One Challenge in Creating and Effective Hearing Conservation Program OR. Using Hearing Protection What s Wrong with Noise Reduction Ratings (NRR)

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Dortha Waters
5 years ago
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1 One Challenge in Creating and Effective Hearing Conservation Program OR Using Hearing Protection What s Wrong with Noise Reduction Ratings (NRR)

2 Determine there is a Hazard Remove the Hazard Keep people away from the Hazard Protect them from the Hazard Keep them Safe

3 Measure the Hazard Noise Measure Exposure measure Noise Exposure Target Exposure = Protection Level Needed NE TE = PL

4 85 dba - 25% of your population will experience some hearing loss 82 dba No hearing Loss 80 dba - EU Standard for HCP 75 dba if you want a stress reduced workforce target 75 under the protector.

6 Device Foam E-A-R / Decidamp Number of Studies Number of Tests Mean RW NRR (db) Labeled NRR (db) NRR Labeled NRR (%) % 3-Flange (misc) % Earplugs (Average) ** ** % Earmuffs Peltor H7P3E % Earmuffs (Average) ** ** % GRAND AVERAGE ** E-A-R 94-17/HP Berger, Franks & Lindgren ** %

canal HPD Wearer 1 Over 30 db difference in

7 TWO MALE HPD WEARERS... Both with large ear canals Both wearing identical foam-type insert HPD s Both inserting the plug fully into their ear canal HPD Wearer 1 Over 30 db difference in attenuation provided! HPD Wearer 2 Study conducted by Dr. K Michael Ph.D. Aud

8 S NRR Test Protocol DECIBELS Insert chart of attenuation values for NRR tests rtz HERTZ

9 S NRR Test Protocol -2δ -1δ 0 +1δ +2δ 125 HERTZ

10 Normal Bell Curve

11 Device Foam E-A-R / Decidamp Number of Studies Number of Tests Mean RW NRR (db) Labeled NRR (db) NRR Labeled NRR (%) % 3-Flange (misc) % Earplugs (Average) ** ** % Earmuffs Peltor H7P3E % Earmuffs (Average) ** ** % GRAND AVERAGE ** E-A-R 94-17/HP Berger, Franks & Lindgren ** %

13 Essence of safety Got to hear to feel safe protection

16 We know what level of protection/attenuation we need We don t know what level of protection we re giving any one person Once we give it to them they re going to frustrate it to feel normal We re measured based on our ability to protect our workers.

17 Consult the Oracle Take up Sky Diving without A chute OR

18 De-rate the protectors Use another Method of Measuring Attenuation Enable Communication

20 Device Foam E-A-R / Decidamp Number of Studies Number of Tests Mean RW NRR (db) Labeled NRR (db) NRR Labeled NRR (%) % 3-Flange (misc) % Earplugs (Average) ** ** % Earmuffs Peltor H7P3E % Earmuffs (Average) ** ** % GRAND AVERAGE ** E-A-R 94-17/HP Berger, Franks & Lindgren ** %

22 Method A measures the Potential of a Hearing Protector Method B measures what a User achieves when wearing the a Hearing Protector

24 Roughly a 15% reduction in attenuation

26 De-Rating formula for NRR (NRR A 2) 7 db NRRA = label on the package 2 = the adjustment for the real world effect - 7 = conversion of NRR (measured on the A Scale) to the same scale as noise is measured (i.e. the C Scale).

27 Therefore: 1. 3M (E.A.R.) Classic NRR 29 = 7.5 db 2. Howard Leight MAX NRR 33 = 9.5 db 3. Bilsom Lighting Earmuff NRR 31 = 17.4 db 4. Peltor Optime Earmuff NRR 30 = 22.5 db

28 Field Attenuation Estimating Systems

29 I have been unable to document any improvement in hearing conservation program outcomes as a result of Fit Testing.

30 Possibly the lure of communication is too strong Or our need to feel safe being able to hear what threatens us overrides intellect

33 Take Aways Ideally, hearing protection should go in/on when they get to work and come off when they go home. The hardest to protect are those in moderate noise 85 to 93 db. Education about the Exchange Rate is a must. Supervisors MUST set the example. Hearing Conservation is top down.

35 Use Method B attenuations for planning your protection level. If you can t, de-rate your protection to be safe.

37 /ANSI new attenuation ratings NRR20 which is the lowest number 80% of your population should achieve NRR80 which 20% of your wearers might achieve Now there s a range for a given hearing protector Problems????

38 Method A attenuation measurement modified slightly in the current standard. For a given protector the new NRR20 will be higher than the previous NRR. What does this tell us about those in the margins? There s no certainty that this rule will be promulgated

39 NRR combines the measurements from 8 frequencies (S ) into one number Octave band measures the attenuation at each frequency db Blocker Convertible Venter Yellow Filter Frequency in Hertz Attenuation Method A Attenuation Method B NRRA Method A 26 db NRRSF Method B 26.1 db Match the Attenuation to the Sound Field

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Standard. and Protection. A new. in Design, Comfort. The power to protect your world. Personal Safety Division 3M Peltor Earmuffs - X Series, Optime & Specialty A new Standard in Design, Comfort and Protection SM The power to protect your world. 3 We live in a LOUD World Introducing the