Noise at work can cause various health effects ranging from tinnitus (ringing, whistling, buzzing or humming in the ears) to temporary or even permanent hearing loss.

Hearing loss is usually gradual because of prolonged exposure to noise.  However, permanent damage can also be caused immediately by sudden, extremely loud, explosive noises such as gun-shots or certain types of machinery.

The Control of Noise at Work Regulations 2005 requires employers to prevent or reduce risks to health from noise at work.  These Regulations require employers to:

• Assess the risks to your employees from noise at work;
• Take action to reduce the noise exposure that produces those risks;
• Provide your employees with hearing protection if you cannot reduce the noise exposure enough by using other methods;
• Make sure the legal limits on noise exposure are not exceeded;
• Provide your employees with information, instruction and training;
• Carry out health surveillance where there is a risk to health.

In many instances, noise may be a nuisance without causing any risk of hearing damage.  However, in simple terms, you may need to do something about 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 2 m 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, eg 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 is measured in decibels (dB).  An 'A-weighting' written as dB(A) is used to measure average noise levels, and a 'C weighting' or dB(C) is used to measure peak, impact or explosive noises.

The Regulations lay down exposure limit values and action values in order to control noise exposure.

In relation to average noise levels, the lower exposure action level we initially need concern ourselves with is a daily or weekly personal noise exposure of 80dB(A).  If exposure is below this level, no further action is required.

Hearing damage is caused by a combination of noise levels and exposure time.  A daily personal noise exposure of 80 dB(A) means that 80 dB(A) was the sound level averaged over an entire 8 hour period.  However, because exposure time and noise level combine to give us a 'noise dose', an employee could be exposed to a higher noise level for a shorter time to give an equivalent 'noise dose' over the 8 hour period.  

The Health & Safety Executive (HSE) have developed a weekly/daily noise exposure calculator to help employers work out weekly/daily noise exposures. A noise exposure ready reckoner has also been developed which helps estimate weekly/daily noise exposures

These can be downloaded from the following website www.hse.gov.uk/noise/calculator.htm

We also know that a rise or fall of 3 dB(A) doubles or halves the sound pressure level respectively.  This means that the following combinations of noise level and exposure time would deliver the same 'noise dose':

• 80 dB(A)8 hours
• 83 dB(A)4 hours
• 86 dB(A)2 hours
• 89 dB(A)1 hour

An earlier example of when you may need to take action in relation to noise is if the noise is intrusive, like a busy street, a vacuum cleaner or a crowded restaurant for most of the working day.  This example is used because the probable noise level is 80 dB(A).  If the exposure time was only 5 or 6 hours, then the 'noise dose' over the full 8 hour period would be less than 80 dB(A) and no further action would be required.  The table below details some other examples of when nothing more is required.

• The noise is intrusive but normal conversation is possible (like a busy street, a vacuum cleaner etc)  - Probable noise level 80 dB - A risk assessment will be needed if the noise is like this for more than: 6 hours.
• You have to shout to talk to someone 2 m away - Probable noise level  85 dB - A risk assessment will be needed if the noise is like this for more than: 2 hours.
• You have to shout to talk to someone 1 m away - Probable noise level 90 dB - A risk assessment will be needed if the noise is like this for more than: 45 minutes.

If you are satisfied that the noise dose does not exceed the equivalent of 80 dB(A) averaged over an eight hour period, no further action will be necessary, except to record that fact and ensure that noise exposures are not increased.

If this lower action level is likely to have been exceeded, a suitable and sufficient noise assessment must be undertaken which:

• Has been drawn up by someone who is competent to carry out the task;
• Is based on advice and information from competent sources;
• Identifies where there may be a risk from noise and who is likely to be affected;
• Contains a reliable estimate of your employees' noise exposures and a comparison of exposure with the exposure action values and limit values;
• Identifies the measures necessary to eliminate risks and exposures or reduce them to as low a level as is reasonably practicable;
• Identifies those employees who need to be provided with health surveillance and whether any employees are at particular risk.

This may or may not require noise measurements to be undertaken.  It may be possible to estimate exposure based on data from machinery suppliers or information from workplaces similar to yours.

The intricacies and variables associated with noise risk assessments are beyond the scope of this handbook.  The HSE leaflet 'Noise at work: Guidance for employers on the Control of Noise at Work Regulations 2005' (INDG 362 (rev1) provides additional information.

Further guidance for the music and entertainment industry can be found at www.soundadvice.info and www.hse.gov.uk/noise/musicsound.htm

Download presentation material from the noise at work seminar held on the 9th April 2008

Effect of-Excessive-Noise-on-the-Ear-Institute-of-Hearing-Research.pdf

Legal-Duties-and-the-Risk-Assessment-Approach-Nottingham-City-Council.pdf

Premises-Design-and-Sound-Solutions-HSE.pdf

Personal-Hearing-Protection-Audio-Relief.pdf