Exposure to very high noise levels and the effect of double hearing protection

摘要

The risk of noise induced hearing loss increases for operators working in extreme noise environments. Although the use of earplugs and earmuffs as 'double protection' may be the obvious solution, the attenuation of a double hearing protection system is not simply the addition of the individual component attenuations. The choice of devices and the implementation can also result in a number of outcomes: the integration of communications wiring may cause acoustic leaks, the wearer may be overprotected and feel isolated and the interaction of earplug and earmuff may cause discomfort and discourage take-up. A variety of hearing protection devices currently on the market have been examined with a view to their use in a double protection system. Wireless technologies enable the provision of a communications signal to an earplug worn beneath an earmuff without compromising the attenuation benefit of the double protection system. Adaptive systems, such as the 'tactical' communications earplugs and techniques such as adaptive digital active noise reduction, provide a method of tailoring levels of hearing protection to the noise environment. Using military operators as an example user group the application of a range of earplug devices as part of a double protection system have been considered and illustrations have been provided of their relative abilities to meet the users' protection requirements.