An employer has a duty to provide a safe and healthy workplace and that includes the noise levels a person is expected to work in. Noise exposure is measured in terms of sound levels and the duration of exposure, and therefore takes into account variations in exposure and whether a high noise level over a short period or a lower noise level over a longer period is acceptable.
How are noise levels measured?
Noise levels are measured using a digital sound level meter, such as the TIS 770 supplied by Test Instrument Solutions. This allows us to measure sound pressure levels produced in a specific environment and how that compares to the noise exposure or intensity the human ears can handle. Soundwaves are pressure vibrations which travel through the air, and a sound level meter measures this pressure using a microphone, which detects changes in pressure and converts this into an electrical signal. A processor within the instrument converts this into sound readings and factors in the logarithmic behaviour of sound intensity, to produce a digital reading which is a numeric decibel (dB) value.
It is necessary to apply a time weighting to account for sudden or gradual exposure, essentially averaging the levels of exposure over a period of time, and also to account for sound frequencies, ie. the frequency ranges humans can hear most comfortably.
So a sound level meter enables us to monitor locations and environments to establish if they are safe to work in. Complete or partial hearing loss can greatly reduce the quality of life for a person, and sometimes is only discovered later in life, long after the noise exposure has occurred. Noise level testing is therefore required to:
- Confirm an environment is safe to work in
- Identify where control measures are required to reduce exposure
- Confirm that noise levels are not causing a public nuisance
What are the legal noise levels in the UK?
The Control of Noise at Work Regulations 2005 require employers to test and monitor noise levels at work and to take measures to reduce exposure where this is identified as being needed. This requires the employer to account for both noise levels and the average exposure over a day or a working week.
First Action exposure values indicate the levels at which an employer should make hearing protection available, these are:
- Daily or weekly exposure of 80dB or a peak sound pressure of 135 dB
Second Action exposure values indicate the levels at which an employer must enforce hearing protection, and take measures to reduce the noise exposure above and beyond enforcing PPE (for example, looking at the root cause of the noise and establishing whether this can be mechanically reduced, or erecting barriers to deflect the noise etc). These levels are:
- Daily or weekly exposure of 85 dB or a peak sound pressure of 137 dB
Exposure limit values are the levels of noise exposure which must not be exceeded. These levels are:
- Daily or weekly exposure of 87 dB or peak sound pressure of 140 dB
Order your digital sound level meter from Test Instrument Solutions
At Test Instrument Solutions our TIS 770 digital sound level meter is capable of carrying out your regular noise monitoring readings in order to help you identify where the action levels are in your workplace, so order your instrument today.
Please note that this section is for information purposes only. Anyone using equipment referred to in this section must be suitably qualified and/or experienced within the respective field. If in doubt before use, please consult a qualified electrician or engineer & thoroughly read all instruction booklets.