1. Hearing Conservation Training
For At Risk Workers
LESSON TOPIC: Hearing Conservation
AVERAGE TIME: 60 Minutes
INSTRUCTIONAL MATERIALS:
Copy of State OR-OSHA standards
TERMINAL OBJECTIVE:
The student should be able to identify the causes of hearing loss, understand the difference between temporary and permanent hearing loss, and know safe and hazardous noise levels. Each student should be familiar with the types of hearing protection available, how how to select the appropriate hearing protection, and realize the purposes of audiometric testing, and procedues needed to prevent noise exposure.
TRAINING REQUIREMENT:
Hearing conservation training is required annually for all employees enrolled in a hearing conservation program. Both managers of employees enrolled as well as employees enrolled must receive training.
RECOMMENDED CLASS SIZE: No more than 12 students to facilitate questions.

2. Is There a Problem?
More than 30 million Americans are exposed to hazardous sound levels on a regular basis
10 million have suffered irreversible noise induced hearing loss
Rate of hearing loss is increasing in the U.S.

3. Good Hearing is Important
Construction sites are dangerous
your ears help you detect hazards
back up alarms
vehicle traffic
changes in equipment noise
verbal warnings from other workers
Workers suffering from noise induced hearing loss are not only denied the ability to converse normally with others, but are also endangered in the work environment as their ability to perceive audible warnings is seriously compromised.
Picture shows a “pipe ramming” operation. Specialized equipment is used to force a pipe through the ground under Interstate 5 in southern Oregon. When equipment is fully loaded and ramming noise levels can exceed 120 dB in the pit.

4. Good hearing is important
Commercial Motor Vehicle Operators & Equipment operators
dump trucks
cement trucks
vacuum trucks
paint trucks
backhoes
crane operators
Need to hear
the vehicle & surroundings while driving
communication by radio & with workers on sites
detection of external warning signals
detection of mechanical signals
performance of routine driving tasks

5. Good hearing is important
Commercial motor vehicle operators with a CDL
FHWA requires CDL holders to maintain good hearing
meet physical qualifications (FHWA)
hearing loss in better ear no more than…
average of 40 dB at 500, 1000, Hz with or without hearing aid

6. Group Exchange What is your favorite sound?
Could you hear your favorite sound if you had a hearing loss?
What sound on a construction site alerts you to danger?

7. The ear is a delicate tool
The ear receives sounds from the environment and transmits them to the brain.
The ear consists of three parts.
The outer ear is those parts of the ear that are visible on the sides of your head plus the canals that enter into your head.
These canals lead to the eardrum, which is attached to three small bones, the ‘ossicles’, that amplify and conduct sound to the inner ear. The area that contains these small bones is called the ‘middle ear’.
Did you know the ear grows out? The eardrum grows radially out from the center and then the growth continues along the canal walls at a rate of migration of about 1.5 mm/month.
The inner ear consists of an organ called the ‘cochlea’, which is shaped like a snail shell. The cochlea contains tiny cells called ‘hair cells’ (which vibrate when a sound is conducted to them by the eardrum and ossicles of the middle ear). The movement of the hair cells transmits electrical impulses down the auditory nerve to the brain. That is when you ‘hear’ the sound.

8. Inner ear Cochlea Continuous noise
inside are nerve cells called hair cells
fragile
Continuous noise
above 90 dBA
as bad for hair cells as continuous foot traffic is to grass
The hair cells in your inner ear (cochlea) are very fragile, exposure to excessive noise will flatten them. With time and exposure to quiet, the hair cells will recover and “pop back up.” This is what happens when you have a temporary threshold shift or a temporary loss of hearing. If you allow your ears to rest in a quiet place, your hearing will recover.
If however you are exposed to noise that is intense or loud enough - generally above 115 dBA without protection - or if you are exposed to noise continuously (above 90 dB) day after day the hair cells will flatten and die, resulting in a permanent hearing loss.
A well manicured lawn is a good example, if cared for grass will spring back after being walked on. If however you continuously walk over the same patch of grass it will eventually brown and die.
Ask the class if anyone has ever had ringing of the ears after exposed to loud noise? Did the ringing go away after an evening? - if yes this is an example of temporary hearing loss.

9. What is Noise?
Noise is a physical energy that moves through the air like ripples in a pond
noise is directional
noise will bounce off walls and other objects

10. Two Components of Noise
Frequency
perceived as “pitch”
measured in hertz (Hz)
human ear most sensitive in the 1,000 to 4,000 range
speech frequency ranges
Intensity
perceived as “loudness”
measured in decibels (dB)
“A” scale minics the human ear
used for noise surveys
High pitch sounds tend to “squeal” - air powered tools, hydraulic operated equipment.
Low pitch sounds tend to “growl” - most heavy equipment noise.
Human speech is generally in the Hz range.
Say the word FISH
Consonant sounds - like the F and SH in FISH - tend to be soft, low energy and high frequency sounds
Vowel sounds- the I in FISH - tend to be loud, high energy, low frequency sounds.
Women’s voices usually have a higher pitch or frequency then men’s.
Noise induced hearing loss generally shows up first at the 4,000 Hz range, making it harder to hear consonants in words, so FISH may sound like IS to someone with a high frequency loss.

11. How is noise measured? Sound level meter Noise dosimeter
instant noise readings
generally A scale used
mimics the human ear
Noise dosimeter
measure a workers noise exposure over a shift
daily dose of noise
very accurate

12. Units of Measurement for Noise
Decibel dB
little increases on the decibel scale make a big difference
a 6 decibel increase in noise is equal to doubling the intensity or loudness of the noise
Earplugs needed
noise above 90 dBA
recommended at 85 dBA
Examples at Home
20 dBA whispered voice
40 dBA refrigerator humming
60 dBA normal conversation
74 dBA average TV
80 dBA blender
95 dBA lawn mower
110 dBA leafblower
115 dBA chainsaw
Sound level meters use computer chips to calculate the decibel level that equals the pressure wave (noise) traveling in air.
The calculation that is used is confusing and not important to this class. What is important is to know that little changes on the decibel scale result in big changes in how loud you think the noise is.

13. Noisy Hobbies Guns riding motorcycles snowmobiles Woodworking
large caliber short barrel = 130 dBA
shotguns & high powered rifles = 140 dBA
riding motorcycles
90 dBA
snowmobiles
120 dBA
Woodworking
electric drill = 95 dBA
power saw = 110 dBA
air tools = 120 dBA
belt sander = 93 dBA
walkman headsets
90 dBA
rock concerts
140 dBA
Guns produce an intensely loud impulse noise and although it lasts only a few thousands of a second, the extreme force it generates has the potential to destroy the delicate tissue of the inner ear.
Hearing protection should always be used during target practice.
Motorcycles are fun but can be noisy. BMX type motorcycles tend to be louder than street cycles. Once again, hearing protection is recommended if the you will be operating a loud motorcycle.

14. Noise in your workplace
pneumatic hand held grinder 101 dBA
air hammer dBA
pavement breaker 114 dBA
power actuated nail gun dBA
portable saw 105 dBA
air wrench 107 dBA
Hydraulic post driver 123 dBA
arc welder 116 dBA
traffic line grinder dBA
loader dBA
paver dBA
snowplow dBA
10 yard truck dBA
vactor truck during operation dBA
Ask your employer for a copy of the noise survey for your work area.
If you have a copy of your employers noise survey this is the time to review it. Give the class a few minutes to review the noise survey results & ask questions.

15. Communication in noisy environments
Hard to hear someone talking in noisy environments
the speaker needs to be louder than background noise
CB’s & radios or cell phones will need to be turned up
if you have a hearing loss, it will be harder to distinguish speech in this environment
The ability to hear someone talking in a noisy environment depends upon: how loud the speakers voice is; how loud the background noise is.
People with normal hearing need for a speaker to be at least decibels louder than the background noise so they can understand what they are saying.
Generally, people who have a moderate hearing loss need the speaker to be at least 10 dB louder than the background noise.
So if you are driving in the cab of a truck with background noise of 84 dB the radio will need to be turned to approximately decibels if you have good hearing and 94 + decibels if your hearing is impaired.
Have you ever gotten into a truck at the beginning of the shift only to find the radio “blaring.” This is due to the fact that the radio was set at a higher volume when the background noise was greater.
Remember to “speak up” and slow your speech down when you are trying to communicate in noisy areas. Use of earplugs or muffs generally makes people speak softer by 3-4 dB, so remember to speak up and speak slow & clear.

16. How do you know you are exposed to damaging noise
Feel the need to shout in order to be heard 3 feet away
sound levels probably approaching 85 dBA
If immediately after a period of high noise exposure
ringing, buzzing or whistling is noticed
Equipment is tagged or marked as noise hazardous
Ringing, buzzing or whistling after high noise exposure is a warning sign. It is like a sunburn of the hair cells of the inner ear (or you might call it a “soundburn”) indicating that the hair cells have been irritated and overworked.
Tinnitus (ringing of the ears) is especially noticeable in quiet place, such as when trying to go to sleep at night. If you don’t protect your ears from noise, Tinnitus can become a permanent constant annoyance in your life.

17. How much noise can you be exposed to?
OSHA rules
90 dBA averaged over an 8 hr shift
requires the use of PPE or other controls to reduce your exposure
earplugs should be used whenever noise is 90 dB +
85 dBA averaged over an 8 hr shift
requires your employer to enroll you in a hearing conservation program
training
hearing tests & follow up

18. What is a TWA?
This is a daily “dose” of noise not a single exposure to a noisy piece of equipment
Your daily dose of noise (TWA) is a function of:
how loud the equipment is (intensity)
how close you are to the noise
how long you are exposed to the noise

19. 5 main causes of hearing loss
Heredity
Infections
Acustic trauma
Prescription drugs
Presbycusis
Sidebar- The Five Main Causes of Hearing Loss
1. Heredity. At least 100 heredity syndromes can result in hearing loss Infections, such as bacterial meningitis and rubella (German measles). Colds, Earaches, Sinus problems and allergies can all affect the ear Acoustic trauma produced by acute or chronic exposure to loud sounds Prescription drugs, such as streptomycin and tobramycin, and chemotherapeutic agents, such as cisplatin Presbycusis, the hearing loss of old age, is thought to result from repeated acoustic trauma and hardening of microscopic blood vessels in the inner ear with aging.

20. Types of Hearing Loss 2 Basic Types of Hearing Loss Mixed hearing loss
Conductive
A hearing problem involving the outer ear or middle ear
Sensorinural
A hearing problem involving the inner ear
Mixed hearing loss
A problem involving the outer, middle and inner ear is a mixed hearing loss

21. Conductive hearing loss
Causes
middle ear infections,
collection of fluid in the middle ear
blockage of the outer ear (by wax),
damage to the eardrum by infection or trauma,
otosclerosis, a condition in which the ossicles of the middle ear become immobile because of growth of the surrounding bone,
rarely, rheumatoid arthritis affects the joints between the ossicles.
Conductive hearing loss is caused by anything that blocks the conduction of sound from the outer through to the inner ear.
Usually, the causes of conductive hearing loss can be treated with medicine or surgery.
Symptoms of conductive hearing loss include:
speaking with a soft voice
the person will be able to hear specific words spoken by a co-worker if the co-worker just speaks up loud enough. Words are not garbled.

22. Sensorineural hearing loss
age-related hearing loss,
acoustic trauma (loud noise, etc.) to the hair cells,
viral infections of the inner ear
certain drugs, such as aspirin, quinine and some antibiotics, affect the hair cells,
Meniere’s disease
acoustic neuroma (a benign – non-cancerous – tumor of the auditory nerve),
meningitis (infection of the coverings of the brain),
encephalitis (infection in the brain),
The other type of hearing loss is called ‘sensorineural’ and refers to damage to the pathway for sound impulses from the hair cells of the inner ear to the auditory nerve and the brain. Sensorineural hearing loss is permanent damage and is untreatable. Hearing aids may help some people with this type of loss.
Some of the viral infections that can lead to hearing loss include: mumps; measles; chickenpox
If a pregnant woman has rubella, the fetus is at risk of being born with profound deafness. For this reason, girls are vaccinated against rubella before child-bearing age.
Menier’s disease causes abnormal pressure in the inner ear.
Acoustic neuroma is a benign non-cancerous tumor of the auditory nerve
Symptoms of sensorineural hearing loss include the a lack of loudness when people are speaking as well as distorted hearing - in other words words do not sound as they are spoken.
People with sensorineural hearing loss may also have Tinnitus (ringing of the ears), may speak with a very loud voice and may have difficulty hearing the spoken word when background noise is loud.

23. Tinnitus Hearing loss may not be silent ….
Persistent (often or all the time)
Ringing, roaring, clicking or hissing sound
12 million Americans have Tinnitus
should be evaluated by a Dr.
smoking, alcohol & loud noise can make it worse
use earplugs whenever exposed to noise

24. In addition to hearing loss….
Exposure to noise can….
Cause increased fatigue
headaches
increase the heart rate and blood pressure
cause muscles to become tense
cause indigestion
can lead to impaired balance
make it more difficult to hear audible warning devices
Noise may also put stress on other parts of the body by causing abnormal secretion of hormones and tensing of muscles.
Workers exposed to noise sometimes complain of nervousness, sleeplessness and fatigue. Excessive noise exposure also can reduce job performance and may cause high rates of absenteeism.

25. Noise induced hearing loss
Entirely preventable
“People would pay more attention to hearing loss if it caused a lot of physical pain”
NIHL is caused by exposure to sound levels or duration's that damage the hair cells of the cochlea. Initially, the noise exposure may cause a temporary threshold shift-that is, a decrease in hearing sensitivity that typically returns to its former level within a few minutes to a few hours. Repeated exposures lead to a permanent threshold shift, which is an irreversible sensorineural hearing loss.

26. How do you know how well you hear - Hearing Testing
Required annually for those employees enrolled in a hearing conservation program
identifies anyone with a change in hearing
this is just a “screening test” and should not be used to diagnose the type or extent of hearing loss
testing helps determine the effectiveness of an employers hearing conservation program

27. Audiograms Computer generated graph of normal hearing
Computer generated “tape” showing normal hearing
The degree of hearing loss indicated on these results is determined by measuring hearing threshold, or the levels in decibels (dB) at which a signal (tone or beep) is just barely heard. The louder sounds must be made to be heard, the greater the degree of hearing loss.
Thresholds are measured at several frequencies (pitches) and graphed on the audiogram. In some cases instead of graphing the results a computer provides a printout of the results. The frequencies tested are those important for hearing and understanding speech and other environmental sounds. Frequency is noted in Hertz (Hz).
When reading an audiogram, keep in mind that a value of zero dB is a reference level. Zero represents the softest sound that an young adult (with good hearing) can hear at that test frequency. In fact some people with exceptionally good hearing will have audiograms showing responses below zero dB. In this audiogram, the worker has particularly good hearing at 125, 1,000, and 2,000 Hz
Computer generated graph of normal hearing

28. Degrees of Hearing Loss
Normal dB
Mild dB
Moderate dB
Severe dB
Profound dB
Those with mild hearing loss (26-45 dB) typically hear one-on-one conversation if they can see the speaker's face and are listening at close range. With a mild hearing loss, there may be difficulty hearing and understanding someone who is speaking from a distance or has a soft voice. Understanding conversation in noisy backgrounds also may be difficult. For young children who are learning speech and language, even a mild hearing loss can have serious effects on speech and language development.
With moderate hearing loss (45-65 dB) conversational levels of speech are difficult to hear and understand, even in quiet backgrounds. Listening in noise is extremely difficult.
With severe hearing loss (66-85 dB) hearing is difficult in all situations. Speech may only be heard if a speaker is talking loudly or at close range.
Those with profound hearing loss may not hear even loud speech or environmental sounds and may not use hearing as a primary method of communicating.

29. Example of hearing loss
Have you had a STS?
an average shift of greater than or equal to 10 dB at 2000, 3000, 4000 Hz
calculated by
comparing your baseline test with your present hearing level
This audiogram shows a worker with noise induced hearing loss. Generally noise induced hearing loss will cause a loss of hearing in the high frequencies first.
If you have had an STS you should always use hearing protection when exposed to noise and should evaluate your noise exposure to see if you can reduce it.
OSHA requires that if you suffer a permanent threshold shift that you be counseled on your loss; be provided hearing protection that fits.

30. Did you do poorly on your last hearing test?
The following can result in a bad test result
exposure to noise without hearing protection before the test
failure to follow the technicians instructions
fatigue
substance abuse
Tinnitus
pseudohypacusis (faking it)
Pseudohypacus is “faking it” in order to get workers compensation.
Employees may be referred for further follow up with a doctor if any of the following are reported:
ear pain
drainage
dizziness
severe persistent Tinnitus
sudden, fluctuating or rapidly progressing hearing loss
feeling of fullness of discomfort in one or both ears
If the baseline exam shows quite a lot of hearing loss the employee may be referred and if the annual audiogram shows consistent loss the employee may be referred out.

31. How to Prevent Further Hearing Loss at Work
Identify noise hazardous equipment
Put distance between you and the noise source
Limit the amount of time you are exposed
Modify the noise source so it is quieter
Use hearing protection when around loud noise

32. PREVENTION:Identify noise hazardous equipment
Measure noise sources at your job site to determine what poses a risk to hearing
include any equipment that produces 85 dB or greater in your inventory

33. PREVENTION:Identify noise hazardous equipment
Label or ID any equipment that exposes the operator to 90 dBA or more
always use hearing protection when working with labeled equipment

34. PREVENTION: Put distance between you and the noise
Walk away from the noise source
Doubling your distance from the sound source decreases intensity by 6 dB
a 50% reduction in intensity!
Move the source away from people
Move noise sources away from
reflective surfaces (concrete or brick walls)
estimated to reduce levels by 3 dB
corners
estimated to reduce levels by 6 dB

35. PREVENTION: Limit the amount of time you are exposed
Schedule noise activities for fewest workers needed for the job
Take breaks away from the noise hazardous area
Limit the amount of time employees are exposed to noise

36. PREVENTION: Modify the noise source
Noise Control - Maintain Equipment
Reasons machines get noisier over time
worn components
loose parts
poor lubrication
imbalances
obstructed airways
blunt cutting surfaces
damaged/removed silencing equipment

37. PREVENTION: Modify the noise source
Control types - barriers or pads
Prevents sound from travelling on a path
Portable welding-type noise barrier
Cover metal surfaces with a coating, cloth, pad or blanket to reduce impact noise
Clamping material while cutting with a circular saw

38. PREVENTION: Modify the noise source
Enclosures on equipment cabs
Keep driver from equipment noise
open bulldozer is on average 6 dB higher than a closed bulldozer
Glassed in cranes are on average 10 dB lower than non-enclosed
Keep your windows rolled up!!

39. PREVENTION: Modify the noise source
Purchasing & Contracting
Purchase quieter equipment
specify in contracts for new equipment that low noise & vibration levels are desired
Specify in contracts with prime or subcontractors that low noise practices will be incorporated into the job when feasible

40. PREVENTION: Modify the noise source
Retrofit old Equipment
Modify existing equipment
you may need the assistance of a trained mechanic or a noise engineer
Purchase noise reducing components like mufflers & silencers
Install quieter components
Jackhammer/chipper: rubber chucks, seal lines

41. PREVENTION: Use hearing protection
It is common for less than 50% of the employees who should be wearing hearing protection actually wear them in most industries
If you have a hearing impairment it is critical you use them whenever you are exposed to noise
both on and off the job site!

42. HPD used - earplugs Earplugs pre formed (latex)
hand formed (polyurethane or PVC)
INSTRUCTOR- Demonstrate Proper Wear for both types of earplugs
Pre-formed earplugs:
pull up and back on pinna
insert earplug so plug is snug in ear canal
Advantages of pre-formed earplugs:
inexpensive
can be washed and re-used
Hand formed plugs:
roll earplug between thumb & index finger to the smallest size possible
insert earplug so that at least 2/3 of the plug is in the ear canal
use index finger to hold earplug in place while it expands (about 1 min)
ensure there are no creases in the plug
Advantages of hand formed earplugs:
comfortable
least expensive

43. HPD used - canal caps & ear muffs
inserted as far in the ear canal as possible
headband placement can be on top of the head; behind the head, or under the chin.
ADVANTAGES of Canal Caps:
quickly inserted without soiling
good for intermittent noise exposure
Muffs:
ear muffs should seal around the ear
eyeglass temple bars or respirators should not interfere with the seal
seals should be soft and pliable
ADVANTAGES of Ear Muffs:
universal fit
good attenuation
can be worn with earplugs

44. Noise Reduction Rating
All hearing protection devices have a NRR assigned
NRR’s do not accurately reflect attenuation in the real world
Field testing indicates……
NRR is approximately half of what is listed for earplugs
NRR is approximately 75% of what is listed for earmuffs

45. NRR’s - Good Rule of Thumb
Take the NRR on the package and divide the number by 2
for example……
earplug with NRR of 30 dB most likely has a working attenuation of 15 dB
Goal
select protection that will reduce your exposure below 85 dBA
Backhoe = 93 dBA
earplug with a NRR of 20 so attenuation is about 10
= 83 dBA

46. NRR the myth Bigger is not necessary better
Large NRR may not be appropriate if
noise levels are in the high 80 dB to low 90 dB range
what is needed is not an NRR of 30 dB but a well-fitted and comfortable device that can provide an actual delivered 10 or 15 dB of noise reduction
if the need to speak and be understood is needed in the noise environment
flat and moderate attenuation passive devices can be used

47. Flat Attenuating Devices
Good for
noise exposures averaging dBA as a TWA
environments were the spoken word needs to be heard
those employees with a hearing impairment
EAR UltraTech
One of the biggest complaints that those with a hearing loss have about using hearing protection is that they can not hear the equipment and people around them. Most hearing protection blocks out the higher speech frequencies better than lower frequencies, making it difficult for those employees with noise induced hearing loss to hear equipment and people.
These following hearing protectors have a filter installed that allows the wearer to hear instructions, machinery, warning signals, alarms, etc:
Ultra Tech earplugs made by EAR available with a NRR of 12 and 16
EAR Ultra 9000 ear muffs with a NRR of 17
Dalloz/Bilsom NST (Natural Sound Technology) Ear Muff two models available with a NRR of 20 and 27. This model is also available for use with hard hats.
These protectors attenuate noise equally allowing the speech frequencies to be heard as well as low frequencies. These are the same type of attenuating earplugs used by musicians.
Workers who have hearing impairment should be encouraged to try these protectors out.
Bilsom NST 817

48. Hearing aids are not hearing protection
Hearing aids do not block out enough sound for most occupational exposures to noise
When hearing aid users are exposed to harmful levels of noise they should
remove their hearing aids and use hearing protection or
turn off their hearing aids and put ear muffs on over them
Hearing aids amplify noise into the wearers ear. Recent research has found that amplified exposure to otherwise safe levels of industrial noise did result in 8 hr Time Weighted Averages (TWAs) that exceeded OSHA’s limit of 90 d/BA as a TWA. They cited an example of one mild gain (low power) hearing aid that increased exposure from 83 to 91 dBA. A stronger hearing aid increased the same industrial noise to over 115 dBA.
Newer digital hearing aids and those with compression or automatic gain control (hearing aids that turn off automatically when noise levels exceeding 85 dBA are present) may not be damaging to the user in noisy settings.
Most hearing aids do not block out enough sound to prevent occupational exposures in high noise level areas.
Having a hearing loss does not protect an individual from additional hearing loss. Hearing aid users need to protect their hearing from getting worse. Hearing aid users should take a copy of the noise measurements for equipment in their area to their audiologist or hearing aid dispenser they can be adequately be counseled on how to protect themselves from noise.

49. The bottom line…...
Your ears are a delicate tool - if your working with broken equipment you need to address your exposure by…
getting further evaluation from an audiologist; otogaryngologist; physician
choosing hearing protection that is right for you
asking for your employers help in evaluating your working environment and making changes to reduce your exposure

50. Wrap Up Want more information…..
Stay tuned & watch the video that will provide more information for those with a hearing impairment
MODIFY
THE SOURCE
IDENTIFY
EQUIPMENT
LIMIT EXPOSURE
TIME
MOVE AWAY
PROTECT YOUR EARS