Powiadomienia systemowe
- Sesja wygasła!
Identyfikatory
Warianty tytułu
Języki publikacji
Abstrakty
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.
Wydawca
Rocznik
Tom
Strony
287--293
Opis fizyczny
Bibliogr. 6 poz., rys., wykr.
Twórcy
autor
- Central Institute for Labour Protection – National Research Institute (CIOP-PIB), Poland
autor
- Central Institute for Labour Protection – National Research Institute (CIOP-PIB), Poland
autor
- 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.
Typ dokumentu
Bibliografia
Identyfikator YADDA
bwmeta1.element.baztech-b5727fc3-5ea3-445e-8f20-54177085ba0f