Damage‐Risk Criterion for the Impulsive Noise of “Toys”

1967 ◽  
Vol 42 (1) ◽  
pp. 268-268 ◽  
Author(s):  
Kjell Gjaevenes
2015 ◽  
Vol 58 (5) ◽  
pp. 1425-1439 ◽  
Author(s):  
Ingo R. Titze ◽  
Eric J. Hunter

Purpose Schoolteachers have become a benchmark population for the study of occupational voice use. A decade of vibration-dose studies on the teacher population allows a comparison to be made between specific dose measures for eventual assessment of damage risk. Method Vibration dosimetry is reformulated with the inclusion of collision stress. Two methods of estimating amplitude of vocal-fold vibration are compared to capture variations in vocal intensity. Energy loss from collision is added to the energy-dissipation dose. An equal-energy-dissipation criterion is defined and used on the teacher corpus as a potential-damage risk criterion. Results Comparison of time-, cycle-, distance-, and energy-dose calculations for 57 teachers reveals a progression in information content in the ability to capture variations in duration, speaking pitch, and vocal intensity. The energy-dissipation dose carries the greatest promise in capturing excessive tissue stress and collision but also the greatest liability, due to uncertainty in parameters. Cycle dose is least correlated with the other doses. Conclusion As a first guide to damage risk in excessive voice use, the equal-energy-dissipation dose criterion can be used to structure trade-off relations between loudness, adduction, and duration of speech.


Author(s):  
W. I. Acton ◽  
R. R. A. Coles

Detailed noise surveys of twenty-one modern power stations indicated that the main sources were turbo-alternators and fuel pulverizing plant, with boiler feed pumps, fans of various types, and high-pressure steam valves and pipes as secondary sources. Furthermore, noise levels increased with increasing capacity of plant. The noise levels measured in certain locations in power stations exceeded recent hearing damage risk criteria and it is likely that, unless protected, exposed personnel will eventually suffer hearing damage. The exposed personnel may be divided into two groups: those such as fitters, cleaners, etc., who are only exposed intermittently and the unit control staff who are often exposed continuously for 8-hour periods for five days every week. The principal features of noise-induced hearing loss and of a hearing conservation programme are outlined. The first steps are reduction of noise at source and in transmission; in the situations described, provision of acoustically isolated control rooms is indicated. Where noise levels exceed the damage risk criterion, even for short intermittent exposures, ear protection is required; different types of ear protector, their advantages and disadvantages, and their effects on communications and on the hearing of other important sounds will be reviewed. In addition, a programme of hearing tests (monitoring audiometry) may be desirable.


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