One of the main effects of noise in the workplace is noise-induced hearing loss (NIHL). Taking steps to provide a safe level of noise exposure for your workers is important to help prevent NIHL and potential Workers Compensation claims.
NIHL can be immediate or it can take a long time to be noticeable. It can be temporary or permanent, and it can affect one ear or both ears. Even if you can’t tell that you are damaging your hearing, you could have trouble hearing in the future, such as not being able to understand other people when they talk, especially on the phone or in a noisy room. Regardless of how it might affect you, one thing is certain: noise-induced hearing loss is something you can prevent.
This 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.
People vary in their susceptibility to noise damage. 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).
For more information see Section 1.2 of the Code of Practice, Managing noise at workplaces.
Noise can also contribute to other health effects such as increased blood pressure, stress and tinnitus (ringing in the ears). Safe levels of noise to guard against these effects have not yet been determined and research is continuing. As a guide, stress can be reduced by keeping levels below 55 dB(A) in areas where people need to do work requiring concentration.
A Noise survey or noise assessment is conducted in areas where noise exposure is likely to be hazardous. Noise level refers to the level of sound. A noise survey involves measuring noise level at selected locations throughout an entire plant or sections of a workplace to identify noisy areas. This is usually done with a sound level meter (SLM).
See more on noise surveys and the associated WorkSafe legislation in WA.
Communication in noisy environments
Another effect of noise is difficulty communicating and hearing warning signals or other sounds needed to work safely. A safe level of noise in these situations will vary depending on the level of the signals and the hearing capabilities of the listeners.
Why do employers have to reduce noise at the source when employees can wear hearing protectors?
The various types of hearing protectors (earmuffs, ear plugs, semi-inserts) are not the best forms of protection because they rely on individual employees being able and willing to use the equipment correctly. Failure to wear the hearing protectors correctly 100% of the time in excessive noise will significantly decrease the effective protection. Their effectiveness is also reliant on their condition and whether they fit correctly, which is particularly 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.
Who needs audiometric testing in WA?
It is compulsory for all employers to arrange baseline hearing tests in prescribed noisy workplaces, even if your workers are wearing hearing protection. All workers employed in a prescribed workplace for the first time must have a baseline hearing test within twelve months of commencing employment. See more on your WorkCover WA requirements
How can noise levels of loud machines and equipment be reduced?
Depending on the source, noise can be reduced in several ways, as follows:
- buying quiet machinery and equipment;
- routinely maintaining machinery and equipment;
- reducing machinery and equipment vibration;
- muffling engine and compressed air noise;
- isolating the noise source in an insulated room or enclosure;
- placing a barrier between the noise source and the employee; or
- isolating the employee from the source in an insulated booth or room
All of the above strategies can help to ensure your workers are exposed to a safe level of noise in the workplace.