Businesses that operate in noisy environments can greatly benefit from the information that sound meters can provide. The use of such instruments can give an organisation crucial insight into the noise levels to which its workers are exposed. From there, the business can make informed decisions on how to control the risks presented to its employees.

In Great Britain, for instance, the Control of Noise at Work Regulations 2005 impose clear legal duties on employers to manage and control such risks. So, the accurate measurement of noise levels at a given business’s premises is not “just” about the practical and moral imperative to protect employees’ hearing health; it is also about providing a crucial foundation for compliance with the law.

Here are some of the key aspects of measuring occupational noise exposure that businesses, particularly in the UK, should know about and understand.

The Legal Framework and All-Important Noise Exposure Values

Keeping to the topic of the law that businesses in Great Britain must abide by (Northern Ireland has its own equivalent rules), the Control of Noise at Work Regulations 2005 require employers to:

  • Assess the risks that noise presents.
  • Eliminate or reduce exposure as far as is reasonably practicable.
  • Provide hearing protection where needed.
  • Ensure exposure limit values are not exceeded.
  • Provide information, training, and health surveillance where appropriate.

These regulations are also distinctive in the specific action and limit values that they set. These values are based on daily or weekly personal noise exposure and peak sound pressure.

In-depth information and guidance in relation to these decibel thresholds, and employers’ associated legal duties, can be found on the website of the UK Health and Safety Executive (HSE).

Nonetheless, for quick reference, the values are:

  • Lower exposure action values of 80 dB(A) daily/weekly or 135 dB(C) peak.
  • Upper exposure action values of 85 dB(A) daily/weekly or 137 dB(C) peak.
  • Exposure limit values of 87 dB(A) daily/weekly or 140 dB(C) peak.

As the respective terms suggest:

  • Exposure action values require employers to take certain actions if they are reached. For example, the lower exposure action values oblige employers to assess risks, provide information and training, and make hearing protection available. Meanwhile, more stringent organisational and technical measures will be required in the event of the upper exposure action values being hit.
  • Exposure limit values are thresholds that must not be exceeded. They take account of the attenuation that hearing protection provides.

How Can Occupational Noise Exposure Be Measured?

A competent person should carry out or oversee the assessment.

The question of what constitutes “competent” in this regard will depend on the complexity of the given workplace. For example, some situations may be straightforward enough to be manageable in-house, as long as suitable training and equipment are provided. Complex or variable environments, though, often require the expertise of an acoustic consultant.

As for the key measurement approaches that tend to be taken, these encompass the likes of:

  • Sound Level Meters

The standard tool used for this purpose is an integrating (averaging) meter that complies with IEC 61672 (typically Class 1 or Class 2). Depending on the specific instrument, sound level meters can typically measure equivalent continuous A-weighted levels (LAeq) for tasks or locations, as well as C-weighted peak levels (LCpeak).

  • Noise Dosimeters

These are personal devices that wearers directly wear, as a means of recording cumulative noise exposure over an entire shift. Noise dosimeters can be particularly useful for mobile workers or highly variable noise environments.

  • Supporting Data

When it comes to initial estimates in particular, it can be helpful for employers to consult any available manufacturer noise emission information and HSE industry guidance, in addition to comparing with similar workplaces.

The free exposure calculators and ready-reckoners on the HSE website allow for the straightforward conversion of measured levels and durations into daily or weekly exposures.

Final Thoughts: Workplace Noise Measurement Is Not a Mere ‘Legal Obligation’ or ‘Nice to Have’

Ultimately, the proper and accurate measurement of occupational noise exposure is far from a mere regulatory “box-ticking” exercise.

That’s because it is an important practical route to the better protection of employees’ long-term health, the reduction of risk to the given business, and the demonstration of sound health and safety management.