2. Hearing The following list highlights standards related to noise and hearing conservation: The following list highlights standards related to noise and hearing conservation: 1910.95, Occupational noise exposure. 1910.95, Occupational noise exposure. 1910.95 Appendix A, Noise exposure computation. Appendix A, Noise exposure computation. Appendix A Appendix A Appendix B, Methods for estimating the adequacy of hearing protector attenuation. Appendix B, Methods for estimating the adequacy of hearing protector attenuation. Appendix B Appendix B Appendix C, Audiometric measuring instruments. Appendix C, Audiometric measuring instruments. Appendix C Appendix C Appendix D, Audiometric test rooms. Appendix D, Audiometric test rooms. Appendix D Appendix D Appendix E, Acoustic calibration of audiometers. Appendix E, Acoustic calibration of audiometers. Appendix E Appendix E Appendix F, Calculations and application of age corrections to audiograms. Appendix F, Calculations and application of age corrections to audiograms. Appendix F Appendix F Appendix G, Monitoring noise levels non-mandatory informational appendix. Appendix G, Monitoring noise levels non-mandatory informational appendix. Appendix G Appendix G Appendix H, Availability of referenced documents. Appendix H, Availability of referenced documents. Appendix H Appendix H Appendix I, Definitions. Appendix I, Definitions. Appendix I Appendix I 1904, Recording and Reporting Occupational Injuries and Illness. [Topic Page] 1904, Recording and Reporting Occupational Injuries and Illness. [Topic Page] 1904Topic Page 1904Topic Page 1904.10, Recording Criteria for cases involving occupational hearing loss. 1904.10, Recording Criteria for cases involving occupational hearing loss. 1904.10 1926.52, Occupational noise exposure. 1926.52, Occupational noise exposure. 1926.52

34. 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.

35. 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.

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

63. OSHA

65. 1910.95(c)(1) The employer shall administer a continuing, effective hearing conservation program, as described in paragraphs (c) through (o) of this section, whenever employee noise exposures equal or exceed an 8-hour time-weighted average sound level (TWA) of 85 decibels measured on the A scale (slow response) or, equivalently, a dose of fifty percent. For purposes of the hearing conservation program, employee noise exposures shall be computed in accordance with appendix A and Table G-16a, and without regard to any attenuation provided by the use of personal protective equipment. The employer shall administer a continuing, effective hearing conservation program, as described in paragraphs (c) through (o) of this section, whenever employee noise exposures equal or exceed an 8-hour time-weighted average sound level (TWA) of 85 decibels measured on the A scale (slow response) or, equivalently, a dose of fifty percent. For purposes of the hearing conservation program, employee noise exposures shall be computed in accordance with appendix A and Table G-16a, and without regard to any attenuation provided by the use of personal protective equipment.

91. 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

92. These definitions apply to the following terms as used in paragraphs (c) through (n) of 29 CFR 1910.95. Action level Action level Audiogram Audiogram Audiologist Audiologist Baseline audiogram Baseline audiogram Criterion sound level Criterion sound level Decibel (dB) Decibel (dB) Hertz (Hz Hertz (Hz Medical pathology Medical pathology Noise dose Noise dose Noise dosimeter Noise dosimeter Otolaryngologist Otolaryngologist Representative exposure Representative exposure Sound level Sound level Sound level meter Sound level meter Time-weighted average sound level Time-weighted average sound level

94. Using Decibels