How Well do Hearing How Well do Hearing Protectors Work? Protectors Work? Compiled Field Hearing Compiled Field Hearing Protector Protector Fit-Testing Fit-Testing Results Results Lee D. Hager Lee D. Hager Hearing Conservation Specialist Hearing Conservation Specialist 3M Occupational Health and Environmental 3M Occupational Health and Environmental Safety Division Safety Division 517.647.5882 517.647.5882 [email protected][email protected]
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How Well do Hearing Protectors Work? Compiled Field Hearing Protector Fit-Testing Results Lee D. Hager Hearing Conservation Specialist 3M Occupational.
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How Well do Hearing How Well do Hearing Protectors Work? Protectors Work?
Compiled Field Hearing Compiled Field Hearing Protector Protector Fit-TestingFit-Testing Results Results
Lee D. HagerLee D. HagerHearing Conservation SpecialistHearing Conservation Specialist
3M Occupational Health and Environmental Safety 3M Occupational Health and Environmental Safety DivisionDivision
Pure data harvestPure data harvest– Company techsCompany techs– No interventionNo intervention
Information extractedInformation extracted– ProductProduct– PARPAR
L and RL and R
Information collectedInformation collected– NRRNRR19791979
Information calculatedInformation calculated– MeansMeans– Standard deviationsStandard deviations– 8080thth and 20 and 20thth Percentiles Percentiles– RangeRange
MIRE - E-A-RfitMIRE - E-A-Rfit Dual element microphoneDual element microphone Simultaneous measurement Simultaneous measurement
inside and outside HPD yields inside and outside HPD yields noise reduction (NR)noise reduction (NR)
Specially prepared/probed Specially prepared/probed HPDHPD– Surrogate for regular HPDSurrogate for regular HPD
– Most distributions Most distributions appear to approach appear to approach normal normal n ≥ 150n ≥ 150 Center near NRRCenter near NRR19791979 Individual outliers are Individual outliers are
people toopeople too
Case studyCase study– About 60% OK pre-About 60% OK pre-
interventionintervention– 100% OK post-100% OK post-
interventionintervention 25% needed retraining25% needed retraining 16% using improper 16% using improper
HPDHPD Individual fit testing Individual fit testing
appears to be the appears to be the only way to assess only way to assess individualindividual– SufficiencySufficiency– SelectionSelection– FitFit