Hearing Conservation Program

Exposure to excessive noise in the workplace can cause permanent hearing loss. Although Purdue University attempts to control noise exposures on campus, certain operations and workstations may expose faculty, staff, or students to significant noise levels. The Hearing Conservation Program has been established to help ensure that members of the campus community do not suffer health effects from exposure to excessive noise while at work.

• OSHA 29 CFR 1910.95, “Occupational noise exposure” and relevant appendices
• OSHA 29 CFR 1904.5, “Determination of work-relatedness”.
• OSHA 29 CFR 1904.10, “Recording Criteria for Cases Involving Occupational Hearing Loss”.
• ANSI S1.11-1971 “Specification for Octave, Half-Octave, and Third-Octave Band Filter Sets”
• ANSI S1.25-1978 “Specification for Personal Noise Dosimeters”
• ANSI S1.4-1971 “Specification for Sound Level Meters” ANSI S3.6-1969 “Specifications for Audiometers”

The provisions of the Hearing Conservation Program apply to all personnel at Purdue University’s West Lafayette campus, regional campuses, University research farms and agriculture centers, and related facilities and operations.

This program shall apply to all operations either stationary or mobile where employees are expected to be exposed to noise levels of 85 dBA or above for 8 hours as a time weighted average.

1. Action Level: An 8-hour time weighted average (TWA) of 85 decibels measured on the A-weighted scale, slow response, or equivalently a dose of 50%. This is the level of sound exposure at which employee participation in the Purdue Hearing Conservation Program is mandatory.
2. A-Weighted Sound Level (dBA): The weighting of sound levels that represents the function of the human ear.
3. Audiometric Testing Program: The portion of the Hearing Conservation Program that consists of measuring an employee’s hearing threshold to establish a baseline and for subsequent comparisons.
4. Decibel (dB): Unit of measurement of sound level.
5. Dose: A ratio of noise exposure relative to the noise criterion level of 90 decibels, expressed as a percentage. Ninety decibels represents a dose of 100% over an 8-hour work shift. Eighty-five decibels represents a dose of 50% over an 8-hour work shift. Dose is based on the OSHA 5 dB exchange rate. Dose may be determined from the equation given in Table 1 for non-continuous noise or estimated from Table 2 based on the TWA.
6. Hearing Conservation Program (HEACP): A written program that establishes procedures to ensure the protection of employees from high noise areas or operations in compliance with the OSHA Occupational Noise Regulation 29 CFR 1910.95.
7. Hearing Protection Attenuation: The estimated reduction in the noise level at the eardrum as a result of the use of hearing protection. Estimated using the formula: Attenuated TWA, dBA = TWA – (Noise Reduction Rating, NRR, – 7) for A – scale weighted sound levels. Attenuated TWA, dBC = TWA – NRR for C-scale weighted sound levels.
8. Noise Induced Hearing Loss, NIHL: The OSHA recordable occupationally related hearing loss, as defined by 29 CFR 1904.10 and 29 CFR 1904.5, and includes a Standard Threshold Shift (STS) of 10 db, with age correction, averaged over the 2K, 3K, and 4K frequencies from baseline in either ear and a 25 db shift from audiometric zero, in the same ear as the 10 dB STS at the same frequencies.
9. Noise Reduction Rating (NRR): The theoretical maximum amount of noise reduction that can be achieved using a hearing protection device. This is a manufacturers’ calculated value and must be displayed with the hearing protection device.
10. Monitoring: The sampling of noise levels using a sound level meter, octave band analyzer, or personal noise dosimeter.
11. Permissible Noise Exposure: The maximum daily noise exposure which may be experienced by employees not using hearing protectors from a continuous 8-hour exposure to a sound level of 90 dBA or equivalent dose of 100%.
12. Standard Threshold Shift (STS): A change in hearing threshold, relative to the most recent audiogram for that employee, of an average of 10 decibels (dB) or more at 2000, 3000, and 4000 hertz in one or both ears and substantiated within 30 days with a follow-up audiogram.
13. Time Weighted Average (TWA): The [equivalent] noise level, in dB, based on an 8-hour exposure time frame. If the noise is not constant over an 8-hour exposure, then a calculated 8-hour TWA must be made using the equation in Table 1. The TWA may also be estimated from the dose or percent noise exposure, based on noise exposure continuous over 8-hours, as given in Table 2.

A. Environmental Health and Safety Shall:

1. Develop the written Hearing Conservation Program and revise the program as necessary.
2. Identify and establish a written agreement with an audiometric testing clinic for occupationally exposed employees. The written agreement is established with the Purdue University Audiology and Speech Sciences Department, M.D. Steer Audiology Clinic (AUS) for the West Lafayette campus. The written agreement with AUS is included as Appendix A. Regional campuses may have a different clinic agreement and shall include the written agreement in Appendix A.
3. Conduct monitoring to identify areas or operations requiring inclusion in a hearing conservation program.
4. Assist in noise control measures (i.e. hearing protection, noise control).
5. Identify approved hearing protection for use by Purdue employees requiring protection.
6. Oversee calibration and servicing of monitoring equipment (sound level meters, noise dosimeters, and other such equipment as necessary to protect the health of the employees) as manufacturers’ guides instruct.

B. Audiometric Testing Clinic Shall:

1. Conduct hearing testing for University employees potentially exposed to noise levels at or above the OSHA Action Level of 85 dBA as an 8 hour TWA in accordance with 29 CFR 1910.95 including:
   1. Conduct audiograms.
   2. Provide training on effects of noise.
   3. Provide training in the use, care, and limitations of hearing protection devices.
2. Provide EHS with written results for employees that have experienced a standard threshold shift of 10 dB or more following loss correction for age, regardless of a 25 dB shift from audiometric zero.
3. Retain audiometric testing results for the duration of an employee’s employment. Audiometric testing record forms are included in this program as Appendix J.
4. Provide EHS with written audiometric testing results for employees upon termination of employment from the University.
5. Maintain written calibration of audiometers and daily operational pre-testing checks. Conduct an exhaustive calibration, as specified in 29 CFR 1910.95(h)(5)(iii), of the audiometric measuring instruments at least every two years.

C. Departments, Supervisors, Directors, Managers Shall:

1. Identify potentially hazardous noise locations and operations and contact EHS for evaluations.
2. Ensure that employees required to participate in the hearing conservation program complete their annual audiometric testing, at the clinic with which a written agreement has been established and all other requirements of the program.
3. Pay the costs of required hearing protection devices for employees. Departments shall also pay any fees assessed for scheduled audiometric testing appointments for which an employee does not appear and does not notify the clinic of the cancellation.
4. Cooperate with EHS in implementing disciplinary steps for employees who fail to cooperate in a timely and reasonable manner with the requirements of the program, including but not limited to failure to schedule or attend audiometric testing at the specified service provider and failure to wear required hearing protection devices. Furthermore, departments will assume the expense of services provided by non-approved service providers.

D. Employee Shall:

1. Assist the supervisor in identifying potentially hazardous noise locations or operations to which they may be exposed.
2. Schedule and complete audiometric testing or exposure assessments as instructed.
3. Use hearing protection as required and in accordance with training received.

A. Monitoring

When information indicates that an employee’s exposure may equal or exceed the action level of 85 dBA for an 8-hour TWA assessment, monitoring shall be conducted by EHS. Affected employees shall be notified of the results of the monitoring where levels at or above the action level are identified. Monitoring activities may consist of:

1. Sound level measurements for locations where the noise level is stationary and expected to be continuous or
2. Personal noise dosimetry for work operations that are highly mobile or random in noise level.
3. Re-monitoring, if a change in equipment, process or controls increases the noise level to the extent that:
   1. Additional employees may be exposed at or above the action level or;
   2. The attenuation provided by the hearing protectors used by the employee(s) does not reduce the noise exposure level to 90 dBA for an 8 hour TWA or 85 dBA as 8 hour TWA for employees that have experienced a standard threshold shift.
   3. Follow-up monitoring if an STS has occurred.
4. The opportunity for affected employees to observe the noise measurements during collection.

B. Audiometric Testing Program

All employees exposed to noise at or above the Action Level are required to participate in the program. This program consists of:

1. A baseline test to be completed within 6 months of the employee’s first exposure above the action level. This test must be preceded by at least 14 hours without exposure to workplace noise at or above 85 dBA or hearing protection devices must be used prior to testing.
2. Annual testing thereafter provided that exposure at or above the action level is expected.
3. Training of affected employees regarding the hazards of noise exposure, and where necessary the fitting of employees with appropriate hearing protection devices and training about their use, care and limitations.
4. A follow-up audiogram may be provided within 30 days if a standard threshold shift has been identified. The employee shall be informed in writing within 21 days of the determination.
5. Audiometric testing reviewed by an audiologist. The audiologist will determine if further evaluation or retraining is needed.
6. Maintenance of audiometric testing equipment in accordance with the requirements of the OSHA Occupational Noise Standard (29 CFR 1910.95 and its appendices).

C. Noise Control

Where noise levels for non-mobile sources are found to be in excess of 90 dBA or above the Permissible Noise Exposure as listed in Table 1 on a continuous basis and employees are required to work in such areas the following measures shall be taken:

1. Engineering controls will be reviewed for feasibility in noise reduction. Until they are implemented or if adequate controls are not feasible then;
2. Hearing protection devices shall be worn by employees whose exposure is at or above 90 dBA as an 8 hour TWA. Hearing protection devices will be made available to exposed employees at no cost. Hearing protection attenuation shall reduce the exposure below 90 dBA as an 8 hour TWA using the NRR of the rated device.
3. For employees exposed to noise levels at or above 85 dBA, but below 90 dBA as an 8 hour TWA the use of hearing protection devices shall be strongly encouraged.

D. Record-keeping

The audiometric testing clinic shall maintain audiometric exams for each tested employee for the duration of that employee’s participation in the program. Upon leaving employment from the University or discontinuance in the Hearing Conservation program, all records will be transferred to EHS. EHS shall maintain all noise monitoring data.

Table 1: 8-Hour TWA Sound Levels and Allowable Exposure Times

Appendix A: Audiometric Testing Clinic Agreement Form

Appendix B: Noise Dosimetry Data Sheet

Appendix C: Area Noise Survey Data Form

Appendix D: Nuisance Noise Report Letter

Appendix E: STS Notification Letter

Appendix F: Noise Comparison Chart

Notes

• Multiple examples within a single row are separated by semicolons for clarity.
• Relative loudness comparisons are based on 70 dB as a reference point.
• “8-hour exposure” references typical occupational exposure guidance.
• The highlighted row in the original table (70 dB) has been converted into a clearly labeled reference row instead of relying on color.

Source

Temple University Department of Civil/Environmental Engineering and related environmental noise studies (as cited in the original document).

Appendix G: Hearing Conservation Program Evaluation Checklist

Appendix H: OSHA Standards and Appendices Hearing Loss Related

• OSHA Occupational Noise Exposure Standard and Appendices 29 CFR 1910.95
• OSHA Determination of Work Relatedness 29 CFR 1904.5
• OSHA Recording Criteria for Cases Involving Occupation Hearing Loss 29 CFR 1904.10

Appendix I: Audiometric Testing Data Sheet