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Testing
of Hearing Protection Devices
Experimental
studies on the assessment of attenuation characteristics and
comfort levels of a variety of ear plugs and ear muffs have
also been carried out by NIOH. The attenuation characteristics
of two models of ear plugs (A and B) and five models of ear
muffs (A, B, C, D & E) were assessed in the acoustic
chamber. The results showed that both models of ear
plugs yielded low attenuation values of 9-11 dB at frequencies
2000-8000 Hz. The ear muff (Model E) afforded maximum
sound attenuation (35-40dB) at frequencies 3000-8000Hz.
The attenuation values of other ear muffs were relatively low
ranging 28-32 dB for model ‘A’, 26-30 dB for model
‘B’, 32-35 dB for model ‘C’ and 15-20 dB for model
‘D’.
Absolute
impression of comfortable-uncomfortable sensation
(psycho-physical method) produced by the wearing of ear
protectors revealed high percentage of comfort responses for
ear muff model ‘E’ due to its overall low application
force and especially smaller application force of its headband
spring compared to those of the other ear muffs. Models
‘A’ and ‘B’ were graded as less comfortable compared
to model ‘E’ because the application force of these two
models was comparatively high as were the tightness of the
headbands. Model ‘C’ was rated as less comfortable and
model ‘D’ as least comfortable, despite low application
force and less tightness of the spring. Thus the five models
of ear muff were graded for comfort in wear.
Dust Control Techniques for Prevention of Pneumoconiosis
Prevention of Green Tobacco Sickness among Tobacco Harvesters
Testing of Hearing Protection Devices
Compensation of Occupational Diseases
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