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.
Preliminary Estimate of a Hearing Damage Risk Criterion for Steady State Noise
