An Evaluation Of Industrial Acoustic Radiation Above 10KHZ.
Michael-PL; Kerlin-RL; Bienvenue-GR; Prout-JH
NIOSH 1974 Feb:202 pages
A field study was conducted to measure acoustic radiation above 10 kiloHertz (kHz) in various workplaces to determine the effects of exposure to workers. Sound pressure was measured around ultrasound cleaners, tube drawing equipment, sewing machines, dental drills, and other ultrasonic equipment. Subjective reactions were solicited from workers and supervisors and medical records were examined. An overall evaluation indicated that few persons were exposed to a constant or predictable time pattern of airborne acoustic energy above 10kHz. High frequency exposures were unpredictable because of the presence of standing waves and directionality of sound waves. Only a small number of workers were sensitive. Confounding factors included lack of knowledge of the ear's mechanism of response to high frequency sounds, differences in individual sensitivity, attitudes towards high frequency sounds, and differences in physiological and psychological conditions of the same person or between different persons to the same sound source. Since psychological stress could result in physiological effects it was impossible to separate the effects from each other. Other factors involved were differences in other stresses to which the individual workers were exposed and in parameters related with production and propagation of high frequency energy which could change the exposure and frequencies patterns. The authors conclude that the study did not provide an adequate basis on which an accurate exposure limit to airborne acoustic energy above 10kHz could be developed.
NIOSH-Contract; Exposure-levels; Safety-research; Industrial-safety; Occupational-health; Noise-measurement; Noise-frequencies; Sound-attenuation; Sound-analyzers; Medical-research; Contract-099-72-0125;
NTIS Accession No.
Physical Agents Branch, NIOSH, Cincinnati, Ohio, NTIS PB83-257-253