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Presented by Brad Witt

STOPPING NOISE-INDUCED HEARING LOSS. Presented by Brad Witt. STOPPING NOISE-INDUCED HEARING LOSS. NIOSH Safe-In-Sound Award Recipient ▪ “M easurable achievements in reducing or eliminating noise-induced hearing loss” ▪ 2011 industrial recipient: Shaw Industries Group Plant WM

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Presented by Brad Witt

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  1. STOPPING NOISE-INDUCED HEARING LOSS Presented by Brad Witt

  2. STOPPING NOISE-INDUCED HEARING LOSS NIOSH Safe-In-Sound Award Recipient ▪ “Measurable achievements in reducing or eliminating noise-induced hearing loss” ▪ 2011 industrial recipient: Shaw Industries Group Plant WM ▪Elimination of noise-induced hearing loss (see www.safeinsound.us)

  3. NOISE AND ACOUSTICS Hazardous noise exposures are cumulative and off the job. on the job ..…

  4. NOISE AND 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 over-exposure Is permanent and 100% preventable

  5. Noise-induced hearing loss is the most common permanent and preventable occupational injury in the world. ~ World Health Organization 1997 Report on Occupational Noise NOISE AND ACOUSTICS

  6. NOISE AND ACOUSTICS NON-OCCUPATIONAL ► 140 dB Immediate physical damage ► 120 dB Pain threshold ► 85 dB OSHA Action Level Hearing damage possible ► 60 dB Comfortable noise level

  7. 83 dB If the noise source is doubled 86 dB The noise level only goes up 3 dB 89 dB Small increases in decibel level 92 dB Represent enormous increases in noise level and risk NOISE AND ACOUSTICS The decibel scale is a logarithmic scale, not a linear scale

  8. NOISE AND ACOUSTICS 83dB 89dB 86dB 92 dB 95 dB

  9. NOISE AND ACOUSTICSSound Level Meter vs. Noise Dosimeter “Area Sampling” “Personal Sampling” Sound is measured immediately in a specific area Sound is ‘averaged’ throughout the day for a sample employee or job photos courtesy of Quest Technologies

  10. ADMINISTRATIVE CONTROLS • Rotate Workers • Extended Breaks • 2nd/3rd Shift PERSONAL PROTECTIVE EQUIPMENT NOISE AND ACOUSTICS ~ Hierarchy of Controls • ENGINEERING CONTROLS • Buy Quiet • Vibration Pads • Enclosures • Barriers • Isolation

  11. EVALUATING NOISE REDUCTION 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)

  12. 0 dB 0 dB 33 dB Which ear is protected?

  13. EVALUATING NOISE REDUCTIONThe Noise Reduction Rating (NRR) • A laboratory estimate of the amount of attenuation achievable by most 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.

  14. EVALUATING NOISE REDUCTIONDeveloping the NRR • 10 human subjects tested in a simulated industrial room • Tested with ears open / occluded at nine frequencies • Each subject tested 3x • NRR calculated to be population average A test subject in the Howard Leight Acoustical Lab, San Diego, CA, accredited by the National Voluntary Laboratory Accreditation Program (NVLAP)

  15. SAFE NOISE NOISE LEVEL _ NRR =

  16. ? SAFE NOISE ? HUMAN FACTOR NOISE LEVEL _ =

  17. Real user attenuation 0 – 38 dB EVALUATING NOISE REDUCTIONReal-World Protection May Not Equal NRR 192 users of a flanged multiple-use 27 dB earplug 50 Multiple-Use Earplug Rated for 27 dB 40 30 Retraining and refitting resulted in an average 14 dB improvement in attenuation for this group Attenuation in dB 20 10 0 -10 From Kevin Michael, PhD and Cindy Bloyer “Hearing Protector Attenuation Measurement on the End-User”

  18. The Biggest Factors in Achieving the NRR 30 min 5 min 10 min 15 min EVALUATING NOISE REDUCTION 1.FIT 2. WEAR TIME 30dB A worker who selects an earmuff with an NRR of 30 but then removes that HPD for just … effectively reduced his 8-hour NRR to just … 15 dB 12 dB 19 dB 17 dB In noise exposures, small intervals of no protection quickly cancel large intervals of adequate protection.

  19. EVALUATING NOISE REDUCTION 30 dB = 1000x 20 dB = 100x 10 dB = 10x 3 dB = 2x 100 dB 90 dB 80 dB 70 dB 60 dB 0 1 2 3 4 5 6 7 8 8-Hour Workday

  20. Insufficient Protection Acceptable Protection Optimal Protection Acceptable Protection Over Protection EVALUATING NOISE REDUCTIONThe Hazards of Overprotection • Choosing a protector with an NRR higher than necessary may result in overprotection • Verbal communication may be hindered • Warning alarms, telephones, machine noises may not be heard dB • 85 • 80 • 75 • 70 Worker Exposure at the Ear With Protectors

  21. 20th % Proficient Users 80th % Minimally-trained EVALUATING NOISE REDUCTIONThe Noise Reduction Rating (NRR) Current NRR Label Mock-up of New Label

  22. REDUCING COSTS & CLAIMS

  23. REDUCING CLAIMS Lagging Indicators vs Leading Indicators

  24. REDUCING CLAIMS In-Ear Dosimetry Fit Testing

  25. REDUCING CLAIMS Published Rating

  26. REDUCING CLAIMS Personal Factors Gender Age Years in Noise Ear Canal Size Familiarity Model of Earplug Program Factors # Group Trainings # Personal Trainings What predicts a good fit?

  27. REDUCING CLAIMS Published Rating Trying a second earplug often improves attenuation

  28. FIT TESTING Complete Check ● 5 freqs in each ear ● Best for new users, reliability checks ● ↑ accuracy, ↑test time Report Mode ● Individual ● Historical ● Results by freq Quick Check ● 1 critical freq in each ear ● ↓ accuracy, ↓test time ● Can use with severe hrg loss Fit Training ● Videos

  29. REDUCING CLAIMS In-Ear Dosimetry Fit Testing

  30. In-ear dosimetry measures actual noise dose, with and without protection • Alerts when worker approaches safe limits • Only metric to measure and prevent further progression of occupationalhearing loss

  31. IN-EAR DOSIMETRY • Dosimeter records … • Good fit • Bad fit • No fit • Indicator lights give immediate feedback of noise level and dose

  32. IN-EAR DOSIMETRY

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

  34. REDUCING CLAIMS In practice, identifying a shift in hearing 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 annual audiometric testing In-ear dosimetry “worst case” scenario … 1 Day • Audiometric test •Retest •Notification 0 2 4 6 8 10 12 14 16 Months

  35. REDUCING CLAIMS PROS - Estimate Measure - NRR obsolete - Eliminates need for de-ratings - Medico-legal cases - Delineates non-occupational - Eliminates double protection - Provides employee feedback CONS - Cost - Time Investment - Not standardized

  36. REDUCING CLAIMS Off-job+ On-job = Shift Off-job+ On-job = Shift

  37. CASE STUDIES - CARPET MILL • NIOSH Safe-In-Sound Award Recipient • Engineering controls • Brought noise levels down to 100-104 dBA. • Annual fit-testing and training • Documented successful reduction of noise exposures under the hearing protector below 85 dBA for all employees. • 3. End result: reduction of STS to zero in the most recent years of annual audiometric testing.

  38. CASE STUDIES – MILITARY INSTALLATION U.S. Navy ▪ 60 sailors experienced in earplug use - command-issued standard foam earplug OR - a second earplug of their choosing ▪Prior to testing with the “variety” earplug, sailors received brief training (less than one minute in duration) by someone modeling the correct fit of that style of earplug. ▪Despite no prior experience with the “variety” earplug, 45 of the 60 sailors (75%) achieved higher attenuation with the variety earplug over the command-issued earplug. Median attenuation for ‘variety’ earplugs = 18 dB Median attenuation for command-issued earplugs = 9 dB

  39. CASE STUDIES - AEROSPACE Fit-Testing / 1:1 Training for 337 noise-exposed workers

  40. CASE STUDIES - AEROSPACE • Pre-Test • Which type of hearing protectors do you normally use on the job? • 2. How would you rate your ability to fit your earplugs? • Post-Test • After this fit-test, are you better able to fit your earplugs? • 2. Did you change your choice of earplugs as a result of the fit-test? Don’t normally use on-the-job, 16% - Not sure, 1% - - Yes, 93% - Earplugs, 76% No, 6% - Earmuffs, 8% - Expert, 10% - - Good, 51% Don’t know how, 2% - Poor, 1% - - Yes, 63% No, 37% - Okay, 36% -

  41. Hearing Loss Due To Noise Exposure Is … Painless Permanent Progressive … and very Preventable!

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