Hearing Conservation

Purpose

This program is designed to prevent hearing loss for students, staff and employees while engaged in university-sponsored activities.

Scope and Applicability

This program shall apply to all employees, students and visitors to the University who are expected to be exposed to noise great enough to cause hearing damage.  As a reference, 85 decibels, A-scale, (dBA) for an average of 8-hours per day shall be used.  If octave band analysis is used to determine noise exposure, table G-9 in 29 CFR 1910.95 can be used. The provisions for audiometric testing and associated record keeping and training shall not apply to students or visitors.  This program shall not apply to individuals attending events on campus for entertainment purposes.

Abbreviations and Definitions

Abbreviations

ANSI – American National Standards Institute

dBA – decibels (A-scale)

EHS – Environmental Health and Safety

NRR – Noise reduction rating

OSHA – Occupational Safety and Health Administration

Definitions

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%.

Weighted Sound Level (dBA): The weighting of sound levels that represents the function of the human ear.

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.

Decibel (dB): Unit of measurement of sound level.

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.

Hearing Protection Attenuation: The estimated reduction in the noise level at the eardrum as a result of the use of hearing protection.

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.

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.

Monitoring:  The sampling of noise levels using a sound level meter, octave band analyzer, or personal noise dosimeter.

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%.

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.

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.

Roles and Responsibilities

University Administration shall provide:

1. Endorsement of the written plan.
2. Delegation of sufficient authority to the respective department heads involved to implement the plan.
3. Appropriate the necessary resources required to implement the plan.

Supervisors shall:

1. Assure that the authorized individual(s) receive all necessary training to discharge their duties.
2. Assure that all equipment necessary to protect the health and safety of the workers are provided and maintained in a good state of repair.
3. Enforce the written control program.

EHS shall:

1. Develop a written Noise Conservation policy and perform a periodic review to determine if revisions are necessary.
2. Monitor compliance of the respective departments’ compliance with the Hearing Conservation Program.
3. Provide guidance and technical assistance to departments in the design and selection of appropriate engineering and administrative controls.
4. Provide guidance and technical assistance to departments in the selection of the most appropriate types and quantities of personal protective equipment.
5. Provide consultation to the departments to assist them in fulfilling their training needs.
6. Promote campus compliance with the OSHA Standard.
7. Provide a means by which employees can direct suggestions, complaints, and concerns regarding the campus Hearing Conservation Program.
8. Identify, evaluate, and make recommendations regarding those operations and locations requiring hearing protection.

Employees shall:

1. Participate willingly in all training programs offered by the University and learn as much as possible about the Hearing Conservation Program.
2. Abide by all rules and apply to the fullest extent possible the safety and health precautions specified by the University.
3. Report any problems that are observed, which could compromise health and safety, to the University administration through their immediate supervisor.
4. Maintain his or her hearing protection equipment in a safe and sanitary condition and use hearing protection as required.

Program elements

Determination of Noise Hazards and Monitoring

EHS shall conduct periodic survey of the campus to identify equipment, processes and locations that generate substantial noise.  Individuals exposed to noise levels exceeding an 8-hour, time- weighted average of 85 dBA shall be included in the Hearing Conservation Program.  A sufficient number of measurements shall be taken to account for random fluctuations in employee noise exposure.

Sound level survey readings shall be taken to document the findings.  In some cases, it may be necessary to use dosimetry to determine the individual’s noise exposure.

Noise levels shall be checked (monitored) periodically.  The frequency of monitoring shall be determined by EHS.  Any individual in the University community may request a sound level survey.

Impact Noise

Impact or impulsive noise is defined as noise that reaches a maximum at an interval exceeding one second in duration. The maximum permit impact noise is 140 dBA. The following table shall be used to determine the permissible level of impact noise.

Sound Level (dB)	Permitted Number of Impact or Impulses Per Day
140	100
130	1000
120	10000

 

Controls

Personal protective equipment is considered the last choice with respect to controlling an employee’s exposure to a noise source.  This fact is based on low employee acceptable and improper use of personal protective equipment.  It may be necessary to use several control methods in combination to assure workers’ health.  Hearing protectors may be used to prevent noise exposure while engineering or administrative controls are being developed.  The following controls are arranged in descending order, with the first being the preferred method of control.

Engineering controls are the best choice, when feasible, for dealing with an occupational hazard. The first control to consider regarding a noise sources is elimination of the source. Other engineering controls include equipment that produces lower sound level pressure, shielding or enclosure of equipment.

The second control method is known as administrative controls, which are also known as work practices. Examples of this control method involves rotation of workers, providing greater distance between the worker and the noise source, using less power or pressure to accomplish the task.

The third control method is personal protective equipment. Personal protective equipment can take the form of ear plugs, ear muffs, helmets or circumaural protectors.  Some personal protective equipment uses active noise attenuation which is based on generation of a pressure wave that is 180 degrees out of phase with the noise source.

Selection of Hearing Protectors

The type(s) of hearing protection used by the employee shall reduce the sound level pressure to an 8-hour, time-weighted average of 85 dbA or less.  All hearing protection has a noise reduction rating (NRR) which is expressed in decibels.  These ratings were developed under laboratory conditions and do not represent actual use.  The measurement of the effectiveness of the hearing protector varies based on whether the A-scale or C-scale is used and whether dosimetry or area exposures are measured.  Consult EHS with regards to the field or adjusted NRR.

Employees shall be offered several different types of hearing protectors (e.g. plugs, muffs) that meet the necessary sound level attenuation.

Care, Maintenance and Storage of Hearing Protectors

Employee exposed to excessive noise shall be furnished with hearing protection.  The University shall provide all necessary hearing protection at no cost to employees.  Hearing protectors shall be inspected by the employee before each use for damaged, worn, or missing parts.  Hearing protection devices shall be kept in good repair or replaced if unserviceable.

Audiometric Testing

Each employee exposed to noise levels in excess of 85 dBA (8-hour average) shall be offered an audiometric test. Employees shall be tested within six months of the date of their initial exposure to a time weighted average of 85 dBA or higher.  Tests shall be preceded by at least 14 hours without exposure to noise (work or non-work related). Retesting shall be offered annually. All testing shall be offered the employee at no charge.  The initial test shall serve as a baseline against which all subsequent tests are compared.  The test shall be administered and reviewed by an individual(s) meeting the requirements set forth in 29 CFR 1910.95.

The effects of non-occupational noise exposure, age, disease, and drugs shall be considered during evaluation of the audiograms.

Training and Information

Employee Training

Employees shall be trained in hearing conservation.  Refresher training shall be conducted on an annual basis.  The following training requirements were taken from OSHA and ANSI and must be covered during training:

1. Noise hazards and the effects on hearing.
2. Engineering and administrative controls being used and the need for hearing protectors.
3. Reasons for selecting a particular type of control.
4. The function, capabilities, and limitations of the selected hearing protector.
5. The proper fitting of the hearing protector.
6. Maintenance, inspection, and storage or hearing protectors.
7. The University’s program for hearing conservation and
8. The purpose of audiometric testing.

Acceptable sources of training include courses offered through Environmental Health and Safety, and other courses offered outside the University.  Records shall be kept on employees who have been trained in the hearing conservation program.

Recordkeeping

Listed below are various records that must be maintained under the hearing conservation program.

Record	Location where record is kept	Minimum length of record retention
Audiometric testing	Department	40 years
Employee training	Department	3 years
Medical opinion	Department	40 years
Sound level measurements – dosimetry and surveys	EHS	10 years
Sound level meter calibration	EHS	3 years

 

The medical opinion and audiometric testing are considered medical records and shall be kept secure by the employee’s department or by EHS.

Records may be kept in paper or electronic form.

Employee Notification

Employees shall be notified, either verbally or in writing, when their noise exposure exceeds a time-weighted average of 85 dBA.

Each employee who has experienced a standard threshold shift shall be notified in writing within 21 days of the date of determination.  A standard threshold shift shall be defined as an average hearing loss of 10 dBA at 2,000, 3,000, and 4,000 Hz.

Off-site Noise Hazards

Members of the university community shall be covered by this plan when noise hazards are encountered off site.  It shall be the responsibility of the dean, director, department head or immediate supervisor to identify employees and students, under their supervision, who may be exposed to high noise levels.  EHS is available to assist departments manage off-site hearing conservation programs.

Examples of such locations include hand gun certification for University police officers and graduate students’ field practice in various industries.

References

OSHA General Industry – 29 CFR 1910.95

 

Disclaimer

The information provided in these guidelines is designed for educational use only and is not a substitute for specific training or experience.

The University of Tennessee Knoxville and the authors of these guidelines assume no liability for any individual’s use of or reliance upon any material contained or referenced herein. The material contained in these guidelines may not be the most current.

This material may be freely distributed for nonprofit educational use. However, if included in publications, written or electronic, attributions must be made to the author. Commercial use of this material is prohibited without express written permission from the author.