Noise is part of everyday life and is present in just about every human activity. Most types of noises are classified as either occupational noise or involve random exposure to sources in your environment, such as traffic, appliances, sporting events, or music.
In looking at workplace or occupational areas in particular, there is a high potential for noise to be sustained and quite loud. Exposure to noises like that can permanently damage your hearing, and once you lose it, you can never get it back.
Everyone is at risk
High levels of occupational noise have created problems all over the world, rendering occupational hearing loss as one of the most common occupational concerns for more than 25 years, and causing hundreds of thousands to suffer from preventable hearing loss.
To get an idea of just how many workers are at risk, here are some statistics:
• Great Britain has more than one million employees who are exposed to levels of noise that put their hearing at risk
• In Germany the figure is five million workers
• In the United States, about 30 million people are occupationally exposed to hazardous noise every year
• Additionally, the CDC (Centers for Disease Control and Prevention) estimates that nearly $242 million is spent annually on workers’ compensation for hearing loss disability in the United States alone
The health consequences
In general, health consequences are likely to be similar regardless of the country or region for a given level of occupational noise. Any workplace where workers are exposed to high levels of noise can cause permanent hearing loss, and unfortunately, neither surgery nor a hearing aid can help correct the loss of hearing in this way.
Short term exposure to loud noise can also cause a temporary change in hearing, or a ringing in your ears, but may go away within a few minutes or hours after leaving the noisy environment.
Damage to the ear is not always caused by loud noises – sometimes even a noise that sounds like a ‘low hum’ may cause negative reaction over time.
Repeated exposure to both loud and some less loud noises can lead to permanent tinnitus – a continuous noise in the ear, such as ringing or roaring – and/or hearing loss.
Noise irritations at work can also create physical and psychological stress, initiating a complex set of physiological stress responses within the human body.
At first, noise can interfere with sleep, lower general attentiveness, and chip away at good health. This can lead to reduced productivity and interference with communication and concentration in the workplace, as well as possible contributions to workplace accidents and injuries by making it difficult to hear warning signals.
Noise induced hearing loss limits your ability to hear high frequency sounds, understand speech, and seriously impairs your ability to communicate.
Later on, those same noises that interfere with your work and hearing can result in your body having higher blood pressure, a change in the heart rhythm, and/or an increase in hormone levels. Over time, this may lead to cardiovascular or circulatory problems.
The effects of hearing loss can be profound. It can get in the way of your enjoyment of socialising with friends, playing with your children or grandchildren, or participating in other social activities, and can also lead to psychological and social isolation.
What sounds are dangerous?
Sound is measured on the decibel scale, and an increase of ten means that a sound is ten times more intense or powerful to your ears – it sounds twice as loud.
People should wear a hearing protector if the noise or sound level at the workplace exceeds 85 decibels (dB). To put hazardous noises in perspective, here is a list of common sources of noise and the United States Occupational Safety & Health Administration’s (OSHA) level for a hearing conservation programme.
While noise induced hearing loss is permanent and irreversible, it is completely preventable, making it critical to find ways to reduce and prevent exposure to excessive workplace noise.
Two types of noise controls – engineering and administrative – are the first line of defence and should aim to reduce the hazardous exposure to the point where the risk to hearing is eliminated or minimised.
With the reduction of even a few decibels, the hazard to hearing and noise related annoyance is reduced.
There are several ways to control and reduce worker exposure to noise in a workplace. The surest method is to reduce noise at the source by the use of engineering methods, such as modifying or replacing equipment, or along the transmission path to ensure the worker is not overexposed.
According to OSHA, here are some examples of inexpensive, effective engineering controls:
• Choose low noise tools and machinery
• Maintain and lubricate machinery and equipment
• Place a barrier between the noise source and employee
• Enclose or isolate the noise source
In certain workplace conditions, however, there is very little or nothing one can do to reduce noise at the source. In such workplaces, workers use the next best method – administrative controls – which create changes in the workplace through distance and separation from the noise source to reduce or eliminate the workers’ exposure.
• Operating noisy machines during shifts when fewer people are exposed
• Limiting the amount of time a person spends at a noise source
• Providing quiet areas where workers can gain relief from hazardous noise sources, such as a sound proof room
• Restricting worker presence to a suitable distance away from noisy equipment
Hearing protection devices (HPDs) such as earmuffs and plugs are considered an acceptable but less desirable option to control exposures to noise. These are generally used during the time necessary to implement engineering or administrative controls, when such controls are not feasible, or when workers’ hearing tests indicate significant hearing damage.
If hearing protection devices are required, then a complete hearing conservation programme should be instituted within the company. For example, OSHA requires employers to have a workplace hearing conservation programme when workers are exposed to noise levels that meet or exceed 85 decibels over an average period of eight hours.
Hearing conservation programmes should not be isolated efforts, but instead should be integrated into the overall hazard prevention and control programme for the workplace. These efforts are imperative in protecting workers to prevent hearing loss, and should contain provisions for identifying and evaluating high noise exposures, controlling and reducing noises in the workplace, and ways to monitor workers’ hearing.
According to the World Health Organization, hazard prevention and control programmes require:
• Political will and decision making
• Commitment from top management, with a clear and well circulated policy
• Commitment from workers
• Well defined goals and objectives
• Adequate human and financial resources
• Technical knowledge and experience
• Adequate implementation of the programme and competent management
• Multidisciplinary teams
• Communication mechanisms
• Monitoring mechanisms (indicators)
• Continuous programme improvement
Types of hearing protectors
Hearing protectors can be used effectively by making sure they provide enough protection depending on the work environment they will be used in, as well as how they will be used in conjunction with other protective equipment, e.g. hard hats, dust masks or eye protection.
Some other factors to look at in hearing protection are the comfort and fit of the device for the worker. Comfort is essential. The hearing protector will often need to be worn securely throughout the day, so it shouldn’t cause any irritation.
The correct choice of hearing protection can avoid the danger of workers removing them due to discomfort, exposing their ears to damaging noise. As the employer, it is also important to be able to provide a range of protectors so that employees can choose the one that suits them best.
While the primary purpose of hearing protection is to block the exposure to hazardous noise, it is also just as important that the employee still has the ability to communicate, understand instructions, or hear warning signals.
Most of the time, the right level of noise reduction should be a considered balance between what is blocked out and what needs to be heard. To help understand what hearing device would work best for your workers and working environment, there are three main types of hearing protectors:
• Ear plugs – are inserted into the ear to block the ear canal. They can be pre-molded/pre-formed or moldable, e.g. foam ear plugs. Ear plugs are sold as disposable products or reusable plugs, and custom molded ear plugs are also available
• Semi-insert ear plugs – consist of two ear plugs held over the ends of the ear canal by a rigid headband
• Ear muffs – consist of sound-attenuating material and soft ear cushions that fit around the ear and hard outer cups, held together by a head band
Regular maintenance checks must be conducted in order to ensure the device remains in good, clean condition and is undamaged to provide the best possible protection.
Off the job noise risk
The workplace is not the only environment where risk is present for the adverse affects of hazardous noise; daily life permits exposure to unwanted noise countless times during the day.
There are several noise sources that we can become acclimatised to – lawnmowers, firearms, hobby tools, motor sports, appliances, or personal music players, for example. These can all contribute to noise-induced hearing loss.
Compared to the workplace, where the offending noisy equipment is clearly posted with warning signs, the warnings on consumer products are often tucked away in the frequently skimmed-over section of the user’s manual.
In all of Europe, about 71 million adults from the ages of 18 to 80 years old have a hearing loss greater than 25 dB – the definition of hearing impairment recognised by the World Health Organization (WHO).
To help with non-occupational safety techniques that reduce noise exposure, there are some self help tools that will help prevent noise damage at home and at noisy recreational events:
• Where and whenever possible, double the distance between you and the noise. This reduces the noise level by about 3 dB
• Plan ahead to carry hearing protectors. Don’t rely on makeshift earplugs made from cotton or tissues – they only provide less than 10 dB of protection in critical frequencies. Tie earplugs to the lawnmower handle, or hang an earmuff near the power switch of the garage table saw. Keep a few packs of disposable earplugs in the car or truck toolbox
• To protect against sudden unexpected noise, close your ears by pushing closed the tragus (that flap at the entrance of your ear canal). This offers around 35 dB of temporary protection
Remember: the best way to protect your hearing from hazardous noise exposure is to consistently use hearing protectors around loud noise.
Are you at risk?
You may ask yourself, “Am I at risk from high levels of noise exposure?” Well, there are some easy ways to find that out. Ask these questions about the noise you encounter at work:
• Is the noise intrusive, such as the sound of a busy street, a vacuum cleaner or a crowded restaurant, for most of the working day?
• Do you have to raise your voice to have a normal conversation for at least part of the day?
• Do you use noisy powered tools or machinery for more than half an hour a day?
• Do you work in a noisy industry such as construction, demolition or road repair; woodworking; plastics processing; engineering; textile manufacture; general fabrication; paper or board making; canning or bottling; foundries?
• Are there noises because of impacts such as hammering, drop forging, pneumatic impact tools, explosive sources such as cartridge-operated tools or detonators, or guns?
• Do you have muffled hearing at the end of the day, even if it is better by the next morning?
If you can answer “yes” to any of these questions, your hearing is at risk. Despite efforts all over the world to control noise, an estimated 15 percent of workers will develop hearing loss this year from exposure to hazardous noise levels, according to the National Institute for Occupational Safety and Health.
Don’t become a part of this statistic – find out for yourself if you are at risk of hearing loss at your job. As a good rule of thumb: if you have to shout to be heard by a co-worker who is arm’s length away, or hear ringing or humming in your ears when you leave work, these are warning signs of a workplace that has excessive noise levels.
Sound advice would be to prevent the loss of your hearing.
Published: 21st Jan 2013 in Health and Safety International