Impulse noise generated by starter pistols

Abstract

Objective: This study describes signals generated by .22 and .32 caliber starter pistols in the context of noise-induced hearing loss risk for sports officials and athletes. Design: Acoustic comparison of impulses generated from typical .22 and .32 caliber starter pistols firing blanks were made to impulses generated from comparable firearms firing both blanks and live rounds. Acoustic characteristics are described in terms of directionality and distance from the shooter in a simulated outdoor running track. Metrics include peak sound pressure levels (SPL), A-weighted equivalent 8-hour level (L_eqA8), and maximum permissible number of individual shots, or maximum permissible exposures (MPE) for the unprotected ear. Results: Starter pistols produce peak SPLs above 140 dB. The numbers of MPEs are as few as five for the .22-caliber starter pistol, and somewhat higher (≤ 25) for the .32-caliber pistol. Conclusion: The impulsive sounds produced by starter pistols correspond to MPE numbers that are unacceptably small for unprotected officials and others in the immediate vicinity of the shooter. At the distances included in this study, the risk to athletes appears to be low (when referencing exposure criteria for adults), but the sound associated with the starter pistol will contribute to the athlete's overall noise exposure.

Key Words::

• Impulse noise
• starter pistol
• noise level
• noise exposure
• noise-induced hearing loss
• sports injury
• occupational health and safety
• track and field

Acknowledgements

The authors thank Edward Zechmann (CDC/NIOSH Taft Laboratories) for the MATLAB software routines used for data analyses. Preliminary findings from this study were presented at the 10th International Congress on Noise as a Public Health Problem (ICBEN) 2011; London, UK.

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.

Declaration of interest: Jacob Soendergaard is an employee of G.R.A.S. Sound and Vibration, a manufacturer of sound measurement instrumentation used in this research study.