Controlling the risks of occupational noise exposure

Sadly, damage to hearing caused by working in noisy environments, is far too common. According to estimates from the Health and Safety Executive (HSE), the UK’s independent regulator for work-related health, safety and illness, approximately 170,000 individuals in Britain suffer from hearing loss and other ear-related problems, such as tinnitus, due to prolonged exposure to dangerous levels of sound.

To help decrease the risk of workers suffering from hearing problems due to occupational noise exposure, legislation is in place to ensure employees do not exceed the sound exposure levels deemed as safe.

Controlling the risk

The Noise Regulations 2005 are aimed at ensuring individuals do not suffer damage to their hearing by exceeding average sound levels and being exposed to noise decibels considered dangerous.

If a business environment does have areas which surpass the average sound exposure level that is considered as being dangerous, the employer should endeavour to use quieter machinery, alternative processes and generally working methods that ensure workers are not exposed to levels of noise that exceed average sound levels deemed as being potentially damaging to the hearing.

Average noise dose measuring with noise exposure ready-reckoners

One way to estimate average noise dose exposure is through ready-reckoners. Noise exposure ready-reckoners enable employers, health and safety executives, or anybody with an interest in average sound levels, to estimate their weekly or daily noise exposure levels.

In order to use a daily exposure ready-reckoner, the person measuring the noise exposure levels will need to have knowledge of, not only the levels of noise a person is exposed to during a working day, but also the duration of the average noise dose.

In terms of weekly noise exposure ready-reckoners, a person’s average sound exposure levels will need to be known for every day of the working week.

How do you measure average sound levels?

Noise levels are measured in decibels dB(A). Different sounds have different decibel levels. For example, a quiet room would be approximately 20 dB(A), a typical conversation between two people would be around 60 dB(A), whilst an aeroplane taking off approximately 25 metres away, would be around 140 dB(A).

Lower and upper exposure action values

If average noise dose exposure exceeds certain levels, action is required. These levels are known as a lower exposure action value of a daily or weekly average sound level exposure of 80 dB(A), and an upper exposure action value of a daily or weekly exposure of 85 dB(A).

An employer must, by law, provide employees with information about the risk and what types of measures can be implemented to protect hearing in the workplace if noise levels are found to be of lower exposure action values. If higher exposure action values are measured, the regulations state that hearing protection must be provided by the employer and worn by the employee and it is the employer’s responsibility to ensure this happens. Every effort must also be carried out by the employer to reduce noise levels at work, including modifying or changing equipment and machinery to less noisy alternatives.

Why sound level meter calibration is important

By ensuring sound levels and noise exposure is monitored, managed and maintained, sound level meters are an invaluable investment for numerous industries and institutions. Though like most equipment, sound level meters cannot be simply purchased, used and forgotten about. On the contrary, it is vital these important sound monitoring devices are regularly calibrated so they maintain their accuracy and performance, especially if they are being used to ensure standards, regulations and guidelines related to the Noise at Work Regulations are met.

The calibration of sound level meters refers to the process of ensuring the device measures sound pressure correctly.

Legal action

If the calibration of noise level meters is not regularly carried out, an organisation or individual may even be a risk of having legal action made against them, as the noise measurements being produced by the sound level meter, might not be accurate.

Sound calibrators were invented during a time when it was more straightforward to create a stable calibrator rather than an accurate noise level meter. Whilst today many sound level meters are accurate devices, due to the fact that the microphone located in the noise level meter is extremely delicate, it run the risks of becoming damaged and therefore failing to pick up noise and sound pressure accurately.

What exactly is a sound calibrator and how are they used?

A sound calibrator is used to produce a sound pressure level when used in conjunction with a noise level meter. A calibrated sound level meter has is achieved by mounting the calibrator onto the microphone of the sound level meter. If a noise level meter does not display the correct pressure of sound level, the sensitivity of the microphone is adjusted until the device displays the correct value.

How often should the calibration of a noise level meter be carried out?

Certain regulations and standards require calibration of noise level meters to be done before and after every sound level monitoring and measurement session. This meticulous calibration of noise level meter helps to guarantee the device is operating as accurately as possible and giving a highly precise reading of sound. By calibrating before and after each monitoring session, health and safety executives or anyone using a sound level meter will have reassurance that the data collected by the noise level meter is accurate and nothing has been altered during the session.

Even if a noise level meter is not used that often, it is important that the calibration of noise level meters is regularly achieved in order for the device to maintain its accuracy and the standards set within noise level and exposure regulations are met. Failing to meet such standards and requirements by not using a calibrated sound level meter will mean any measurements you make could be called into question and doubted, exposing you to potential risk of legal action.

Don’t run that risk, calibrate your sound level meter every time before you use it and, ideally, each time you have used it.