Noise

What you need to know

Woodworking has some of the noisiest work places in industry. Short exposure to high noise levels can cause temporary hearing loss, but longer exposures can result in permanent damage.

Sufferers often do not realise their hearing is being damaged, as hearing loss tends to be gradual. However, some effects such as tinnitus can develop more quickly. Tinnitus can be a permanent ringing or whooshing sound in the ears which can be very distressing, particularly when it's quiet, such as when you are trying to go to sleep

This demonstration shows what it's like to suffer noise-induced hearing loss.

What you need to do

The law says that employers must control the risk of hearing damage at work. If you cannot eliminate noise, you must reduce it as low as possible at source. There are noise exposure limits that must not be exceeded.

Understand action values

People working in most woodworking shops are likely to have a noise exposure that exceeds the upper exposure action value of 85 dB. This means that you must put noise controls in place. Particularly noisy machines include:

Vertical spindle moulders [around 100dB]
Thicknessers [around 104dB]
Multi-cutter moulders [around 105 dB]
Note: as decibels (dB) work on a logarithmic scale a 3 dB increase will double the noise.

Measure and reduce noise levels

There are several ways in which noise levels can be reduced in a workshop, such as:

Consider the positioning of sources of noise such as machines, the extraction unit, radios etc.
Provide enclosures around noisy machines.
Ensure machines and the extraction is well maintained.
Change to quieter tooling

Provide hearing protection

If noise levels are still too high after you have done all you can to reduce the noise at source, you need to provide hearing protection and make sure operators use it. Hearing protection will only provide the right level of protection if it is worn properly and for the whole time that users are exposed to high noise levels.

Hearing protection should at least reduce the sound level reaching the ear to below 85 dB. However, you should not try to reduce the level at the ear to below 70 dB, as this can cause difficulties with communication and operators may not hear warning signals.

In general, hearing protection should have a SNR (Single Number Rating) of around 25 to 30. SNR is the measure of protection that describes how many decibels of sound the hearing protection will stop. If you have noise survey results for your workshop, then a calculator on the HSE website can help you check if your hearing protection gives the right level of protection.

You need to offer your operators a choice of hearing protection. They are far more likely to use it if they are comfortable and can still communicate. Smaller woodworking shops are likely to have repeated and short-term noise exposures, but the workshop will be fairly quiet between these periods. Operators might then be tempted to remove hearing protection. In this case they may prefer earmuffs and semi-aural/semi-insert earplugs because they are quick and easy to fit and remove. Operators should also be trained to wear their hearing protection correctly and how to maintain it.

When you are deciding which hearing protectors to buy, ask yourself if cheap, basic earplugs will provide the most cost effective form of protection. If each employee is wearing several pairs per day, it may be be more cost effective to invest in repeated use protection.

Think about hearing protection that offers additional benefits such as:

level-dependent protectors that allow easier communication during quieter intervals
custom moulded plugs that employees may find more comfortable and easier to fit.

Health surveillance

Health surveillance (hearing checks) must be provided for all employees who are regularly exposed above the upper exposure action values (daily or weekly exposure of 85dB or peak sound pressure of 137dB) or are at risk, for example already suffer from hearing loss.

Noise at work: A brief guide to controlling the risks INDG362