NOISE+AND
Noise
Acoustics
ACOUSTICS ~ Hierarchy of Controls
Ototoxic Chemical Exposures
Confirmed Ototoxics
• Ethyl Benzene
• Lead and Inorganic
Compounds (Pb)
Ototoxic
Chemicals
Noise
• Styrene
• Toluene
• Trichloroethylene
Possible
• Carbon disulfide
• n-Hexane
• Xylene
Hearing
Loss
How We Hear
The Auditory System
Chem/Elec
Acoustical
Hydraulic
Mechanical
Hearing Protection Selection
Hearing Protection Devices (HPDs)
Single-Use / Multiple-Use /
Detectable Earplugs
Banded Earplugs
Radio & Stereo Earmuffs
Sound Amplification
Earmuffs
Passive Earmuffs
Intelligent Hearing
Protection
Hearing Protection Selection
Uniform / Flat Attenuation HPDs
PRO
• More natural sounds
• Lower attenuation ideal for
moderate noise environments
• Ideal for hearing-impaired workers
CON
• Lower attenuation than most
earplugs
• Slightly higher cost
Hearing Protection Selection
Uniform / Flat Attenuation HPDs
Speech will
sound more
natural with this
earplug.
8000
4000
2000
1000
500
250
125
50
Attenuation in dB
Variation in
attenuation is
only 5 dB in
speech range
(250 - 4kHz)
63
Frequency in Hz
45
40
35
30
25
20
15
10
5
0
Uniform Attenuation Earplug
Conventional Earplug
Hearing Protection Selection
Intelligent Hearing Protection
PRO
• Communicate in high, changing
noise
• Increased situational awareness
• Can integrate active hearing
protection, ANR, fit testing, PSEM
• Connect with radios
• Compatible with other PPE
CON
• Higher cost than passive HPD
• Control unit as additional PPE to
wear
• Appropriate for specific applications
or environments (eg. intrinsically
safe)
Hearing Protection Selection
Hazards of Overprotection
Choosing a protector with an NRR higher than
necessary may result in overprotection
• Verbal communication may be
hindered
• Warning alarms may not be heard
• Machine noises may be too
diminished
• HPDs may be removed
Hearing Protection Selection
Hazards of Overprotection
Insufficient Protection
85 dB
Acceptable Protection
80 dB
Optimal Protection
75 dB
Acceptable Protection
70 dB
Possible Overprotection
Hearing Protection Selection
Hazards of Overprotection
In the United States, 76%
of noise-exposed workers
need no more than 10 dB
of protection. 90% need
no more than 15 dB of
protection.
Hearing Protection Selection
Hearing Protection Selection Factors
Comfort
• The right hearing
protector should feel
comfortable
• One protector may not
satisfy all workers
• Offer a variety of earplugs
or earmuffs to meet
varying worker needs and
preferences
Hearing Protection Selection
Hearing Protection Selection Factors
Noise Reduction
• Selecting HPDs with
suitable attenuation for
noise environment
• Avoid overprotection in
marginal noise
environments
• Consider banded earplugs
for intermittent noise or
electronic earmuffs for
impact noise.
Hearing Protection Selection
Hearing Protection Selection Factors
Size
• Every ear canal has its
own shape and size
• Ensure proper fit with
variety of earplug sizes
and shapes
• Sized multiple-use
earplugs
• Low-pressure foam
earplugs for smaller ear
canals
Hearing Protection Selection
Hearing Protection Selection Factors
Communication
• Keep workers connected
to their environment
• Uniform attenuation allows
speech/signals to be hear
more naturally
• Sound amplification
earmuffs for workers with
hearing impairment
Hearing Protection Selection
Hearing Protection Selection Factors
Job Requirements
• Consider job requirements
in HPD selection
• Detectable earplugs for
process industries
• Hi-visibility earmuffs for
dark/high traffic areas
• Dielectric HPDs for
electrical environments
Hearing Protection Selection
Hearing Protection Selection Factors
•• Proper
Roll vs.care
No-Roll
and
earplugs
maintenance can
lifemultiple-use
and
• extend
Foam vs.
performance
of HPDs
earplugs
Hygiene
•• Examine
cleanear
Clean andand
replace
all
multiple-use
cushions
on earmuffs
every
4-6 months
earplugs
daily
•• Clean
replace
Clean and
and examine
ear cushions
on
multi-use
earplugs
daily
earmuffs every 4-6
months
Hearing Protection Selection
Hearing Protection Selection Factors
Use w/ Other PPE
• Cap-mounted earmuffs for
hard hats
• Multiple-position earmuffs
for full-brim hard hats
• Ultraslim neckband
earmuffs with welding
shields
• Respirators preventing
communication
• Eyewear interfering w/seal
of earmuffs, attenuation
Hearing Protection Selection
Hearing Protection Selection Factors
• Awareness of surroundings
• Understand what is
happening around you
• Communicate with coworkers (face-to-face or 2way radios)
• Increased personal safety,
avoid other risks
• Avoid isolation from
environment
Connect w/ Environment
Noise Reduction Rating
How much noise is reaching the
ear of the worker ?
Noise Level
NRR
100 dBA
25 dB
It’s completely
UNKNOWN!
Noise Reduction Rating
Noise Reduction Rating
• A laboratory estimate of the
amount of attenuation
achievable by 98% of users
when properly fit
• A population-based rating ―
some users will get more
attenuation, some will get
less
The NRR is only a population estimate,
not a predictor of individual attenuation.
Noise Reduction Rating
Determining the NRR
• 10 human subjects tested in a
simulated industrial room
• Tested with ears open / occluded
at nine frequencies
• Each subject tested 3x
• NRR calculated to be population
average
A test subject in the Howard Leight Acoustical Lab,
San Diego, CA, accredited by the National Voluntary
Laboratory Accreditation Program (NVLAP)
Noise Reduction Rating
NRR
Determining the NRR
NRR
Number of test subjects
5
4
3
2
1
14
18
19
20
22
23
Attenuation
24
26
28
25 27
30
32
Noise Reduction Rating
De-Rating Methods (US/CAN)
NRR ÷ 2
Reduce NRR
Class System
pending feasibility of
engineering controls
Earmuffs NRR – 25%
Formable Earplugs
NRR – 50%
All Other Earplugs
NRR – 70%
A up to 100
Fit
Test
B up to 95
C up to 90
Noise Reduction Rating
Real-World Attenuation
≠ NRR
50
Attenuation in dB
40
30
20
10
Retraining and
refitting resulted
in an average
+14
0
-10
192 Users of a Flanged Multiple-Use Earplug (NRR 27)
Noise Reduction Rating
Three New Labels
LABEL
DESCRIPTION
Conventional
HPD
 Perform lab test with subjects who fit the protector
after brief training
 Estimates the range of protection achieved by
20% and 80% of users
Active Noise
Reduction
(ANR)
• Uses a Microphone-in-Real-Ear (MIRE) method to
estimate protection
• Measured with ANR turned OFF and ON to show
the additional attenuation from the ANR
Level Dependent/
Impulse Noise
Reduction
• Testing will occur over a range of impulse noise
levels. Multiple tests to determine lower and upper
ranges of impulse noise reduction
• Will include two ranges to identify attenuation for
passive and active modes
Noise Reduction Rating
Determining New NRR
• 20 human subjects tested in a
simulated industrial room
• Subject trained then fits their own
earplugs
• Tested with ears open / occluded
at 9 frequencies
• Each subject tested 2x
• NRR calculated to be population
average
Noise Reduction Rating
New NRR (NRsa)
20% achieved > 26 dB
Number of test subjects
5
80% achieved
> 20 dB
4
3
2
1
11
14
18
19
20
22
23
24
26
28
25 27
Attenuation
30
33
Noise Reduction Rating
How to Apply the New Label
Two-number range
displays the
estimated
protection
achievable by
minimally-trained
users [80%] versus
proficient users
[20%].
80%
20%
A wider range
indicates greater
variability in the fit
of that HPD.
Smaller ranges
indicate more
consistency of fit.
For example,
earmuffs will
usually have a
tighter fitting range
than earplugs, and
may have a
smaller NRR
range.
Noise Reduction Rating
NRR Change Resources
PDF and other articles available at
www.hearforever.org
Noise Reduction Rating
Biggest Factors in Achieving PAR
2. WEAR TIME
1.FIT
A worker who selects an earplug
with an PAR of 30
but then removes that
HPD for just …
effectively reduced his
8-hour PAR to just …
30
dB
5 min
10 min
15 min
30 min
26 dB
24 dB
22 dB
18 dB
In noise exposures, small intervals of no protection quickly
void large intervals of adequate protection.
Noise Reduction Rating
Dual Protection
EARPLUG
+
EARMUFF
• For extreme noise
environments
• To estimate the protected
noise level, add about 5 dB
to the higher NRR protector
=
DUAL
PROTECTION
Earplug PAR
Earmuff NRR
Maximum Dual
Protection
29 dB
29 dB
34 dB
Noise Reduction Rating
What Can I Do Now?
Although the new labeling regulation takes effect whenever
the final rule is published by the EPA, there are a number of
actions you can take now to prepare your Hearing
Conservation Program for the change.
Evaluate Noise Spectra
• Determine if spectral balance corrections
will be necessary
One-on-One Training
• Research studies confirm that one-onone training is superior to group training
Noise Reduction Rating
What Can I Do Now?
Evaluate HPD Selection
• Determine whether they are appropriate
for your noise environment.
• Use the Howard Leight Hearing Protector
Selector for recommendations.
Update Training Program
• Hold “Toolbox Training” with fit training
refresher
Noise Reduction Rating
What Can I Do Now?
Use Earplug Fit Testing
• Train how to properly fit HPDs
• Select appropriate HPDs
• Document adequate protection
Use In-Ear Dosimetry
• Measure, document noise dose
employee is exposed to during work
shift
Next
Generation
of Hearing
Conservation
Technology
Next Generation of Hearing Conservation Technology
New Measurement Technologies
Earplug Fit Testing
Personal Sound Exposure
Monitoring (PSEM)
Next Generation of Hearing Conservation Technology
Earplug Fit Testing
Provides an accurate, real-world picture of your
employees’ hearing protector effectiveness.
ID if your employees are
• Getting the right protection
• Need additional training
• Need different earplug
Problem Solver:
• Eliminate De-Rating Schemes
• Improve One-on-One Training
• Validate Hearing Protector Selection
• Adapt to Impending NRR Change
Next Generation of Hearing Conservation Technology
Fit Testing Systems
Real Ear at Above Threshold (REAAT)
Loudness Balance
Commercial Available System
Next Generation of Hearing Conservation Technology
Personal Measurement Systems
Personal Sound Exposure Monitoring (PSEM)
Commercial Available Systems
Next Generation of Hearing Conservation Technology
Fit Testing as Best Practice
OSHA / NIOSH / NHCA Alliance
Research studies have suggested that when
individuals are involved in the fitting process
and receive positive feedback on the proper
fit of their earplug, they will be more likely to
have a positive attitude about protecting their
hearing and will be more apt to use hearing
protection correctly and consistently in the
workplace. This positive outcome should
result in reducing noise-induced hearing loss
in the workplace.
Available for download at
www.hearingconservation.org
Next Generation of Hearing Conservation Technology
Fit Testing Comments from Workers
"I know how to better
fit my earplugs now.”
"Recently had a
threshold shift.
Found better
earplugs."
"I had no idea I was
not using my
earplugs correctly."
"Learned A LOT
about best earplugs
for me."
"I found a more
comfortable fit. It was
very beneficial."
"Very glad I did the
fitting test. Now I
know the correct way
to fit my ear plugs.”
"I was amazed with
the results after
being shown the
proper way to use
earplugs.
"Feel like am
protected now!"
Next Generation of Hearing Conservation Technology
PROs & CONs of Fit Testing
PRO
CON
Estimate / Measure
Cost
NRR Obsolete
Time Investment
Fulfills OSHA
Compliance
Not Standardized
Eliminate De-Ratings
Medico-Legal Cases
Work-Relatedness
No Dual Protection
Employee Feedback
Hearing Protector Fitting
0 dB
0 dB
>33 dB
EAR #1
EAR #2
EAR #3
How much protection?
Hearing Protector Fitting
Good Fit vs Bad Fit
90
Attenuation in dB
80
70
60
50
40
30
20
10
0
-10
Max Good Fit
NRR = 33dB
Max Poor Fit
NRR = 0dB
8000
6300
4000
3150
2000
1000
500
250
125
Frequency in Hz
Hearing Protector Fitting
Roll-Down Foam Earplugs
1. Roll
entire earplug
into a crease-free
cylinder
2. Pull Back
pinna by reaching over head
with free hand, gently pull top
of ear up and out
3. Insert
earplug
well into
ear canal
and hold
until it fully
expands
Training + Motivation
Personalize Hearing Loss
Show, Don’t Tell
• Provide copy of annual
audiogram to worker
• Use personal examples to
demonstrate consequences
of hearing loss
• Ask questions:
• What is your favorite sound?
• What sound would you miss
the most if you couldn’t hear?
• What sounds connect you to
people and your environment?
Training + Motivation
Demonstrate Future Risk
Training Materials
www.hearforever.org
www.hearingconservation.org
www.grc.nasa.gov/www/acoustics
www.cdc.gov/niosh/topics/noise
www.dangerousdecibels.org
www.hearforever.org/ AIH
Training + Motivation
www.hearforever.org
Training + Motivation
Send Clear Message On + Off Job
HC Part of Everyday Life
• Include recreational hearing
conservation in annual training
• Provide extra HPDs for home
use
• Promote Hearing Conservation
at company/family events
Training + Motivation
Remove Barriers to HPD Use
Make HPDs Available
• Highlight “where to find HPDs” in
annual training
• Make sure HPDs are wellstocked and accessible
• Include group of workers in
selection process for increased
acceptance
• Offer wide variety to match
comfort, job requirements
Training + Motivation
Checking Off the OSHA Amendment List
Health effects of noise
Purpose of hearing
protection
Advantages/
disadvantages of various



Selection, fit, use and
care of HPD
 Purpose and procedures
of audiometric testing

Training + Motivation
Professional Organizations
www.hearingconservation.org
Training + Motivation
Online Resources
www.youtube.com/hlhearforever
Bringing It Together
Challenges in Industry
Hearing
Protection
vs
Situational
Awareness
Hearing
Protection
vs
Two-Way
Communication
Situational
Awareness
vs
Two-Way
Communication
Bringing It Together
Challenges in Industry
Too LITTLE
Hearing
Protection
Noise Exposure,
Risk for Occ
Hearing Loss
Too MUCH
Hearing
Protection
Worker Isolation,
Safety Risk to
Self and Others
Bringing It Together
Challenges in Industry
Difficulties in managing two-way
communications in extreme noise environments
Bringing It Together
Challenges in Industry
High Noise Exposure
• Most provide attenuation
>25 dB (without de-ratings)
• Oil platforms > 110 dBA
• Mining > 105 dBA
Passive Protection
• Most designed for constant noise levels
• Do not adapt for changing noise levels
or types of noise (intermittent, impact)
• Communication without two-way radios
Photo: Øyvind Hagen / Statoil
Bringing It Together
Challenges in Industry
Difficult Speech Intelligibility
• Communication in high noise
levels requires concentration by
the user
• Often raise headset volume to
compensate for high ambient
noise
• Additional risk for NIHL
• Boom microphones may pick up
ambient sound when transmitting
speech
• Position critical for boom mics
• Outgoing communications may be
compromised
Bringing It Together
Challenges in Industry
Wear with Other PPE
• Hearing protectors with headsets or
boom mics not always compatible with
other PPE
Dual Protection Requirements
• Requirements for earplugs and
earmuffs in noise levels >100-105 dBA
• Properly fit earplug inhibits worker’s
ability to hear through a headset
• Workers do not like to wear both
Bringing It Together
Challenges in Industry
Improper Use = Unknown Attenuation?
• Workers wearing one cup on,
one cup off to hear surroundings
• At risk for binaural NIHL
Extreme Climates / Weather
• Earmuffs very uncomfortable to wear
in very hot and humid conditions
• Earmuffs preferred in colder climates
• Wear with hats and balaclavas may
compromise optimal attenuation
Bringing It Together
Challenges in Industry
Low Frequency Sounds
• Noise felt as vibration
• More intense in closed or
confined spaces
• Continued exposure can lead
to worker fatigue, annoyance
Mobile Workers
• Exposed to changing noise throughout work day
• May require different hearing protectors for each
environment or task
• Intelligent protection solutions
Photo: Helge Hansen / Statoil
Bringing It Together
Case Study #1: Shaw Industries
Noise Levels
105-112 dBA
HPD Requirements
Dual Protection
Key Challenges
•Reducing noise levels, especially in high
noise areas, via engineering controls
•Ensuring workers wearing hearing
protection properly, especially in extreme
heat/humidity
•Validate amount of attenuation each
worker achieves
Bringing It Together
Case Study #1: Shaw Industries
Tactic #1: Engineering Controls
Location
Pre-Enclosure dBA
Post-Enclosure dBA
Hood Insulation dBA
Total Reduction dB
F/16 #2
111.4
104.9
103.9
7.5
F/16 #6
110.8
102.7
101.8
9.0
F/16 #11
107.3
100.2
99.7
7.6
Packout Table
106.4
98.6
96.8
9.6
Bringing It Together
Case Study #1: Shaw Industries
Tactic #2: Earplug Fit Testing
Site Procedure
• All workers showing a shift (decrease)
in hearing now receive a fit-test as
part of “retraining.”
• All new (or re-hire) employees receive
a fit-test prior to beginning work to
• Departments prioritized and tested per
protocol
• Find the appropriate earplug
• Ensure they know how to fit it properly.
Bringing It Together
Case Study #1: Shaw Industries
The Results
The Data
• 17% achieved adequate
Personal Attenuation
Rating (PAR) on their first
test
• 78% were able to achieve
adequate protection at
their first training session
to bring their noise
exposure to 82 dB or
below
• 67% of workers changed
from their initial ear plug
selection, mostly due to
comfort of proper fit
Bringing It Together
Case Study #1: Shaw Industries
The Results: Distribution of PAR Shifted
Goal of > 25 dB of protection achieved by most workers
Bringing It Together
Case Study #1: Shaw Industries
The Results: Reduction in Recordables
Year
2006
2007
2008
2009
2010
Confirmed
STS
5
Comment
Prior to noise control
0
0
1
0
Non-production associate
Best practices at this plant have been adopted
at other Shaw locations
Bringing It Together
Case Study #1: Shaw Industries
The Results: Hearing Conservation Program Changes
HC Program Improvements
•Expanded HPD offerings from 3 to 6
choices
• Workers are “certified” to a particular
earplug
• Mandated job rotation in departments
• Emphasis on equipment maintenance
www.hearforever.org/shaw
Bringing It Together
Case Study #1: Shaw Industries
The Results: Award Winner
www.safeinsound.us
Recognized for the
demonstrated results in
noise control and its use
of fit testing to better
train and protect workers
Bringing It Together
Case Study #2: Gulfstream Aerospace
Noise Levels
87-90 dBA TWA
HPD Requirements
100% wear when on plant floor
(even walking through)
Key Challenges
•Intermittent noise exposures
•Moderately low TWAs
•Possible overprotection
Bringing It Together
Case Study #2: Gulfstream Aerospace
Tactic #1: Engineering Controls
Quieter Equipment
•Purchase new equipment that
does not exceed 82 dB during
normal operation
•Implement engineering controls
around test generator
www.buyquietroadmap.com
Bringing It Together
Case Study #2: Gulfstream Aerospace
Tactic #2: Earplug Fit Testing
Test Worker with Usual Earplug
“Fit the way you normally wear it.”
Pass > 15 dB
Next
Fit Training with
Same Earplug
Try a Different
Earplug
Photo courtesy of Gulfstream Aerospace
Bringing It Together
Case Study #2: Gulfstream Aerospace
Earplug Fit Testing: Value-Added Time Investment
1600
Number of Employees
1400
1200
Did not meet 15 dB criterion
688
Met 15 dB criterion
1000
800
600
320
400
852
200
345
0
Test 1
55%
Test 2
52%
142
118
70
32
16
9
Test 3
45%
Test 4
31%
Test 5+
36%
Identified workers with poor fit and spent value-added time
Bringing It Together
Case Study #2: Gulfstream Aerospace
Earplug Fit Testing: Goal
Personal Attenuation
n = 688
60
Light Blue – Initial Fitting
Dark Blue = Final Fitting
Number of Employees
50
40
30
20
10
0
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
Mean Personal Attenuation in dB
Goal of > 15 dB protection now achieved by most workers
Bringing It Together
Case Study #2: Gulfstream Aerospace
The Results: OSHA Recordable Drop
Dramatic Drop in Recordable Hearing Loss Cases
Bringing It Together
Case Study #2: Gulfstream Aerospace
The Results: Hearing Conservation Program Changes
HC Program Improvements
• Workers are “certified” to a specific earplug
• High worker engagement in safety solution
• Continued earplug fit testing in other business units
• Possible development of earplug fit testing stations
throughout facility
• Expanded hearing protector offering