Plant & Works Engineering
Make the right noises
Published:  03 March, 2016

Noise-induced hearing loss continues to be a major issue for many industries across the globe. In the UK alone, research estimates that over 1 million people are exposed to noise levels at work that may be harmful. Some 17,000 people in the UK suffer deafness, tinnitus or other hearing deficiencies caused by excessive noise at work. As such increasingly stringent noise at work noise and environmental noise legislation regulations have been put into place. PWE reports.

With vast amounts of heavy machinery in operation in industry, it is inevitable that workers will be exposed to some level of noise in the workplace. With this exposure comes greater risk to their health and safety. And while the use of personal protective equipment can lessen the problem, more excessive measures are often required.

The challenges that the Control of Noise at Work Regulations 2005 – which came into force in April 2006 and remain the current directives with regard to the control of noise at work – present to the industrial trade are considerable.

Stiffer control requirements mean the latest regulations reduced the upper and lower action levels by 5 dB from 90 and 85 dB (A) in the previous directive to 85 and 80 dB (A) and introduced a new exposure limit of 87 dB (A).

The guidance to the regulations states that, as a simple guide, action to reduce exposure may need to be considered if people have to raise their voices to carry out a normal conversation when about two metres apart; if they use noisy powered tools or machinery for more than half an hour a day; or the work produces very loud impact or explosive sounds.

Despite the dangers of exposure to immoderate noise levels at work being well documented, noise induced hearing loss remains a problem all around the world. Measuring noise levels in the workplace and finding effective solutions for reducing these levels at the source is the most effective way to prevent workers being exposed to potentially dangerous noise levels.

Noise-induced hearing loss is irreversible but entirely preventable. While the focus of earlier legislation was on assessment, quantification of exposure levels and consequent hearing protection, the latest regulations focus on controlling noise at source and the implication and monitoring of a noise control action plan over a given period of time.

This most recent legislation also requires that where possible noise should be controlled at source, removing the need for over-reliance on personal protective equipment, which should only be used when other forms of noise control have been exhausted.

Although personal protective equipment such as hearing protectors can offer some level of protection for employees, it can also carry a number of problems and should only be used as a last line of defence.

Training for the proper use of such equipment is often overlooked, with employers assuming hearing protection is self-explanatory, and as such workers remain exposed to potentially dangerous levels of noise despite having the protection in place. Companies should not use hearing protection as an alternative to controlling noise by technical and organisational means, but rather when extra protection is needed about what has been achieved by implementing noise control.

The key to practical and cost-effectively treating noise problems is to start with a very accurate diagnosis of the noise source. Firstly, you need to identify and then treat the dominant source. This is best achieved by taking a range of sound readings at various frequencies and turning off machinery to attempt to identify and isolate dominant noise sources.

Organisations that are affected by high noise levels from machinery are much more likely to require a full noise audit and the involvement of more specialist noise control expertise – much like those provided by companies such as Wakefield Acoustics*.

An effective noise control audit, undertaken as part of an overall noise control action plan, can identify the benefits in terms of noise control options available and the potential costs involved.

As a direct result of legislation, many manufacture companies previously not affected by the regulations have noise levels that are just above the upper action levels of 85 dB (A) daily exposure levels. It is these companies who are most likely to benefit from a consultation with a noise control engineer. However with the increased trend in claims for industrial hearing losses it is sensible for all companies that have a potential for employees being exposed to noise levels in excess of 80 dB (A) to carry out regular audits and keep detailed records of all noise mitigation measure undertaken.

Where it is possible to isolate noisy machinery, the erection of enclosures, screens and baffles around equipment should be considered. An alternative would be to install sound booths to isolate workers from noise sources.

Housing noisy machinery in less prominent areas, meaning workers are less likely to be exposed to high noise levels, can help reduce the risks inherent with prolonged exposure. While improved working techniques, adjusting working patterns to reduce lengthy exposure and implementing a low-noise machinery policy can also reduce risk. However with the use of loud machinery in many industries, it is not often possible to take this action and as such other noise control measures have to be put into place.

Whilst reductions in noise levels can be achieved by thorough examination, consideration of practical solutions, engineering controls and isolation, inevitably – and despite undertaking these in-house actions – situations will arise that require the use of noise control products.

This will often result in workers being protected from potentially hazardous noise levels in the workplace, and the harmful effects they can cause, by adopting the strategy of separation.

The strategy of separation requires the use of noise control products such as acoustic enclosures, sound havens, screens and barriers, which are designed to isolate ‘the receiver’ from the noise source such as the sound haven.

A further example of industrial noise can be environmental noise pollution, which can be a nuisance to the local environment. This employs the use of BS4142 to assess the levels being experienced. Solutions can often include acoustic screens to site boundaries to prevent noise contamination to the local area.

When attempting to tackle and address the above noise issues it is important that specialists in the field are consulted to assist with the analysis, diagnosis and provision of noise control measures.

* Wakefield Acoustics design, manufacture and install industrial and environmental noise control solutions and offers a Total Acoustics Responsibility Service from measurements and assessment to product manufacture, installation and commissioning.

The company provides a wide range of acoustic products and services including acoustic enclosures and screens, air and gas process silencers, sound havens, acoustic louvres, acoustic consultancy, project management along with a full in house installation service.

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