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

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

2. Topics Noise And Acoustics Motivating Workers Noise Reduction Reducing Costs for Hearing Loss

3. Noise + Acoustics Is Permanent + 100% Preventable • 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

4. Noise + Acoustics Noise-induced hearing loss is the most common permanent and preventable occupational injury in the world. World Health Organization

5. 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)

6. 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)

7. Noise + Acoustics Non-Occupational Occupational

8. Noise + Acoustics • Noise Measurement Devices 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 • ADMINISTRATIVE CONTROLS • Rotate Workers • Extended Breaks • 2nd/3rd Shift PERSONAL PROTECTIVE EQUIPMENT • ENGINEERING CONTROLS • Buy Quiet • Vibration Pads • Enclosures • Barriers • Isolation

10. NOISE AND ACOUSTICS ~ Hierarchy of Controls Noise + Acoustics Confirmed Ototoxics Ethyl Benzene Lead and inorganic compounds (as Pb) Styrene Toluene Trichloroethylene PossibleCarbon disulfide n-Hexane Xylene • Synergistic Ototoxics • Carbon Monoxide • Hydrogen Cyanide NOISE • Ototoxic Chemicals • Ototoxic by themselves • Synergistic effect with noise • Large differences in sensitivity • Recommend: increased frequency of audiometric testing

11. Noise Reduction Rating(NRR)

12. Hearing Protection Selection • 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 • 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 • Select HPDs that can work with other PPE without compromise • Cap-mounted earmuffs for hard hats • Multiple-position earmuffs for full-brim hard hats • Ultraslim neckband earmuffs with welding shields Comfort Noise Reduction • Selecting HPDs with suitable attenuation for noise environment • Avoid overprotection in marginal noise environments • Consider banded earplugs for intermittent noise or electronic earmuffs for impact noise. • 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 • Consider job requirements in HPD selection • Detectable earplugs for process industries • Hi-visibility earmuffs for dark/high traffic areas • Dielectric HPDs for electrical environments 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 Communication Job Requirements Hygiene Use with Other PPE Hearing Protection Selection Factors

13. Noise Reduction Rating • How much noise is reaching the ear of the worker ? Noise Level =100 dB Noise Reduction Rating =30 dB That is completely unknown … (55 – 104 dB)

14. 0 dB 0 dB 33 dB EAR #1 EAR #2 EAR #3 How much protection?

15. Fitting Tips Frequency in Hz 1000 2000 3150 4000 6300 8000 250 500 125 90 Max Good Fit NRR = 33dB Max Poor Fit NRR = 0dB 80 70 60 Attenuation in dB 50 40 30 20 10 0 -10 Good Fit vs Bad Fit

16. 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.

17. 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 A test subject in the Howard Leight Acoustical Lab, San Diego, CA, accredited by the National Voluntary Laboratory Accreditation Program (NVLAP)

18. NRR Noise Reduction Rating – Determining an NRR NRR 5 4 Number of test subjects 3 2 1 26 28 30 32 24 22 14 18 20 19 23 25 27 Attenuation

19. Noise Reduction Rating Real user attenuation <0 to 38 dB Real-World Attenuation≠ NRR 192 users of a flanged reusable earplug ~ 27 NRR 50 NRR = 27 Multiple-Use Earplug 40 Retraining and refitting resulted in an average 14 dB improvement for this group 30 Attenuation in dB 20 10 0 -10 From Kevin Michael, PhD and Cindy Bloyer “Hearing Protector Attenuation Measurement on the End-User”

20. 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

21. 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

22. 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

23. New NRR (NRsa) 80% achieved > 20 dB 20% achieved > 26 dB 5 4 Number of test subjects 3 2 1 24 22 11 14 18 20 26 28 30 33 19 23 25 27 Attenuation

24. Noise Reduction Rating 20th % Proficient Users 80th % Minimally-trained Current NRR Label Mock-up of New Label

25. 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%

26. Noise Reduction Rating 30 min 5 min 10 min 15 min Factors in Achieving the NRR 1.FIT 2. WEAR TIME 30dB 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 … 22 dB 18 dB 26 dB 24 dB In noise exposures, small intervals of no protection quickly void large intervals of adequate protection.

27. 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.

28. 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

29. 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

30. Noise Reduction Rating • Earplug Fit Testing • As a problem solver: • Derating Schemes • One-on-One Training • HPD Selection • NRR Change

31. 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!

32. Reducing Costs of Hearing Loss

33. Reducing Costs of Hearing Loss Sample HL Compensation* *NMER= No minimum exposure required *Source: AIHA Noise Manual

34. Reducing Costs of Hearing Loss • Indicators for Hearing Loss: • Standard Threshold Shift • Temporary Threshold Shift • Recordable Hearing Loss • Dosimetry • In-ear Dosimetry • Personal Attenuation Level (PAR) • Hearing Loss Compensation

35. Reducing Costs of Hearing Loss Lagging Indicators vs. Leading Indicators

36. Reducing Costs of Hearing Loss • Indicators for Hearing Loss: • Standard Threshold Shift • Temporary Threshold Shift • Recordable Hearing Loss • Dosimetry • In-ear Dosimetry • Personal Attenuation Level (PAR) • Hearing Loss Compensation

37. Reducing Costs of Hearing Loss In-Ear Dosimetry Fit Testing

38. 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 occupationalhearing loss

39. Reducing Costs of Hearing Loss

40. Research > Alcoa Intalco Works Reducing Costs of Hearing Loss • Mean Hearing Threshold (2k, 3k, 4kHz): 2000 – 2007 (N = 46) • Employees using continuous in-ear dosimetry starting in 2005

41. Preventive Action After NIHL Reducing Costs of Hearing Loss • Audiometric test •Retest •Notification 0 2 4 6 8 10 12 14 16 Months 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

42. In-ear dosimetry as a Problem Solver Reducing Costs of Hearing Loss In-ear monitoring 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

43. Reducing Costs of Hearing Loss Real-Ear Attenuation at Threshold (R.E.A.T.) Loudness Balance (Real-Ear Attenuation Above Threshold) Microphone in Real-Ear (M.I.R.E.) In-Ear Dosimetry

44. Ear plug fit-testing methods

45. Reducing Costs of Hearing Loss OSHA Alliance: Best Practice Bulletin www.hearingconservation.org Additional Information www.howardleight.com

46. Pre and Post-Test Fit-Testing as a Training Tool • “How well can users predict their attenuation after a short fit-testing training session?"

47. Pre and Post-Test Fit-Testing as a Training Tool 20 18 16 14 12 Number of Ears (Each subject estimated atten. for each ear) 10 8 6 4 2 0 Within 5 dB category +/- 7.5 dB (one Category off) +/- 12.5 dB (2 categories off) • Ability to Predict Noise Reduction 56% 32% 12%

48. Reducing Costs of Hearing Loss Published NRR

49. Reducing Costs of Hearing Loss Personal Factors Gender Age Years in Noise Ear Canal Size Familiarity Model of Earplug Program Factors # Group Trainings # Personal Trainings

50. REDUCING COSTS / CLAIMS Reducing Costs of Hearing Loss Published NRR Trying a second earplug often improves attenuation