1. Getting “Real” about Hearing Protection A. Gregg Moore, CCC-A Senior Occupational Audiologist The EI Group

2. 2 Hearing Protection MUST… Be made available for all employees exposed to 85 dBA TWA or more Be worn by all employees exposed to an 85 dBA TWA or more who have experienced a Standard Threshold Shift (STS) Be worn by all employees exposed above the PEL of 90 dBA TWA

3. A protector may provide TOO MUCH noise reduction in some situations. This can: Cause an employee to reject protection Interfere with speech communication Typically occurs in noise levels of 80- 90 dBA 3

4. Underprotection occurs when the hearing protector does not reduce the exposure level to at least 85 dBA. Underprotection can lead to hearing loss. 4

5. Underprotection May Be Caused By… Not enough noise reduction from the hearing protector in very high noise levels. Improper fitting of the hearing protector by the hearing conservationist Inadequate insertion of the hearing protector by the worker Total employee non-compliance 5

6. 66 The Standard Says Employer shall evaluate hearing protector attenuation for the specific noise environments in which the protector will be used

7. OSHA HPD Fitting Requirement It is required the employer ensure the proper initial fit of a worker’s hearing protectors… And shall supervise correct use. This is a weak requirement! No requirement for ongoing fit-testing. 7

8. 88 E ar canals come in a variety of shapes and sizes Some earplugs May be uncomfortable May not fit May not stay in place

9. 99 Earmuffs, too, are not “one size fits all” Headband may not expand or collapse enough Cup openings may not fit large ears Head shape may be irregular

10. 10 Remember… When fitting an earplug, the most important step is to evaluate which provides an air- tight seal. Without an airtight seal, nothing else matters!!!!

11. 11 So, how much protection do we need?

12. 12 The Standard Says HPDs must attenuate employee exposure to 90 dBA TWA or less If the employee has experienced an STS, then HPDs must attenuate to below 85 dBA TWA

13. 13 Suggested Target Values under the Hearing Protector per EN 458 Sound Level dBAProtection 85 or aboveInadequate 80 - 85Good 75 - 80Best 70 - 75Good Below 70Over-protection

14. 14 Attenuation Different HPDs provide different amounts of attenuation Amount of attenuation shown by Noise Reduction Rating (NRR) printed on package

15. 15 How do they rate? (based upon NRR) User molded (foam) plugs26 – 33 dB Pre-molded & custom plugs21 – 27 dB Muffs 21 – 27 dB Canal caps < 20 dB

16. 16 What is the NRR? A measure of best attenuation when HPD fitted to laboratory specifications NOT a measure of attenuation obtained in the real world

17. The NRR is calculated in a laboratory The amount of noise reduction is measured using the “C” scale Noise levels in industry are taken using the “A” scale 17

18. Weighting: A vs.C 18

19. Converting the NRR In order to convert the C-weighted NRR to the “A” scale, seven (7) dB must be subtracted from the NRR BUT…the true amount of NRR is directly dependent on proper fit Examples: Ear Classic 29 -7 = 22 Airsoft 27 -7 = 20 Earmuff 25 -7 = 18 19

20. 20 Let’s try an example… Has TWA of 103 dBA Never had an STS Chooses HPD with NRR of 27 dB Is this OK?

21. 21 Step 1 Subtract 7 from NRR to convert from dBC scale to dBA scale 27 – 7 = 20 dBA NRR of 27 dBC measured in the laboratory is equal to an NRR of 20 dBA

22. 22 Step 2 Subtract the new NRR from the workplace noise level 103 dBA TWA – 20 dBA = 83 dBA TWA Which is 90 dBA TWA or less. So this earplug is OK, right????

23. 23 Well…maybe not!!!!!

24. 24 NRR vs. Real World Attenuation (Cabot Safety Corp. – Earlog 20)

25. 25 So – what to do? After converting from dBC to dBA, We “de-rate” the new value by 50% So in our example 27 dBC NRR – 7 dB = 20 dBA 20 dBA ÷ 2 = 10 dBA This plug with a 27 dB NRR is estimated to provide 10 dB of “real world” attenuation

26. 26 So if the “real world” NRR is 10 dBA… 103 dBA TWA – 10 dBA NRR = 93 dBA TWA Which is NOT enough protection!!!!

27. 27 And why is getting him down to 93 dBA TWA not enough protection? (remember: he has not shown an STS)

28. 28 Because it doesn’t bring the employee’s noise exposure level down to 90 dBA TWA or below

29. 29 If he had shown a previous STS what level would we have to attenuate to?

30. 30 < 85 dBA TWA

31. 31 Here’s another example Works in 93 dBA TWA noise Has had an STS Wants to use earplug with NRR of 25 dBC

32. 32 What’s the procedure? Convert manufacturer’s NRR from dBC to dBA by subtracting 7 25 dBC NRR – 7 = 18 dBA De-rate by 50% to get “real world” NRR, which gives us 9 dBA of “real world” attenuation

33. 33 Final step… Subtract “real world” NRR from workplace noise level 93 dBA TWA – 9 dBA = 84 dBA TWA Is it enough? Yes - according to OSHA, it is, because noise level reaching the ear is now below 85 dBA TWA Would you be happy with this fitting?

34. 34 Dual Protection In some instances it may be impossible to provide enough attenuation using earplugs or earmuffs alone Dual protection may be necessary Calculate “real world” attenuation of both devices Add 5 dB to the higher value (See Standard Interpretation dated 5-8-1984)

35. 35 Dual Protection- Example Earplug: 30 dBC NRR – 7 = 23 dBA 50% of 23 = 12.5 dBA Earmuff: 26 dBC NRR – 7 = 19 dBA 50% of 19 = 9.5 dBA Add 5 dB to the higher value 12.5 + 5 = 17.5 dBA of dual-protection attenuation

36. 36 Dual Protection (cont.) If the attenuation provided by dual protection is not adequate, then Administrative controls or Medical removal should be employed Peltor High Performance Series

37. 37 Remember that the Noise Standard says Employees must wear HPDs when: Exposed to an 8-hr TWA greater than 90 dBA Exposed between 85-90 dBA TWA and have had an STS

38. 38 Let’s think about this Noise level is 103 dBA TWA Earplug NRR is (33-7)/2= 13 Add 5 dB for dual protection = 18 103 dBA TWA – 18 dBA = 85 dBA TWA Is it enough if person has an STS? No – must protect below the Action Level! This is why OSHA will consider citing for lack of engineering noise controls at about 100 dBA TWA

39. 39 So … All we have to do is require everybody to wear HPDs at 85 dBA TWA, and Use a 50% derating of the NRR, and Use high NRR earplugs, and Use dual protection over 100 dBATWA.. And all will be well…right???

40. 40 50% Derating Accurate?

41. Real-World Hearing Protection …..high variability 41 50 40 30 20 10 0 -10 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 Real user attenuation 0 – 38 dB

42. 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) 42

43. Which ear is protected? 0 dB 33 dB 43

44. Real-World Hearing Protection: Some Conclusions NRR-7 does not mean much! (NRR-7)/2 guarantees nothing! You cannot trust your eyes! Many are underprotected despite the derated NRR! Many are overprotected because of the derated NRR…at least if they wear them properly…and this creates safety issues! 44

45. But all is not lost… 45

46. 46 Measure the earplugs! Personal Attenuation Rating (PAR) Test with and without earplugs Can use your audiometer and headphones but won’t be accurate. Special HPD fit- testing systems are available.

47. 47 E-A-Rfit Microphone in Real Ear (MIRE) Fast testing permits multiple passes Quite accurate Uses probed earplugs, not the earplugs actually worn by the worker Valid for earplugs other than E-A-R?

48. 48 VeriPRO Real Ear above Threshold (REAT) Test with and without earplugs Uses loudness balancing approach to calculate PAR Some variability but still quite accurate Works with any earplug

49. 49 WellFit Real Ear at Threshold (REAT), the gold standard Test with and without earplugs Much like a routine hearing test i.e. threshold testing Works with any earplug

50. 50 QuietDose In-ear dosimetry over the entire work shift Alerts worker to poor fit and overexposure Probably the most accurate approach Limited selection of probed earplugs A probed earmuff is also available

51. 51 Fit-Validation Systems are not…. A guarantee of “No more recordables” A guarantee of “No more Workers Compensation for hearing loss” A guarantee that the worker properly wears earplugs when not being monitored Rather, it is one tool in the tool kit to decrease the likelihood of workplace- related noise induced hearing loss

52. 52 Hearing Loss Prevention Training

53. 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 30 20 10 0 -10 Attenuation in dB 40 50 53

54. Real-World Hearing Protection Did You Know… 75% of noise-exposed workers only need about 15 dB or less of real-world hearing protection. Unless the noise situation is extreme (over 100 dBA TWA), nearly ANY earplug will offer sufficient protection if it fits properly, is comfortable, and is worn consistently. 54

55. Research shows that Hearing Conservation Training is MORE important than which type of earplug is worn or its NRR…but only if it is really, really good training! 55

56. OSHA Requires Three Topics Covered Annually for All Action Level Exposed Employees Effects of noise on hearing Purpose and procedure of the annual hearing test Hearing protectors available, fit, care, use, advantages and disadvantages, attenuation (NRR) 56

57. Types of Training One-to-One Group Videos Posters Games 57

58. So What is Missing From OSHA’s Required Training that Would Really Make the Most Difference? One-on-One Earplug Training at the time of the hearing test!!!! The MOST important part of the HCP is something not required by OSHA! 58

59. One-on-One Earplug Training “Show me how to insert your earplugs” Correct improper insertion technique Teach the “Tug Test” Try another earplug Invite employee to return if having earplug problems 59

60. Earplug Training and Fit-Validation The various earplug-fit validation systems are great for training Shows the impact of insertion technique Shows how much more protection you get with a well-fitting vs. a poorly fitting earplug 60

61. 61 Final Thoughts Don’t fit ’em and forget ’em! Supervision of the use of hearing protectors is required by the Noise Standard … And is critical to the success of the program

62. 62 It’s Really Pretty Simple… Wear these now… Or these later!

63. 63 And if all else fails…