Published: 10th Apr 2009
Protecting irreversible damage to hearing
The environment we live in is a massive issue and one that’s having a growing impact on all our lives, and everyone’s being encouraged to play their part.
- We are surrounded by noise in all areas of modern life
- People do not like loud noises or intense sounds
- Our ears are delicate structures that are easily damaged
Noise at Work Regulations
The Control of Noise at Work Regulations 2005, places a duty on all employers to prevent or reduce the risks to health and safety from noise exposure at work. Employees also have duties under the new regulations.
Action levels for continuous noise
- The first action level is set at an 8-hour average noise exposure level (or daily personal noise exposure level, LEP,d) of 80 dB(A), at which the employer has to provide information and training and make hearing protection available
- The second action level is set at a LEP,d of 85 dB(A), above which the employer is required to take reasonably practicable measures to reduce noise exposure, such as engineering controls or other technical measures
- The use of hearing protection is also mandatory if the noise cannot be controlled by these measures, or whilst these measures are planned or carried out. There is a limit value of dB(A) above which no worker can be exposed (taking hearing protection into account)
Deafness is caused by damage to the structures within the cochlea (part of the ear). This damage results in loss of both frequency sensitivity and increase in hearing threshold i.e. noises need to be louder to be able to hear them.
Sometimes after being subjected to loud noises people experience deafness that goes away after a while. This is called temporary threshold shift. But after sudden, extremely loud explosive noises, or more usually prolonged lower level exposures to noise over a number of years, permanent hearing loss can occur. It may be that the damage caused is only noticeable when it becomes severe enough to interfere with daily life.
This incurable hearing loss may mean that the individual’s family complains about the television being too loud, the individual cannot keep up with conversations in a group, or they have trouble using the telephone.
Eventually everything becomes muffled and people find it difficult to catch sounds like ‘t’, ‘d’ and ‘s’, so they confuse similar words. Social situations can become very difficult.
Noise Induced Hearing Loss - This occurs when you have been regularly exposed to damaging levels of noise over a long period of time. The hearing loss is similar in each ear and will become gradually worse, the longer you are exposed to sound.
Temporary Threshold Shift - This occur when you are subject to a loud noise for a short time. You suffer form partial deafness but after a short while your hearing returns. E.g. after to a loud rock concert.
Acoustic Trauma - This can occur when you are exposed to a very loud noise for a short period of time. It is often more severe in the ear that is closest to the sound.
Tinnitus - This is used to describe the noises people hear ‘in their ears’ or ‘in their head’, often buzzing, hissing, whistling or other sounds. These sounds do not come from outside the head, although often they appear as though they do.
Hyperacusis - This can occur after a sudden exposure to high sounds. If you have hyperacusis you may find certain sounds uncomfortable or painful, even if they don’t bother other people. The area around the ear may also become painful.
Affecting peoples lives
If a person develops tinnitus or hyperacusis they may feel anxious, stressed, frightened, find it difficult to concentrate and become very frustrated.
Age and general fitness are no protection from hearing loss - young people can be damaged as easily as the old. Someone in their mid-twenties can have the hearing that would be expected in a 65 year old. Once ears have been damaged by noise there is no cure.
Training and education
Failures or deficiencies in hearing conservation programs (hearing loss prevention programs) can often be traced to inadequacies in the training and education of noise-exposed employees and those who conduct elements of the program.
- Assess the risk to your employees from noise at work
- Take action to reduce the noise exposure that produces those risks
- Provide employees with hearing protection, if you cannot reduce the noise exposure enough by other means
- Ensure the legal limits on noise exposure are not exceeded
- Provide your employees with information, instruction and training
- Carryout surveillance where there is a risk to health
For noise measurements to be useful, they need to be related to noise exposure risks or the prioritization of noise control efforts, rather than merely filed away. In addition, the results need to be communicated to the appropriate personnel, especially when follow-up actions are required.
Engineering and administrative controls
Controlling noise by engineering and administrative methods is often the most effective means of reducing or eliminating the hazard. In some cases engineering controls will remove requirements for other components of the program, such as audiometric testing and the use of hearing protectors.
Monitoring and record keeping
The skills of audiometric technicians, the status of the audiometer, and the quality of audiometric test records are crucial to hearing loss prevention program success. Useful information may be ascertained from the audiometric records as well as from those who actually administer the tests.
Hearing protection devices
When noise control measures are infeasible, or until such time as they are installed, hearing protection devices are the only way to prevent hazardous levels of noise from damaging the inner ear. Making sure that these devices are worn effectively requires continuous attention on the part of supervisors and program implementers as well as noise-exposed employees.
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Published: 10th Apr 2009 in Health and Safety International