Noise Exposure and
Hearing Conservation Policy
Douglas County has adopted its Noise and
Hearing Conservation Policy and Procedures to protect
its work force from
hearing loss and ensure compliance with the OSHA Noise regulations. The
regulations require that each employer implement a hearing conservation
program if employees noise exposure levels exceed 85 decibels for an average
of 8 hours.
OAR 437 Division 2 Subdivision
"Occupational noise exposure" 1910.95 and
OAR 437 Division 2 Subdivision 'I'.
Permissible Noise Exposure:
There are actually two exposure levels that if exceeded required
specific compliance activities.
Permissible Noise Exposure: eight hour time-weighted average level
90 decibels on the A scale or a dose of 100%.
B Action Level is an
eight hour time-weighted average of 85 decibels on the A scale or a dose of
Representative Noise Exposure:
Measurements of an employee=s
dose or 8 hour time-weighted average
sound level that the employers deem to be
representative of the exposures of
other employees in the workplace.
Sound measurements as
Noise dosimeter: An instrument that integrates a function of sound
pressure over a period of
in such a manner that it directly indicate a noise dose.
Sound level meter: An instrument for the measurement of sound
Time-weighted average sound level:
That sound level, which if constant over an 8-hour exposure,
would result in
the same noise dose as is measured.
RESPONSIBILITIES & TRAINING
is responsible to see that noise controls are implemented and maintained and
that all employees at noise exposures in excess of 85 dBA time-weighted
average are part of an effect hearing conservation program. This includes
auditing the on-going program and training employees in the hazards of noise
and required controls.
are responsible for maintenance of records, employee training and auditing
the overall program.
Resources is responsible to maintain employee medical records and all
past employee records per the OSHA standard.
4. All Employees
whose noise exposures exceed a time-weighted average of 85 dBA or greater
are responsible to wear appropriate hearing protection, take an active part
in the annual training and take annual hearing tests.
NOTE: APPENDIX A PROVIDES THE NOISE SURVEY
AND LISTING OF THE JOBS INCLUDED
IN THIS PROGRAM.
A. Noise Surveys
1. Noise surveys are required to
be done on work operations that have potentially
high noise levels (85
dBA and above).
a. The noise measurements will be
retained by the Section Managers or designees and will be
of this overall noise data maintained at each location.
b. Additional noise surveys will be taken
when the Department introduces additional equipment or
processes which could result in higher noise levels and periodically to re-verify the results.
c. Assistance with noise monitoring can
be obtained from the Risk Manager
2. The noise survey measurements are
recorded on the employees hearing test records or
the current noise exposure levels. The noise surveys are
available for review by the employees by
contacting their supervisor.
3. Each employee exposed to noise at or
above the 85 dBA average is to be informed of the results.
will be done by posting the data and including the information at the
employee initial and annual
employee noise training classes.
1. Hearing protection is required
to be worn during the operation of equipment or processes that
exceed 85 dBA
noise levels as a time weighted average exposure.
a. The hearing protection (ear barrier
plugs and foam plugs) are available in variety of locations at
facilities which will be pointed out to each new employee during their
b. EMPLOYEES REQUIRED TO WEAR HEARING
PROTECTION WHEN EXPOSED TO
ABOVE 85 dBA.
2. Employees will be trained in
how to properly fit the hearing protectors by their supervisor with
assistance from the County Safety Manager or outside safety/health
consultants. If anyone has
problems with the devices please contact your
3. Employees will be provided with at
least two styles of protection - plugs or inserts to try on
determining which device would be best for them. All the devices provided
will be evaluated to
determine that they provided adequate noise attenuation
for the noise exposures levels.
4. Each employee will be responsible for the maintenance of his/her
a. Disposable plugs will be discarded at
end of shift or when they become excessively
b. Inserts or barriers will be checked
prior to each use for any defectives. If barriers are
head band needs to be checked to ensure that it is tight and the insert are not
torn, disfigured or
do not properly seal.
ALL DEFECTIVE EQUIPMENT MUST BE REPLACED.
c. Follow manufacturer's
recommendations on maintenance.
1. New employees assigned to a noise area
will be given an baseline hearing test and then will be
tested annually thereafter. The Hearing Test will be given by an outside provider who
Baseline or initial test will be given to new employees at the
time of hire.
The baseline tests require that the employee not be in
occupational noise area for 14 hours
prior to the test. This test will be
the reference for the further tests to determine if hearing levels
2. Annual hearing test can be
taken any time during a work shift. These results will be compared
the baseline tests.
a. Annual audiograms will be given by the
outside provider who has certified audiometric
b. Significant threshold shift
(STS) criterion: The hearing loss criterion is a change in
threshold relative to the baseline audiogram of an average of 10 dB
at 2000, 3000, and
4000 hertz (Hz) in either ear.
Oregon, does not permit age as a
factor in hearing loss as does Federal OSHA.
The employee may be retested within 30 days
and consider the results of the retest to
if a permanent shift has occurred.
c. Employees will be informed if their
tests show significant changes in their
hearing levels based
on Oregon OSHA standards by written letter and follow-up by the Supervisor and/or the
employees supervisor once notified of that
change by our contract audiologists. The employee
be notified within 21 days of receipt of the
information from Industrial Hearing Service.
d. In all cases of hearing loss the
employee will be re-instructed on how to properly wear
protection. The supervisor will follow-up on all hearing tests that show a reduction in the
employees hearing from the baseline.
3. Our contractor audiologist will
determine if additional tests are needed and the status of the
D. Employee Training
1. New employee will receive Hearing
Conservation training at initial assignment to a noise area. The
will be repeated annually for all noise exposed
employees. The specific training
are provided in this manual and are to
be a guideline for our supervisors and/or safety
representatives to use.
2. A copy of the training materials
will be available to our employees by contacting his/her supervisor.
3. A copy of the Oregon OSHA Noise &
Hearing Conservation Rules are posted on the safety bulletin
at each of our
locations where employees are potentially
exposed to hazardous noise
Management is responsible to determine if
there are feasible engineering controls
reduce noise levels to below 90 dBA as a time-weighted 8 hour average.
Engineering Control Feasibility
Studies: In some cases there may be records of noise control
studies done on pieces of equipment or processes. These records should
be kept to show
compliance with Oregon OSHA noise engineering
control standard. The records should be
maintained for the duration the equipment or
process is in use.
Records must be maintained for the various
elements of the program. This includes the following
1. Noise Exposure Measurement:
Current plus 2 years of results (note: the current record may represent
taken longer than 2 years ago, this is permitted long as the readings are
noise exposure levels).
2. Audiogram records:
Duration of employment plus 5 years
3. Training Records
There is no time frame given in the rules but it is the policy to keep the training records for
employee the duration of employment and then
forward all records to the Human
4. OSHA 300 Log Record
1. If an employee=s
hearing shift is permanent it must be recorded on the
2. Employee must be informed in
writing within 21 days of the determination of
3. Record Keeper: Human Resources and
each Department has staff assigned responsibility for
OSHA 300 Injury and Illness Log for each Department.
SUMMARY OF THE OSHA NOISE STANDARD
Oregon OSHA standards
Noise and Exposure
requires that employers develop and implement a Hearing Conservation program
where noise levels exceed an eight hour time weighted
average (TWA) of 85
dBA or the equivalent of a 50% exposure dose. The rules also require that
feasible engineering controls be implemented to reduce employee noise
exposures to below 90 dBA as an eight hour average or the equivalent of a
100% exposure dose. The following provides an outline of the specific rule
requirements. This should be reviewed by employees providing training or
managing the hearing conservation program.
Conservation Program Elements:
1. Noise Exposure
Monitoring: Employers are to monitor the noise levels in their
operations and identify those employees whose exposures exceed the 85 dBA average. This can be done by noise survey and/or noise dosimetry. The overall monitoring goal is to ensure that all
potentially overexposed employees are identified and the basic noise
levels are determined for the proper selection of hearing protection.
a. Accuracy of the measurements:
The monitoring is required to meet a
2 decibels accuracy
specifications. Noise equipment needs
to be pre and post calibrated to verify that the readings are
b. Employee notification: Each
employee exposed at or above the 85 dBA average is to be
of the results. This can be done by posting the data and
including the information in your initial and
annual employee noise
c. Noise measurement record retention:
At a minimum we are required to retain the noise
measurement records for 2 years or for as long as they are representativeof the noise exposure
Employee Testing Program: Employers are required to provide initial
baseline test for all employees assigned to work in a noise area (85 dBA for eight hours). This test is required to be provided within
180 days of assignment to noisearea. Then annual hearing test
must be given which are compared
to the baseline. Specific rules on who
can give the tests and comparison data are found in the regulations
and need to be carefully followed.
Protectors: Employers are to make available hearing protectors for employees exposed to noise at 85 dBA for an average over 8 hours. If
the persons shows a hearing loss and the noise exposure
is between 85
and 90 the protection must be mandatory worn. If the noise levels
are above an average 90 dBA protection is always mandatory. It is a
good practice to require hearing protection to be worn when noise
levels are above 85 dBA.
a. Employees are required to be trained
on how to wear hearing protective devices.
b. Employees are to be given an
opportunity to select their hearing protectors from a variety
OSHA views this as at least two types of protective devices.
c. Employees need to be given initial
fitting and supervised on the correct use of hearing
d. The protectors must attenuate the
noise level to below 85 dB or lower. This calculation is
the Noise Reduction Rating (NRR) found on the packaging of the protectors, then subtracting at
least 7 dB and comparing
that number to the average noise level found.
An example is the noise level average of 95
95 - 85 = 10 minimum required noise
If the NRR for the hearing protection is 27
then the OSHA accepted protection would be:
27 - 7 = 20 dB, thus this be adequate
hearing protection if worn properly. (95 - 20 = 75 dB)
4. Training program: Each
employer is required to institute a training program for all
are exposed to noise at or above a TWA of 85 dB, and shall ensure employee participation in such
Training is required as an initial
orientation and annually thereafter. The information provided is to
be updated to be consistent which changes in the
protective equipment and work processes. The
of the training program include:
a. The effects of noise on hearing.
b. The purpose of hearing protectors, the
advantages, disadvantages, and attenuation of
types, and instructions on selection, fitting, use and
c. The purpose of hearing tests and the
5. Access to
Information, Training Materials and Recordkeeping:
a. The employer is to make available
copies of the noise standard and post a copy in
b. All training materials are to be
available to OSHA representative upon
c. Records are to be kept of the noise
exposure measurements, training program,
The hearing tests are to be retained for the duration of the affected employee=s
five years. Exposure
records are to be kept for 2 years and current exposure records are to
always be available.
Administrative and Engineering Controls (Rule 437-002-1910.95):
The standard requires that feasible
administrative or engineering controls be implemented to reduce
exposure to below a time-weighted average of 90 dBA.
1. Administrative controls involve
the control of the employee's
noise exposure time by job rotation
an area that
has noise levels below 90 dBA. An example would be an
employee who works in an
area with an average of 95 dBA. If the
employee worked in this area for 4 hours or less and
an area below 90 dBA his/her noise exposure average would be
below an average 90 dBA.
This type of control can be difficult to
manage and often does not match with an employer's
dealing with different levels of job skill and training. The use of administrative controls does involve
of employee work schedule and on-going noise monitoring
to ensure that the
rotation positions do not have
noise levels over 90 dBA.
2. Engineering Controls - Noise
controls usually involves three elements:
A source of noise.
A receiver of noise - one or more observation points at which noise might affect the employees
in the noise path.
The various paths noise can travel between the source and the receiver.
If a given noise emission cannot be reduced
at the source, noise control engineering entails
inhibiting the propagation of sound between source and receiver. This can involve enclosures of the
path or sound enclosure for the operator and other engineering changes.
NOISE EXPOSURE PROTECTION, HEALTH EFFECTS
PROTECTION AREAS or EQUIPMENT
Hearing protection is
required when an employee's eight hour average noise exposure exceeds OSHA's
permitted exposure of 85 decibels or a noise dose of 50% as measured by a
noise dosimeter. Douglas County employee noise exposure levels have been
measured are based on the exposure during the use of equipment or
HOW WE HEAR
Sound waves move
through the outer ear and set up vibrations in the middle ear. The
vibrations are then transferred to the inner ear. The wave motion in the
inner ear is sensed by the nerves in the inner ear (cochlea), which
transmits neural messages to the brain. Thus the mechanical energy
generated by sound is transferred in our ears to an electrical signal that
our brain interprets as sound.
Figure 1 - Basic Anatomy
of the Ear - Illustration of Air Conduction & Bone Conduction Sound Path
EFFECTS OF NOISE ON
Prolonged exposure to
excessive noise levels can cause a noise-induced hearing loss. When you are
exposed to excessive noise levels, the first effect usually is a temporary
hearing loss. You may have
difficulty in hearing conversation or your ears
may feel "plugged" and "ring." Over a period of time, an individual who
experiences repeated temporary hearing loss will have some permanent,
irreversible hearing loss.
loss (or acoustic trauma) involves damage to the receptor cells in the inner
is classified as sensor-neural impairment (see Figure 2). A
noise-induced hearing loss typically begins
with a drop in hearing level at
the higher frequencies of 3000 hertz (Hz), 4000 Hz, and 6000 Hz. As the
hearing loss increases, it normally spreads to lower speech frequencies of
500 Hz, 1000 Hz, and 2000 Hz.
hearing loss normally is not detected by an individual, since it occurs
above the speech range. By the time an individual is aware of a hearing
loss, the amount of loss may be significant.
Figure 2: Noise Induced Hearing Loss
There are three types
of ear protectors: a muff which covers the entire ear, a plug
which is inserted into the ear canal, and a "stopper" which covers
the outer end of the ear canal. All three types are designed to reduce the
amount of noise reaching the inner ear.
Easy to fit in place and Causes pressure on
take on and
Easy for management
to May not have a good
use seal with glasses or
Do not irritate the
ear Are hot to wear in the
Inexpensive Difficulty in
(must fit tightly to
accepted Tend to loosen with
workers jaw movement
Can irritate the ear
Easy and quick to fit
Cause pressure on the
place ear and may
SELECTION OF EAR PROTECTORS
The reduction of noise by hearing protectors is called
attenuation. This is expressed in decibels. The manufacturer of
each hearing protector will indicate the amount of attenuation for each type
of protector. It will be listed on the package as the Noise Reduction
Rating (NRR). The noise reduction levels needed for our employee exposures
vary but in general require 20 to 30 dB attenuation level.
We have selected hearing protectors which are
convenient and comfortable, and provide the proper amount of protection for
the noise encountered. Under attenuating would lead to excessive noise
exposure. Over attenuating in moderate noise levels can lead to excessive
sound attenuation reducing the ability to hear and, consequently, poor
acceptance of the protectors.
Earplugs must fit tightly to provide a good seal. The
earplug is inserted by grasping the ear with the opposite hand, pulling it
up and out to open the ear canal, and then inserting the plug with the other
Muffs will normally fit all people without any
difficulty. Eyeglasses may interfere with the proper fitting of the muff.
Muffs that attach directly to hard hats are also available.
Ear stoppers are usually easy to position. The
headband can be worn on top of or behind the head, or under the chin.
When hearing protectors are initially worn, it may take
a short time to adjust to the new sounds. The same noises are heard, but at
a much lower level. After this adjustment period, voices, machinery noises,
etc., can still be heard and understood the same as before, if not better.
CARE AND USE OF EAR PROTECTORS
The primary type of hearing protectors we use are
disposable, however, they can be reused especially during the day as long as
they are clean. If oil, dirt or other materials are embedded into the foam
then it must be discarded.
Ear protectors must be maintained in sanitary
condition. It is important that earplugs be clean when inserted into the
ears. If plugs are dirty when inserted, they may cause irritation which
could lead to infection of the ear canal. The same applies to stoppers.
Earplugs, when not in use, should be stored in some
type of container which can be closed to seal out dust or dirt. Earplugs
should be replaced when they no longer can be cleaned or lose their
pliability. Ear muffs have a replaceable seal which should be kept clean.
The seal should be replaced whenever it becomes stiff or cracked.
Audiometric testing is a means of determining your
hearing ability. "Normal" hearing is the median hearing level of a large
group of American adults between 18 and 25 years of age, having no known
history of ear disease and no appreciable high-level noise exposure. The
accepted normal range of hearing is between 0 and 25 decibels.
The audiometric test consists of exposing each ear
separately to sound at six different frequencies. The audiometric test will
show the amount of hearing loss, if any, of an individual. The higher the
decibel reading, the greater the hearing loss. As an individual ages, there
is a natural hearing loss which takes place. This is called presbycusis. A
cold, an ear infection, or recent high noise exposure can cause a temporary
hearing loss which would produce poor test results.
NOISE TRAINING REVIEW
The following issues were reviewed with the employee
regarding noise exposure in their work area.
______ Overexposure to
noise can cause noise-induced hearing loss which and can be permanent.
______ Noise damage is
to the inner ear nerve cells.
protection is required to protect your hearing.
______ Loss due to
noise is cumulative including on and off the job exposure
______ Loss is not
evident to you during the early states of hearing damage
______ A person
generally hears better in a noisy environment with hearing protection
______ Noise exposure
increases general fatigue and in some cases blood pressure during the noise
REVIEWED THIS MATERIAL NAME DATE
EMPLOYEE HEARING CONSERVATION & NOISE TEST
Name:__________________________________ Date: __________
Initial Training______________________ Annual
True False QUESTIONS
____ ____ 1. Hearing protection is
only required for the Finishers.
____ ____ 2. OSHA requires that hearing
protection be worn when employees noise exposure exceeds 85 dBA
for an eight hour average.
____ ____ 3. Best way to determine noise
exposure level is to measure the levels using a noise dosimeter
(meter that integrates
the noise levels).
____ ____ 4. We hear when sound waves
enter the ear and are transmitted through the middle ear into the inner
which transfers the noise as an electrical signal to our brain that interprets the
____ ____ 5. Prolonged exposure to
excessive noise levels can cause a noise induced hearing loss.
____ ____ 6. When you are exposed to
excessive noise levels, the first effect usually is a temporary hearing
____ ____ 7. Noise-induced hearing loss
involves damage to the inner ear.
____ ____ 8. Early noise-induced hearing
loss normally is not detected by an individual, since it occurs above
speech range. By the time an individual is aware
of a hearing loss,
the amount of loss may be
____ ____ 9. Muffs provide the highest
level of protection as compared to foam plugs.
____ ____ 10. There are not disadvantage in
using foam plugs.
____ ____ 11. The reduction of noise by
hearing protectors is called attenuation.
____ ____ 12. Douglas County has selected
hearing protectors which are convenient and comfortable, and
provide the proper amount of protection for the noise encountered.
____ ____ 13. Earplugs including foam plugs
must fit tightly to provide a good seal.
____ ____ 14. The reason we are generally
not using earmuffs is because safety glasses interfere with the proper
fitting of the muff over the ear.
____ ____ 15. When hearing protectors are
initially worn, it may take a short time to adjust to the new sounds.
____ ____ 16. The primary type of hearing
protectors we use are disposable, however they can be reused
especially during the day as long as they are clean.
____ ____ 17. Audiometric testing can
protect your hearing.
____ ____ 18. Audiometric testing is a
means of determining your hearing ability.
____ ____ 19. The accepted normal range of
hearing is between 0 and 25 decibels.
____ ____ 20. The audiometric test will
show the amount of hearing loss. The higher the decibel reading, the
greater the hearing loss.
NOISE COMPLIANCE CHECKLIST
The following checklist can be used of management and
safety committee members when conducting an overall audit on
our noise and
hearing conservation program.
Any areas not in compliance should be explained on the
back of the checklist. Recommendations for corrections should also be made.
A. Noise Exposure Monitoring
(Y - N)
1. Current noise exposure levels are available for all work positions that
may be _________
over 85 dBA as an 8 hour
time weighted average.
2. The noise readings were done with a calibrated
3. Noise measurement are retained and would be available to employees
4. The noise readings are noted on employee audiogram
5. Employees are notified of the noise exposure level
6. Employee representatives were allowed to observe noise exposure
B. Noise Control
Measures & Hearing Protection
1. All feasible noise controls have been implemented for employees=
noise exposures exceed
2. Records of noise control measures are maintained and would be
for an OSHA inspector.
3. All employees whose noise exposure exceeds 90 dBA or 85 dBA
hearing loss are wearing hearing protection.
4. Employees were trained and fitted in hearing
5. Employees were offered a variety of suitable protections to choose
6. Hearing protection attenuation was calculated and provides adequate
protection for employee=s
noise exposure (at least to less than 85 dBA TWA).
7. Employees are wearing protection per manufacturer=s
(Y - N)
1. All employees whose exposure exceeds 85 dBA TWA are part of
Program. (Includes hearing tests, noise protection,
and annual employee
2. Only audiometric technicians or audiologists, or physicians
requirements are conducting the hearing tests.
3. Baseline audiograms are obtained within 180 days of assignment to
areas over 85 dBA.
4. The Baseline audiogram is taken with the employee away from
noise for 14 hours.
5. The employees are receiving annual audiograms which are compared
the baseline audiogram.
6. The audiograms are taken with audiometers that are properly calibrated:
Functional before use
Exhaustive calibration every 2
7. All significant threshold shift audiograms are evaluated by an
otolaryngologist, or a
8. Recommendations of professional reviewer were
9. Proper follow-up is done for all employees showing an significant
A Employee is
notified of the change within 21 calendar
Employee is retrained and refitted in hearing protection
Employee is referred for medical attention as
The STS is recorded on the OSHA 200 injury/illness
1. All employees with noise exposures equal to or greater than TWA of 85
have received initial
and annual noise training.
2. Training covers the following topics:
Effects of noise on
Hearing protectors use, maintenance,
Purpose of hearing
E. Access to
1. The noise
standard is posted and copies are available to employees or their ______
2. Training and
educational materials are available to an OSHA inspector _________
1. Noise exposure monitoring records are maintained
and available. _________
2. Audiometric test record must have following:
B Name &
job classification of the
C Date of
name and certification
E Date of
last acoustic or exhaustive
most recent noise exposure
3. Sound readings as octave band levels in test room
are available _________
APPENDIX A -
PUBLIC WORKS NOISE SURVEY RESULTS
LOCATION/EQUIPMENT NOISE LEVEL
Grader - 140 G
Power Broom - RJ
Front End Loader -International
Cat D7H Open
Note: All measurements were
taken using a Metrosonic Noise Meter/Dosimeter as short term exposures to
provide initial noise survey.