Simple steps to reduce the risk
Posted on: 28/07/2016 By: Lee Rance
The definition of noise is an unwanted sound, or sound that is especially disturbing.
Sound is a form of energy made by vibrations. When any object vibrates, it causes movement in the air particles. These particles bump into the particles close to them, which makes them vibrate too causing them to bump into more air particles. This movement, called sound waves, keeps going until they run out of energy. If your ear is within range of the vibrations, you hear the sound.
Sound enters the human ear via the auditory canal and vibrates on the eardrum. The vibrations move three small bones: the hammer, anvil and stirrup, which cause fluid in the cochlea to move tiny cilia (hair cells). These hairs are connected to the nerve cells which respond as the cilia move and they send electrical signals to the brain, which informs us that we are hearing sound.
The cilia can easily be damaged by noise, causing a temporary loss of hearing and if they are not given a chance to recuperate they will be permanently damaged, and irreversible hearing loss will occur. Very loud noise can also damage the eardrum.
Noise level is measured in decibels (dB) which runs from 0-160, but this does not directly translate to how the ear responds and hears. As a general rule, doubling the intensity of noise increase its level by 3 dB.
The Control of Noise at Work regulations 2005 aims to ensure that workers’ hearing is protected from excessive noise at their place of work. The Regulations require employers to:
- Assess the risks to your employees from noise at work;
- Reduce the noise exposure that produces those risks;
- Provide hearing ear protection if the noise exposure cannot be reduced enough by using other methods;
- Make sure the legal limits on noise exposure are not exceeded;
- Provide workers with information instruction and training;
- Carry out health surveillance where there is a risk to health.
The regulations specifies action values and exposure limit values for daily or weekly personal noise exposure and peak sound level.
Daily personal noise exposure is a measure of the total noise received by an employee over the working day. Daily personal noise exposures depend both on noise levels experienced at work and on the time spent in the noise. A high level noise for a short time will give the same noise exposure as a lower level noise for a longer time.
The lower exposure action values are:
- 80 dB(A) daily (8hrs) or weekly (40hrs) exposure; and
- 135 dB(C) The highest instantaneous (peak) level of the sound
Where noise exposures exceed the lower exposure action value the employer must make suitable hearing protection available to any employee who wants to use it, though employees do not have to wear it. The employer must also provide information and training on the risks.
The upper exposure action values are:
- 85 dB(A) daily (8hrs) or weekly (40hrs) exposure; and
- 137 dB(C) The highest instantaneous (peak) level of the sound
If any employee is likely to be exposed to noise at or above an upper exposure action value, the employer must reduce exposure to as low a level as is reasonably practicable by establishing and implementing a programme of organisational and technical measures which are appropriate to the activity. These measures can include:
- using quieter equipment or a different, quieter process;
- engineering/technical controls to reduce, at source, the noise produced by a machine or process;
- using screens, barriers, enclosures and absorbent materials to reduce the noise on its path to the people exposed;
- designing and laying out the workplace to create quiet workstations;
- improved working techniques to reduce noise levels;
- limiting the time people spend in noisy areas.
The provision of hearing protectors is a last resort, to be used where the preferred methods of reducing noise exposures are not reasonably practicable.
There are also levels of noise exposure that you must not exceed.
These are called the exposure limit values:
- 87 dB(A) daily (8hrs) or weekly (40hrs) exposure; and
- 140 dB(C) The highest instantaneous (peak) level of the sound
The exposure limit values must never be exceeded. If a limit value is exceeded the employer must identify the reason and take steps to ensure that it cannot happen again.
The HSE’s Noise at work guidance document (indg362) describes the harm that noise can cause in two simple paragraphs:
Noise at work can cause hearing damage that is permanent and disabling. This can be hearing loss that is gradual because of exposure to noise over time, but also damage caused by sudden, extremely loud noises. The damage is disabling as it can stop people being able to understand speech, keep up with conversations or use the telephone. Hearing loss is not the only problem. People may develop tinnitus (ringing, whistling, buzzing or humming in the ears), a distressing condition which can lead to disturbed sleep.
If you would like more information on noise at work, the HSE has comprehensive information on the subject. Alternatively if you think noise is a problem in your work place and would like advice on the subject, give us a call on 01908 632418 or send us an email.
Until next time.