This work has looked at selection of hearing protectors for use
within the mining industry and has been concerned primarily to
identify any relationship between physical characteristics of
circumaural hearing protectors (earmuffs) and subjective assessment
of comfort and overall acceptance. Twenty-four types were submitted
for test and measured for headband force, contact surface area of
ear cushions and pressure exerted. This number was reduced to eight
by an initial selection procedure based on the above parameters. Ten
samples of each type were procured and measured as above with
additional measurements of ear cushion compliance and headband force
at different headwidths. Subjective assessments of performance were
obtained by questionnaire from twenty-seven men involved in underground
trials at four collieries. A rank order preference was determined for
categories of comfort, convenience, pressure and acceptance.
From the measurements obtained it was concluded that a weight
per unit pressure ratio was- the best indicator of comfort of a device.
In this study, a ratio of approximately 40: 1 was acceptable, with
satisfaction declining as the ratio increased. An objective method
for measuring attenuation was investigated and a simplified procedure
suggested as an in-service monitoring test for deterioration of earmuff
A Master's Thesis. Submitted in partial fulfilment of the requirements for the award of Master of Philosophy of Loughborough University.