Hearing Conservation

OSHA Technical Manual: Hearing Conservation

OSHA 29 CFR 1910. 95 - Noise Protection Standards


Evidence is well established that worker exposure to noise of sufficient intensity and duration can result in hearing damage. Noise-induced hearing loss rarely results from just one exposure; it can progress unnoticed over a period of years. 

1.1 Policy

To provide employees of College of St. Benedict and St. John's University (CSB/SJU)  with a safe and healthful working environment. 

Goal -  to prevent, reduce, and or eliminate hearing loss due to workplace noise exposures. Elements of the program includes the following:

  • survey of work environments  to identify potentially hazardous noise levels and personnel at risk.
  • contain or modify equipment that produce potentially hazardous noise,  wherever technologically and economically feasible, to reduce the noise  to acceptable levels.
  • employ administrative controls and/or the use of hearing protective devices,  where engineering controls are not feasible.
  • conduct hearing tests to monitor the effectiveness of the hearing conservation program. Early detection of temporary threshold shifts will allow further protective action to be taken before permanent hearing loss occurs.
  • is vital to the overall success of a hearing conservation program. An understanding by employees of the permanent nature of noise-induced hearing loss, CSB/SJU hearing conservation program, and the employee's responsibilities under the program are all essential for program effectiveness.

The following  American Conference of Governmental Industrial Hygienists (ACGIH) noise exposure limits referred to as threshold limit values (TLV),  have been adopted as a standard for our program.

Duration per day, hours  Sound level (dBA)













When the sound levels listed above are exceeded, feasible administrative or engineering controls will be instituted. If the controls fail to reduce the sound levels to within those listed above, hearing protection will be provided and used to reduce the sound levels to an acceptable level. In addition, OSHA requirements dictate that whenever employee noise exposures equal or exceed an 8-hour time-weighted average (TWA) of 85 dBA, slow response, a continuing effective hearing conservation program shall be instituted.

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2.1 Environmental Health and Safety Office

The Environmental Health and Safety Office will coordinate the development, implementation, and administration of the Hearing Conservation Program. 

2.1.2 Occupational Health Clinic

The designated Occupational Health Clinic will conduct baseline and annual audiograms for new employees who may be assigned to tasks with potential exposure to elevated levels of noise. Occupational Health Clinic will also schedule and conduct audiograms on an annual basis for employees exposed to sound levels greater than or equal to 80 dBA. The Occupational Health Clinic will notify the EHS, of all areas where employees have experienced significant changes in hearing (standard threshold shifts) in order that follow-up investigations may be conducted.

2.2 Supervisors

Supervisors will  ensure that all of their employees exposed to noise levels equal to or greater than 80 dBA have access to appropriate hearing protective devices in the work area. Supervisors are also responsible for enforcing the use of hearing protective devices and engineering and administrative controls in designated noise hazardous areas.

2.3 Employees

Employees are responsible for wearing and maintaining hearing protective devices as instructed. Employees exposed to excessive levels of noise must also participate in annual training programs and the medical surveillance program which includes audiometric testing.

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Noise Evaluation and Surveillance Procedures

3.1 Identification of Hazardous Noise Areas

EHS will identify work areas within CSB/SJU facilities where noise levels equal or exceed 80 dBA. Records shall be maintained by EHS and updated at least every two years to determine if any alteration in noise levels has occurred. Those areas where the noise levels are below 80 dBA will not be routinely monitored. Identification of hazardous noise areas and equipment and any subsequent noise monitoring will be conducted or arranged to conducted by EHS.

Signs will be posted at the entrance to any work area where noise levels exceed 80 dBA, requiring anyone entering the area to wear proper hearing protection. Personnel who work in these areas shall have hearing protection supplied to them, shall be instructed in its proper use, and be required to wear this equipment when in these identified areas. It is the responsibility of the area supervisor to ensure that these precautions are maintained.

Equipment which produces noise levels greater than 80 dBA, or 120 dB peak sound pressure levels shall also be appropriately labeled.

3.2 Noise Measurements and Exposure Assessments

In order to effectively control noise it is necessary that the noise be accurately measured according to standard procedures and that the measurements be properly evaluated against accepted criteria. All noise monitoring will be conducted in accordance with established standard operating procedures.

The monitoring of employees for noise exposure is made up of two parts, area and personal monitoring. Area measurements are generally obtained first. If noise levels are at or above 80 dBA, personal monitoring using dosimeters is then performed. Sample data sheets will be used to record monitoring data for both area and personal noise monitoring results.

3.2.1 Area Measurements

In an area survey, measurements of environmental noise levels are recorded using a sound level meter to identify work areas where employees' exposures may be above hazardous levels, and where more thorough exposure monitoring may be needed. Area monitoring is conducted using a calibrated sound level meter set to the A scale, slow response. Within the area of interest, several different locations will be measured. Typical measurement locations would include:

  • In the hearing zone at the employee's normal work location.
  • Next to the noise source(s).
  • At the entrance(s) to the work area.
  • At other locations within the area where the employee might spend time working.

A rough sketch of the area will be included with the results showing the locations where the noise readings were obtained.

If the noise levels are below 80 dBA on a time-weighted average basis in the area, no further routine monitoring will be required for that area. Should any of the noise measurements equal or exceed 80 dBA, records shall be maintained as to the noise levels recorded, where they were taken, and the source(s) of the noise. These records shall be updated at least once every two years to determine if any changes have occurred that would warrant remonitoring of exposed personnel. If any of the measurements equal or exceed a noise level of 80 dBA, employees who work in or near the high noise area or equipment shall have their noise exposure determined through personnel monitoring using dosimeters.

3.2.2 Personnel Monitoring

Determination of the noise exposure level will be accomplished using calibrated noise dosimeters. Each employee to be monitored will have a dosimeter placed on him/her at the beginning of his/her normal work shift with the microphone placed in the "hearing zone". The dosimeter will be worn for the full duration of the work shift while the employee performs his/her normal work routine. At the end of the work shift, the dosimeter will be removed and information printed out as soon as possible. Background information will be collected from each employee detailing job description, unusual job activities, etc., for the time period sampled. Those employees whose noise exposure equals or exceeds 80 dBA on an 8-hour TWA will be referred to the designated Occupational Health Clinic for inclusion in the Hearing Conservation Medical Surveillance Program.

3.3 Re-monitoring of Hazardous Noise Areas

All areas where noise levels equal or exceed 80 dBA shall be re-monitored at least every two years. Employees who work for extended periods of time (>2 hours) in the high noise areas and where their 8-hour TWA equals or exceeds 80 dBA will be monitored every year to determine their personal noise exposure.

Whenever an employee exhibits a standard threshold shift, as determined by the Occupational Health Clinic, the employee's work place shall be re-monitored to identify and ameliorate the cause.

3.4 Re-monitoring Due to Changes

Any area with noise levels that equal or exceed 80 dBA shall also be re-monitored whenever a change in production process, equipment, or controls increase the noise exposure such that additional employees are exposed to noise levels at or above 80 dBA on a time-weighted average basis. Areas where the noise levels have dropped below 80 dBA due to alterations in equipment, controls or process changes shall be eliminated from the monitoring program.

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Noise Control Methods

4.1 Engineering and Administrative Controls

The primary means of reducing or eliminating personnel exposure to hazardous noise is through the application of engineering controls. Engineering controls are defined as any modification or replacement of equipment, or related physical change at the noise source or along the transmission path that reduces the noise level at the employee's ear. Engineering controls such as mufflers on heavy equipment exhausts or an air release valves are required where possible.

Administrative controls are defined as changes in the work schedule or operations which reduce noise exposure. If engineering solutions cannot reduce the noise, administrative controls such as increasing the distance between the noise source and the worker or rotation of jobs between workers in the high noise area should be used if possible.

The use of engineering and administrative controls should reduce noise exposure to the point where the hazard to hearing is eliminated or at least more manageable.

4.2 Personal Protective Equipment

Hearing protective devices (ear plugs, muffs, etc.) shall be the permanent solution only when engineering or administrative controls are considered to be infeasible or cost prohibitive. Hearing protective devices are defined as any device that can be worn to reduce the level of sound entering the ear. Hearing protective devices shall be worn by all personnel when they must enter or work in an area where the operations generate noise levels of:

  • Greater than 80 dBA sound levels, or
  • 120 dB peak sound pressure level or greater

4.2.1 Types of Hearing Protective Devices (HDPs)
Hearing protective devices include the following:

      • Premolded earplugs are pliable devices of fixed proportions. Two standard styles, single flange and triple flange, come in various sizes, and will fit most people. Personnel responsible for fitting and dispensing earplugs will train users on proper insertion, wear, and care. While premolded earplugs are reusable, they may deteriorate and should be replaced periodically.

      • Formable earplugs come in just one size. Some are made of material which, after being compressed and inserted, expands to form a seal in the ear canal. When properly inserted, they provide noise attenuation values that are similar to those from correctly fitted premolded earplugs. Individual units may procure approved formable earplugs. Supervisors must instruct users in the proper use of these earplugs as part of the annual education program. Each earplug must be held in place while it expands enough to remain firmly seated. A set of earplugs with a cord attached is available. These earplugs may be washed and therefore are reusable, but will have to be replaced after two or three weeks or when they no longer form an airtight seal when properly inserted.

      • A small percentage of the population cannot be fitted with standard premolded or formable earplugs. Custom earplugs can be made to fit the exact size and shape of the individual's ear canal. Individuals needing custom earplugs may be referred to an audiologist.

      • Earmuffs are devices worn around the ear to reduce the level of noise that reaches the ear. Their effectiveness depends on an air tight seal between the cushion and the head.

Insert Type Earplugs
A device designed to provide an air-tight seal with the ear canal. There are three types of insert earplugs - premolded, formable, and custom earplugs.

Premolded Earplugs


Custom Molded Earplugs


4.2.2 Selection of Hearing Protective Devices

Employees should be given the opportunity to select hearing protective devices from a variety of suitable ones. In all cases the chosen hearing protectors shall have a Noise Reduction Ratio (NRR) high enough to reduce the noise at the ear drum to 80 dBA or lower.

4.2.3 Issuance of Hearing Protective Devices

The issuance of hearing protective devices is handled at department level, in consultation with both the CSB/SJU Occupational Health Clinic and EHS. The Occupational Health Clinic may issue and fit the initial hearing protective devices (foam inserts, disposables). Instruction on the proper use and care of earplugs and earmuffs will be provided whenever HPDs are dispensed. Personnel requiring earmuffs in addition to earplugs will be informed of this requirement and educated on the importance of using proper hearing protection. The department managers will dispense ear muffs when necessary and will maintain a supply of disposable earplugs.

4.2.4 Use of Hearing Protective Devices

  • Always use and maintain HPDs as originally intended and in accordance with instructions provided.
  • Earmuff performance may be degraded by anything that compromises the cushion-to- seal. This includes other pieces of personal protective equipment such as eyewear, masks, face-shields, and helmets.

4.2.5 Maintenance of Hearing Protective Devices

  • Reusable earplugs, such as the triple flange or formable devices should be washed in lukewarm water using hand soap, rinsed in clean water, and dried thoroughly before use. Wet or damp earplugs should not be placed in their containers. Cleaning should be done as needed.
  • Earmuff cushions should be kept clean. The plastic or foam cushions may be cleaned in the same way as earplugs, but the inside of the muff should not get wet. When not n use, ear muffs should be placed in open air to allow moisture that may have been absorbed into the cups to evaporate.

4.2.6 Hearing Protection Performance Information

The maximum of sound attenuation one gets when wearing hearing protection devices is limited by human body and bone conduction mechanisms. Even though a particular device may provide outstanding values of noise attenuation the actual noise reductions may be less because of the noise surrounding the head and body bypasses the hearing protector and is transmitted through tissue and bone pathways to the inner ear.

The term "double hearing protection" is misleading. The attenuation provided from any combination earplug and earmuff is not equal to the sum of their individual attenuation values.

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Medical Surveillance

5.1 Notification

Upon identification of employees whose 8-hour TWA equals or exceeds 80 dBA, EHS will recommend to the Occupational Health Clinic and the employee's Supervisor, in writing, of the need to enroll certain employee(s) in the Hearing Conservation Medical Surveillance Program. Information supplied to the OHC will include the employee(s) name, supervisor's name, telephone number, and the noise levels recorded in the employee's work area, including dosimetry data. It will be the responsibility of the Supervisor to enroll his/her employee in the Hearing Conservation Medical Surveillance Program.

In work locations where either through administrative or engineering controls, noise levels are found to have fallen such that the employee's 8-hour TWA is below 80 dBA, EHS shall notify the Clinic and the employee's Supervisor, by memo, that the employees working in that area are no longer required to be enrolled in the Hearing Conservation Program. The final decision as to an employee's enrollment status will be left with the Occupational Health Clinic Physician.

The results of area and personal remonitoring shall be forwarded to the Clinic upon completion of the noise surveys.

Any personnel experiencing difficulty in wearing assigned hearing protection (i.e., irritation of the canals, pain) will be advised to immediately report this to their supervisor and make arrangements to go to the Occupational Health Clinic for evaluation as soon as possible.

5.2 Audiometric Testing

The designated Occupational Health Clinic has the responsibility for administering the Audiometric Testing Program portion of the CSB/SJU Hearing Conservation Program. The object of the audiometric testing program is to identify workers who are beginning to lose their hearing and to intervene before the hearing loss becomes worse. Audiometric testing will be provided to all employees with exposure to noise levels of 80 dBA or greater. Annual retesting will be performed for all personnel enrolled in the Hearing Conservation Medical Surveillance Program.

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The training and education program will provide information about the adverse effects of noise and how to prevent noise-induced hearing loss. At a minimum, all training will cover the following topics:

  • Noise-induced hearing loss;
  • Recognizing hazardous noise;
  • Symptoms of overexposure to hazardous noise;
  • Hearing protection devices - advantages and limitations.
  • Selection, fitting, use, and maintenance of HPDs.
  • Explanation of noise measurement procedures.
  • Hearing conservation program requirements.

Participating employees will also have access to copies of the OSHA noise standard (29 CFR 1910.95) and other handouts describing the CSB/SJU Hearing Conservation Program. Information provided in Appendix C of this document may also be used.

CSB/SJU employees are encouraged to use hearing protective devices when they are exposed to hazardous noise during activities at home; e.g., from lawn mowers, chain saws, etc.

All personnel identified for inclusion in the hearing conservation program should receive initial instruction in the requirements of the program. Ideally this will be done when hearing protection is dispensed.

Appropriate and documented refresher training annually thereafter, will be provided by the immediate supervisor. Supervisors will be provided annual refresher training/material by the Environmental Health and Safety Office.

Supervisors can contact the EHS or Occupational Health Clinic to schedule training for new personnel assigned to work in noisy environments and if needed, for retraining of current personnel.

Program Evaluation

Periodic program evaluations will be conducted to assess compliance with federal and state regulations and CSB/SJU Program requirements. Both the monitoring and audiometric testing portions of the CSB/SJU Hearing Conservation Program will be reviewed annually to assure its quality and effectiveness.

An evaluation of the Program, including wearer acceptance, appraisal of protection afforded, and field audits of hearing protection use and record keeping will be conducted at least annually. Items to be considered include:

  • Standard operating procedures
  • Training records and course content for supervisors and employees.
  • Maintenance of HPDs
  • Field audits of HPD use
  • Review of recorded threshold shifts on OSHA log.

The findings of the CSB/SJU Hearing Conservation Program evaluation will be documented, and this documentation will list plans to correct faults in the program and set target dates for the implementation of the plans.

Standard Operating Procedures

An important element of the CSB/SJU Hearing Conservation Program is the development of detailed standard operating procedures (SOPs). The SOPs outline the steps necessary to meet the goals of the Procedure (Appendix A) and document Hearing Conservation Program activities within the Environmental Health and Safety Office. The SOPs are periodically reviewed and revised by the Health and Safety Officer.

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Record Keeping

The Hearing Conservation Program records will include and be kept as follows:

Record  Location

Medical Evaluation and Audiograms 

Personnel file at Human Resource Office
Designated Occupational Health Clinic. 

Training Records 

Environmental Health and Safety Office 
Department Manager/Supervisor's Office 

Hearing Conservation Program  

Environmental Health and Safety Office 
Designated Occupational Health Clinic 
Department Manager/Supervisor's Office

Hazard Evaluations (Work area noise surveys, personnel monitoring) 

Environmental Health and Safety Office 
Department Manager/Supervisor's Office

Program Evaluations 

Environmental Health and Safety Office 
Department Manager/Supervisor's Office

All non-medical records (ex., work area and equipment surveys) will be maintained for a period of five years. Results of hearing tests and medical evaluations performed for hearing conservation purposes as well as noise exposure documentation shall be recorded and shall be a permanent part of an employee's health record.

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ACGIH, Threshold Limit Values and Biological Exposure Indices, Physical Agents, Noise, current edition

Berger, E. H., et.al., Ed., Noise & Hearing Conservation Manual, 4th ed., Akron, OH: American Industrial Hygiene Association, 1986.

NIOSH, A Practical Guide to Effective Hearing Conservation Programs in the Workplace, September 1990.

OSHA, General Industry Standard, 29 CFR 1910.95, "Occupational Noise Exposure"


Appendix A - Noise - Training Information


Supervisors and exposed workers must become aware of and understand about the adverse effects of noise and how to prevent noise-induced hearing loss. People exposed to hazardous noise must take positive action, if progressive permanent hearing loss is to be prevented. Each exposed worker and supervisor should know the following.

  • Noise exposure may result in permanent damage to the auditory system and there is no medical or surgical treatment for this type of hearing loss. Though the use of a hearing aid may provide some benefit, normal hearing will not be restored. Many people don't realize loud sounds can cause hearing loss. Furthermore, in its initial stages, the person may not notice a problem since noise-induced hearing loss is invisible, painless, and occurs in the high frequencies. It is dangerous to ignore the temporary characteristics of noise-induced hearing loss (such as ringing or buzzing in the ears, excessive fatigue, etc.).
  • Each person should know how to recognize hazardous noise even if a noise survey has not been conducted and or warning signs posted. Recognizing and understanding the adverse effects of off-duty noise exposures is also important. The best rule to follow is: "If you have to shout at arms length (approximately three feet) to talk face-to-face, you are probably being exposed to hazardous levels of noise."
  • Preventing noise-induced hearing loss is accomplished by reducing both the time and intensity of exposure. Reducing exposure time is accomplished by avoiding any unnecessary exposure to loud sound. Reducing intensity is usually accomplished by wearing personal hearing protection. Each person must be able to properly wear and care for the particular type of hearing protection selected. Speech communication is difficult in high intensity noise. However, most people don't realize it's easier to understand speech if hearing protection is worn in a hazardous noise environment. Hearing protection reduces the noise and the level of speech, resulting in a more favorable listening level. hearing protection reduces the intensity of frequencies above the speech range; thus, reducing the noise and accentuating speech. People who claim wearing hearing protection makes it difficult to hear speech are probably in noise levels less than 85 dBA or have already developed a hearing loss.
  • Each person must know how to tell if they have been overexposed to loud sound. Overexposure may occur even while wearing hearing protection. Earplugs and/or earmuffs alone may not be enough protection. Each time a temporary threshold shift (TSS) occurs, a certain degree of permanent loss results. The recognizable symptoms of overexposure are described as "dullness in hearing or ringing in the ears."

Appendix B

Occupational Safety and Health Administration Standard - 29 CFR 1910.0095 - Noise

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