Noise at work - A Guide for Safety Representatives

Noise is one of the most underestimated workplace risks. The HSE estimates that 170,000 people in the UK suffer hearing damage, tinnitus or other ear conditions as a result of exposure to excessive noise at work. The issue is particularly prevalent in the manufacturing, construction, call centre and music industries , but can effect many other groups of workers.

While noise induced hearing loss is irreversible - it is also 100% preventable.

What is noise?

A lot of people find the issue of noise very confusing because lots of different ways of describing it and measuring it are thrown around such as Hertz, Decibels, frequency etc. So what do these mean?

Frequency is the pitch of the sound and is measured in cycles per second. These are known as Hertz. The loudness or volume of sound is called the intensity. That is the amount of energy that vibrating air particles deliver to the ears

The amount of sound energy can vary enormously. Painful sound is about 10 million-million times as intense as the quietest sound that can be heard. Since a scale of this magnitude would be impossible to handle, a logarithmic scale is used for measuring sound intensity, in units called decibels (dB). When noise is measured at work, emphasis is normally given to the frequencies that have most effect on the human ear. This is done by adjusting the noise meter to take more notice of these frequencies. The scale used is called a 'weighted decibel scale' or dB(A). According to the HSE, some examples of typical noise levels are:

• normal conversation 50-60 dB(A)
• a loud radio 65-75 dB(A)
• a heavy lorry about 7 metres away 95-100 dB(A)
• a jet aircraft taking off 25 metres away 140 dB(A)

Since the scale is logarithmic, a small increase in the decibel scale corresponds to a large increase in intensity. This is very important in understanding the significance of noise measurements. For example:

• if the sound level increases by 10 dB then the sound intensity, that is, the amount of sound energy being transmitted to the ear, increases tenfold.
• an increase of 3 dB corresponds to a doubling of intensity. 83 dB is not just over 80 dB but is in fact twice as intense and is capable of producing correspondingly more damage to hearing.

In most jobs, the risk depends not just on the noise levels but on how long people are exposed to them. The total amount of noise exposure over the whole working day is called the daily personal noise exposure (usually shortened to LEP,d). If noise levels need to be measured, a competent person should measure them. There is a risk of hearing damage from exposures above 80 dB(A). As a rule of thumb, if you cannot hear a normal conversation clearly when you are 2 metres away from the speaker, the noise level is likely to be around 85 dB(A) or higher. If you cannot hear someone clearly when you are about 1 metre away, the level is likely to be around 90 dB(A) or higher.

Why does noise damage your hearing?

Our ears are full of sensitive cells that allow us to hear. Exposure to noise can damage these cells and they can't be repaired. Damage can be caused by a single, loud noise such as an explosion (which can make you deaf immediately), or by longer exposure to loud noise such as machinery or music.

What hearing problems can noise cause?

Prolonged exposure to loud noise can cause permanent hearing loss, and other long-term hearing problems:

- Noise-induced hearing loss happens when you have been regularly exposed to damaging levels of noise over a long period. The hearing loss will be similar in each ear and will get worse if you continue to be exposed to the noise.

- Acoustic trauma can occur when you are exposed to a loud noise for a short period of time, e.g. if you are close to an explosion. The sudden hearing loss is often more severe in the ear that was closest to the sound.

- Tinnitus is the word for noises that some people hear 'in the ears' or 'in the head' - buzzing, ringing, whistling, hissing and other sounds. These sounds do not come from outside the head although they may sound as if they do.

- Hyperacusis can develop after sudden exposure to high sound levels. If you have hyperacusis you may find certain sounds uncomfortable or painfully loud even when they don't bother other people. You may also find that the area around your ear is painful.

The effect on people's lives

A new hearing loss or condition can have surprising effects:

- everyday activities such as watching TV, using a phone or keeping up with a conversation in a group can become difficult. This can lead to feelings of isolation, depression and sometimes people withdraw from society rather than simply getting help for their hearing loss.

- when tinnitus or hyperacusis starts (particularly if it's sudden) it is common to feel anxious, stressed, frightened, unable to concentrate and frustrated because no-one else understands.

And remember - young people can be damaged just as easily as older people.

Do you have a noise problem at work?

This will depend on how loud the noise is and how long people are exposed to it. As a simple guide you will probably need to do something about the noise if any of the following apply:

• Is the noise intrusive - like a busy street, a vacuum cleaner or a crowded restaurant - for most of the working day?
• Do your employees have to raise their voices to carry out a normal conversation when about 2m apart for at least part of the day?
• Do your employees use noisy powered tools or machinery for more than half an hour each day?
• Do you work in a noisy industry, e.g. construction, demolition or road repair; woodworking; plastics processing; engineering; textile manufacture; general fabrication; forging, pressing or stamping; paper or board making; canning or bottling; foundries?
• Are there noises due to impacts (such as hammering, drop forging, pneumatic impact tools etc), explosive sources such as cartridge-operated tools or detonators, or guns?

Noise can also be a safety hazard at work, interfering with communication and making warnings harder to hear.

Noise levels -the law

From April 2006 there will be new laws on noise. The Regulations require your employer to:

assess the risks to their employees from noise at work;

take action to reduce the noise exposure that produces those risks;

provide the employees with hearing protection if they cannot reduce the noise exposure enough by using other methods;

make sure the legal limits on noise exposure are not exceeded;

provide the employees with information, instruction and training;

carry out health surveillance where there is a risk to health.

The Noise Regulations require your employer to take specific action at certain action values. These relate to:

• the levels of exposure to noise of their employees averaged over a working day or week; and
• the maximum noise (peak sound pressure) to which employees are exposed in a working day.

The values are:

lower exposure action values:

- daily or weekly exposure of 80 dB;

- peak sound pressure of 135 dB

upper exposure action values:

- daily or weekly exposure of 85 dB;

- peak sound pressure of 137 dB.

There are also levels of noise exposure which must not be exceeded:

exposure limit values:

- daily or weekly exposure of 87 dB;

- peak sound pressure of 140 dB.

These exposure limit values take account of any reduction in exposure provided by hearing protection.

Employers in the music and entertainment sectors have until 6 April 2008 to comply with the Noise Regulations 2005. Meanwhile they must continue to comply with the Noise at Work Regulations 1989, which the 2005 Regulations replace for all other workplaces.

However these are maximums, and even at lower levels constant noise, especially at certain pitches, can be very annoying and help lead to stress.

100% avoidable

Employers have a legal duty to protect their employees from the harmful effects of noise at work. The best solution is to get rid of the noise at source. Safety representatives should ensure that their employer does a risk assessment on noise and if any risk is identified an action plan for controlling it should be drawn up with the agreement of the unions.

It is likely that any action plan will include replacing any noisy machines or reducing the noise by fitting silencers; moving noisy machinery away from where people are; installing noise insulation; limiting the length of exposure or the number of people exposed.

When these have been tried and there is still a problem the employer has to make suitable ear protection available free of charge (this is always the last resort). However this is not ideal as most ear protection interferes with communication, is often not used, and can lead to complacency about noise. It is also important that workers are involved in the selection of any ear protection.

For more information see Chapter 34 of the TUC book 'Hazards at Work'

The HSE also have several WebPages on noise that will be of use to Safety Representatives. Go to http://www.hse.gov.uk/noise

RNID Information Line can give you detailed information about the conditions mentioned:

RNID Information Line, 19-23 Featherstone Street, London EC1Y 8SL
Telephone: 0808 808 0123. Textphone: 0808 808 9000. Fax: 020 7296 8199.
E-mail: informationline@rnid.org.uk . Web: www.rnid.org.uk.

Fact sheet (1,600 words) issued 7 Oct 2005