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Occupational Noise Exposure
OSHA 29 CFR 1910.95
Occupational Noise Exposure
This presentation will cover the following topics:
The effects of noise on hearing;
Hearing protection – purpose,
types and use;
The purpose of audiometric
testing and how it works; and
Your right to see noise
measurement records and
hearing test results.
Occupational Noise Exposure
Noise, or unwanted sound, is one of the most
common health problems in American
workplaces.
The National Institute for Occupational Safety
and Health (NIOSH) estimates that 30 million
workers in the U.S. are exposed to hazardous
noise.
Effects of Exposure to Loud Noise
Exposure to high levels of noise may cause hearing
loss, create physical and psychological stress,
reduce productivity, interfere with communication,
and contribute to accidents and injuries by making
it difficult to hear warning signals.
Effects of Exposure to Loud Noise
Exposure to loud noise will inevitably
cause hearing loss over time.
Loud noise damages or destroys the
hair cells in the inner ear.
Another effect can be “tinnitus” or
permanent ringing in the ear.
Long Term Exposure to Noise
Our ears can recover from short
exposure to loud noise, but over
time nerve damage will occur.
The longer and louder the noise,
the greater chance permanent
damage will occur.
There is really no such thing as
“tough ears” or “getting used to it”.
Effects of noise to inner ear
Hair cells in the inner ear transmit noise signals to the brain.
Normal hair cells
Noise-damaged hair cells
Hearing Loss From Noise Exposure
Hearing loss from noise exposure
is usually not noticed because it is
so gradual.
Usually a person loses the ability
to hear higher pitches first.
Often the first noticeable effect is
difficulty in hearing speech.
Tinnitus From Noise Exposure
Exposure to high noise levels can also
cause permanent ringing in the ear or
“tinnitus”.
Tinnitus sufferers usually complain of
constant whistling, squealing, roaring
or buzzing in one or both ears.
Severe tinnitus may disrupt sleep,
reduce concentration and cause
irritability and depression.
When is Noise Too Loud?
Noise is measured in units called “decibels” or
“dB”
If two people 3 feet apart must shout to be
heard, the background noise is too loud
(above 85 decibels).
Noise above 140 decibels causes pain
and immediate hearing loss (e.g. gunshots).
What is Too Much Noise Exposure?
Damage from noise exposure
depends on the loudness and
length of exposure.
Scientific studies have shown
that hearing loss can occur when
8-hour average noise exposure
exceeds 85 decibels.
What is Too Much Noise Exposure?
The risk of hearing loss increases
dramatically as noise levels
increase.
Exposure to noise levels above 115
decibels for even five minutes is
very risky.
Impact or banging noise above 140
decibels will cause immediate
damage to nerves in the ear.
Daily Allowable Exposure Times to Noise
The table below shows noise levels and how long a
person can be exposed without hearing protection
before there is damage to the ear.
Noise Level
Allowable Exposure Time
85 decibels
8 hours
90 decibels
4 hours
100 decibels
1 hour
105 decibels
30 minutes
110 decibels
15 minutes
115 decibels
0 minutes
Examples of Noisy Equipment
Equipment
Back Hoe
Chain Saw
Front-end Loader
Gunshot
Jackhammer
Lawn Mower
Tractor
Circular Saw
Noise Level
85-95 decibels
110 decibels
90-95 decibels
140 decibels
112 decibels
90 decibels
95-105 decibels
90-100 decibels
OSHA Noise Exposure Limits
Permissible Exposure Limit (PEL)
OSHA has established noise exposure standards in
order to protect the hearing of employees.
There is a level that
cannot be legally
exceeded. This is called
the “permissible exposure
limit” or PEL.
For an 8-hour Timeweighted Average
(TWA): no more than
90 decibels.
OSHA Noise Exposure Limits
Exchange Rate
OSHA uses a 5 dB exchange rate for the
decibel scale. The exchange rate means that
increasing the noise level by 5 dB doubles the
loudness. For example, 90 dBA is twice as loud
as 85 dBA.
Twice as loud
OSHA Noise Exposure Limits
Action Level
When the amount of noise exposure is above the
“action level” of 85 dBA, employers are required to
implement a hearing conservation program that
includes the following:
- Conduct periodic noise monitoring
- Provide annual audiometric testing
- Provide training
The Action Level is 50% of the permissible exposure limit (PEL).
Hearing Conservation Program
UNC-CH Hearing Conservation
Program
The purpose of the Hearing
Conservation Program is to provide for
the protection of University employees
from long term hearing loss associated
with noise levels in the workplace in
compliance with OSHA Standard 29
CFR Part 1910.95 Occupational Noise
Exposure.
UNC-CH Hearing Conservation
Program
All University employees whose noise exposures
equal or exceeds an 8-hour time weighted average
(TWA) of 85 decibels are enrolled in a hearing
conservation program (HCP). Environment, Health
and Safety (EHS) administers the HCP for the
University. The program includes:
Periodic monitoring of noise exposures
Annual training on noise exposures
Use of hearing protection
Annual audiometric (hearing) testing
UNC-CH Hearing Conservation
Program
Current program participants:
Chilled Water Systems
Cogeneration Systems
Department of Laboratory Animal MedicineAnimal Care Technicians
Finley Golf Course Maintenance Department
Public Safety
Grounds Department
Construction Masonry Shop
Monitoring
Noisy Areas & Equipment at UNC-CH
EHS conducts noise surveys and personal
monitoring to identify areas or activities where
noise exposure may exceed the action level.
The following slides present noise data for
departments enrolled in the HCP.
Chilled Water Systems
Chilled Water Systems
employees are exposed
to noise generated by
the mechanical
equipment used to
provide chilled water to
the campus.
Row of chillers at the South Annex Plant
The chillers and pump
motors generate the
higher noise levels.
Row of pumps at the South Plant
Chilled Water Noise Survey Summary
Plant
Minimum dBA
Maximum dBA
Cobb
86.5
90.9
South Annex
89.7
93.3
South
90.1
96.5
East
86.1
96.9
This table displays the minimum and maximum noise
levels measured during a survey of four Chilled Water
plants. Chilled Water employees should wear hearing
protection when working in the plants to help prevent
occupational noise-induced hearing loss.
Cogeneration Systems
Cogeneration Systems
employees are exposed
to noise generated by
the mechanical
equipment used to
provide steam to the
campus.
Coal crusher
The coal crushers and
the turbine generator
create the higher noise
levels.
Housing for the turbine generator
Cogeneration Systems
Fuel handling employees are exposed
to the highest noise levels from the
railcar shaker.
The railcar shaker produces
approximately 112 dBA.
The action level is exceeded after 15
minutes of exposure at this level
during a 10 hour shift.
Employees should remain in the
control room during the operation of
the shaker to reduce noise exposure.
Coal railcars
Division of Laboratory Animal
Medicine (DLAM)
The Division of Laboratory Animal Medicine (DLAM)
is responsible for the care of all vertebrate animals
on the UNC-CH campus.
DLAM animal care technicians are exposed to noise
levels that can reach up to 104 dBA when caring
for some of the larger animals.
Technicians must wear hearing protection when
handling the animals.
Finley Golf Course
The equipment used by the Finley Golf Course
Maintenance Department to maintain the
course produces high noise levels as shown below.
Equipment
Sound Level in dBA
Grand Master 3000-D
86.0
Reel Master 6500-D
89.0
Toro 1000
85.0
Speed Roller (Salsco)
96.5
Toro Multi Pro 1100
87.5
Suzuki M 120X
Toro Side Winder
(Reel Master 3100-D)
99.5
90.0
Public Safety
UNC Public Safety police
officers are exposed to noise
levels that reach up to 111
dBA near the student risers
during basketball games.
The firearms used during annual
training/qualifications can exceed
140 dBA.
Grounds Department
The Grounds Department
has over 60 employees,
each an expert in various
aspects of landscape design
and maintenance, irrigation,
tree care, and vehicle
maintenance.
Here are some of the
equipment commonly used
by employees to maintain
the campus landscape and
their respective noise levels
as measured by EHS.
Equipment
Chain Saw (Stihl)
Edger (weed eater)
Bush Cutter (Stihl)
Leaf Blower (Stihl)
Lawn Mower (Toro, riding)
Seeder (Lesco)
Lawn Mower (Scag, walk behind)
Tractor (Ford 3930)
Generator (Honda)
Lawn Mower (Jacobsen, riding)
Aerator (Ryan)
Lawn Mower (Honda, walk behind)
Lawn Mower (Ransoms, riding)
Forklift (Caterpillar)
Lawn Mower (Toro, walk behind)
Lawn Mower (John Deere, riding)
Tiller (Honda)
Bluebird Seeder (Honda)
Bed Edger (Honda)
Gator (John Deere)
Sound Level
dBA
106.7
104.0
103.5
102.7
98.0
95.5
95.0
94.4
93.0
92.7
92.0
92.0
92.0
90.8
90.4
90.2
89.5
88.0
85.9
83.5
Masonry Department
EHS monitored a UNC
Masonry employee
while the employee
used a jackhammer.
The noise levels
reached 106 dBA.
The University of
Washington has
conducted research on
the noise levels of tools
used by masonry
workers.
Hearing Protection
Hierarchy of Noise Control
Employers must first implement feasible engineering or
administrative controls when employees are subjected
to sound exceeding the PEL (90 dBA for an 8-hr TWA).
If such controls fail to reduce sound levels below the
PEL, hearing protection must be provided and used to
reduce sound levels below the PEL.
Engineering controls involve modifying the noise source
so it is quieter.
Administrative practices may include shift rotation or
exposure limitation.
Hearing Protection
Hearing protection devices (HPDs) are considered
the last option to control exposures to noise.
Employers must make HPDs available to all
employees exposed at or above the action level.
Employees must wear HPDs when exposed at or
above the PEL.
HPDs must be provided at no cost to employees
and must be replaced as necessary.
Types of Hearing Protection
There are three types of hearing
protection – ear muffs, earplugs and
ear caps.
Ear muffs and earplugs provide
about equal protection, ear caps
somewhat less.
earmuffs
earplugs
ear caps
Types of Hearing Protectors
All hearing protectors are designed to
reduce the intensity (loudness) of
noise to the inner ear.
They work much better than wads of
cotton or bits of cloth stuffed in the
ear.
All three types have advantages and
disadvantages and people vary on
which they prefer to use.
Cotton doesn’t
work!!
Hearing Protection – Ear Plugs
Earplugs are made of foam, rubber
or plastic and are either one-sizefits-all or in sizes small, medium and
large.
Some are disposable, some are
reusable.
They are lightweight, and require no
maintenance.
They are inserted into the ear canal.
Ear Plug Comfort
Some people may find ear plugs
uncomfortable to wear for long
periods at first.
Ear plugs rarely cause infection or
prolonged irritation of the ear canal.
Most people can find a comfortable
fit by trying several different sizes,
types or brands.
Custom-molded earplugs can be
obtained for maximum comfort.
custom molded
earplugs
Inserting Foam Earplugs
Foam type earplugs are one-size-fits-all and
must be inserted properly into the ear.
Roll earplug into a small cylinder first, then insert in ear
while pulling the ear upwards and outwards. Click here
to watch a 5-minute video on fitting foam earplugs.
Inserting Foam Earplugs
Earplug incorrectly inserted
Earplug correctly inserted
Checking the Fit of Foam Earplugs
To check if foam earplugs are fitted properly press
firmly cupped hands over your ears while listening
to a steady noise.
With properly fitted plugs the noise levels should
be about the same whether or not the ears are
covered.
Premolded Earplugs
Premolded earplugs are reusable and made of
rubber or plastic.
To check if premolded earplugs are fitted properly
gently tug on the stem of the inserted earplug.
Then, gently move the stem in and out.
With properly fitted plugs you should feel slight
pressure on your eardrum. This technique is called
the tug and pump test.
For safe removal, carefully twist the plug to break
the seal.
Ear Muffs
Ear muffs cover the whole ear
and are preferred by some
people.
They have replaceable pads
and some high-tech styles
filter out specific noise pitches.
They last longer than most
plugs.
Attached Earmuffs
Some muffs are attached to hard
hats or goggles.
Some high-tech muffs can filter out
certain frequencies or have radios
inside for communication in high
noise areas.
Ear Muff Comfort & Glasses
Muffs can be uncomfortable in
hot weather.
Muffs don’t seal well for someone
with glasses or heavy sideburns.
Ear Caps
Ear caps are like earplugs,
except they do not go into
the ear canal, they only
block it.
They are good for occasional
use or for people who find
earplugs uncomfortable.
They are not as protective
as earplugs or muffs.
Noise Reduction of Hearing Protection
The “noise reduction
rating” or “NRR” of
hearing protection is
measured in decibels.
The NRR is found on the
earmuff or earplug
package. The higher the
number, the greater the
protection.
The NRR is determined in a
laboratory. The NRR must
be adjusted for workplace
conditions.
How can you hear anything
with earmuffs on?
Using earmuffs or plugs in noisy
areas can actually make it easier
to hear coworkers or machinery.
They reduce overwhelming loud
background noise.
They are similar to dark glasses
that reduce the sun’s glare
making it easier to see.
Proper Use of Hearing Protection
Earmuffs and plugs provide
good protection only when
used properly.
Sometimes people will
remove hearing protection
for “just a minute” in a noisy
area.
In areas of very high noise
exposure, this could result in
noise overexposure.
It won’t protect your ears if it is
around your neck!!!
Proper Use of Hearing Protection
It takes just a few minutes of
unprotected exposure at noise
above 115 decibels to risk
hearing damage.
Earplugs not well inserted into
the ear canal will not provide
complete protection.
Likewise, earmuffs not snug
against the head will “leak”
noise into the ear.
Hearing Aids Are Not Hearing
Protection
Hearing aids do not block out
enough sound for most workplace
noise.
Some hearing aids can actually
increase the noise level at the ear.
Just turning off the hearing aids
will not prevent further hearing
loss from noise exposure.
Portable Radios/CD Players/iPods
These devices do not provide protection
from noise.
The earphones are not earmuffs and
the music only adds to background
noise.
The music level in the earphones
themselves can exceed 85 decibels and
cause hearing loss.
Audiometric Testing
What is Audiometric Testing?
“Audiometric testing” is the
same thing as hearing tests.
It is done by trained
technicians to detect any
hearing loss.
Audiometric testing is required
for any employees enrolled in
the HCP.
Purpose of Audiometric Testing
Most of us develop a mild hearing
loss as we age, especially in the
higher pitches.
A severe or significant hearing
loss at a younger age may mean
you have had excessive noise
exposure.
Audiometric testing done yearly
can detect early stages of hearing
loss.
Audiometric Testing
Audiometric testing results can be
used to check the following:
If the hearing protection in use
is adequate,
If there is a change in noise
exposure,
If there is a medical condition of
the ear unrelated to noise
exposure.
How Does Audiometric Testing
Work?
When you are first hired, a
baseline test is taken.
The testing is repeated
every year after that and
compared to the baseline
test result.
If a hearing loss is
detected, you will be
referred to a doctor or
audiologist.
Audiometric Testing
Audiometric testing produces
printed audiograms which show
hearing ability at several pitches or
frequencies.
These frequencies include those of
the human voice.
The second and following year
tests are compared to the first
year tests or baseline.
If there is hearing loss of 10 decibels or more in
the human voice frequencies, you will be sent to
the doctor or audiologist.
What is a Standard Threshold Shift?
A Standard Threshold Shift (STS) is an average
hearing loss of 10 decibels or more in the human
voice frequencies of 2000, 3000, and 4000 hertz.
Employees identified as having a STS are required
to obtain an additional audiometric test within 30
days.
The retest will verify if the shift is temporary or
permanent.
What is an Audiogram?
An audiogram is a printed chart of the results of the
hearing test. They look similar to the results below.
Noise Measurement Records &
Hearing Test Results
Employees have the right to see noise
measurement records and get copies of their
hearing test results.
Contact EHS for access to previous noise
measurement records and audiometric testing
results.
Obtain current audiometric test results during
annual audiometric testing.
UNC-CH EHS would like to acknowledge the
Washington State Department of Labor &
Industries for providing portions of the training
content.