Hearing loss is a cross-industry, international problem that anyone exposed to too much noise can suffer with.
As one of the most common work related illnesses, the global burden of noise-induced hearing loss has a heavy price to pay, with 16 percent of cases worldwide put down to occupational noise exposure.
Caused by experiencing loud noise of a level that’s over and above what the ear can medically cope with, the condition is fundamentally a reduction of the ability to hear sound. Although it’s gradual and develops over time, anyone experiencing it will carry it with them for the rest of their life.
Another form of hearing damage is tinnitus, where the sufferer experiences either a constant ringing or hissing in their ear because the healthy exposure level has been exceeded. This condition can be either temporary or permanent, but the nature of it is such that some people can experience mental health issues in trying to cope with adjusting their lives to manage the condition.
Who is affected by noise in industry?
Any company within any industry or sector can find they have unacceptable levels of noise in the workplace. Typically, it’s those with powered tools or machinery, explosives, or any that operate drills, hammers, saws or engines that will be most at risk. From this list, it’s fair to deduce that high risks industries are construction, manufacturing, rural industries including forestry and farming, or even the events industry, where loud music is so often a factor. Any employer creating significant noise levels must do all they can to identify hazards, assess the risks and judge the potential for damage upon exposure. From here, they must manage those risks using controls which, ideally, remove the possibility of coming into contact with noise enough to create hearing problems.
How loud is safe?
Regulations on noise levels vary slightly across the globe. In the UK, the Control of Noise at Work Regulations (2005) specifies an average daily or weekly exposure limit of 80 decibels (dB). At this point, a company must provide information and training to employees and make hearing protection available to them if they ask. Once the average exposure reaches 85dB, then the employer needs to carry out a risk assessment to identify the sources of noise, who is affected and to decide what noise control measures need to be introduced. The maximum average dB a worker can be exposed to is 87dB. Some manufacturing processes, or where a worker is in the proximity of aircraft, for example, will expose the workers to peak sound pressures. In the UK, employers need to provide hearing protection on request from 135dB, but they must do a risk assessment from 137dB. The maximum sound pressure a worker can be exposed to is 140dB, which is equivalent to a jet taking off. A change of 2dB or 3dB might not look much, but it’s important to remember that an increase of 3dB means that the sound is twice as loud. Meanwhile, an increase of 10dB corresponds to a tenfold increase.
Eliminating the risk of hearing loss
Any noise above the limit that humans are comfortable with, or can cope with before their ears are damaged, must be properly mitigated against. To assess these levels and determine what measures to take to reduce noise, employers should undertake a noise assessment to see how many decibels are being produced in each working area. This will tell them whether the levels are illegal and will help to determine the best ways to keep staff from harm. Hearing protection is a good way of providing a solution to the problem. It should only be used, however, as a last resort after other noise control methods have already been put in place, or while other protections are being developed and installed. Any form of ear protection is classed as personal protective equipment (PPE) and carries with it the possibility for human error, where it can be worn incorrectly or forgotten altogether. A noise risk assessment will assist the employer in identifying the sources of noise, who is affected by it and what control measures would be needed to reduce exposure. It is usual to undertake a noise survey of all equipment under usual operating conditions. To do this, there are many types of sound level meters available, the latest ones using digital technology and being simple to operate. They can also include a facility to record a voice tag by speaking into the microphone, so the user can record notes about the measurement location, describe what is being measured, or record any other useful information.
Workers can also be provided with a personal noise dosimeter which they wear like a badge. This measures, stores and calculates the parameters essential for compliance with regulations, and stores a time history or noise profile for that worker. These measurements can then be downloaded onto a computer and reports produced. In terms of noise - just like any hazard that can cause damage to someone - the preferred option is always to eliminate that risk of harm. That means taking it away altogether, or reducing any chance of hearing loss from that source. The next option is to reduce the risk, using engineering solutions to improve the situation, or limiting contact with whatever is producing the noise. Failing that, isolation is the next option, where a company might be able to screen off a noise process so that its workers cannot come into contact with it. Nearer the bottom of the hierarchy are controls using organisational procedures, such as specifying safe systems of work, training and supervision. The least preferred is personal protective equipment - the final resort for limiting risk of damage to ears, which is where hearing protection falls. This is not to say that hearing protection does not have value. It is widely used in many sectors and businesses as an essential barrier between good health and ear damage. In addition, as technology improves, methods become more high tech and able to protect employees, provided that the levels of behavioural health and safety are high, and staff understand and wear their protection as a matter of course. Companies should also ensure that the protection they provide is comfortable, so involving workers in the choice is a good way to get buy-in/wearer compliance, and ensure the fit is good.
Before the PPE
As previously stated, there is a hierarchy of controls that should be explored to find the best ways to control noise. Those nearer the top are always the better options and a combination of methods works best. Employers should always try to eliminate or reduce noise first, before controlling it using operating procedures, or resorting to PPE to tackle the problem. These last two always carry with them the potential for human error, which can easily mean correct ways of working and ear defenders are forgotten. Much of the noise generated in a factory or on a construction site can be mitigated with various techniques to lessen the damaging impact it can have on workers. At design stage, the layout can be arranged to promote low noise emission, with noisy machinery and processes kept away from quieter areas. Employees’ jobs can also be designed so that where they spend most of their time isn’t in close contact with noise-producing equipment. There will often be quieter processes or equipment available, as well as silencers or absorptive materials like mineral wool, or open cell foam to reduce reflected sound. Employers should ideally develop a low-noise purchasing policy, to ensure anyone responsible for buying machinery doesn’t opt for those that produce a lot of noise. It’s good practise to implement engineering controls prior to commissioning the equipment. Mufflers can be introduced to heavy equipment, or noise-reducing saws and blades fitted to machinery - equipment with metal on metal impacts and heavy vibration should always be avoided. Continuous loud sounds can be isolated using sound barriers and enclosures to protect workforces in areas such as building sites. In venues, speakers can be muffled or angled and high frequencies toned down to limit the effect in the long term. Often, venues will use techniques that modify the path the noise travels through the air to people - an idea other industries can adopt. While cost is a constant issue when it comes to a company’s ability to implement a good health and safety strategy, it’s always best to take a long term view. After all, injuries and issues relating to ill health can mean expensive legal bills, poor efficiency and reduced lost time due to sick leave. Noise controls might seem expensive in the short term, but they’ll more than likely prove to be hugely cost effective.
Types of hearing protection
Hearing protection can be broadly divided into three groups: earmuffs, which cover the whole ear; canal caps, or semi-inserts, which cover the entrance to the ear canal; or earplugs, which go into the ear canal. Earplugs can be washable and reusable, or disposable, but both are suitable to protect against long term exposure to noise. They come in a variety of colours and designs and protection factors, and there are also banded earplugs, which are a cost effective and convenient option against intermittent noise during the day. These are anatomically shaped and there are no contact points - so they avoid annoying contact noise. For those workers who find earplugs uncomfortable, however, earmuffs are ideal. Whatever the chosen option, any form of ear defender will need to reduce the sound well below the relevant legal upper limit. No employer should be attempting to provide what is only just acceptable - they should be striving to get the sound levels as comfortable and as low as they can, without compromising staff’s ability to do their job. Remember, earplugs that block out too much sound increase the likelihood of a worker feeling isolated, which can lead to unwillingness to wear ear protection. Employers should also be aware of advancements in technology, and as such know that hearing protection is now able to cancel or reduce dangerous background noises, while allowing the wearer to hear a conversation face to face. On a construction site, in a music venue, at an airport, or in a manufacturing plant, these earplugs and defenders are all widely utilised as a way of staying aware of the working environment, while staying safe from harm. Other PPE staff wear is likely to be another factor to take into consideration - a hard hat, dust mask, eye goggles, or other item might get in the way of bulkier designs, so it takes careful planning to find the right hearing protection solution. To help solve these problems, it’s ideal to involve those people who will be wearing them in the selection process. After all, if they feel they are impractical or uncomfortable, it’s likely they’ll get removed or will be unworn altogether. Consulting employees on their preferences on fit and comfort will improve their effectiveness as they will be used properly.
Ensuring it’s used correctly
If hearing protection isn’t properly used, it probably won’t protect people against the noise levels employees are exposed to. It’s not just training on maintenance and proper use that’s needed - behavioural safety must be woven into sessions to help people understand why it’s necessary - and what can happen if they don’t use hearing protection correctly. Without proper maintenance, any protection can deteriorate or become less effective. Earplugs and other products must be kept in good condition, with seals that are undamaged and plugs that are soft, pliable and clean. If any protectors have seals that act as a barrier between the ear and the noise, they must be regularly checked for any breaks or damage. It’s also important that headbands retain their tension so drums or plugs aren’t allowed to slip. It might be tempting for employees to ‘modify’ their own pieces of equipment, but again, this might reduce the effectiveness of the protector in preventing hearing loss and tinnitus. Employers must make it clear where it is compulsory for employees to wear hearing protection by marking out zones using signs, if possible. Training and information on how to use and maintain hearing protection must be provided and not only that, companies must make sure that this is being carried out in practise. The wearing of hearing protection might be something to include in existing safety policies. One way of ensuring hearing protection is placed on the map in a business and remains in good working condition is to include it in a company safety policy, where advice and rules are set out in relation to their use and maintenance. A good policy will have someone in charge of this area, responsible for checking, organising replacements and repairs and reporting to chains of command on progress. Spot checks are a useful way of seeing whether rules and procedures are being followed - their unannounced nature means staff are more likely to abide by the policy all of the time. Anyone failing to comply should be subject to the normal disciplinary procedure. It’s always best to lead by example, so managers and supervisors should be walking the walk, not just talking the talk, and donning their ear protection whenever it’s necessary in hearing protection zones. Fundamentally, time is of the essence when it comes to noise-induced hearing loss. It’s important for an employee to remember the direct correlation between the level of noise and the time a worker can be exposed to it. As they experience higher levels, there will be a smaller amount of time before some level of ear damage is sustained. When it comes to protecting people from hearing loss, it’s far better to be safe than sorry and take an approach where the aim is to eliminate workers’ contact with noise as much as is possible. After all, protectors only do their job if they’re worn properly.
Published: 01st Aug 2012 in Health and Safety Middle East