Such surveys and detailed noise impulse assessments are not possible by simply using a sound level meter and that is why a dedicated impulse noise measurement system is needed. Knowing the characteristics of the impulse waveform is critical to understanding the risk of any high-level impulse noise exposure. Using the NIOSH impulse noise system allows our researchers to capture impulses and calculate risk metrics, in real-time, and provide appropriate recommendations to reduce the risk of hearing loss. As data acquisition, digital signal processing, and storage capabilities continue to improve, it is crucial for sound measurement instruments targeted at measuring impulsive noise to:
- be redesigned to capture high-level impulses,
- have the capability to store the entire impulse waveform or impulsive event, and
- incorporate appropriate impulse-specific metrics into their capabilities.
We are currently wrapping up a study to develop new guidelines for exposure to impulsive noise, which will be used to update our occupational noise exposure criteria document. NIOSH hearing loss prevention researchers have also conducted studies on the performance of hearing protection devices in impulse noise environments; a follow-up blog on that subject will be published soon. For more information about impulsive noise research and hearing loss prevention in general, check out our topic page and follow us on Twitter at @NIOSHNoise.
CAPT Chucri (Chuck) A. Kardous, MSEE, PE, is a senior research engineer in the NIOSH Division of Applied Research and Technology.
CAPT William J. Murphy, PhD, is a senior research physicist in the NIOSH Division of Applied Research and Technology.
CHABA . Hazardous exposure to impulse noise. Washington, DC: National Research Council, Committee on Hearing, Bioacoustics, and Biomechanics. http://www.dtic.mil/docs/citations/ADA382167
Kardous CA, Willson RD  Limitations of using dosimeters in impulse noise environments. J Occup Environ Hygiene 1(7):456-462. DOI: 10.1080/15459620490465839
Kardous CA, Franks JR, Davis RR . NIOSH/NHCA best-practices workshops on impulsive noise. Noise Contr Eng J 53(2):53-60. DOI: 10.3397/1.2839245
U.S. DOD . MIL-STD-1474E. Design Criteria Standard, Noise Limits. U.S. Department of Defense, Washington, D.C. https://www.arl.army.mil/www/pages/343/MIL-STD-1474E-Final-15Apr2015.pdf