stereo, and I cannot imagine sitting there with the meters hovering at 0 VU (er, -14 dBFS) for eight hours continuously -- I would find it absolutely exhausting and deafening. For music work, I would suggest that you consider one quarter of these exposure times (90 dBC Sound Pressure Level for two hours, for instance) as manageable and safe maximums.

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