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Kardous C, Morata TC. Occupational and recreational noise exposures at stock car racing circuits: an exploratory survey of three professional race tracks. Noise Control Engineering Journal 58(1): 54-61, Jan-Feb, 2010.


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Noise in stock car racing is accepted as a normal occurrence but the exposure levels associated with the sport have not been adequately characterized. Researchers from the National Institute for Occupational Safety and Health (NIOSH) conducted an exploratory assessment of noise exposures to drivers, racing team members, and spectators at three stock car racing events. Sound level measurements were conducted using sound level meters, personal noise dosimeters, and a digital audio tape recorder that made sound recordings for later laboratory analysis. Area sound level measurements were made during race preparation, practice, qualification, and competition. Personal dosimetry measurements were conducted on drivers, team members, and spectators. Findings showed time-weighted averages (TWA) that ranged from A-weighted 96 decibels (dBA) for a spectator in the stands during a race to 114 dBA for a driver inside a car during practice. Peak sound pressure levels exceeded the maximum allowable limit of 140 dB during race competitions. Personal exposure measurements exceeded the NIOSH recommended exposure limit of 85 dBA as an 8-hr TWA in less than a minute for one driver during practice, within several minutes for team members, and less than one hour for spectators during the race. Hearing protection use was variable and intermittent among team members and spectators. Among drivers and team members, there was greater concern for communication performance than for hearing protection. © 2010 Institute of Noise Control Engineering.
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The National Institute for Occupational Safety and Health (NIOSH) surveyed noise exposure for a professional stock car team at their race shop and during two races at one racetrack. At the team's shop, area sound pressure levels (SPLs) were measured for various work tasks. Equivalent levels (Leqs) ranged from 58 to 104 decibels, A-weighted (dBA). Personal noise dosimetry was conducted for at least one employee for each job description in race car assembly (n = 9). The Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) of 90 dBA for an 8-hour, 5-dB exchange rate time-weighted average (TWA) was never exceeded, but in two instances values exceeded OSHA's action level of 85 dBA for hearing conservation implementation. The NIOSH recommended exposure limit (REL) of 85 dBA for a 3-dB exchange rate Leq was exceeded for five of the measured jobs. During the races, SPLs averaged above 100 dBA in the pit area where cars undergo adjustments/refueling, both before and during the race. Peak levels reached 140 dB SPL. NIOSH REL was exceeded for every personal noise dosimetry measurement. Recommendations for hearing protection and communication are presented.
Professional racing drivers are exposed to extreme noise pollution by their high-capacity cars. For the purpose of evaluating the emissive noise of racing-cars, noise-level measurements on race-courses were undertaken. As a result noise-levels up to 130 dB (A) for the outer noises and 125 dB (A) for the inner region of the car were measured. Moreover, eighteen professional racing drivers as well as eleven employees, working in the pit, underwent audiometric investigations. Only one of the racing drivers showed noise deafness. This result can be explained by the short periods of exposure to the noise, which is 150-180 hours every year, and the regular wearing of ear-plugs. The employees working in the pits, however, showed distinct hearing impairments, explained above all, by their activities at the motor-test blocks. Incidentally this paper also deals with the noise sources of vehicles and the origin of noise deafness. There is no risk of noise deafness for this group of persons.
Two solutions to the problem of excessive noise exposure and consequent hearing loss in motorcyclists were investigated and are described. One was an antecedent behaviour-modifying 'prompting' strategy, where a set of earplugs and an advice sheet were provided at the point of sale to consecutive purchasers of new motorcycle crash helmets. Forty-eight riders were recruited but data for analysis were only available in 41. The earplug usage rate was significantly increased from 27% to 83% by this intervention. The second solution involves various aerodynamics and sound-proofing helmet modifications made in an effort to reduce interior noise levels. The only modification which achieved a significant reduction from previously reported average sound levels was the incorporation of a pair of 'standard' earmuffs under the helmet shell. This gave noise levels of 84 dB(A) at 22 m/s (50 mph) and 93 dB(A) at 36 m/s (80 mph), compared to known average values of 95 dB(A) and 107 dB(A), respectively. Both solutions are eminently feasible and desirable, and we hope that the motorcycle industry will act on them.
Conventional hearing protection devices represent a mature technology that has been widely used since the late 1950s. When worn consistently and correctly such devices can provide suitable hearing protection in many, if not most noise-hazardous or aurally annoying situations. However, such devices have often been implicated in compromised auditory perception, degraded signal detection, and reduced speech communication abilities. In some instances this can create hazards for the wearer, or at the very least, resistance to use by those in need of hearing protection. Recent technological developments have been used to augment hearing protectors in an attempt to alleviate these problems for the user while providing adequate attenuation. Operational characteristics, design alternatives, performance data, and applications for active noise reduction, active sound transmission, frequency selectively, adjustable attenuation, amplitude sensitivity, and uniform attenuation features in hearing protectors are discussed, and recommendations are provided.
An investigation to ascertain the most suitable earplug and its efficacy for use by motorcyclists was undertaken. To qualify for testing the earplugs had to be both easily available and cost less than £10. Consequently, three types of earplugs (‘Silisoft’, EARfit and AQUAfit [both Cabot Safety Ltd]) were tested fro sound attenuation scores using an ‘insertion loss’ technique both with and without a motorcycle helmet and scored for comfort by the test subjects. The optimal plug was then assessed as to its effect on the temporary threshold shift occurring in motorcyclists after prolonged high speed riding. There were no significant differences between the sound attenuation scores of the three plugs tested, with all three earplugs providing approximately 15 dB of sound attenuation at the low frequencies (250, 500, 1000 Hz) when worn under a helmet. The soft yellow foam earplug was felt to be the optimal plug for motorcyclists as it was significantly more comfortable (Wilcoxon paired: P < 0.01), readily available (X2= 15.2, P < 0.001) and the cheapest. After one hour of high speed riding (80 mph), riders suffered a mean maximal temporary threshold shift of 11 dB at 1000 Hz which was abolished by wearing these earplugs. Earplugs appear to provide useful protection against the excessive noise levels experienced by motorcyclists. The soft yellow foam plug (EARfit, Cabot Safety Ltd) would appear to be the most suitable, on the grounds of its low cost, comfort and ease of availability.
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