Attenuation of Noise by Motorcycle Safety Helmets

• Autorzy: Młyński R. , Kozłowski E. , Żera J.
• Języki publikacji: EN

Abstrakty

EN

For workers such as police motorcyclists or couriers, traffic and engine noise reaching the ears is an important factor contributing to the overall condition of their work. This noise can be reduced with motorcycle helmets. In this study, insertion loss of motorcycle helmets was measured with the microphone-in-real-ear technique and sound attenuation with the real-ear-at-threshold method. Results for 3 Nolan helmets show essentially no protection against external noise in the frequency range <250 Hz. In the frequency range >500 Hz, attenuation increases linearly at a rate of 8–9 dB per octave, to ~30 dB at 8 kHz. Lack of attenuation in the low-frequency range may cause annoying effects. In addition, high attenuation in the high-frequency range may decrease intelligibility of speech signals for a rider in a helmet. Attenuation measured in this study does not take into account noise generated by turbulent wind around the helmet. Thus, the measured values of attenuation represent a motorcycle rider’s best conditions of hearing.

Słowa kluczowe

EN

noise attenuation; measurements on subjects; motorcycle helmets; motorcyclist conditions of work

• Wydawca: Taylor & Francis
• Czasopismo: International Journal of Occupational Safety and Ergonomics
• Rocznik: 2009
• Tom: Vol. 15, No. 3
• Strony: 287--293
• Opis fizyczny: Bibliogr. 6 poz., rys., wykr.

Twórcy

autor

Młyński R.

• Central Institute for Labour Protection – National Research Institute (CIOP-PIB), Poland

autor

Kozłowski E.

• Central Institute for Labour Protection – National Research Institute (CIOP-PIB), Poland

autor

Żera J.

• Central Institute for Labour Protection – National Research Institute (CIOP-PIB), Poland
• Institute of Radioelectronics, Faculty of Electronics and Information Technology, Warsaw University of Technology, Warszawa, Poland

Bibliografia

• 1.Lower MC, Hurst DW, Claughton AR, Thomas A. Sources and levels of noise under motorcyclists’ helmets. In: Proceedings of the Institute of Acoustics. Vol. 16. St. Albans, Herts., UK: Institute of Acoustics; 1994. p. 319–26.
• 2.Lower MC, Hurst DW, Thomas A. Noise levels and noise reduction under motorcycle helmets. In: Proceedings of Internoise 96. Indianapolis, IN, USA: Institute of Noise Control Engineering; 1996. p. 979–82.
• 3.Ross BC. Noise exposure of motorcyclists. Ann Occup Hyg. 1989;33(1):123–7.
• 4.European Committee for Standardization (CEN). Sound attenuation of hearing protectors. Part 1: Subjective method of measurement (Standard No. EN 24869-1:1992). Brussels, Belgium: CEN;1992.
• 5.Patel J, Irving F. Measuring the noise attenuation of shotblasting helmets. Ann Occup Hyg. 1999;43(7):471–84.
• 6.Żera J, Młyński R. Attenuation of outside noise by shotblasting helmets. Arch Acoust. 2004;29(2):347–58.