What is it about?
The assessment of firearm noise exposure is complicated because the sound pressure levels are typically in excess of 150 dB peaks. When assessing the exposure using a microphone at a fixed location, the measurement accuracy is compromised when the subject moves nearer or further from the microphone. This innovative system measures the noise in the ear canal of the subjects and tracks their locations on an outdoor firing range. We examine the exposure levels for the five subjects during a live fire exercise and report on their exposures
Photo by Thomas Tucker on Unsplash
Why is it important?
This study is the first that has location information, in-ear and on-body dosimetry measurements, and a comprehensive noise mapping of the exposure throughout the exercise. It compares different methods to estimate the exposure and demonstrates the superiority of the in-ear dosimeter.
Read the Original
This page is a summary of: In-ear and on-body measurements of impulse-noise exposure, International Journal of Audiology, January 2019, Taylor & Francis, DOI: 10.1080/14992027.2018.1534012.
You can read the full text:
In-ear and On-body Measuremetns of Impulse Noise Exposure
In-ear dosimetry for high-level impulse noise presents significant challenges. External peak sound pressure levels (>140 dB SPL) combined with hearing protection can result in earcanal levels approaching 140 dB. MIT Lincoln Laboratory has developed a modified commercial-off-the-shelf recorder that simultaneously measures signals from both ear canal and just outside the ear at a sample rate of 96 kHz. Validation measurements were conducted with a GRAS 45CB fixture and an acoustic shock tube. An exploratory study was conducted with a small sample of experimenters during a recent Navy-sponsored noise survey conducted at Quantico Marine Corps Base. Results will be presented from the nominal instructor’s position as well as from bystanders observing at a firing range. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health. Mention of any company or product does not constitute endorsement by NIOSH.
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