According to WorkSafe WA, a safe level of noise, to protect the most noise-sensitive people from any hearing loss during a working lifetime, would be an average over the work shift of about 75 dB(A). People vary in their susceptibility to noise damage.
Noise Induced Hearing Loss
One of the main effects of noise at work is noise-induced hearing loss (NIHL).
NIHL can happen in two ways:
- noise of very high peak levels (more than about 135-140 decibels (dB)) can cause immediate damage to the structures of the inner ear; or
- noise of a lower level over an extended period of time can cause gradual damage.
Baseline hearing test
Noise Survey requirements
Like all hazards in the workplace, WorkSafe WA expect employers to be aware of noise hazards to which they expose their employees. As such the OSH legislation requires employers to quantify the level of noise in their work place. this is done via a Noise Survey.
A survey measures existing noise levels and personal exposure risks. The noise survey report should tell you where and how to reduce noise at the source, and identify those individuals who should be wearing hearing protectors and possibly also have audiometric testing.
Basically, a noise survey should help you to work out a plan to achieve a safe level of noise and to reduce the risk of noise-induced hearing loss in your workplace.
Why do employers have to reduce noise at the source when employees can wear hearing protectors?
Hearing protectors (earmuffs, ear plugs) should not be the first strategy for managing noise because their effectiveness depends on individual employees being able and willing to use the equipment correctly and the equipment being suitable to the employee and the environment.
Failure to wear the hearing protectors correctly 100% of the time in excessive noise will significantly decrease the effectiveness of the protection. Their effectiveness is also reliant on their condition and whether they fit correctly, which can be difficult if other protective equipment also needs to be worn. They can also fail or be inefficient without this being visibly obvious.
For all these reasons, hearing protectors are regarded as a last resort risk reduction measure, to be used only when other practicable steps to reduce excessive noise have been taken.
WorkSafe WA’s Code of Practice, Managing Noise at Workplaces is an excellent reference source to help you manage a safe level of noise at work.
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