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Hi-Def Safety Hearing Conservation Program

Sorry, could you repeat that a little louder please?


That's a phrase that is all to common with people who don't take care of their hearing and end up with hearing loss later in life. We're here to help prevent that question being asked with our hearing conservation program!


Can noise really hurt my ears that much?


Absolutely it can - noise can be very dangerous and have lifelong consequences, including permanent hearing damage if you are exposed to loud enough noise for a long enough period of time. These two variables that are the most important to pay attention to are Intensity (how loud it is) and Duration (time exposed to the sound).


The damage caused by noise is called Sensory Neural Hearing Loss or Nerve Loss and can be caused by several other factors than just exposure to loud noise. The reason that noise-induced hearing loss is different in one VERY important way:

IT CAN BE REDUCED OR PREVENTED COMPLETELY!

So lets talk about how it all works.


How does the ear work?


The ear has 3 main parts:

  • Outer Ear

  • Middle Ear

  • Inner Ear

The outer ear (the part visible on the side of your head) opens into the ear canal which is separated from the middle ear by the ear canal. Small bones in the middle ear help to transfer sound to the inner ear. The inner ear contains the auditory (hearing) nerve, which leads directly to your brain.


Any source of sound sends vibrations or sound waves into the air. These funnel through the ear opening and down the ear canal, strike your eardrum and cause the eardrum to vibrate. The vibrations are then passed to the small bones of the middle ear which interprets that impulse as a sound!

Diagram of the inner ear.

When a noise is too loud (intensity), it begins to kill the nerve's endings in the inner ear. As the exposure time (duration) to loud noise increase, more and more nerve endings are destroyed.


As the number of nerve endings decreases, so does your hearing. There is no way to restore life to dead nerve endings; This means the damage is PERMANENT.


Sound can be measured scientifically in two ways. Intensity, or loudness of

sound is measured in decibels. Pitch is measured in frequency of sound vibrations per second. A low pitch such as a deep voice or a tuba makes fewer vibrations per second than a high voice or violin.



What does Frequency have to do with hearing loss?


Frequency is measured in cycles per second, or Hertz (Hz). The higher the pitch of sound, the higher the frequency. Young children, who generally have the best hearing, can often distinguish sounds from about 20Hz, such as the lowest note on the large pipe organ, to 20,000 Hz, such as the high shrill of a dog whistle that many people are unable to hear.


Human speech, which ranges from 300 to 4,000 Hz, sounds louder to most people than noises at very high or very low frequencies. When hearing impairment begins, the high frequencies are often lost first, which is why people with hearing loss often have difficulty hearing the high pitched voices of women and children. They also may find difficulty hearing in a crowd. They know that there is speech, but they are unable to distinguish what is

being said.


What about Decibels?


Intensity of sound is measured in Decibels (dB). The scale runs from the faintest sound the human ear can detect, which is labeled 0dB, to over 180dB, the noise at a rocket pad during launch. Decibels are measured logarithmically, which means that as decibel intensity increases by units of 10, each increase is 10 times the lower figure. Thus, 20 decibels is 10x the intensity of 10 decibels, and 30 decibels are 100x as intense as 10 decibels. Here's some decibel level examples:

​Sound

Decibels (dB)

Near total silence

0 dB

A whisper

15 dB

Normal Conversation

60 dB

Lawnmower

90 dB

Concrete Saw

105 dB

A car horn

110 dB

A rock concert or a jet engine

120 dB

A gunshot or firecracker

140 dB

How high can the decibels go without affecting my hearing?


Many experts agree that continual exposure to more than 85 decibels may become dangerous. You can read more from the CDC Here.


Who should wear hearing protection?


If you work in an excessively noise environment (classified as 85 dB or above), you should be wearing hearing protection. You should also wear them when you are using power tools, noisy yard equipment (see: lawnmower at 90 dB) or firearms (see: gunshot at 140 dB).


What is hearing protection? How effective is it?


We broke down hearing protection in one of our other blogs, and you can find the full guide HERE, but for now we'll give a brief explanation of the different types!

earplugs
Foam earplugs

Earplugs are small inserts that fit into the outer ear canal. To be effective they must totally block the ear canal with an airtight seal. They are available in a variety of shapes and sizes to fit individual ear canals and can be custom made. For people who have trouble keeping them in their ear, they can be fitted to a headband. Earplugs must be snugly sealed so the entire circumference of the ear canal is blocked. An improperly fitted, dirty or worn-out plug may not seal and can irritate the ear canal.


Earmuffs fit over the entire outer ear to form an air seal so the entire circumference of the ear canal is blocked, and they are held in place by an adjustable band. Ear muffs will not seal around eyeglasses or long hair, and the adjustable headband tension must be sufficient to hold earmuffs firmly around the ear.


Properly fitted earplugs or muffs can reduce noise by 15 to 25 dB. The better quality earplugs and muffs are approximately equal in sound reductions, although earplugs are better for low frequency noise and earmuffs for high frequency noise. Simultaneous use of earplugs and muffs usually adds 10-15 dB more protection than either used alone. Combined use should be considered when noise exceeds 105 dB.



What are the common problems of hearing protection?


Studies have shown that half of all workers wearing hearing protectors receive half or less of the noise reduction potential of their protective gear because these devices are not worn continuously while exposed to noise, or because they do not fit properly.


A hearing protector that gives an average of 30 dB of noise reduction, if worn continuously throughout an 8-hour workday becomes equivalent to only 9 dB of protection if taken off for one hour during the exposure to noise. This is because decibels are measured on a logarithmic scale with a 10x increase in noise energy with each 10 dB increase.


During an hour with unprotected ears, the worker is exposed to 1000 times more sound energy than if earplugs or muffs had been worn. In addition, noise exposure is cumulative. So the noise at home or at play must be counted in the total exposure during any one day. A maximum allowable while on-the-job followed by exposure to a noisy lawnmower or loud music will definitely exceed the safe daily limit.


Even if earplugs, and/or muffs, are worn continuously while in noise, they do little good if there is an incomplete air seal between the hearing protector and the skin. When using hearing protectors, you will hear your own voice as louder and deeper. This is a useful sign that the hearing protectors are properly positioned.



Can I hear other people, machine problems or alarms clearly if I am wearing hearing protection?


Just as sunglasses help vision in very bright light, so do hearing protectors enhance speech in very noisy places! Even in a quiet setting, a normal person wearing hearing protection would be able to clearly understand a regular conversation. It has been argued that hearing protectors might reduce a worker's ability to hear noises that signify improperly functioning machinery, however most workers readily adjust to the quieter sounds and can still detect these problems when they occur!



Why have my hearing tested?


An audiometric test (a.k.a. hearing test) is a valuable tool for assessing the presnce of hearing loss and appropriate referrals for treatment/hearing aids can be made, you can learn more about them in our blog post - find it HERE! The first time an employee is tested is referred to as a "baseline test", and the following tests are referred to as "periodic tests" and usually occur annually. The periodic test assesses whether there has been a significant change from the baseline test!


Baseline Test Results


Normal - all hearing thresholds are within normal limits (no worse than 25 dB) at all test frequencies.


Early Warning - Hearing thresholds at frequencies of 2000 Hz through 8000 Hz is greater than 25 decibels.


Abnormal Hearing Referrals

  • The hearing threshold in either ear is greater than 25 dB at 500, 1000, and 2000 Hz

  • The hearing threshold in either ear is greater than 60 dB at 3000, 4000 or 6000 Hz

  • There is a one sided hearing loss with a difference in hearing threshold level between the better and the poorer ear exceeding the average of 30 dB at 3000, 4000 and 6000 Hz - Paper referral to an audiologist or physician is required at this point

Annual Test Results


There are three possible categories categories for grouping the annual test results:


Normal - Any deviation from baseline for the frequencies of 1000 - 6000 Hz is less than 15 dB with no shift from the baseline measurements.


Early Warning - Hearing thresholds at frequencies of 2000 - 8000 Hz is greater than 25 dB with no shift from the baseline measurements.


Abnormal - Any deviation from a baseline of 15 dB or more at two consecutive frequencies from 1000 Hz up to and including 6000 Hz when compared to the baseline with a significant shift from the baseline measurements.


Action required for a Significant Threshold Shift - Paper referral to an Audiologist for a more detailed assessment.



Your hearing is important - you use it every moment of everyday from the second you wakeup until the second you fall asleep. Don't neglect your hearing! Everyone from industry professionals, to videographers, musicians, tradespeople, anyone who works with heavy machinery, we could go on but you get the point - you need to protect your hearing!


Don't forget, if you think you are suffering from hearing loss or at risk of it, get your hearing tested, and take preventative measures! Click HERE to book audiometric testing for you and your company or employees today!


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