Noise Induced Hearing Loss in Industry
Posted By Kerry Budworth on 2015-08-02 10:17
What is noise-induced hearing loss?
Every day, we experience sound, such as the sounds from television and radio, household appliances, and traffic. Normally, these sounds are at safe levels that won't and don’t damage our hearing. However, sounds can be harmful when they are too loud, even for a brief time, or when they are both loud and long-lasting. These sounds can damage sensitive structures in the inner ear and cause noise-induced hearing loss (NIHL).
NIHL can be immediate, usually as a result of an exposure to an explosion, or more commonly it can take a long time to be noticeable. It can be temporary or permanent, and it can affect one ear or both ears. Even if you can’t tell that you are damaging your hearing, you could have trouble hearing in the future. The main feature of NIHL types of loss is a difficulty with being able to understand other people when they speak, especially on the phone or in a noisy room. Regardless of how it might affect you, one thing is certain: noise-induced hearing loss is something you can prevent.
Who is affected by NIHL?
Exposure to harmful noise can happen at any age. People of all ages, including children, teens, young adults, and older people, can develop NIHL. Approximately 15 percent of Americans between the ages of 20 and 69—or 26 million Americans—have hearing loss that may have been caused by exposure to noise at work or in leisure activities. As many as 16 percent of teens (ages 12 to 19) have reported some hearing loss that could have been caused by loud noise, according to a 2010 report based on a survey from the Centers for Disease Control and Prevention (CDC).
What causes NIHL?
NIHL can be caused by a one-time exposure to an intense “impulse” sound, such as an explosion, or by continuous exposure to loud sounds over an extended period of time, such as noise generated in a woodworking shop or some other industrial concern.
Recreational activities that can put you at risk for NIHL include sport shooting and hunting, quad riding, listening to MP3 players at high volume through earbuds or headphones, playing in a band, and attending loud concerts. Harmful noises at home may come from sources including lawn mowers, leaf blowers, and woodworking tools.
Sound is measured in units called decibels. Sounds of less than 75 decibels, even after long exposure, are unlikely to cause hearing loss. However, long or repeated exposure to sounds at or above 85 decibels can cause hearing loss. The louder the sound, the shorter the amount of time it takes for NIHL to happen.
Here are the average decibel ratings of some familiar sounds:
- •The humming of a refrigerator 45 decibels
- •Normal conversation 60 decibels
- •Noise from heavy city traffic 85 decibels
- •Motorcyles 95 decibels
- •An MP3 player at maximum volume 105 decibels
- •Sirens 120 decibels
- •Firecrackers and firearms 150 decibels
Intensities of Common Sounds in Decibels & Exposure Limits
|Sounds||Intensities||Permissible exposure time|
|City Traffic, inside the car||85 dB||8 hours|
|Bulldozer||88 dB||4 hours|
|Jazz Concert||91 dB||2 hours|
|Power Mower||94 dB||1 hour|
|Nightclub||97 dB||30 minutes|
|Ambulance Siren, inside driver window down||100 dB||15 minutes|
|Rock Concert, Leaf Blower||115 dB||30 seconds|
Your distance from the source of the sound and the length of time you are exposed to the sound are important factors in protecting your hearing. A good rule of thumb is to avoid noises that are too loud, too close, or last too long.
How can noise damage our hearing?
To understand how loud noises can damage our hearing, we have to understand how we hear. Hearing depends on a series of events that change sound waves in the air into electrical signals. Our auditory nerve then carries these signals to the brain through a complex series of steps.
1.Sound waves enter the outer ear and travel through the ear canal, which leads to the eardrum.
2.The eardrum vibrates from the incoming sound waves and sends these vibrations to three tiny bones in the middle ear. These bones are called the malleus, incus, and stapes.
3.The bones in the middle ear transmit and amplify the sound vibrations from the air to fluid vibrations in the cochlea of the inner ear, which is shaped like a snail and filled with fluid. An elastic partition runs from the beginning to the end of the cochlea, splitting it into an upper and lower part. This partition is called the basilar membrane because it serves as the base, or ground floor, on which key hearing structures sit.
4.Once the vibrations cause the fluid inside the cochlea to ripple, a traveling wave forms along the basilar membrane. Hair cells—sensory cells sitting on top of the basilar membrane—ride the wave.
5.As the hair cells move up and down, microscopic hair-like projections (known as stereocilia) that perch on top of the hair cells bump against an overlying structure and bend. Bending causes pore-like channels, which are at the tips of the stereocilia, to open up. When that happens, chemicals rush into the cell, creating an electrical signal.
6.The auditory nerve carries this electrical signal to the brain, which translates it into a sound that we recognize and understand.
Most NIHL is caused by the damage and eventual death of these hair cells. Unlike bird and amphibian hair cells, human inner ear hair cells don’t grow back. Once they are damaged, they are gone for good.
What are the effects and signs of NIHL?
When you are exposed to loud noise over a long period of time, you may slowly start to lose your hearing. Because the damage from noise exposure is usually gradual, you might not notice it, or you might ignore the signs of hearing loss until they become more pronounced. That is one of the common things with NIHL, it is happening slowly over time so you aren't necessarily aware of the damage you are doing.
Over time, sounds may become distorted or muffled, and you might find it difficult to understand other people when they talk or have to turn up the volume on the television. The damage from NIHL, combined with ageing, can lead to hearing loss severe enough that you need hearing aids to magnify the sounds around you to help you hear, communicate, and participate more fully in daily activities.
Hearing Loss & Tinnitus
NIHL can also be caused by extremely loud bursts of sound, such as gunshots or explosions, which can rupture the eardrum or damage the bones in the middle ear. This kind of NIHL can be immediate and permanent. Loud noise exposure can also cause tinnitus—a ringing, buzzing, or roaring in the ears or head. Tinnitus may subside over time, but can sometimes continue constantly or occasionally throughout a person’s life. Hearing loss and tinnitus can occur in one or both ears.
Sometimes exposure to impulse or continuous loud noise causes a temporary hearing loss that disappears 16 to 48 hours later. Recent research suggests, however, that although the loss of hearing seems to disappear, there may be residual long-term damage to your hearing.
Can NIHL be prevented?
NIHL is the only type of hearing loss that is completely preventable. If you understand the hazards of noise and how to practise good hearing health, you can protect your hearing for life. Here’s how:
- •Know which noises can cause damage (those at or above 85 decibels).
- •Wear earplugs or other protective devices when involved in a loud activity (activity-specific earplugs and earmuffs are available at hardware and sporting goods stores).
- •If you can’t reduce the noise or protect yourself from it, move away from it.
- •Be alert to hazardous noises in the environment.
- •Protect the ears of children who are too young to protect their own.
- •Make family, friends, and colleagues aware of the hazards of noise.
- •Have your hearing tested if you think you might have hearing loss.
Protecting Your Staff From Hearing Loss
NIHL is preventable and you can protect your staff and your business from the effects of NIHL. HealthScreen UK Ltd can manage the use and provision of hearing protection so that “reasonable care” can be legally demonstrated from the initial assessment. We can advise on such areas of suitability and sufficiency, frequency attenuation, medical exemption from PPE and in the event of all other types of PPE being unsuitable we can mould employees ears in order that they can have personalised hearing protection.
Custom Made Ear Protection
Custom made noise protection can offer the ultimate protection for your most valuable assets – your staff. You’ll be amazed how competitively priced this protection can be. Our service will include visiting your site, taking impressions, and the provision of one pair of custom made ear plugs for each employee. We can also offer industrial hearing screening and ongoing hearing health surveillance for your staff.
If You Want A Quote On Industrial Hearing Screening or Custom Hearing protection For Your Staff, Call Us On 01455 234 600
What research is being done on NIHL?
The National Institute on Deafness and Other Communication Disorders (NIDCD) supports research on the causes, diagnosis, treatment, and prevention of hearing loss. NIDCD-supported researchers have helped to identify some of the many genes important for hair-cell development and function and are using this knowledge to explore new treatments for hearing loss.
Researchers are also looking at the protective properties of supporting cells in the inner ear, which appear to be capable of lessening the damage to sensory hair cells upon exposure to noise.
For The Moment, Hearing Loss is Not Curable, So Prevention Makes The Most Sense
If you are interested in learning more about industrial hearing screening, looking for health & Safety services in Leicester, or you are looking for help with your health and safety strategy, call us on 01455 234 600 or contact us online now.