1. Hearing Conservation Theresa Y. Schulz, PhD. Lt. Col. USAF (ret.)

2. Reducing Costs for Hearing Loss Motivating Workers
Agenda
Noise & Acoustics
Noise Reduction
Reducing Costs for Hearing Loss
Motivating Workers

3. Noise-Induced Hearing Loss
Noise + Acoustics
Noise-Induced Hearing Loss
Causes no pain
Causes no visible trauma
Leaves no visible scars
Is unnoticeable in its earliest stages
Accumulates with each overexposure
Takes years to notice a change
Noise damage is different from most other occupational injuries. It causes no pain or visible trauma (the ears do not bleed when hearing is being damaged), it leaves no visible scars, it is unnoticeable in its earliest stages (workers with noise-induced hearing loss often do not even notice themselves that they are losing hearing until it is too late), it accumulates with each over-exposure, and it generally takes years to diagnose. (<Space> to add bottom line message) But Noise-Induced Hearing Loss (NIHL) is permanent and 100% preventable.
Is Permanent + 100% Preventable

4. Noise + Acoustics
Noise-induced hearing loss is the most common permanent and preventable occupational injury in the world.
The extent of the problem is shown in this statistic: The World Health Organization reported a few years ago that noise-induced hearing loss is the most common permanent and preventable occupational injury in the world.
World Health Organization

5. Worker’s Compensation
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)
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)

6. United States Statistics
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)
Most common occupational injury in the United States. 30 million US workers are exposed to hazardous noise at work on a daily basis. Approx. 10 million Americans suffer from NIHL. (Source: NIOSH)

7. Noise + Acoustics Non-Occupational Occupational
Typical noise levels on-the-job and off-the-job … a lawnmower at 94 dB, heavy equipment at 100 dB a rock concert at 120 dB. Unprotected exposures at these levels can cause damage. According to OSHA regulations, no exposures of any duration are allowed over 115 dB.

8. Noise Measurement Devices
Noise + Acoustics
Noise Measurement Devices
There are two commonly used methods of monitoring noise levels – area sampling (with a sound level meter) or personal sampling (with a noise dosimeter, also called a sound exposure meter). The sound level meter tells us the instantaneous noise level in a specific area, and is accurate only when noise levels are fairly constant in the area. For mobile workers or fluctuating noise exposures, the noise dosimeter gives a more accurate measure of the unprotected exposure. Using this method, the dosimeter is placed on the belt or pocket of the worker to be monitored, and the microphone is clipped on the collar near the ear. The meter remains on the worker for a certain sampling period – several hours, or even the entire workday – and continuously monitors the incoming noise. At the end of the sampling period, a readout shows the average noise level (or equivalent noise level, Leq) for that entire sampling period. Both of these methods measure the unprotected exposure and then an estimate must be made for the protected exposure.
The newest method to measure exposure is to directly measure the individual’s protected exposure with “in-ear dosimetry.”
Integrated into earplugs or earmuffs, QuietDose’s in-ear dosimetry measures and records the worker's actual noise dose, with and without protection, over their entire work shift. QuietDose provides real-time monitoring throughout the workday, and alerts the worker when noise dose approaches or exceeds safe limits.
When deployed, QuietDose provides the only metric with a direct potential to measure and prevent noise-induced hearing loss from on-the-job exposures, empowering both worker and safety manager to make intelligent decisions about Hearing Conservation.
SOUND LEVEL METER
Sound is measured immediately in a specific area
PERSONAL DOSIMETER
Sound “averaged” throughout day for sample employee/job
IN-EAR DOSIMETER
Collects personal noise dose – the only real measure of risk

9. NOISE AND ACOUSTICS ~ Hierarchy of Controls
Noise + Acoustics
Hierarchy of Controls
ENGINEERING CONTROLS
Buy Quiet
Vibration Pads
Enclosures
Barriers
Isolation
ADMINISTRATIVE CONTROLS
Rotate Workers
Extended Breaks
2nd/3rd Shift
PERSONAL PROTECTIVE EQUIPMENT
For hazardous noise exposures, the hierarchy of controls should be …
1) Engineering Controls
2) Administrative Controls
3) Hearing Protection

10. Synergistic Ototoxics
NOISE AND ACOUSTICS ~ Hierarchy of Controls
Noise + Acoustics
Ototoxic Chemicals
Ototoxic by themselves
Synergistic effect with noise
Large differences in sensitivity
Recommend: increased frequency of audiometric testing
Confirmed Ototoxics
Ethyl Benzene
Lead and inorganic compounds (as Pb)
Styrene
Toluene
Trichloroethylene
Possible Carbon disulfide
n-Hexane
Xylene
Synergistic Ototoxics
Carbon Monoxide
Hydrogen Cyanide
NOISE
Over the decades, a number of chemical exposures have been indentified that also impair hearing. In some cases, the chemical exposure alone can cause hearing loss; in other cases, there is a synergistic effect between noise and chemicals increasing a worker’s sensitivity to noise damage.

11. Noise Reduction Rating (NRR)

12. Noise Reduction Rating
Noise Level = 100 dB
Noise Reduction Rating = dB
How much noise is reaching the ear of the worker ?
Confusion about the proper application of a hearing protector’s rated attenuation has led to many to assume that most workers obtain protection at a level that equals noise minus NRR. But the amount of noise reaching the eardrum of a particular worker is completely unknown.
That is completely unknown …
(55 – 104 dB)

13. 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 Noise Reduction Rating is a laboratory estimate of the amount of attenuation achievable by 98% of users when properly fit. It is 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.

14. Noise Reduction Rating
NVLAP-Accredited Labs
San Diego, CA
Indianapolis, IN
State College, PA
There are currently three acoustic laboratories accredited by the National Voluntary Laboratory Accreditation Program (NVLAP) for testing hearing protectors against the EPA-required standard (ANSI S ).

15. Noise Reduction Rating – Determining an NRR
10 human subjects tested in a reverberant room
Tested with ears open/occluded at nine frequencies
Each subject tested 3x
NRR calculated to be population average
Hearing protectors are tested in a laboratory sound room which is intended to simulate a typical noisy setting in industry. Subjects are tested with ears open (no hearing protectors) and occluded (with hearing protectors), and the difference between those measurements is the noise reduction of the HPD. The attenuation measurements for all subjects are then input into a formula (the measurements are logarithmically added, two standard deviations are subtracted to account for variability, and 3 dB is subtracted to account for the different noise spectrums in industry). The result is the Noise Reduction Rating (NRR).
A test subject in the Howard Leight Acoustical Lab, San Diego, CA, accredited by the National Voluntary Laboratory Accreditation Program (NVLAP)

16. Noise Reduction Rating –
Real-World Attenuation ≠ NRR
Real user attenuation <0 to 38 dB
192 users of a flanged reusable earplug ~ 27 NRR 50
NRR = 27 Multiple-Use Earplug 40 30
Retraining and refitting resulted in an average
14 dB improvement for this group
Attenuation in dB 20
There is quite a bit of variability in the attenuation obtained by users in the real world. This may be due to intentional factors (not inserting the HPD far enough in order to make it less intrusive, or more comfortable) or unintentional factors (improper sizing of HPD, poor seal around earmuffs, etc.). This scattergram shows the results of one study, indicating a wide variety of real-world attenuations for 192 workers wearing an earplug with a laboratory NRR of 27 dB. (<Space> to show retraining benefit.) Researchers in this study then took the workers with the lowest attenuation, and refit/retrained them in using the HPD properly. This resulted in an average 14 dB improvement in measured attenuation. The moral of the story? The effectiveness of an HPD relies heavily upon proper training and fitting by the wearer. 10
-10
From Kevin Michael, PhD and Cindy Bloyer “Hearing Protector Attenuation Measurement on the End-User”

17. Noise Reduction Rating
De-Rating Methods
OSHA
NRR ÷ 2
(feasibility of engineering controls)
NIOSH
Earmuffs
NRR – 25%
Formable Earplugs
NRR – 50%
All Other Earplugs
NRR – 70%
CSA
Class
A up to 100
B up to 95
C up to 90
Fit Test
The mistrust of NRRs has led to the promulgation of several de-rating schemes. But once again, none of these does anything to predict the individual protection to be expected from a particular user.

18. 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
At the beginning of August 2009, 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

19. 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
This slide covers the three new proposed labels, and the different types of HPDs will be tested.

20. Noise Reduction Rating
80th %
Minimally-trained
20th %
Proficient Users
The EPA has announced its intention to modify the EPA label, changing the single number rating to a two-number range. The low point on that range would represent the 80th percentile (the level that most minimally-trained users could achieve), and the high point of that range would represent the 20th percentile of protected workers (the level the some proficient users could achieve).
Current NRR Label Mock-up of New Label

21. Noise Reduction Rating
Rating methods are based upon idealized laboratory testing
NRR has been criticized for being too generous in its prediction of noise reduction [attenuation]
Studies indicate that while some workers in real-world worksites achieve the NRR on the package or even greater protection, many workers do not
This has led to a variety of inappropriate de-rating methods for hearing protectors
Contributed too much confusion in knowing how to accurately estimate a HPD’s attenuation
As background, attenuation rating methods are based upon idealized laboratory testing. NRR has been criticized for being too generous in its prediction of noise reduction [attenuation]. Studies indicate that while some workers in real-world worksites achieve the NRR on the package or even greater protection, many workers do not. This has led to a variety of inappropriate de-rating methods for hearing protectors. Contributed too much confusion in knowing how to accurately estimate a HPD’s attenuation.

22. Noise Reduction Rating
The New System: A Range
Represents a range of expected protection
Uses a new ANSI-standard lab testing to generate the attenuation ratings
New NRR will provide an indication of how much attenuation minimally-trained users [the lower number] versus highly-motivated trained users [the higher number] can be expected to achieve
For some hearing protectors, the spread of this range may be quite significant
The EPA has proposed changing the Noise Reduction Rating [NRR] from a fixed number to a range of attenuation. Represents a range of expected protection. This new NRR uses a new ANSI-standard lab testing to generate the attenuation ratings. The new NRR will provide an indication of how much attenuation minimally-trained users [the lower number] versus highly-motivated trained users [the higher number] can be expected to achieve. For some hearing protectors, the spread of this range may be quite significant.

23. Noise Reduction Rating
Current vs. Proposed NRR
Current NRR
Proposed NRR
Rating
A single-number estimate of protection
A high/low range of estimated protection
Description of Rating
Estimates the 98th percentile of protection obtained by users when properly fitted
Estimates the 80th and 20th percentile of protection obtained by users
Test Protocol
ANSI S [Experimenter Fit]
10 subjects for earplugs and earmuffs, HPDs fit by experimenter
ANSI S Method A [Supervised Subject-Fit]
20 subjects [for earplugs] or 10 subjects [for earmuffs], HPDs fit by subject after brief training
This slide demonstrates the differences between the current and proposed NRR.

24. Noise Reduction Rating
Current vs. Proposed NRR
Current NRR
Proposed NRR
Application
Intended for use with dBC noise measurements Requires a 7 dB correction for use with dBA noise measurements.
Can be applied directly to dBA noise measurements
De-Rating
Various de-rating schemes promulgated by various organizations [including OSHA]
Designed to be used with no required de-rating
Retesting
Currently, no retesting of HPDs required
Periodic retesting of HPDs required every 5 years

25. Noise Reduction Rating
NRR Labels
The proposed EPA regulation addresses for the first time the rating of non-standard hearing protectors, such as Active Noise Reduction [ANR] or level-dependent [or impact noise] protectors
Under the old labeling requirements, these specialized protectors were rated with a low NRR, simply because they were not tested in the higher noise ranges where their noise reduction capability is activated
EPA has included these types of hearing protectors in its new labeling regulation so that purchasers can make informed choices
The proposed EPA regulation addresses for the first time the rating of non-standard hearing protectors, such as Active Noise Reduction [ANR] – such as noise cancellation headsets used during travel - or level-dependent [or impact noise] protectors – such as Impact Sport-styled earmuffs. Under the old labeling requirements, these specialized protectors were rated with a low NRR, simply because they were not tested in the higher noise ranges where their noise reduction capability is activated. EPA has included these types of hearing protectors in its new labeling regulation so that purchasers can make informed choices.

26. 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%].
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%
The new label will display a range of attenuation for each HPD.
Two-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.

27. Noise Reduction Rating
Factors in Achieving the NRR
1.FIT
2. WEAR TIME
30 dB
A worker who selects an earplug with an NRR of 30
5 min
10 min
15 min
30 min
but then removes that HPD for just …
effectively reduced his 8-hour NRR to just …
Regardless of which HPD is selected, there are two factors that determine whether an employee in the real-world will achieve the laboratory NRR: Fit, and Wear Time. This slide addresses wear time (fit will be discussed a bit later). This slide shows examples of a user who removes his HPD for just 5 minutes (cumulative) in an 8-hour workday. In noise exposures, small intervals of no protection quickly void large intervals of adequate protection. [<space> to show the effect of removing HPD for 10/15/30 minutes per workday] If a worker selects an earplugwith 30 dB of rated protection, but then removes that earplug for just 30 minutes cumulative in his 8-hour workday, it is as though he is only wearing a protector rated with an NRR of 18 dB.
26 dB
24 dB
22 dB
18 dB
In noise exposures, small intervals of no protection quickly void large intervals of adequate protection.

28. 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
Update HC Training Program on proper fit of hearing protectors. Hold a “Toolbox Training” and hold a refresher fit training session.
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.
1. Re-evaluate Current HPD Selection – to determine whether they are appropriate for your noise environment. Use the Howard Leight Hearing Protector Selector – - for recommendations.
2. Provide Better Training – on proper fit of hearing protectors. Hold a “Toolbox Training” and hold a refresher fit training session.

29. 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.
Upgrade to 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.
1. Re-evaluate Current HPD Selection – to determine whether they are appropriate for your noise environment. Use the Howard Leight Hearing Protector Selector – - for recommendations.
2. Provide Better Training – on proper fit of hearing protectors. Hold a “Toolbox Training” and hold a refresher fit training session.

30. Noise Reduction Rating
Earplug Fit Testing
Provides an accurate, real-world picture of your employees’ hearing protector effectiveness.
Identify if your employees are:
Receiving optimal protection
Require additional training
Need to try a different earplug style
Use VeriPRO fit testing to train how to properly fit HPDs, select appropriate HPDs and document adequate protection.
Use QuietDose in-ear dosimetery to document the noise dose employee is exposed to during their work shift.

31. Noise Reduction Rating
Earplug Fit Testing
As a problem solver:
Derating Schemes
One-on-One Training
HPD Selection
NRR Change
Use VeriPRO fit testing to train how to properly fit HPDs, select appropriate HPDs and document adequate protection.
Use QuietDose in-ear dosimetery to document the noise dose employee is exposed to during their work shift.

32. Noise Reduction Rating
In-Ear Dosimetry
As a Problem Solver
Continuously monitors in noise level at the workers ear
The only true measure of the hazard!
Use VeriPRO fit testing to train how to properly fit HPDs, select appropriate HPDs and document adequate protection.
Use QuietDose in-ear dosimetery to document the noise dose employee is exposed to during their work shift.

33. Reducing Costs + Claims

34. Reducing Costs + Claims
“Attenuation provided by hearing protectors to individuals in actual workplace is impossible to predict using any laboratory measurements.”
This quote from one acoustic lab manager highlights the difficulty we face in using population averages for ratings: there is simply no laboratory measurement that can accurately predict the actual protection being received by real workers in the workplace.
~ Dr. Kevin Michael

35. *Source: AIHA Noise Manual
Reducing Costs + Claims
Sample HL Compensation*
Jurisdiction
One Ear
(Max)
Both Ears (Max)
Comments
D.C.
$34.8K (39 wks)
$134.2K (50 wks)
Rhode Island
$1, (17 wks)
$9, (100 wks)
Trauma/injury only
New York
$24 K (125 wks)
$60K (250 wks)
Exp. for 90 days
DOL -LSA
52 wks
200 wks
*Source: AIHA Noise Manual

36. Indicators for Hearing Loss:
Reducing Costs + Claims
Indicators for Hearing Loss:
Standard Threshold Shift
Temporary Threshold Shift
Recordable Hearing Loss
Dosimetry
Labeled NRR (derated?)
In-ear Dosimetry
Personal Attenuation Level (PAR)

37. Lagging Indicators vs. Leading Indicators
Reducing Costs + Claims
Lagging Indicators vs. Leading Indicators

38. Indicators for Hearing Loss:
Reducing Costs + Claims
Indicators for Hearing Loss:
Standard Threshold Shift
Temporary Threshold Shift
Recordable Hearing Loss
Dosimetry
Labeled NRR (derated?)
In-ear Dosimetry
Personal Attenuation Level (PAR)

39. Fit Testing In-Ear Dosimetry
Reducing Costs + Claims
Fit Testing
In-Ear Dosimetry
There are now two methods that allow users to measure the fit and exposure protection in the workplace”
Fit Testing (using a system like VeriPRO)
In-ear Dosimetry (using a system like QuietDose)

40. 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
In-ear dosimetry records and monitors a worker’s actual noise dose, both with or without hearing protection.

41. In-ear dosimetry as a Problem Solver
Reducing Costs + Claims
In-ear dosimetry as a Problem Solver
Employees with Documented Noise-Induced Hearing Loss or Standard Threshold Shift [STS]
Employees At-Risk for NIHL
Employee Training + Sampling
Dual-Protection/Extreme Noise Exposure
Engineering Controls
There are several instances where QuietDose can improve a Hearing Conservation Program. It can be used with:
Employees with Documented Noise-Induced Hearing Loss or Standard Threshold Shift [STS]
Employees At-Risk for NIHL
Employee Training + Sampling
Dual-Protection/Extreme Noise Exposure
Engineering Controls

42. Reducing Costs + Claims
The typical sequence of measurements from in-ear dosimetry on an individual worker may look something like this. Initially, measured noise doses are quite high (over 100%). As the worker receives feedback about the overexposures, the daily noise doses work their way downward, until nearly all noise doses are below 50%.

43. Research > Alcoa Intalco Works
Reducing Costs + Claims
Research > Alcoa Intalco Works
Mean Hearing Threshold (2k, 3k, 4kHz): – 2007 (N = 46)
Employees using continuous in-ear dosimetry starting in 2005
Case Study: ALCOA Intalco (presented by Dr. Kevin Michael et.al. at AIHA 2007, used with permission)

44. Preventive Action After NIHL
Reducing Costs + Claims
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
Months
• Audiometric test • Retest • Notification
By itself, OSHA’s Standard Threshold Shift is not a preventive measure. It documents hearing loss after the fact, and simply resets the clock for retesting without verifying whether preventive measures were successful. The annual audiogram is a “lagging indicator” of whether a Hearing Conservation Program is successful. In-ear dosimetry, however, gives users immediate feebback, allowing them to immediately adjust their protection level until they reach sufficient levels. In-ear dosimetry thus becomes a “leading indicator.”

45. Earplug fit-testing as a Problem Solver
Reducing Costs + Claims
Earplug fit-testing as a Problem Solver
Training tool for noise-exposed workers
Train-the-trainer tool
Follow-up on significant threshold shifts in hearing
Documentation of HPD adequacy
Assessment of overall HCP effectiveness
Match HPD to worker’s specific noise level
Selection of appropriate HPDs for new hires
Benefits per Best Practices Bulletin (OSHA Alliance)
There are several instances where QuietDose can improve a Hearing Conservation Program. It can be used with:
Employees with Documented Noise-Induced Hearing Loss or Standard Threshold Shift [STS]
Employees At-Risk for NIHL
Employee Training + Sampling
Dual-Protection/Extreme Noise Exposure
Engineering Controls

46. www.hearingconservation.org www.howardleight.com
Reducing Costs + Claims
OSHA Alliance: Best Practice Bulletin
Additional Information
What does OSHA feel about fit testing systems for hearing protection? In an OSHA Alliance Best Practices Bulletin (see link), seven benefits of fit-testing systems are offered, and the concept is endorsed as a best practice for Hearing Conservation Programs.

47. Attenuation at Threshold (R.E.A.T.) Loudness Balance
Field Verification – Fit Testing
Real-Ear
Attenuation at Threshold
(R.E.A.T.)
Loudness Balance
(Real-Ear Attenuation Above Threshold)
At the 2006 NHCA conference, we hosted a workshop to review the four common methods of measuring attenuation of an earplug in the field. These methods are as follows:
- Real Ear Attenuation at Thresholds (REAT), as used in FitCheck by Dr. Kevin Michael
- Real-Ear Attenuation Above Threshold (REA-AT), as used in VeriPRO
- F-MIRE, as used by Sonomax / AEARO
- In-Ear Dosimetry, as used in DoseBuster by Dr. Kevin Michael
Microphone in Real-Ear
(M.I.R.E.)
In-Ear Dosimetry

48. Selected modified earplugs Special training required
Field Verification – Earplug Fit Testing Methods
Audiometric
FitCheck
EARfit
VeriPRO
REAT
MIRE
REAAT
Sound booth
Very Quiet Room
Quiet Room
Anywhere
PAR
Derived PAR
Any earplug
Selected modified earplugs
Special training required
Anyone can perform

49. Reducing Costs + Claims
Published NRR
Taken from a study of 101 workers at eight different companies, this scattergram shows how far away each worker was from the published NRR of the respective earplug they were using. About 1/3 of the workers had measured attenuation that were higher than the published NRR. About 1/3 were within the range about 5 dB below the published NRR. And about 1/3 of the workers had attenuation that was more than 5 dB below the published NRR. The bottom left photo shows the variety of earplugs that were tested in this study.
This scattergram shows the danger in using de-rating policies like the oft-misapplied 50% de-rating by OSHA. If we were to summarily just assume that all earplugs only achieve 50% of the published NRR in the field, then clearly 2/3 of the workers are seriously overprotected, since they are achieving much higher protection than 50%.

50. Personal Factors Program Factors Reducing Costs + Claims Gender Age
Years in Noise
Ear Canal Size
Familiarity
Model of Earplug
Program Factors
# Group Trainings
# Personal Trainings
What is the best predictor of a worker achieving good attenuation from an earplug? We looked at the following personal and program factors, and concluded there was only one strong factor that correlated with good protection: that factor was individual training. Workers who receive individual training in how to use their hearing protectors are more likely to achieve a high personal attenuation. All other factors just followed a random distribution.

51. REDUCING COSTS / CLAIMS
Published NRR
A second important factor in achieving good attenuation in the field is the option of trying a second hearing protector. If a worker obtains low attenuation with one type of earplug, will he obtain low attenuation with all types of earplugs? Our study showed the answer is definitely NO. Workers who tried a second pair of earplugs often had major leaps in attenuation, bringing them closer to the published attenuation.
Trying a second earplug often improves attenuation

52. Tools for HCP Prevention Metrics
Reducing Costs + Claims
Tools for HCP Prevention Metrics
PROS
Estimate Measure
NRR obsolete
Fulfills OSHA compliance
Eliminates need for de-ratings
Medico-legal cases
Delineates non-occupational
Eliminates double protection
Provides employee feedback
(HPD Inventory control)
CONS
Cost
Time Investment
Not standardized
The advantages and disadvantages of fit verification methods are described.

53. Off-job + On-job = STS Off-job + On-job = STS Reducing Costs + Claims
Verification of attenuation of hearing protectors on the job also gives safety managers a much-needed point of differentiation in determining causality of hearing loss. If a worker with NIHL is unprotected from hazardous noise exposures off the job, fit verification helps distinguish the On-Job versus On-Job components of that hearing loss.
Off-job + On-job = STS
Off-job + On-job = STS

54. 0 dB 0 dB 33 dB How much protection? EAR #1 EAR #2 EAR #3
Just having an earplug in the ear is no guarantee of protection. In the photos shown here, a safety supervisor inspecting worker compliance may assume that the middle ear is protected. Actually, that worker is receiving 0 dB of protection, due to a poor fit.
EAR #3
How much protection?

55. Good Fit vs Bad Fit Frequency in Hz Attenuation in dB Max Poor Fit
-10
125
250
500
1000
2000
3150
4000
6300
8000
Frequency in Hz 90 80 70 60 50 40 30 20 10
Attenuation in dB
Max Poor Fit
NRR = 0dB
Max Good Fit
NRR = 33dB
<space> to show two fittings of the same earplug in the same worker’s ear on the same day. In both cases, the earplug was visibly in the ear far enough to satisfy a cursory compliance check. But the difference – a good insertion versus a poor insertion – is enough to cause a 30+ dB improvement in attenuation when the earplug is deeply inserted and achieves a good seal in the ear. The worker may be lulled into a false sense of protection when, even with a poor fit, he detects a slight muffling of high-frequency sounds – some of the “edge” is taken off shrill noise. But because the poor fit has seriously compromised low-frequency attenuation, the effective overall protection is 0 dB!

56. Training + Motivation

57. Personalize Hearing Loss
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?
We can motivate employees to wear their hearing protection if we can prove to them that they are not invincible nor invulnerable to noise-induced hearing loss. This can be accomplished by giving workers a copy of their audiometric test, or by clearly showing workers the noise hazardous noise levels at their worksite.
Getting workers to think about what their hearing means to them can help to personalize their motivation to prevent noise-induced hearing loss.

58. Demonstrate Future Risk
Training + Motivation
Demonstrate Future Risk
Training Materials
atl.grc.nasa.gov/HearingConservation/Resources/index.html
It is human nature to weigh our risks in terms of “here and now.” But with noise-induced hearing loss, we must show the worker the future risk. This can be accomplished by means of audio demonstrations, or simulated hearing losses, so that the worker has a clear understanding of his future risk, and the need for adequate protection today. The links listed on this slide offer great training and educational resources, including audio demonstrations, that can be used in your HC training program.

59. Send Clear Message On + Off Job
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
Many employers encourage their workers to use the company-provided hearing protectors off-the-job. After all, any noise-induced hearing loss (whether on- or off-the-job) will cause hearing loss which will be detected in the company-sponsored audiometric testing program. Proper use of hearing protectors both on and off the job will prevent noise-induced hearing loss.
Emphasize that Hearing Conservation should be a part of everyday life, at both work and home.
Include recreational HC training in your annual training. Many employers encourage their workers to use the company-provided hearing protectors off-the-job. After all, any noise-induced hearing loss (whether on- or off-the-job) will cause hearing loss which will be detected in the company-sponsored audiometric testing program. Proper use of hearing protectors both on and off the job will prevent noise-induced hearing loss.

60. Remove Barriers to HPD Use
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
Compliance in wearing hearing protection will be greatest when we remove the barriers or excuses that employees may raise as objections. Is an adequate supply of hearing protectors available? Is there a reasonable selection of comfortable protectors for workers? Does the amount of attenuation match the noise level?
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

61. Hearing Loss Due To Noise Exposure Is … Painless Permanent Progressive
Training + Motivation
Hearing Loss Due To
Noise Exposure Is …
Painless
Permanent
Progressive
… and very Preventable!