1. VeriPRO® Ear Plug Fit Testing August 2010

2. 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?

3. Hearing Protector Effectiveness
Frequency in Hz
125
250
500
1000
2000
3150
4000
6300
8000 90 80
Max Good Fit
NRR = 33dB
Max Poor Fit
NRR = 0dB 70 60 50
Attenuation in dB 40 30 20
With the well-fit foam earplug, attenuation is high in essentially all frequencies. With the poorly fit plug the leak that we saw on the previous slide is letting low frequency noise in so that the overall attenuation is compromised. Note that there is some attenuation (noise reduction) in the mid to high frequencies. Unfortunately, this poor fit my fool any compliance audit, because it looks like the ear plug is in the ear AND the worker may feel like the earplug is working because it decreases the harsh high frequencies. But noise-induced hearing loss could still occur. 10
-10
Max Earplug - Good Fit vs Bad Fit

4. 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.
If all workers were using the earplug correctly, all of the dots should be within the red box.
<Click> But in the real world, the data falls mainly into two categories. Workers getting adequate attenuation (above about 15 dB) and those getting below 10 dB of protection.
(<Click> 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”

5. 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.

6. 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)

7. NRR Noise Reduction Rating – Determining an NRR NRR5 4
Number of test subjects 3 2
30 Subject test results (10 x 3) 1 14 18 20 22 24 26 28 30 32 19 23 25 27
Attenuation

8. 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

9. 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
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).

10. New Noise Reduction Rating | NRRsa
80% achieved > 20 dB
20% achieved > 26 dB 5 4
Number of test subjects 3 2
40 Subject test results (20 x 2) 1 11 14 18 20 22 24 26 28 30 33 19 23 25 27
Attenuation

11. 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

12. 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.

13. Attenuation can be determined at threshold, or above threshold
Determining Attenuation | Loudness Balance
Attenuation can be determined at threshold, or above threshold
100 90 80 70 60 50 40 30 20 10
100 90 80 70 60 50 40 30 20 10
“Real-Ear Attenuation Above Threshold”
30 dB
“Real-Ear Attenuation at Threshold”
30 dB
Unlike typical audiometry tests that measure the softest level at which a listener can hear a tone, VeriPRO uses a relative measurement of hearing level --- the loudness of a tone in one ear is balanced to a tone in the opposite ear at a known level. This unique “loudness-balance” method allows an accurate attenuation test to be performed in normal background noise that would otherwise interfere with a test at threshold.
VeriPRO allows the user to measure attenuation without interference from background noise levels

14. Result ~ Personal Attenuation Rating (PAR)
VeriPRO Test Protocol
Test Sequence
Part 1:
Both ears unoccluded
This sets the baseline level for each ear, and measures any asymmetry.
Part 2:
Right ear occluded
Attenuation for the right ear is measured.
Part 3:
Both ears occluded
Attenuation for the left ear is measured.
VeriPRO’s test method is simple to learn and fast to complete. Users balance tones using an on-screen slider bar so that the tones are equally loud in both ears. The test is administered in three parts:
Without earplugs
2. Earplug in right ear only
3. Earplugs in both ears
Based on the results, VeriPRO calculates the amount of attenuation at each frequency in each ear, and displays a Personal Attenuation Rating (PAR) for each ear. The user knows exactly how much attenuation he/she is getting from the earplugs, just as they are fit at that instant.
Result ~ Personal Attenuation Rating (PAR)

15. VeriPRO Functions Complete Check ● 5 freqs in each ear ● Includes
reliability
checks
● ↑ accuracy,
↑ test time
Quick
Check
● 1 critical
freq in each
ear
● ↓ accuracy,
↓ test time
● Can use
with severe
hrg loss
Report
Mode
● Individual
● Historical
● By freq.
Fit Training
● Videos
VeriPRO has been designed with four different modes:
- Complete Check Mode: full test, using five frequencies in each ear (takes about minutes to administer)
- Quick Check Mode: a short, simple Pass/Fail test utilizing only one frequency in each ear (takes about 2 minutes to administer)
- Report Mode: Individual and historical reports can be generated for each user
- Training Mode: includes short ‘How-to-Fit’ videos for each earplug, showing proper insertion.

16. If you are testing another manufacturers earplug or custom earplugs, select “Other Earplug” and when you click “Next” a window will open to enter the name of the earplug and its NRR.
Training video’s are provided for each Howard Leight earplug and can be used for similar earplugs by other manufacturers.

18. User name
VeriPRO Step
Earplug
inserted
No earplug
Adjust the left ear

19. The report shows the demographic information for the person, including their time-weighted average. This information can be input individually or uploaded from an Excel spreadsheet.
The Personal Attenuation Rating (PAR) is shown as compared to the published NRR. Two calculations are made. The Protected Exposure Level is simply the Exposure level minus the lowest PAR. The Safe Exposure Level is a variable which calulates the highest level of noise with which the measured ( lowest PAR) attenuation will protect the worker to a pre-determined “safe” level. That level can be set anywhere from 80 to 85 dB.

20. The information that we’ve just explained is shown graphically at the bottom of the page

21. A history of test conducted on that person can be shown on a second page.

22. After a Complete Check, the results can be shown frequency by frequency (optional).

23. Measures real-world attenuation of ANY earplug
VeriPRO Benefits
Measures real-world attenuation of ANY earplug
Fulfills requirement to ‘ensure proper fitting’ of earplugs and evaluate their attenuation
On-screen training videos
Administered anywhere, quiet room not required
Protected exposure level and safe exposure level calculated
Advantages of the VeriPRO method of measuring attenuation in the field.

26. Protection of noise-induced hearing loss only occurs on a personal level as workers adequately protect themselves from hazardous noise. VeriPRO now provides a personal approach to Hearing Conservation, and gives workers and safety managers critical feedback in protecting hearing.

27. VeriPRO® Q&A
Thanks!

28. “Why is 500 Hz tested twice?”
VeriPRO Q&A
“Do Howard Leight earplugs test better than others?”
“Can custom-molded earplugs be used with VeriPRO?”
“Why is 500 Hz tested twice?”
“Can workers with a hearing loss use VeriPRO?”
“Will calibration of VeriPRO be available?”
“Why did I get a Low Attenuation warning?”
“How reliable is VeriPRO?”
“Do Howard Leight earplugs test better than others?” No, the test is a fair assessment of any earplug.
“Can workers with a hearing loss use VeriPRO?”

29. ≤ 6 dB Reliability Report 500 Hz Retest Movement Attenuation Rove
VeriPRO Internal Quality Checks
Rove
500 Hz Retest
(Complete Check Only)
≤ 6 dB
Reliability Report
Attenuation
-10 dB
Movement
The VeriPRO software has four critical built-in quality checks:
1. Roving Slider Bar. The slider bar intentionally changes scale with every new screen. This prevents the user from “benchmarking” his loudness balance, since the middle position of one slider bar will sound very different from the middle position of the next slider bar.
Hz Retest. In the Complete Check, users must demonstrate retest reliability within just a few decibels of their first trial.
3. Minimum Attenuation. Users are warned if they are not achieving minimum levels of attenuation. Users can refit the earplugs if they wish. If minimum attenuation is still not achieved, the user will be warned a second time, but the test will continue.
4. Slider Bar Movement. VeriPRO tracks how many times the slider bar is engaged. If a user simply leaves the slider bar in the same position for much of the test, a warning is displayed on the screen, and the results screen encourages the user to retest.

32. Real-World Studies
In 2007, VeriPRO was validated through field trials at eight different worksites involving over 100 workers. The following slides summarize the results of those field trials.

33. Field Testing with VeriPRO
VeriPRO Real-World Studies
Field Testing with VeriPRO
8 Locations (no pre-screenings)
100 Workers Tested
Casual Test Setting
HPD selected by worker
“Insert as usual”
Training feedback disabled
104 workers were tested at 8 locations with no pre-screening of the subjects. Workers were asked to fit the earplug they normally wear, inserted in the way it is normally worn. No feedback or correction was offered if they fit it incorrectly.

34. VeriPRO Real-World Studies
Published NRR
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%.

35. VeriPRO Real-World Studies
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.
Many workers improve their protection simply by trying a different type of earplug

36. Pilot Study
“How well can users predict their attenuation after a short fit-testing training session?"
If workers get feedback about the effectiveness of their earplugs are they better able to predict the effectiveness of the next (and future) fits of earplugs?
In this study, we fit-test construction workers several times within a few minutes and showed them the numerical result. Then they were tested once more without seeing the result and asked several questions.

37. (Each subject estimated atten. for each ear)
Pilot Study 2 4 6 8 10 12 14 16 18 20
Within 5 dB
category
+/- 7.5 dB
(one Category off)
+/ dB
(2 categories off)
(Each subject estimated atten. for each ear)
Number of Ears
Ability to Predict Noise Reduction
56%
32%
The real question was how closely they could estimate the attenuation provided by a given earplug after this short training session. And most were spot on! In all but 4 of the 34 ears (88%), workers were able to tell about how much attenuation the earplug provided.
The important point is that workers could tell a good fit from a poor fit, even if they were off by 5-8 dB. This is a vast improvement over workers having really no clue about how much attenuation (or protection) their earplugs provide.
12%

38. OSHA Alliance: Best Practice Bulletin www.hearingconservation.org
Solution | Fit Testing
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.

39. VeriPRO Implementation
VeriPRO Usage
VeriPRO Implementation
Annual employee training
New hires
Employees with shift in hearing
Extreme noise exposures (dual protection)
Protection of noise-induced hearing loss only occurs on a personal level as workers adequately protect themselves from hazardous noise. VeriPRO now provides a personal approach to Hearing Conservation, and gives workers and safety managers critical feedback in protecting hearing.

40. Protection of noise-induced hearing loss only occurs on a personal level as workers adequately protect themselves from hazardous noise. VeriPRO now provides a personal approach to Hearing Conservation, and gives workers and safety managers critical feedback in protecting hearing.

41. Attenuation at Threshold (R.E.A.T.) Loudness Balance
Ear Plug Fit Test Methods
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

42. Vs. Ear Plug Fit Test Protocols Loudness Balance F-Mire NRR
Hearing Tests
No corrections required
Worker engaged
PAR
Like REAT
NRR - EPA prohibits objective tests
Corrections required
Worker as test fixture
Predicted PAR

43. Ear Plug Fit Test Methods
FitCheck
EARfit
VeriPRO
REAT
MIRE
REAAT
Very Quiet Room
Quiet Room
Anywhere
PAR
Predicted PAR
Any earplug
Selected modified earplugs – ongoing costs
User generated training
Worker is test fixture
Built in training for worker
Special training required
Anyone can perform
REAT
The first and most numerous field fit-test systems use REAT procedures in field. The technique is to determine the hearing thresholds of subjects with and without the use of the hearing protector. The differences in the thresholds are used to calculate the attenuation of the hearing protector.
These systems use special head phones to minimize background noise interference with obtaining hearing thresholds. They can test several or one representative frequency to determine PAR. Multiple frequencies provide a more accurate PAR but increase the length of the test.
Since REAT is essentially the same tests as the laboratory procedure defined in ANSI S , the field REAT tests produce a direct measure of PAR as it relates to REAT results.
MIRE
F-MIRE uses modified earplugs that the individual fits themselves. These special probed versions of the earplugs are compatible with a dual-element microphone. A known noise source is used to generate a reference noise. The dual-element microphone measures sound pressure levels in the ear canal and external to the earplug simultaneously.
The F-MIRE test produces a Predicted PAR (P-PAR) with the correction mentioned above included relating it to equivalent REAT results. They also calculate “uncertainty” which they define as the difference between the Predicted PAR (P-PAR) obtained using the MIRE system and the REAT results. The MIRE technique uses two microphones to measure the level of sound outside of the hearing protector and inside of the hearing protector (in the ear canal via a wired or probe tube). The differences in the two measurements is the Insertion Loss (IL) which can be used to calculate the predicted attenuation of the hearing protector. Field Microphone in Real Ear (F-MIRE) involves a fairly complicated calculation that attempts to correct for many of the differences between REAT results and MIRE results.
a tonal stimulus is presented monaurally in continuous alternation between the two ears. The level of the stimulus presented to the right ear is fixed and serves as the reference. The level of the comparison stimulus is presented to the left ear and is variable under control of the subject by use of a slider displayed on the PC monitor. The task is to match the loudness of the left ear comparison stimulus to that of the right ear reference stimulus in a single trial by moving the slider up until the loudness match was achieved. The task is performed in three conditions, 1) both ears unoccluded, 2) right ear occluded with earplug and 3) both ears occluded with earplugs.
LOUDNESS BALANCE
The loudness balance test is essentially a Real Ear ABOVE Threshold test so produces a direct measure of PAR as it relates to REAT results. Attenuation appears to be independent of sound level 1.

44. In-Ear Dosimetry As a Problem Solver
QuietDose
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.

45. 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.

46. QuietDose Research
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%.

47. Reducing Costs + Claims
QuietDose Research
Reducing Costs + Claims
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)

48. Preventive Action After NIHL
QuietDose
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.”

49. Off-job + On-job = STS Off-job + On-job = STS QuietDose
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

50. In-ear dosimetry as a Problem Solver
QuietDose
QuietDose Implementation
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

51. Measure actual noise dose
Continuous, real-time monitoring
Notification of pending over-dose of noise
Stops NIHL

52. Expert support
No on-going costs
True PAR
Test any earplug, anywhere
Worker involvement creates self-efficacy
Built-in reliability checks

53. Make Hearing Conservation Part of Your Everyday Life

54. Download today’s presentation at www.hearforever.org/dukeenergy

56. VeriPRO Results
Name
Earplug
Left Ear
Right Ear

57. Lagging Indicators vs. Leading Indicators
Solutions
Lagging Indicators vs. Leading Indicators

58. Indicators for Hearing Loss:
Solutions
Indicators for Hearing Loss:
Standard Threshold Shift
Temporary Threshold Shift
Recordable Hearing Loss
Dosimetry
In-ear Dosimetry
Labeled NRR (derated?)
Personal Attenuation Level (PAR)