Transcript Slide 1

Reducing
the Risk of Noise-Induced
Hearing Loss
Through Best Practices
Theresa Y. Schulz, PhD, LtCol, USAF (ret.)
Topics
Noise And Acoustics
Noise Reduction
Reducing Costs for Hearing Loss
Motivating Workers
Noise +
Acoustics
Noise + Acoustics
Non-Occupational
Occupational
Noise + Acoustics
Noise-induced hearing loss is the
most common permanent and
preventable occupational injury
in the world.
World Health Organization
Noise + Acoustics
Worker’s Compensation
In many countries, excessive noise is
the biggest compensable
occupational hazard. Cost of
NIHL to developed countries ranges
from 0.2 to 2% of its GDP. NIHL
is on the rise globally. (Source: WHO)
Noise + Acoustics
United States Statistics
Most common occupational injury
in the United States. 22 million US
workers are exposed to hazardous
noise at work on a daily basis.
Approx. 8 million Americans
suffer from NIHL. (Source: NIOSH, 2009)
NOISE+AND
Noise
Acoustics
ACOUSTICS
- Hierarchy
~ Hierarchy
of Controls
of Controls
ENGINEERING
CONTROLS
• Buy Quiet
• Vibration Pads
• Enclosures
ADMINISTRATIVE
CONTROLS
• Rotate Workers
• Barriers
• Extended
Breaks
• Isolation
•2nd/3rd Shift
PERSONAL
PROTECTIVE
EQUIPMENT
Noise + Acoustics - OSHA Update
OSHA Update: Feasibility
• Oct 2010 – Intent to change
interpretation of “feasibility”
• Must use engineering controls that are
capable of being done
• First extended comment period
then withdrew that interpretation
• Proposing public hearings and asking NIOSH
and professionals for input
Noise
Reduction
Rating
(NRR)
Noise Reduction Rating
Noise Level =
100 dB
Noise Reduction Rating =
30 dB
How much noise is
reaching the ear of
the worker ?
That is completely unknown …
(55 – 104 dB)
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 an 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 – Determining an NRR
NRR
NRR
Number of test subjects
5
4
3
2
1
14
18 20 22 24 26 28 30 32
19
23 25 27
Attenuation
Noise Reduction Rating
De-Rating Methods
OSHA
NIOSH
CSA
NRR ÷ 2
Earmuffs
NRR – 25%
Class
A up to 100
Formable Earplugs
NRR – 50%
B up to 95
(feasibility of
engineering
controls)
Fit
Test
All Other Earplugs
NRR – 70%
C up to 90
Noise Reduction Rating –
Attenuation in dB
Real-World Attenuation
≠ NRR
192 users of a flanged reusable earplug ~ 27 NRR
50
NRR = 27 Multiple-Use Earplug
40
30
20
10
0
-10
From Kevin Michael, PhD and Cindy Bloyer “Hearing Protector Attenuation Measurement on the End-User”
Retraining
and refitting
resulted in an
average
14 dB
improvement
for this group
Noise Reduction Rating
Biggest Factors in Achieving NRR
2. WEAR TIME
1.FIT
A worker who selects an earplug
with an NRR of 30
but then removes that
HPD for just …
effectively reduced his
8-hour NRR 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
Noise Reduction Rating
• The EPA recently made an announcement about
a proposed change to the Noise Reduction
Rating [NRR]
• This is the first change in hearing protector
regulation in nearly 30 years
Noise Reduction Rating
Current NRR Label
80th %
20th %
Minimallytrained
Proficient
Users
Mock-up of New Label
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
New NRR (NRsa)
80% achieved > 20 dB
20% achieved > 26 dB
Number of test subjects
5
4
3
2
1
11
14
18 20 22 24 26 28 30
19
23 25 27
Attenuation
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
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
to determine if spectral balance
corrections will be necessary
• Upgrade to One-on-one
Training
research studies confirm that oneon-one training is superior to group
training
Estimated Noise Level Reduction, dB
50
possible for a few motivated proficient
users to achieve or exceed
possible for most individually trained
users to achieve or exceed
45
40
35
30
25
20
15
10
5
NRSG
0
-2
0
2
4
6
8
10
12
Noise Spectral Balance, B = L C - L A (dB)
NRSG table
B = L C - L A -1
Protection x = 20% 36.7
Performance x = 80% 29.8
2
34.4
25.5
6
33.5
24.1
13
31.9
22.9
14
16
Noise Reduction Rating
What Can I Do Now?
• Evaluate Current HPD
Selection to determine
whether they are appropriate for
your noise environment. Use the
Howard Leight Hearing Protector
Selector for recommendations.
• Update Hearing
Conservation Training
Program
on proper fit of hearing
protectors. Hold a “Toolbox
Training” and hold a refresher fit
training session.
Noise Reduction Rating
What Can I Do Now?
Use VeriPRO® fit testing
• Train how to properly fit HPDs
• Select appropriate HPDs
• Document adequate protection
Use QuietDose™
• In-ear dosimetry measures and
documents the noise dose
employee is exposed to during
their work shift
Reducing Costs of
Hearing Loss
Reducing Costs of Hearing Loss
Workers Compensation Claims Data
2000-2010 22
0.1
Dermititis
12.4
Radiation
0.3
Occ Disease-Injury
10.5
Loss of Hearing
Contagious Disease
Cancer
10.2
AIDS
Mental Stress
0.4
0.3
26
17.9
Source: Texas Department of Insurance
Cumulative Injury
Other
Reducing Costs of Hearing Loss
Workers Compensation Claims Data
11.8
0.6
Dermititis
18.7
2010
Occ Disease-Injury
13.1
Loss of Hearing
11.6
Contagious Disease
Mental Stress
15.3
Cumulative Injury
28.8
Source: Texas Department of Insurance
Other
Reducing Costs of Hearing Loss
Fit Testing
In-Ear Dosimetry
Noise
Field Reduction
VerificationRating
– Fit-Testing
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
As a problem solver:
• Derating Schemes
• One-on-One
Training
• HPD Selection
• NRR Change
Field Verification – Fit-Testing
Real-Ear
Attenuation at
Threshold
(R.E.A.T.)
Field Verification – Fit-Testing
Loudness Balance
(Real-Ear Attenuation Above
Threshold)
Field Verification – Fit-Testing
Microphone
in Real-Ear
(M.I.R.E.)
Field Verification – Fit-Testing
In-Ear Dosimetry
Microphone
in Real-Ear
(M.I.R.E.)
Field Verification – Fit-Testing
Audiometric,
1,2
IntregaFit,*
MultiFit
1
FitCheck*
HPDWellFit
1
QuickFit
1
EARfit*
VeriPRO*
SafetyMeter*
REAT, One freq
REAT, One freq
MIRE
Loudness
Balance
Sound booth
Quiet Room
Anywhere
Anywhere
PAR
PAR
Derived PAR
PAR
Any earplug
Any earplug
Modified or
custom earplugs
Any earplug
COHC
2
Training
included
COHC
Training provided
Training
included
* Commercially
available
Reducing Costs of Hearing Loss
OSHA Alliance: Best Practice Bulletin
www.hearingconservation.org
Additional Information
www.hearforever.org
Reducing Costs of Hearing Loss
Variation from Published NRR
10
Published
NRR
0
-5
-10
-15
-20
Distribution of PARs
-25
12
-30
0
10
20
30
40
50
10 60
Workers
Workers
Difference in dB
5
70
80
90
100
8
6
4
2
0
-30
-25
-20
-15
-10
-5
0
5
10
Variation from Published NRR
15
20
25
30
Reducing Costs of Hearing Loss
Personal Factors
Gender
Age
Distribution of PARs
12
Years in Noise
Workers
10
Ear Canal Size
8
6
Familiarity
4
Model of Earplug
2
0
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
Program Factors
Variation from Published NRR
# Group Trainings
# Personal Trainings
REDUCING
Reducing
Costs
COSTS
of Hearing
/ CLAIMSLoss
Difference on 2nd / 3rd Test
10
Variation from NRR
5
Published
NRR
0
-5
-10
-15
-20
-25
-30
Subjects
Trying a second earplug often
improves attenuation
Reducing Costs of Hearing Loss
“How well can users predict their
attenuation after a short fit-testing
training session?"
Fitting Tips
Reducing
Costs of Hearing Loss
Ability to Predict Noise Reduction
100
Accuracy of estimate
(75% were within one category of actual PAR)
47%
90
80
70
60
28%
50
14%
40
30
20
10
0
Same Category
One off
Two off
Three off
Four off
Reducing
Field Verification
Costs of–Hearing
Fit-Testing
Loss
"I know how to
better fit my
earplugs now."
"I found a more
comfortable fit. It
was very
beneficial."
"Feel like am
protected now!"
"Learned A LOT
about best
earplugs for me"
"I had no idea I was
not using my
earplugs correctly."
"I was amazed
with the results
after being shown
the proper way to
use earplugs.
"Recently had
threshold shift"
"Found better
earplugs"
"Very glad I did
the fitting test.
Now I know the
correct way to fit
my ear plugs.”
In-ear dosimetry measures/records
worker’s actual noise dose, with and
without protection
Provides real-time monitoring and
alerts when worker
approaches/exceeds safe limits
Only metric with direct potential to
measure and prevent further
progression of occupational hearing
loss
Reducing Costs of Hearing Loss
Research
> Alcoa
Reducing Costs
ofIntalco
HearingWorks
Loss
Mean Hearing Threshold (2k, 3k, 4kHz): 2000 – 2007 (N = 46)
Mean hearing threshold (2,3, and 4 kHz)
Employees using
continuous
in-ear
starting in 2005
Employees
using continuous ESP
starting indosimetry
2005
2000 - 2007 (N=46)
50
ESPIntroduced
45
trend line
Mean HTL 3,4,6kHz
40
35
30
25
20
15
10
5
0
2000
2001
2002
2003
2004
Year of test
2005
2006
2007
Reducing Costs of Hearing Loss
Preventive Action after NIHL
In practice, an OSHA-recordable STS is not a preventive action ….
It is documentation of a hearing loss after the fact.
How soon will an employee suffering NIHL be re-fit / re-trained ?
“Best case scenario” per Hearing Conservation Amendment
In-ear dosimetry “worst case” scenario …
1 Day
0
2
• Retest
• Audiometric test
4
6
8
10
Months
12
14
• Notification
16
Training +
Motivation
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
• http://adl.grc.nasa.gov
• www.cdc.gov/niosh/topics/noise
• www.dangerousdecibels.org
www.hearforever.org/
TXA&M
Training + Motivation
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
Make Hearing
Conservation Part of
Your Everyday Life
Download today’s
presentation at
www.hearforever.org/TXAM