Noise exposure is one of the most widespread health hazards in construction. Prolonged exposure to noise over the years generally causes permanent damage to the inner ear that can't be repaired medically or surgically. Because noise induced hearing loss is usually gradual, impairment isn't noticed until a substantial degree of hearing loss has already occurred. The consequences are significant:
- Workers with NIHL may not hear audible warnings and safety signals.
- Hearing impairment jeopardizes not only affected employees but others who work with them.
- NIHL may interfere with daily life, especially during social activities in noisy settings.
- The increased effort to listen and understand may lead to fatigue, anxiety, and stress.
- Those affected may feel increasingly isolated from family and friends.
- Some people with NIHL also suffer from tinnitus, causing them to hear ringing, buzzing, rushing, whistling, or hissing when there are in fact no sounds to be heard.
Sound and Hearing
Sound stimulates tiny hair-like cells in your inner ear. These vibrate and send auditory messages to your brain. But too much noise for too long can damage the cells. When they no longer send signals to the brain, hearing is lost. Damage often occurs slowly over a number of years and may go unobserved until too late. Most of the workplace sounds that cause permanent damage occur over a long time (for example, about 8 hours per workday over 10 years or more).
Sounds must also be specified in terms of frequency or pitch. Most workplace noises include a wide band of frequencies and are measured through the "A" filter in sound-level meters. The noise level is therefore expressed in decibels (dB) on the "A" scale, or dB(A).
Duration of exposure is equally important. Duration is typically measured over a workday and accumulated through many years.