Limitations of using dosimeters in impulse noise environments.
The National Institute for Occupational Safety and Health (NIOSH) investigated the capabilities of noise dosimeters to measure personal exposure to impulse noise. The two leading types of commercially available dosimeters were evaluated in terms of their ability to measure and integrate impulses generated from gunfire during live-fire exercises at a law enforcement indoor firing range. Sound measurements were conducted throughout the firing range using dosimeters, sound level meters, and a measurement configuration that consisted of a quarter-inch microphone and a digital audiotape recorder to capture the impulse waveforms. Personal dosimetry was conducted on eight shooters, an observer, and the range master. Peak levels from gunfire reached 163 decibels (dB), exceeding the nominal input limit of the dosimeters. The dosimeters "clipped" the impulses by acting as if the gunfire had a maximum level of 146 dB. In other cases, however, peak levels (e.g., 108 dB) were below the dosimeter input limits, but the dosimeters still showed a peak level of 146 dB. Although NIOSH recommends that sound levels from 80 to 140 dB (A-weighted) be integrated in the calculation of dose and the time-weighted average, our present data suggest this criterion may be inadequate. These results showed that some instruments are incapable of providing accurate measures of impulse sounds because of their electroacoustic limitations.
Kardous
Chucri A
CA
National Institute for Occupational Safety and Health, Cincinnati, Ohio 45226, USA. ckardous@cdc.gov
Willson
Robert D
RD
D005389:Firearms; D006801:Humans; D035846:Law Enforcement; D009314:National Institute for Occupational Safety and Health, U.S.; D009623:Noise, Occupational / Q000009:adverse effects*; D016273:Occupational Exposure / Q000032:analysis*; D018570:Risk Assessment; D013637:Tape Recording; D014481:United States