HearingHearing The following list highlights standards related to noise and hearing The following list highlights standards related to noise and hearing

conservation: conservation: 1910.951910.95, Occupational noise exposure. , Occupational noise exposure.

Appendix AAppendix A, Noise exposure computation. , Noise exposure computation. Appendix BAppendix B, Methods for estimating the adequacy of hearing protector , Methods for estimating the adequacy of hearing protector

attenuation. attenuation. Appendix CAppendix C, Audiometric measuring instruments. , Audiometric measuring instruments. Appendix DAppendix D, Audiometric test rooms. , Audiometric test rooms. Appendix E, Acoustic calibration of audiometers. Appendix E, Acoustic calibration of audiometers. Appendix F, Calculations and application of age corrections to Appendix F, Calculations and application of age corrections to

audiograms. audiograms. Appendix G, Monitoring noise levels non-mandatory informational Appendix G, Monitoring noise levels non-mandatory informational

appendix. appendix. Appendix H, Availability of referenced documents. Appendix H, Availability of referenced documents. Appendix I, Definitions. Appendix I, Definitions.

1904, Recording and Reporting Occupational Injuries and Illness. [Topic 1904, Recording and Reporting Occupational Injuries and Illness. [Topic Page] Page] 1904.10, Recording Criteria for cases involving occupational hearing 1904.10, Recording Criteria for cases involving occupational hearing

loss. loss. 1926.52, Occupational noise exposure.1926.52, Occupational noise exposure.

When the fluid moves inside the cochlea, thousands of microscopic hair fibers inside the partition wall are put into motion. There are approximately 24,000 of these hair fibers, arranged in four long rows.

The hair fibers are all connected to the auditory nerve and, depending on the nature of the movements in the cochlear fluid, different hair fibers are put into motion. When the hair fibers move they send electrical signals to the auditory nerve which is connected to the auditory centre of the brain. In the brain the electrical impulses are translated into sounds which we recognize and understand. As a consequence, these hair fibers are essential to our hearing ability. Should these hair fibers become damaged, then our hearing ability will deteriorate.

The hearing conservation program The hearing conservation program requirement is triggered at 85 dBA by requirement is triggered at 85 dBA by both the OSHA standard in 29 CFR both the OSHA standard in 29 CFR 1910.95(c) and by the latest ACGIH TLV. 1910.95(c) and by the latest ACGIH TLV. The 85 dBA is considered an action level The 85 dBA is considered an action level in the OSHA standard and is considered in the OSHA standard and is considered the TLV for an 8-hour exposure in the the TLV for an 8-hour exposure in the TLVs, but in either case this same level TLVs, but in either case this same level triggers the hearing conservation triggers the hearing conservation program requirement. program requirement.

OSHA OSHA

1910.95(c)(1)1910.95(c)(1)

The employer shall administer a continuing, The employer shall administer a continuing, effective hearing conservation program, as effective hearing conservation program, as described in paragraphs (c) through (o) of described in paragraphs (c) through (o) of this section, whenever employee noise this section, whenever employee noise exposures equal or exceed an 8-hour time-exposures equal or exceed an 8-hour time-weighted average sound level (TWA) of 85 weighted average sound level (TWA) of 85 decibels measured on the A scale (slow decibels measured on the A scale (slow response) or, equivalently, a dose of fifty response) or, equivalently, a dose of fifty percent. For purposes of the hearing percent. For purposes of the hearing conservation program, employee noise conservation program, employee noise exposures shall be computed in accordance exposures shall be computed in accordance with appendix A and Table G-16a, and with appendix A and Table G-16a, and without regard to any attenuation provided without regard to any attenuation provided by the use of personal protective equipment.by the use of personal protective equipment.

When the daily noise exposure is composed of two or more periods of noise exposure of different levels, their combined effect should be considered, rather than the individual effect of each. Exposure to different levels for various periods of time shall be computed according to the formula set forth in paragraph (d)(2)(ii) of this section

These definitions apply to the following terms These definitions apply to the following terms as used in paragraphs (c) through (n) of 29 as used in paragraphs (c) through (n) of 29

CFR 1910.95.CFR 1910.95.

Action level Action level Audiogram Audiogram Audiologist Audiologist Baseline Baseline audiogram audiogram Criterion sound Criterion sound level level Decibel (dB) Decibel (dB) Hertz (HzHertz (HzMedical pathologyMedical pathology

Noise dose Noise dose Noise dosimeter Noise dosimeter Otolaryngologist Otolaryngologist Representative Representative exposure exposure Sound level Sound level Sound level meter Sound level meter Time-weighted Time-weighted average sound average sound level level

                                                                                                                                                   

Using Decibels