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 ▪ Elimination of noise-induced hearing loss (see

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

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

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

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

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

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

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

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

Which ear is protected? 0 dB 33 dB

EVALUATING NOISE REDUCTION The 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.

EVALUATING NOISE REDUCTION Developing 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)

NOISE LEVEL NRR SAFE NOISE = _

NOISE LEVEL ? HUMAN FACTOR ? SAFE NOISE = _

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

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

EVALUATING NOISE REDUCTION 100 dB 90 dB 80 dB 70 dB 60 dB Hour Workday 30 dB = 1000x 20 dB = 100x 10 dB = 10x 3 dB = 2x

EVALUATING NOISE REDUCTION The 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 Worker Exposure at the Ear With Protectors dB Insufficient Protection Optimal Protection Acceptable Protection Over Protection

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

REDUCING COSTS & CLAIMS

REDUCING CLAIMS Lagging Indicators vs Leading Indicators

Fit Testing REDUCING CLAIMS In-Ear Dosimetry

Published Rating REDUCING CLAIMS

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

Published Rating Trying a second earplug often improves attenuation REDUCING CLAIMS

FIT TESTING Complete Check ● 5 freqs in each ear ● Best for new users, 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 ● Results by freq Fit Training ● Videos

Fit Testing REDUCING CLAIMS In-Ear Dosimetry

 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 occupational hearing loss

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

IN-EAR DOSIMETRY

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

REDUCING CLAIMS In practice, identifying a shift in hearing is not a preventive action …. It is documentation of a hearing loss after the fact Months 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

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 REDUCING CLAIMS

Off-job + On-job = Shift

CASE STUDIES - CARPET MILL NIOSH Safe-In-Sound Award Recipient 1.Engineering controls Brought noise levels down to dBA. 2.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.

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

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

Pre-Test 1.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 1.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? - Yes, 63% No, 37% - - Yes, 93% Not sure, 1% - No, 6% - Poor, 1% - Okay, 36% - - Good, 51% Don’t know how, 2% - Expert, 10% - - Earplugs, 76% Earmuffs, 8% - Don’t normally use on-the-job, 16% - CASE STUDIES - AEROSPACE

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