1. Hearing Conservation Program NRCC SINGAPORE 21 March 2006

2. References • 29 CFR 1910.95, Occupational Noise Exposure • OPNAVINST 5100.23G, NAVOSH Program Manual, Chapter 18

3. Noise • Any unwanted sound--created by many different sources: • Traffic • Industrial equipment and tools • Music • Gunfire exercises • Ventilation • Excessive noise--over time and certain levels--can cause hearing loss

4. Noise Exposure • Determined by: • Duration of exposure • Type of noise • Continuous • Impulse • Intensity • Frequency

5. Causes of Hearing Loss • Age • Disease (Middle or Inner Ear) • Trauma • Drugs (the “…mycins, tetracycline) • Noise exposure

6. How Hearing Loss Occurs

8. Damage to the Ear • Outer ear-- • Catches dirt and particles in the canal that contains cerumen or wax • Middle ear-- • Has bones (malleus, incus, stapes) and ear drum which can rupture from sudden high sound pressure levels • Inner ear-- • Has cochlea with tiny hair cells connected to nerves. Damage is irreversible Middle ear Cochlea

9. Measuring Sound

10. Terminology • Frequency Measured in hertz (Hz) or cycles per second • Determines how high or low the pitch sounds • Intensity • Measured in decibels (dB) • Determines how “loud” a noise sounds • Logarithmic scale • Exchange (doubling) rate (5 for Navy) • ---------------Audiograms------------------

11. Frequency Weighting Scales

12. Other Information • Ability to hear well depends on • Pitch of the sound • Age of the individual • Distance from noise source • Previous noise exposures • Environment (surroundings)

13. Other Information • Sound level meters used to measure noise levels • 20 Decibels (dB)--faint sound (like a whisper) • 150 Decibels (dB)--F-14 at takeoff on flight deck • Navy Industrial Hygiene Officers (IHO) conduct noise surveys

14. Hearing Conservation Program

15. Program Objective • The objective of the Hearing Conservation Program is to prevent hearing loss as a result of exposure to hazardous noise. How would YOU like to own this?

16. Program Elements • Identifying noise hazardous areas • Engineering controls to reduce the hazard • Posting of noise hazardous areas • Providing hearing protection to personnel • Medical monitoring (audiograms) • Education and training

17. Identifying Noise Hazardous Areas • Limits for continuous noise exposure • DOD = 85 dBA • OSHA = Used to be 90 dBA, now reduced to 85 dBA • Impact (Impulse) noise limit = 140 dB • 84 dBA or less--OK for personnel 8 hours a day, five days a week with no ill effects. • Above 84 dBA--Navy considers noise hazardous

18. Identifying Noise Hazardous Areas • Sound level surveys conducted to determine which spaces routinely have • Continuous noise >84 dBA • Impact noise >140 dB • Survey documents retained for 50 years • Readings repeated if equipment is added/changed • Readings reviewed as part of IH survey

19. Engineering Controls • Noise can be decreased by changes in design or imposing controls • Damping material or sound curtains around equipment • Acoustical tiles for classrooms • Rubber insulating pads at metal-to-metal interface • Moving noise equipment to isolated location • Engineering controls must be considered FIRST, prior to resorting to PPE

20. Posting Noise Hazard Signs • Used when engineering controls do not work, or are not feasible • Use Noise Hazard Warning Labels to mark hazards • Large warning decals for entire areas (NAVMED 6260/2) • Small warning labels (green or orange) for individual equipment (NAVMED 6260/2A) • Post areas as DOUBLE Hearing Protection Required if sound levels >104 dBA

21. Personal Protection • Used as last resort--when exposures cannot be controlled by any other means • Ear plugs and muffs • Mechanically block noise from ear • Rated for specific Noise Reduction Rating (NRR)--reduce decibel levels reaching the ear by the number listed on the package • Actual NRR likely less than advertised NRR

22. Personal Protection • Ear plugs • Fit into ear canal • Fitted/Flanged types issued by Medical • Disposable foam plugs don’t require fitting--also have highest NRR (about 30dB) • Ear muffs • Fit over outer ear • Have NRR of 24-28 dB • Ear caps--like plugs with a head band--NRR of about 22 dB

23. Personal Protection • Single protection • Plugs or muffs • Required when continuous sound levels >84dB continuous or 140 to 165 dB peak • Required when exposed to noise from gunfire, artillery or missile firing • All personnel should be fitted for insert hearing protection. Recruits at recruit depot .

24. Personal Protection • Double protection • Required when continuous sound levels >104dBA • Use combination of ear plugs and ear muffs • Must be kept clean and in good condition • Dirty plugs may cause infections • Muffs with hardened seals DO NOT protect

25. Medical Monitoring • Baseline and routine testing required for all personnel routinely working in noise hazardous areas • Maintain roster of personnel routinely working in noise hazardous areas • All Navy and Marine Corps personnel given baseline audiogram (DD 2215) when entering the service • Annual audiograms (DD2216) given to personnel assigned work in noise hazardous areas

26. Significant Threshold Shift (STS) • A change of 15 dB or more at 1000, 2000, 3000, or 4000 Hz in either ear • OR… • An average change of 10 dB or more at 2000, 3000, or 4000 Hz in either ear

27. Disposition Following Monitoring Hearing Tests • If patient has a STS: follow-up hearing test after 14 hours noise free • If STS still present, conductive hearing loss may be ruled out by tympanometry and otoscopy by MDR • Second follow-up audiogram may be on same day • May refer to audiologist at any point

28. Disposition Following Monitoring Hearing Tests • If second follow-up still shows STS, must refer to audiologist • Termination audiograms given to personnel when leaving the service

29. Questions ???