The hierarchy of control for noise
08 April 2015
Anybody with an interest in workplace health and safety is likely to be aware of the hazards associated with harmful noise. In the UK, exposure to noise at work is one of the most common causes of industrial injury, and thus also of occupational compensation claims. This article from 3M looks at the employer's duty of care and potential methods of noise control, and links to an e-learning course developed in collaboration with HSL.
The effects of unmanaged, or inappropriately managed, noise exposure can be devastating. The damage caused to workers tends to be cumulative, so it may be years before the sufferer becomes aware of it. However, even a single exposure to intensive noise can be harmful.
Most of the damage caused by harmful noise at work is permanent, and includes tinnitus (a ringing, buzzing or other constant noise in the ears) and/or hearing loss. These can cause huge disruption to an individual's life; sufferers may become socially isolated, distressed and depressed and the physical effects are generally lifelong.
According to UK law, employers must protect their staff members - whether they are temporary, permanent or any other type of worker - from the harmful effects of workplace noise. It is important to remember that the level of workplace noise need not be extremely high, nor sustained for a particularly long time, to require management.
Although the idea of controlling noise at work may initially seem very formal and daunting, it is actually something that many people do on a daily basis, at home and elsewhere, without noticing. Noisy washing machines and tumble dryers are usually put out of earshot, living rooms that echo are carpeted - much of this is common sense, and a similar approach can effectively be taken to workplace noise.
As a rule of thumb, if two workers standing two metres apart have to raise their voices to talk, it is likely that noise levels will be harmful - employers may choose to gain a slightly more accurate picture of the actual noise levels and durations of exposure! Action is also likely to be needed if noise in the workplace is intrusive for most of the working day; if noisy machinery or processes occur for more than half an hour daily and/or if people need to be able to hear safety warnings or alerts - but this list is not exhaustive and all employers need to make sure that they are complying with the law.
The employer's duty of care arises from several laws and regulations, but in particular the Control of Noise at Work Regulations 2005 and the Health and Safety at Work Act 1974. The law requires employers to assess, control and review the risks posed by noise exposure in all processes that their workers undertake, and in all locations at various times (because, for example, a given area may be quiet throughout the morning but very noisy for a couple of hours or even less, later in the day - the noise, even if brief, must be assessed as well as the quieter periods).
If employees’ noise exposures, when estimated, are found to be at or above those that trigger action under the law, management must act to control and monitor the situation.
Reduce noise, manage residual exposure with a hierarchical approach
It is best to take a hierarchical approach to noise management. The initial task is to reduce the noise level to the lowest level that is 'reasonably practicable', the ideal being to bring the noise exposure as far as possible below the legal trigger points through noise management and reduction alone. The detail of measures taken to achieve this will vary between sectors and locations, but in general they fall into four categories of descending priority, which should therefore be applied in the following order:
* 1 Elimination, for example by making changes to processes, components or machines so that they make less noise.
* 2 Substitution, replacing noisy machinery with quieter alternatives, for example by adopting a company policy of buying quieter machines.
* 3 Engineering control, for example using screens and barriers made from sound-absorbent materials, enclosing noisy processes and areas such as the maintenance of machinery to keep it running as smoothly and quietly as possible
* 4 Administrative control, and appropriate staff training and rota/roster arrangements, re-locating staff who do not have to be in a noisy area to a quieter place.
In an ideal world, once such measures have been taken, the level of noise will be well below the action trigger points. However, in some cases this is simply not possible, and some residual noise will remain. In such cases, the employer must still protect the staff from that residual noise, and so it is time to move onto the fifth step in the hierarchy: hearing protection devices, or HPD.
HPDs, also known as ear defenders, come in various forms, commonly recognised as earmuffs and earplugs. While these can be invaluable for protecting workers from residual noise that genuinely cannot, with the best will in the world, be reduced, HPD should never be used in place of noise reduction, other than as a temporary measure while permanent noise reduction steps are being taken. This is for several reasons. Firstly, a study by the Health and Safety Executive (HSE) has suggested that around 40 per cent of workers using HPD are inadequately protected, perhaps because the workers are using the HPD incorrectly, or because the form of HPD being used is not suitable for that setting. Secondly, the use of HPD can prevent workers from hearing safety warnings or alarms, which can be a matter of life or death in some situations. Thus the ideal remains to reduce the noise levels as far as possible without the need for HPD, which is the last step in the hierarchy of noise control.
Once noise levels are under control they must still be monitored over the long term. Changes to location, machinery and/or processes may trigger an immediate need to re-evaluate noise exposures and act accordingly.
As has been mentioned, it is impossible to give blanket instructions about how to eliminate noise, because every industry - even every site - varies. However, some industries paint a particularly inspiring picture of how noise control can be achieved and maintained. An HSE study of the printing industry, published in 2013, reveals that noise exposure at work has dropped markedly since the 1980s and 1990s.
Various factors have contributed to this: some machines have been re-designed to make them quieter, some processes have moved from mechanical to electronic forms, and some premises have successfully implemented engineering controls. While there is still more that can be done, the printing industry is a good example of how the hierarchy of control can make a measurable impact on industrial noise exposures on a sustained, industry-wide, basis.
Noise control - best for everybody
The effective management of workplace noise has benefits for everybody concerned. Workers are spared debilitating and long-term industrial injury, and their families and communities are spared its effects. For employers, not only is noise management a fundamental legal duty, it also makes commercial sense. Finding and training cover for absent, injured workers can be costly in terms of time and money - in some cases it may prove impossible. Savings and/or gains may also be made in terms of productivity, staff turnover and the cost of insurance, in particular insurance related to industrial injuries.
Managing the risks of industrial noise can seem intimidating (even though it need not be), which is one of the reasons why 3M and HSL (an agency of the Health & Safety Executive (HSE) have joined forces to produce an interactive e-learning package that helps employers to understand, assess and meet all of their obligations around hearing conservation. With more widespread awareness and implementation of the hierarchy of control, more people are likely to end their working day, and working lives, with their hearing conserved.
For more information on the programme please visit: www.3M.co.uk/hearingconservation
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