Workplace noise is a common problem in many industries and workplaces. It may seem trivial, but in 2007-2008 there were 21,000 employees suffering from hearing problems which they believed to be work related.
If you can answer 'yes' to any of the following questions about your workplace, you are likely to be at risk:
• Is the noise intrusive, like a busy street, machinery or a crowded restaurant?
• Do you have to raise your voice to hold a normal conversation when about 2m apart?
• Do you use noisy, powered tools or machinery for over half an hour a day?
• Do you work in a noisy industry; ie construction, road repair, woodworking, materials processing or manufacture, forging or in a foundry?
• Are there noises because of impact (hammering, pneumatic impact tools etc), explosive sources such as cartridge operated tools or detonators, or guns?
• Do you have muffled hearing at the end of the day?
This video demonstrates how hearing can be affected over years of working in a noisy environment:
Control of workplace noise is regulated by The Control of Noise at Work Regulations 2005. The level at which employers must provide hearing protection equipment is now 85 decibels. At 80 decibels employers are required to assess the risk to workers hearing, provide them with information and training, and provide hearing protection upon request by the employee. There is also an exposure limit value of 87 decibels, taking account of any reduction in exposure provided by hearing protection, above which workers must not be exposed.
Hearing protection should be used where extra protection is needed above what has already been achieved using noise control methods or as a short term measure whilst other methods of controlling noise are being developed.
In work areas where noise exceeds this upper value of 85 decibels the law requires employers to identify them as a 'Hearing Protection Zone' ie; ensure that hearing protection is worn within these areas and mark the area with a sign if possible.
As well as providing hearing protection, employers are required to provide employees with training on the use and maintenance of the equipment. It is important to ensure that hearing protectors are kept in good condition and check that:
• Ear muff seals are undamaged.
• The tension of headbands is not reduced.
• There are no unofficial modifications.
• Compressible earplugs are soft, pliable and clean.
Effective Use of Hearing Protection:
• Ensure the equipment gives enough protection. Aim to get below 85 decibels at the ear but no less than 70dB.
• Target the use of protectors to the noisy tasks in the workplace.
• Select protectors which are appropriate to the working environment. Consider hygiene and comfort.
• Consider other head-worn PPE that they will be worn with (hard hats/ respirators).
• Provide a range of correct specification protectors so employees can choose the most comfortable for them.
• Block out too much noise. This could isolate the wearer and create a further, greater danger.
• Have a blanket approach. Target it to the areas/ tasks where it is most required.
It is worth ensuring that all managers and supervisors set a good example by wearing hearing protection and making sure that only people who need to be there enter hearing protection zones, and stay no longer than they need to.
The purpose of Ear Defenders/ Hearing Protection is to reduce the environmental noise of the workplace to below 85dB at the ear.
Before selecting any PPE, including Hearing Protection, you will need to conduct a Risk Assessment, or refer to a recent, existing one. Look at the working environment, the tasks, practices, machinery and tools in use and consider the excess noise that is being created and that workers are being exposed to. How can this be reduced at the source? Newer or more efficient machinery could greatly improve the noise levels, and slight alterations to working patterns can reduce employees exposure to the noise.
It is also important to know how long employees are exposed to the noise for each day/ week and to measure the noise levels in your work environment so that you are aware of how close you are to the upper legal exposure limit of 85dB, or by how much you need to reduce workplace noise to meet this figure.
For a product to be categorised as Hearing Protection it must be CE marked, indicating that it fulfils the minimum requirements for its purpose. This mark does not mean that a product is suitable for your exact requirements, just that it meets the minimum. The European Standard for Hearing Protection is BS EN352. Within this there will be be several sub-categories defining the level of protection offered.
EN352 -1 -2 and -3 are the basic parts of EN352. Testing and safety requirements for Ear Muffs are outlined in EN352-1 and for Earplugs it is EN352-2. The standards for ear muffs attached to safety helmets are covered in EN352-3.
Hearing protectors will also be labelled with a Single Number Rating (SNR) value. The information below is intended as a guide and will not be appropriate if there is a significant low-frequency noise (for low frequency noise see CSA Class 'L' below):
|Noise Level in dB||Select a Protector with an SNR of:|
|85 - 90||20 or less|
|90 - 95||20 - 30|
|95 - 100||25 - 35|
|100 - 105||30 or more|
Some products will be labelled with a Noise Reduction Rating (NRR) value. This is the American version of the SNR, but needs a little more thought put into working out the actual protection offered. In this case it is important to note that although the NRR is measured in decibels, the hearing protector will not reduce the surrounding noise level by the exact number of dB's noted in the NRR. For example if you are in an environment with a noise level of 100dB and you are using hearing protection with an NRR of 33, this will not reduvce the noise at ear to 67dB. There are a few methods in discussion for calculating the actual protection offered, but our supplier 3M recommend diving the NRR value by 2 to get the actual dB reduction offered by the product.
You may also see the CSA Class rating on products. This is the Canadian version of the SNR and NRR and is a simple system which defines the level of hearing protection a product can offer. A hearing protection device may be rated A, B or C.
CSA recommends that a:
Class C product be used for noise levels of up to 90dB
Class B product be used for noise levels of up to 95dB
Class A product be used for noise levels of up to 105dB
The A and B classes may also have an 'L' associated with them. The L classification means that the hearing protection device attenuates for at least 20dB when tested at 125Hz. This is an important factor when selecting hearing protection for low frequency noise.
Wherever there is noise in the workplace you should be looking for alternative pocesses, equipment and/ or working methods which would make the work quieter or reduce the time that people are exposed to the noise. You should keep up with what is good workplace practice or the standard for noise control within your industry.
Where there are reasonably practicable steps you can take to reduce the risks from noise, these steps should be taken. However where noise exposure limits are below the lower action values, risks are low and so you would only be expected to take relatively inexpensive and simple actions.
Where your risk assessment shows that employees are likely to be exposed to, or above, the upper exposure limit, you must implement a planned programme of noise control.
There are many options for noise control open to you and often a combination of these methods works best. Start by thinking about how you could remove the loud noise altogether and if that is not possible you should do all you can to control the noise at its source: Consider redesigning the workplace to reduce noise or reorganise working patterns to limit the amount of time workers are exposed to the noise. Consider the following points:
• Use a different, quieter process or quieter equipment
- Can the work be done in another quieter way?
- Can you replace whatever is causing the noise with something quieter?
- Introduce a policy to buy low noise machinery and equipment
• Introduce engineering controls
- Avoid metal on metal impacts. Consider using cushioning materials and reduce drop heights
- Vibrating machine panels can cause noise - add material to reduce vibration
- Fit silencers to air exhausts and blowing nozzles
• Modify the paths by which noise travels through the air to the people exposed
- Erect enclosures around machinery to reduce the noise emitted into the work environment
- Use barriers and screens to block the direct path of sound
- Position noise sources further away from workers
• The design and layout of the workplace for low noise emission
- Use absorptive materials within the building to reduce reflected noise, eg - open cell foam or mineral wood
- Keep noisy machinery and processes away from quieter areas
- Design the workflow to keep noisy machinery out of areas where people spend most of their time
• Limit the time people spend in the noisy areas. Every halving of the time spent in the noisy area will reduce noise exposure by 3dB.
Proper and regular maintenance of machinery is essential as it will deteriorate with age and become noisier. Listen out for changes - it may be time to repair or replace worn or faulty parts.
Investing in quieter machinery and equipment, whether bought or hired, can be the most cost effective way of reducing workplace noise. Choosing quieter equipment from the start can save you the time and money of introducing other noise control measures. Set a realistic target to reduce noise levels by and ask the suppliers about the likely noise levels under the conditions which you will be operating it, as well as under standard test conditions. Try to purchase or hire only from suppliers who can demonstrate a low noise design with noise control as a standard part of the machine, not as a costly add on. Remember to keep records of your decision process as evidence that you have met your legal duties to control workplace noise.
For more information on controlling workplace noise, see HSE's guide: http://www.hse.gov.uk/pubns/indg362.pdf
See the HSE Website for further information: http://www.hse.gov.uk/noise/about.htm
Provide employees with HSE's Pocket Card Noise: Don't Lose Your Hearing