1. Hearing Conservation
The training today will consist of a PowerPoint presentation which will cover how we hear, how to protect your hearing both on and off the job and how to interpret your audiogram. We will also show a video and take a few minutes to ensure each of you have the proper fit on your hearing protectors.

2. Agenda How hearing works Protecting your hearing
Health effects of noise
List of general sounds and their associated dB level
Warning signs of potential hearing damage
OSHA requirements
Types of protection devices
Audiometric testing
Benefits of a hearing conservation program
There is a lot to be covered here, so we may go through some of the slides quickly. If you have questions, please feel free to ask, if we are running out of time, we will answer your questions after class is over.

3. Anatomy of Human Ear
For this slide, go over the various structures of the ear, pointing out the cochlea and the Eustachian tubes. Describe how hearing works:
Sound waves come into the outer ear and push against the ear drum
The movements of the ear drum cause the three bones (Malleus, Incus, and Stapes) to move the oval window which is the entrance to the inner ear
Within the inner ear, is the Cochlea, which has approximately 25,000 hair cells
As the hair cells are moved, a neural impulse is developed in the approximately 31,000 sensory neurons connected to the hair cells
The neural activity is transmitted from the Cochlea to the cerebral cortex at specific frequencies
Information from:

4. Sections of Human Ear Outer Ear Middle Ear Inner Ear
The outer ear is the most external portion of the ear. The outer ear includes the pinna, the ear canal, and the very most superficial layer of the eardrum
Middle Ear
An air-filled cavity behind the ear drum, includes three ear bones or ossicles: the malleus, incus, and stapes. The opening of the Eustachian tube is also in the ear.
Inner Ear
Includes the cochlea, vestibule, and semi-circular canals
This slide gives more description of the outer, middle and inner ear structures. Often diseases or symptoms are defined by the placement in the ear – such as an “inner” ear infection. An “outer” ear infection may be an infection of the ear canal.

5. Sounds and the Cochlea
The intensity of sound waves impact the hair cells in the Cochlea
If the hair cells are damaged, it impacts our ability to hear
Compare this diagram to your audiogram
For this slide, point out where 4000 hz is located. Remind the of how the sound wave comes into the outer ear, activates the eardrum, which pushes against the three bones, which then moves the oval window and the waves which moves the hair cells. As the sound is louder, the impact of the wave against the curve is greater. This is why hair cells at 4,000 is often impacted more than other frequencies and it is know as the industrial “notch”. As the wave comes in, it hits the first curve with a “bang”.
This slide also will help the employee understand their specific frequency hearing loss and the damage/health of their cochlea’s hair cells.

6. Damage to Human Ear Outer Ear Middle Ear Inner Ear
Pinna-Laceration from glass, knives, and bites, avulsion injuries, cancer, frostbite, and burns
Ear Canal- Firecrackers or explosives, and mechanical trauma from placement of foreign bodies into the ear
Middle Ear
Firecrackers or explosives, and mechanical trauma from placement of foreign bodies into the ear
Inner Ear
Exposure to elevated sound levels (noise trauma), and exposure to drugs and other substances (ototoxicity)
We often focus on the cochlea when discussing damage to the human ear. However all structures in the human ear have an important role to play in the hearing process.
The outer ear draws the sound waves into the middle ear. If there is damage or blockage, how the sound wave moves the eardrum will be impacted.
If there is damage to the middle ear, the eardrum, three bones, and oval window won’t all work together to move the wave to the inner ear.
Within the inner ear, the damage we often discuss is the elevated sound levels from noise which damages the hair cells within the cochlea. However, drugs can also damage the cochlea causing a loss in the ability to hear.

7. Protecting Your Hearing
Conductive hearing loss
Excessive ear wax
Damaged ear drum or other structures of the ear
Generally reversible by medical or surgical means
Sensory hearing loss
Hair cell and nerve damage
Irreversible
Most often caused by noise exposure
There are two types of hearing loss. Conductive hearing loss and sensory hearing loss. Conductive hearing loss is something that can usually be corrected by your medical provider. However, sensory hearing loss is irreversible – it is permanent and the most common cause is noise exposure.

8. Health Affects Hearing loss effects the ability to communicate
Social interaction is affected
May impact the body’s reaction to stress
Circulatory system
Digestive and elimination system
Immune system
May impact sleep patterns
Loss of hearing is more than silence. It inhibits the ability to communicate, people may limit their social interaction, and it has a documented impact to the physical systems of the body.

9. General Sound Levels Pneumatic Staking 103 dBA Pressure Washer 100 dBA
Radial Arm Saw 103 dBA
Riding Lawn Mower 90 dBA Sprayer, 1,000 gal dBA Table saw 93 dBA
Tractor 92 dBA
Vacuum 87 dBA
Weed eater 96 dBA
Wet/Dry Vac 94 dBA
Airboat 108 dBA
Band Saw 104 dBA
Blower 99 dBA
Concrete Saw 112 dBA
Chain Saw 110 dBA 32
Combine operator 95 dBA Compressed Air 92 dBA Edger 86 dBA
Fire Alarms 95 dBA
Front End Loader 95 dBA
Hedge Trimmer 103 dBA
Miter Saw 109 dBA
Here are some typical noise levels of equipment you may use or be around when they are in operation.
From University of Florida information found at

10. Here are some additional noise levels.

11. Warning Signs of Hearing Loss
People seem to mumble more frequently
You experience ringing in your ears
You often ask people to repeat themselves
Your family complains that you play the radio or TV too loudly
You no longer hear normal household sounds, such as the dripping of a faucet or the ringing of a doorbell
You have difficulty understanding a conversation when in a large group or crowd
You have trouble understanding all the words in a conversation
You find telephone conversation increasingly difficult
You have trouble hearing when your back is turned to the speaker
You have been told you speak too loudly
hearing protectors above 105 dBA.
Information from the Internet site:

12. OSHA Requirements Annual training Area and personal noise monitoring
Audiometric testing and Standard Threshold Shifts
Hearing Protectors
Employee and Supervisor Responsibilities
Recordkeeping
Our hearing conservation program is comprehensive. It not only defines Standard Threshold Shifts, it also outlines your and the safety staff’s responsibilities.

13. Area and Personal Noise Monitoring
Area monitoring
Conducted using a sound level meter and octave band analyzer
Noise maps show areas that are above 85 dBA with a single hash mark and areas above 105 dBA with double hash marks
Corresponds to single and double hearing protection
Personal monitoring
Conducted using a noise dosimeter
Reports are provided to employees to show their daily peak noise exposure, time weighted average, and exposure when wearing hearing protectors
The safety staff is responsible for conducting area monitoring and indicating on an area map where noise levels are above 85 and 105 dBA. The safety staff will also arrange for noise dosimetry monitoring and conducting noise monitoring when specific tools are used. We expect this type of monitoring to increase. Your responsibility is to ensure hearing protection is worn WHENEVER you are in an area identified as requiring hearing protection.

14. Audiometric Testing Annual requirements – within 12 months per code
Testing is conducted from 500 to 8000 hertz
Conversation range is 2000 – 4000 hertz
Comparison with an employee’s baseline test to watch for Standard Threshold Shifts
If a shift is identified, another audiogram is conducted within 30 days to confirm the shift
loud noise exposure can cause a temp. shift
congestion or a cold
medical conditions such as ear infections
Audiograms are not optional for those classifications identified as being in the hearing conservation program. A STS is explained in the next few slides.

15. Standard Threshold Shifts
A decrease in hearing ability resulting in an average shift of 10dB or more in the 2000, 3000, and/or Hertz range
Year
2000
3000
4000
Baseline 10 15
2008 20 35
Change
Average shift is 10 dB
= / 3 = 10
Here is an example of a standard threshold shift. An audiologist or audiometric technician may make a correction due to age.

16. OSHA Requirements Based on an 8 hour time weighted average
Hearing Conservation Program with noise exposure levels over 90 dBA
Hearing protectors required at 90 dBA
Annual audiograms (within 12 months)
Annual training

17. Noise Levels OSHA Noise Level dBA Time (Hours) 90 8 95 4 100 2 105 1
110
115
This explains the 5 dB exchange rate. These exposures are considering NO hearing protection. OSHA has 100% dose at 90 dBA for 8 hours, when the noise levels increase by 5 decibels, the time allowed is cut in ½ to equal 100% dose for the day. Notice employees may not be exposed to continuous noise levels above 115 dBA. Remember this is not considering hearing protectors. Impact noise above 140 is also not allowed.

18. Hearing Protectors Reduce the impact of sound waves to the eardrum
Designed to reduce sound levels in the various ranges of the work environment – especially the 4,000 Hz range.
Much of the industrial noise levels are high in the Hz levels so there is a significant hearing loss called the Hz “notch”
On the audiogram it is often noticed that there is a notch at 4000 Hz
Hearing protectors are designed to protect employees from all types of noise. The hearing protectors at WBI, when used regularly, will reduce the impact of high noise levels to your ability to hear.
The 4000 Hz notch is noticed on the audiograms. It represents where the hair cells become damaged due to the impact of the sound waves hitting the first curve of the cochlea.

19. Types of Hearing Protectors
Ear Muffs
23 to 30 dBA Noise Reduction Rating
When used with other hearing protection an additional 5 dB reduction is provided
There are three styles of ear muffs; regular, behind the neck and those that attach to the hard hat. Both the behind the neck and hard hat styles can be used along with ear plugs or fitted ear protectors.

20. Types of Hearing Protectors
Ear Plugs
DISPOSABLE!!!! Change them often
28 to 33 dBA Noise Reduction Rating (NRR)
Molded Ear Plugs
Made to fit in your ear
25 dBA Noise Reduction Rating but no human error factor
Ear plugs are disposable. Please change them often. Do not hook them over your hard hat harness and leave them there.
Molded ear plugs are molded to your ear shape and have a good fit so they provide good protection even if the NRR is lower than other styles.
The X is through a “cap” type of ear plug and they are not recommended for our facilities due to the noise levels. They are also often worn around the neck and not often replaced even though they are classified as a disposable plug.
The NRR is not the level of protection you ultimately received. For example, the Max earplugs have a NRR of 33. This NRR is determined in a laboratory. So a correction needs to be made to achieve an “A” weighting. 33 – 7 = 26 Then because there is a human factor to fit, 26 must be divided by 2 for a final NRR of 13. It is the human factor that is removed when fitting ear protectors. So even though they have a 25 NRR the calculation is 25 – 7 = 18. So molded ear protectors actually have a higher NRR when calculating actual noise exposure.

21. General Areas of Hearing Loss
When you look at your audiogram, you may get a classification of the type of hearing you have – normal or mild, moderate, severe or profound hearing loss. This chart shows where these classifications are determined.
Information from:

22. Audiogram Notice the 4000 Hz notch
Here is an example of a audiogram showing a mild hearing loss in one ear. Notice the 4000 Hz notch.
Notice the 4000 Hz notch
Information from:

23. 4000 Hz notch is still evident
Moderate Hearing Loss
Here is another example of an audiogram. This person has a moderate hearing loss in one ear and a moderately severe loss in the other.
4000 Hz notch is still evident
Information from:

24. Corresponding Sounds with the Audiogram
This audiogram shows where sounds are represented by frequency. So, vowels are in the 250 to 500 Hz range; consonants are in the 1000 to 8000 Hz range.
Information from:

25. Sounds and the Audiogram
This is another depiction of the difference of where vowels and consonants fall on the Hz frequency chart.
Information from:

26. Sounds and the Cochlea
We learned the intensity of sound waves impact the hair cells in the Cochlea, which then impacts our hearing.
Compare this diagram to your audiogram.
This picture is where the frequencies fall within the cochlea. You can compare your audiogram to this to see where you damage is or to compare where the loss is based on vowels/consonants.

27. Benefits of a Hearing Conservation Program
Quality of life
Ability to participate in conversations
Ability to hear nature sounds – birds, deer, water
Ability to hear a child speak – “Grandpa, I love you.”
Job performance
Ability to detect sounds for maintenance of machinery
Safety and security
Reduce stress and fatigue
The benefits of a hearing conservation is really focused on you. It is your hearing and your responsibility to protect it both on and off the job. Sometimes the most precious sounds in life are nature and hearing someone say, “I love you”.

28. Here is information for noise levels off the job
Here is information for noise levels off the job. Noise is a 24/7 experience. We can help control noise exposure on the job – you have to control it off the job.

29. Wear hearing protection – it is worth the time.
The few moments it takes to put the ear muffs down onto your ear, or rolling the ear plugs and putting them into your ear are well worth the time. Remember it is the quality of life that is important. Being able to hear is part of the quality of life.

30. References
OSHA Hearing Conservation Standard
mons/7/7c/HumanEar.jpg (Wikipidia)
df.pdf (HD Hearing)
Workers Comp. for British Columbia