More than 10 million people in the UK have some degree of hearing loss, which can gradually creep up over many years before it is recognised. Yet despite this huge figure, most people do not have a long-term view of their ability to hear, taking it for granted and adopting the attitude that loss of hearing will never happen to them.
Exposure to undue noise at any level can be dangerous, but exposure to sound at or above 85 decibels (dB) can irreparably damage hearing over time. Young people’s hearing can be as easily damaged as that of the elderly. Many leisure activities, such as nightclubs or gigs, commonly have noise levels of between 100 and 110dB – 10 to 20dB higher than a pneumatic drill – while the maximum volume of some MP3 players can range from 90 to 100dB.
In addition, sound intensity doubles with every extra 3dB. For example, sounds at 88dB are twice as intense as sounds at 85dB, meaning that for every 3dB increase in volume, hearing damage can occur in half the time.
Experiencing too much noise during their leisure activities can have a direct effect on employees’ ability to carry out their work safely if their hearing is damaged. Excessive noise in the workplace itself can also be a safety hazard. Noise creates stress, interferes with communication, acts as a distraction, makes warnings harder to hear and can lead to workers feeling stressed in their jobs.
How noise damages hearing
When vibration from the middle ear enters the cochlea, a fluid-filled chamber in the inner ear resembling a snail shell where the sensory hair cells are housed, it causes movement in the fluid. This is picked up by the sensory hair cells, which then send an electrical signal up the auditory nerve to the brain, where it is recognised as sound. Different hair cells respond to different pitches of sound.
Exposure to loud noise for prolonged periods of time damages these hair cells for good – once they are damaged they cannot be replaced or repaired – and at this point the person starts to notice they are finding it more difficult to hear properly, especially higher-pitched sounds. This damage results in both loss of frequency sensitivity and increase in hearing threshold, so that noises need to be louder for the person to hear them. Tinnitus, or constant ringing or whistling in the ears, can also be caused by excessive noise exposure.
Since once the damage to hearing loss has occurred it cannot be reversed, it is essential that individuals protect their hearing, both at work and during leisure activities, to reduce their chances of noise-induced hearing loss in the long term. Hearing loss caused by noise is completely avoidable. In the case of hearing, prevention is a whole lot better than cure, especially as there is no cure.
How to protect employees against hearing loss
The law regarding the prevention of hearing loss at work is covered by the Control of Noise at Work Regulations 2005.
These say that employers must:
- Conduct a risk assessment on noise in the workplace
- Reduce noise exposure at source as much as possible
- Provide employees with hearing protection if they ask for it, plus information and training, if their average noise exposure over a day or a week is between the lower (80dB) and upper (85dB) exposure action values (EAVs)
- Provide employees with hearing protectors and make sure they use them properly when their noise exposure exceeds the upper EAV of 85dB
- Ensure that no worker can be exposed to the average exposure limit value of 87dB, and peak sound pressure of 140dB, with or without hearing protection
- Identify and mark hearing protection zones, where the use of hearing protection is compulsory
- Provide employees with training, information on how to use and care for hearing protection, and health surveillance
- Ensure that hearing protectors are properly used and maintained.
The above laws apply to any workplace, and especially to noisy industries such as construction, demolition, engineering, manufacturing, fabrication, or foundries, which use loud machinery or power tools.
Under the Equality Act 2010 people who have severe hearing loss and have difficulty hearing and understanding others must not be discriminated against on the grounds of their disability.
Choosing the right hearing protection
The use of hearing protection is a last resort after the risks from noise have been controlled as much as possible. Many different types are available, such as earplugs, earmuffs, disposable earplugs, reusable earplugs and bespoke protection.
Noise levels vary greatly by occupation, type, environment, time and place, and it can be difficult to choose the appropriate device for the wearer. The objective is to achieve an effective residual noise level of between 70 and 75dB into the ear. If the wearer is over-protected with a device that gives too much noise reduction, this can result in difficulties with communication, ability to hear warnings and a possible feeling of isolation.
Whatever type of hearing protector someone chooses or is given to wear, it must have the correct protection level (SNR), be compatible with other items of PPE worn, be practical for the task and working environment, be comfortable but most importantly, it must be fitted and worn correctly to guarantee the optimum protection level.
Earmuffs, or ear defenders, cover the ear completely and are considered to be easy to fit and remove in comparison to conventional earplugs. However, there are practical considerations before making the final choice. For example, compatibility with other items of PPE can limit the effectiveness of the hearing protection particularly if safety spectacles are also to be worn, as the side arms break the cup seal reducing the stated SNR. Another consideration is hygiene.
Not only can the cushions become hot and sweaty, there is the likelihood, when worn in combination with safety helmets, of the transference of dirt and dust from the helmet, where earmuffs are generally parked when not in use, to the skin on the side of the face possibly causing secondary hygiene issues.
However, earmuffs have come a long way over the years. Many are lightweight and adjustable, have soft cushions, padded headbands and heat-resistance to improve the wearer’s comfort.
Earplugs are inserted inside the ear canal to reduce unwanted noise from reaching the inner ear. They may be disposable, reusable or custom moulded, while others have been specifically developed with separate left and right fit to ensure optimum ease of fitting and protection.
Although less expensive than earmuffs per unit, the cost over a period can soon mount up if using a disposable version and therefore, considering a reusable plug together with the appropriate education and training could save money.
In truth, earplugs can be a little trickier to learn to fit correctly initially, however, recent developments in low pressure, soft PU foam have made them much more comfortable. A quick and simple demonstration on the correct fitting method will solve any initial difficulties.
Earplugs are however, smaller, simpler and more convenient to carry, and are easier to integrate with other PPE. They are also highly versatile and used for industrial and leisure pursuits including being used for sleeping, favoured by motorcyclists and ideal for air travel under your headphones.
Canal caps, or semi-insert earplugs incorporate pods that cover the entrance to the ear canal only with a lightweight over the head band to keep them in place. They need to be checked for a good seal, while the headband needs to be kept taut to ensure their effectiveness. Because they are easy and quick to remove and reinsert, semi-insert plugs are appropriate for use in environments where exposure to noise is intermittent.
It is crucial, that in order to provide the most adequate and suitable protection against noise, everyone exposed to potentially hazardous noise levels fully understands the consequences of hearing loss and how it will effect both themselves and those they live and spend time with. All wearers need to be trained in how to fit, wear and look after their hearing protection in order to give them the best chance of protecting their hearing.
Remember, whatever you do inside and outside of work, we are surrounded by sound, or noise. If we have control over the level of noise we are exposed to, then we need to be aware, if we don’t have control over the noise levels, then we need options to protect ourselves.
It is not only the type of noise that does the damage but how much we are exposed to. Once our hearing is gone, we are very unlikely to get it back, so look after it now!