1. HEARING CONSERVATION

2. Parts of the Ear
Outer Ear
Middle Ear
Inner Ear

3. Perception of Sound Otolith Organs Auditory Cochlea Ossicles Nerve
Ear Drum
Middle Ear
External Ear
Eustachian Tube
Opening to Throat 19 19 6 6 5 6 6

4. Causes of Conductive Hearing Loss
Middle ear infection
Foreign body in ear
Congenital malformation

5. Causes of Sensorineural Hearing Loss
Childhood illness
Presbycusis
Congenital
Infections
Medications
High fever
NOISE EXPOSURE

6. Receptors of Sound Detect fluid movement in the cochlea
Transmit electrical impulses to the brain where sound is interpreted 7 7 7 6 7

7. Types of Hearing Loss Conductive hearing loss
Outer or middle ear
Sensorineural hearing loss
Inner ear
Mixed hearing loss

8. Damaged Hair Cells
Damaged hair cells in the various bundles means loss of sound perception 8 8 8 7 8

9. Long Term Hair Cells Damage
Prolonged, unprotected exposure to noise could cause irreversible damage. 9 8 9

10. Typical Noise Levels Rustling leaves 20dB Whisper 35 dB
Normal conversation 65dB
Diesel truck at 25 feet 92dB
M16 rifle 156dB peak SPL
M60 machine gun 160dB peak SPL
155 mm Howitzer 185dB peak SPL

11. Effects of Noise Non-auditory effects Annoyance Fatigue
Speech interference
Hearing loss 5 5 11 12 11 12 12

12. How loud is allowed?

13. Noise Induced Hearing Loss
Painless
Progressive
Permanent
PREVENTABLE

14. Noise Induced Hearing Loss
Temporary Threshold Shift (TTS)
Hearing recovers eventually
Fullness, tinnitus
Permanent Threshold Shift (PTS)
No recovery
Treatment is hearing aids

15. Audiometric Hearing Levels
* Class * Class 2, 3, 4
* Only Physicians May Diagnose Hearing Loss 45 44 45 44 45

16. Noise in Army Aircraft (General Findings)
Overall noise levels are equal to or exceed 100 dB’s
Most intense noise below 300 Hz
Low frequency noise will produce high frequency hearing loss
Must Use Hearing Protection 43 35 47 50 49 50 48

17. Rotary-Wing Aircraft Noise Levels
Aircraft dB UH AH
OH-58C
OH-58D
CH-47D 56 55

18. Rotary-Wing Aircraft Noise Levels
Aircraft dB
UH-60A
AH NA NA NA NA NA NA NA NA
TH NA NA NA NA NA NA NA NA
RAH NA NA NA NA NA NA NA NA
* “ NA ” indicates incoming new data or data not available 57 56

19. Components of the Army HCP
Noise hazard identification
Engineering controls
Hearing protection
Monitoring audiometry
Annual health education
Enforcement
Program evaluation

20. Noise Hazard Identification
Noise surveys and site visits conducted by industrial hygiene
When noise levels exceed Army standards, noise signs/decals must be posted in area (unit commander or supervisor responsibility)

21. Engineering Controls Noise control at the source is most desirable
Hard to do after the fact
Most practical at early stages of procurement

22. Noise Control at the Source
Enclosures
Acoustical treatment
Mufflers
Control vibration
Partial height barriers

23. Hearing Protection Ear plugs - Ear canal caps Noise muffs Helmets
hand formed
triple/single flange
custom
Ear canal caps
Noise muffs
Helmets

24. Mean Real Ear Sound Attenuation In Decibels

25. Mean Real Ear Sound Attenuation in Decibels

26. Hearing Protection Responsibility Issued free of charge
ALL personnel in noise hazardous areas
Individual responsibility to wear hearing protection
Issued free of charge
Unit hearing conservation responsible for keeping adequate supply of ear plugs

27. Effective Exposure Levels Protective Helmets / Headsets
Aircraft Hearing Protector EEL
AH-1S HGU
SPH-4B
SPH
UH-1H HGU
SPH-4B
SPH
OH-58D HGU
SPH-4B
SPH 69 68

28. Effective Exposure Levels Protective Helmets / Headsets (cont.)
Aircraft Hearing Protector EEL
OH-58C HGU
SPH-4B
SPH
UH-60A HGU
SPH-4B
SPH
CH-47D HGU
SPH-4B
SPH 70 69

29. Protective Helmets and Ear Plugs
Protector UH-60A CH-47D AH-1S OH UH-1H
120 kn kn kn kn kn
SPH-4 w/
triple flange
plug
SPH-4 w/
single flange
SPH-4 w/
foam plug 73 72

30. Non-Occupational Noise Exposure Levels
Single engine aircraft dB
Shotgun dB
Bartending dB
Music at the club dB
Lawn mowers dB
Vacuum cleaners dB 70 69 78 77 72

31. Hearing Protection Care and maintenance
Ear plugs and be washed and reused
Noise muffs and helmets must be fitted correctly, ear cups and chin straps must be maintained

32. Monitoring Audiometry
Annual requirement
Testing done by microprocesser audiometer
DD2215 is baseline evaluation
DD2216 is annual evaluation
Individuals with a significant shift in hearing are referred to Audiology

33. Health Education At least annually
Can be done in form of films, video, or lecture
Posters, pamphlets, videos, and films can be ordered through commercial sources or your local audiovisual support center

34. Enforcement
Unit commander or supervisor is responsible for enforcing the HCP to include use of hearing protection
Failure to comply with the HCP requirements can result in disciplinary action for both military and civilian employees

35. Program Evaluation Participation Quality Assurance
Program Effectiveness

36. QUESTIONS ??