Hearing protectors
Noise destroys hearing
It is a well-known fact that excessive noise can cause permanent damage to hearing.
In the process of occupational noise management the use of hearing protectors lies at the low end of the hierarchy in the reduction of noise exposure.
Even so, the use of personal protective equipment, such as earmuffs and earplugs, has a significant place in the management of the noise exposure of individuals.
What are hearing protectors?
Hearing protectors are devices that fit over or in the ears. Typical examples are earplugs and earmuffs. There are, however, many different types of hearing protectors on the market.
The purpose of hearing protectors is to break the path of the sound reaching your ears. By breaking the sound path and providing an attenuation or reduction in the sound level they can assist in reducing the risk of excessive exposure to loud noise.
Do hearing protectors work?
The underlying assumption that is always made when an individual is supplied with and wears hearing protectors is that they work, that is, that they are actually reducing the total amount of noise reaching the ear.
For hearing protectors to work effectively, they must be worn for the whole duration of the exposure to the noise. This means that they must be positioned before you enter the noisy area, removed after you have left the area and not removed for any length of time, no matter how short, while you are still exposed to the noise.
Impulse noise
Impulse noise can cause instantaneous and permanent damage to hearing. If you are involved with impulse noise such as gunfire, explosives, nail guns or heavy metal work, you will need extra protection.
To provide this extra level of protection you should use both earplugs and ear muffs and seek expert advice from a reputable source.
Comfort
All things considered, the most important parameter when selecting hearing protectors is comfort. If a hearing protector is not comfortable, it will not be worn. It is better to sacrifice a few decibels in the rating of the device for greater comfort as the chances it will be worn are also then greater.
Comfort is also the reason why you should never select a hearing protector for another person. Always lets the user select their own hearing protector.
Selection
There are numerous methods for selecting an appropriate hearing protector for specific uses. By far the simplest system is the Classification system outlined in Australian Standard AS/NZS 1269.3.
The Class of a protector is determined by its SLC80. This will be printed on the packaging. The table below relates the Class of a protector, the corresponding SLC80 range and the noise exposure for which appropriate attenuation is provided.
| The Hearing Protector Classification System | ||
|---|---|---|
| Class |
SLC80 range [dB] |
Noise exposure [dB(A)] |
| 1 | 10 to 13 | up to 90 |
| 2 | 14 to 17 | 90 to less than 95 |
| 3 | 18 to 21 | 95 to less than 100 |
| 4 | 22 to 25 | 100 to less than 105 |
| 5 | 26 and greater | 105 to less than 110 |
| The use of the Classification system is simple. If, for example, an individual has a noise exposure of 97dB(A), then a protector of Class 3 would be chosen. If the exposure level is 100dB(A) then a protector of Class 4 would be suitable. | ||
Maintenance
You need to maintain your hearing protectors. Not only should you keep them clean for the obvious hygiene reasons but also to protect them from any chemicals that may downgrade their performance.
A regular physical inspection of earmuffs should also be carried out in order to ensure their integrity. Things to note are:
- the clamping force;
- the condition of the earcups and the ear cushions; and
- the condition of the acoustic absorber inside the ear cups.
All should be in good condition. If not they should be replaced with new parts recommended by the manufacturer.
Re-useable earplugs may need to be cleaned by rinsing in warm, soapy water and dried after each use. Many earplugs are not meant for re-use so check with the manufacturer’s recommendations.
Hazardous noise
In most Australian jurisdictions, if an individual is subject to a noise exposure level greater than the specified criterion level, usually a noise exposure level (LAeq,8h) of 85dB(A), then the work area is considered to be hazardous. If an employer is serious about noise exposure reduction they must demonstrate that a responsible hearing protector programme is in place.
This process of implementing a hearing protector programme is outlined in the Australian/New Zealand Standard AS/NZS 1269.3 Occupational noise management Part 3: Hearing protector program and includes hearing protector selection, fitting, education about its use and maintenance programmes.
Last Reviewed: 17 August 2005
