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NOISE AND ACOUSTICS ~ Hierarchy of Controls. Noise + Acoustics. Ototoxic Chemical Exposures. Confirmed Ototoxics Ethyl Benzene Lead and Inorganic Compounds ( Pb ) Styrene Toluene Trichloroethylene Possible Carbon disulfide n-Hexane Xylene. Ototoxic Chemicals. - PowerPoint PPT Presentation
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NOISE AND ACOUSTICS ~ Hierarchy of ControlsNoise + Acoustics
Ototoxic Chemical ExposuresConfirmed Ototoxics
•Ethyl Benzene
•Lead and Inorganic Compounds (Pb)
•Styrene
•Toluene
•Trichloroethylene
Possible
•Carbon disulfide
•n-Hexane
•Xylene
NoiseOtotoxic
Chemicals
Hearing Loss
How We Hear
The Auditory System
Acoustical
Mechanical
Hydraulic
Chem/Elec
Hearing Protection Selection
Hearing Protection Devices (HPDs)
Single-Use / Multiple-Use / Detectable Earplugs Banded Earplugs Passive Earmuffs
Radio & Stereo Earmuffs Intelligent Hearing Protection
Sound Amplification Earmuffs
Hearing Protection Selection
PRO CON
• More natural sounds• Lower attenuation ideal for
moderate noise environments• Ideal for hearing-impaired workers
• Lower attenuation than most earplugs
• Slightly higher cost
Uniform / Flat Attenuation HPDs
Hearing Protection Selection
Uniform / Flat Attenuation HPDs
Variation in attenuation is only 5 dB in speech range (250 - 4kHz)
50
45
40
35
30
25
20
15
10
5
0
63
12
5
25
0
50
0
10
00
20
00
40
00
80
00
Frequency in Hz
Att
enu
atio
n in
dB
Uniform Attenuation Earplug
Conventional EarplugSpeech will sound more natural with this earplug.
Hearing Protection Selection
Intelligent Hearing Protection
PRO CON
• Communicate in high, changing noise
• Increased situational awareness• Can integrate active hearing
protection, ANR, fit testing, PSEM• Connect with radios• Compatible with other PPE
• Higher cost than passive HPD• Control unit as additional PPE to
wear• Appropriate for specific applications
or environments (eg. intrinsically safe)
Hearing Protection Selection
Choosing a protector with an NRR higher than necessary may result in overprotection
Hazards of 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
Acceptable Protection
Acceptable Protection
Optimal Protection
Possible Overprotection
85 dB
80 dB
75 dB
70 dB
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• 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
Comfort
• 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
Noise Reduction
• 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
Size
• 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
Communication
• 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
Job Requirements
• Proper care and maintenance can extend life and performance of HPDs
• Examine and clean all multiple-use earplugs daily
• Clean and replace ear cushions on earmuffs every 4-6 months
Hearing Protection Selection
Hearing Protection Selection Factors• Roll vs. No-Roll
earplugs
• Foam vs. multiple-use earplugs
• Clean and replace ear cushions on earmuffs every 4-6 months
• Clean and examine multi-use earplugs daily
Hygiene
• 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
Use w/ Other PPE
• Awareness of surroundings• Understand what is
happening around you• Communicate with co-
workers (face-to-face or 2-way radios)
• Increased personal safety, avoid other risks
• Avoid isolation from environment
Hearing Protection Selection
Hearing Protection Selection Factors
Connect w/ Environment
How much noise is reaching the ear of the worker ?
Noise Reduction Rating
Noise Level 100 dBA
NRR 25 dB
It’s completely UNKNOWN!
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
• 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 the NRR
NRR
Attenuation
Num
ber o
f tes
t sub
ject
s
1
2
3
4
5
14 1819
20 22 2423 25
28 30 322627
NRR
Noise Reduction Rating
Determining the NRR
De-Rating Methods (US/CAN)
Noise Reduction Rating
Class SystemA up to 100
B up to 95
C up to 90
Reduce NRREarmuffs NRR – 25%
Formable Earplugs NRR – 50%
All Other Earplugs NRR – 70%
Fit Test
NRR ÷ 2pending feasibility of engineering controls
Real-World Attenuation ≠ NRR
Noise Reduction Rating
192 Users of a Flanged Multiple-Use Earplug (NRR 27)
Att
enua
tion
in d
B 30
20
10
0
-10
40
50
Retraining and refitting resulted in an average +14
Real use
r
attenuatio
n
<0 to
38
dB
Three New LabelsLABEL 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
• 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
Determining New NRR
Noise Reduction Rating
New NRR (NRsa)
Attenuation
Num
ber o
f tes
t sub
ject
s
11 14 18
1
2
3
4
1920 22 24
23 25 2730 33
5
20% achieved > 26 dB
80% achieved > 20 dB
2826
Noise Reduction Rating
Noise Reduction Rating
How to Apply the New LabelTwo-number range displays the estimated protection achievable by minimally-trained users [80%] versus proficient users [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.
80% 20%
Noise Reduction Rating
NRR Change Resources
PDF and other articles available at www.hearforever.org
1.FIT 2. WEAR TIME
A worker who selects an earplug with an PAR of 30
effectively reduced his 8-hour PAR to just …
but then removes that HPD for just …
30 dB
5 min 10 min 30 min15 min
26 dB 24 dB 22 dB 18 dB
In noise exposures, small intervals of no protection quickly void large intervals of adequate protection.
Biggest Factors in Achieving PAR
Noise Reduction Rating
• For extreme noise environments
• To estimate the protected noise level, add about 5 dB to the higher NRR protector
+ DUAL PROTECTION=
EARPLUG EARMUFF
Dual Protection
Noise Reduction Rating
Earplug PAR 29 dB
Earmuff NRR 29 dB
Maximum Dual Protection
34 dB
What Can I Do Now?
Evaluate Noise Spectra
• Determine if spectral balance corrections will be necessary
One-on-One Training
• Research studies confirm that one-on-one training is superior to group training
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.
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
Noise Reduction Rating
Next Generation
of Hearing Conservation
Technology
Personal Sound Exposure Monitoring (PSEM)
New Measurement Technologies
Earplug Fit Testing
Next Generation of Hearing Conservation Technology
Earplug Fit TestingProvides 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 SystemsReal Ear at Above Threshold (REAAT)
Loudness Balance
Commercial Available System
Next Generation of Hearing Conservation Technology
Personal Measurement SystemsPersonal Sound Exposure Monitoring (PSEM)
Commercial Available Systems
Next Generation of Hearing Conservation Technology
Fit Testing as Best PracticeOSHA / 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.”
"I was amazed with the results after being shown the
proper way to use earplugs.
"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.”
"Recently had a threshold shift. Found better
earplugs."
"Feel like am protected now!"
"I had no idea I was not using my
earplugs correctly."
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
Next Generation of Hearing Conservation Technology
How much protection?
0 dB 0 dB>33 dB
EAR #1EAR #2
EAR #3
Hearing Protector Fitting
-10
12
5
25
0
50
0
10
00
20
00
31
50
40
00
63
00
80
00
Frequency in Hz
90
80
70
60
50
40
30
20
10
0
Att
enu
atio
n in
dB
Max Poor FitNRR = 0dB
Max Good FitNRR = 33dB
Good Fit vs Bad Fit
Hearing Protector Fitting
Hearing Protector Fitting
Roll-Down Foam Earplugs
2. Pull Back pinna by reaching over head with free hand, gently pull top of ear up and out
1. Roll entire earplug into a crease-free cylinder
3. Insert earplug well into ear canal and hold until it fully expands
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
Personalize Hearing Loss
Training + Motivation
Training Materialswww.hearforever.org
www.hearingconservation.org
www.grc.nasa.gov/www/acoustics
www.cdc.gov/niosh/topics/noise
www.dangerousdecibels.org
Demonstrate Future Risk
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 well-
stocked 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
Challenges in Industry
Bringing It Together
Hearing Protection Situational Awareness
vs
Hearing Protection Two-Way Communication
vs
Situational Awareness
Two-Way Communication
vs
Challenges in Industry
Bringing It Together
Too LITTLE Hearing Protection
Worker Isolation, Safety Risk to Self
and Others
Too MUCH Hearing Protection
Noise Exposure, Risk for Occ Hearing Loss
Challenges in Industry
Bringing It Together
Difficulties in managing two-way communications in extreme noise environments
Challenges in Industry
Bringing It Together
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
Challenges in Industry
Bringing It Together
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
Challenges in Industry
Bringing It Together
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
Challenges in Industry
Bringing It Together
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
Challenges in Industry
Bringing It Together
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
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
Case Study #1: Shaw Industries
Bringing It Together
Case Study #1: Shaw Industries
Bringing It Together
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
Case Study #1: Shaw Industries
Bringing It Together
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.
Case Study #1: Shaw Industries
Bringing It Together
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
Case Study #1: Shaw Industries
Bringing It Together
The Results: Distribution of PAR Shifted
Goal of > 25 dB of protection achieved by most workers
Case Study #1: Shaw Industries
Bringing It Together
The Results: Reduction in Recordables
Year Confirmed STS
Comment
2006 5 Prior to noise control2007 02008 02009 1 Non-production associate2010 0
Best practices at this plant have been adopted at other Shaw locations
Case Study #1: Shaw Industries
Bringing It Together
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
Case Study #1: Shaw Industries
Bringing It Together
The Results: Award Winner
Recognized for the demonstrated results in noise control and its use of fit testing to better train and protect workers
www.safeinsound.us
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
Case Study #2: Gulfstream Aerospace
Bringing It Together
Case Study #2: Gulfstream Aerospace
Bringing It Together
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
Case Study #2: Gulfstream Aerospace
Bringing It Together
Tactic #2: Earplug Fit Testing
Photo courtesy of Gulfstream Aerospace
Case Study #2: Gulfstream Aerospace
Bringing It Together
Earplug Fit Testing: Value-Added Time Investment
852
345
118 32 9
688
320
142
70160
200
400
600
800
1000
1200
1400
1600
Test 155%
Test 252%
Test 345%
Test 431%
Test 5+36%
Nu
mb
er o
f E
mp
loye
es
Did not meet 15 dB criterion
Met 15 dB criterion
Identified workers with poor fit and spent value-added time
Case Study #2: Gulfstream Aerospace
Bringing It Together
Earplug Fit Testing: Goal
0
10
20
30
40
50
60
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46
Nu
mb
er o
f E
mp
loye
es
Mean Personal Attenuation in dB
Personal Attenuationn = 688
Goal of > 15 dB protection now achieved by most workers
Light Blue – Initial Fitting
Dark Blue = Final Fitting
Case Study #2: Gulfstream Aerospace
Bringing It Together
The Results: OSHA Recordable Drop
Dramatic Drop in Recordable Hearing Loss Cases
Case Study #2: Gulfstream Aerospace
Bringing It Together
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