FEBRUARY 23, 1995
HEARING CONSERVATION PROGRAM
1.0 Purpose:
1.1 To establish a policy and procedures to protect employees from potentially damaging levels of workplace noise.
1.2 To outline the procedures and requirements for the evaluation of noise levels, protecting worker's hearing acuity, and audiometric evaluations in accordance with 29 Code of Federal Regulations (CFR) 1910.95. The program required under this OSHA Standard is called a Hearing Conservation Program for occupational noise exposure.
1.3 To identify those operations where Hearing Protection Devices (HPD's) would be appropriate and necessary.
2.0 Scope:
2.1 Occupational noise exposure, for the purposes of this program, shall be known as unwanted and/or excessive noise in the workplace that may cause damage to human hearing. Such noise may be impulse noise of short duration or sustained noise experienced through most of a work shift. The noise level established by OSHA requiring action is an average eight-hour exposure of 85 decibels or above measured on the A-scale. Individuals having this exposure during a full shift shall be included in the Hearing Conservation Program.
2.2 This Directive applies to any employee performing operations or in areas having noise levels which are identified as potentially causing sustained hearing loss.
2.3 This Directive references the City's Hearing Conservation Program which is based on criteria developed by OSHA, the American National Standards Institute (ANSI), and the National Institute for Occupational Safety and Health (NIOSH).
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3.0 Policy:
3.1 Noise monitoring will be conducted for all operations having full shift exposures which may exceed 85 decibels (dBA) on the average. Noise monitoring shall be repeated whenever a change in the process, equipment or controls increases noise exposure where additional employees may be exposed above 85 dBA; the action level. The employee shall be able to observe monitoring, and will receive notification of the results of the testing if found to have an 8-hour Time Weighted Average (TWA) exposure at or above 85 dBA
3.2 All individuals in the Hearing Conservation Program shall receive baseline and annual hearing exams in accordance with OSHA (29 CFR 1910.95). Along with these exams, training shall be given in protecting one's hearing and an interpretation of test results.
3.3 When efforts made to lessen noise exposure such as the use of mufflers, sound absorbing or reflecting barriers, etc. are unsuccessful, the use of HPD's may be necessary to prevent excessive noise from entering the ear canal. The operations where hearing protection shall be required will be identified through noise monitoring.
3.4 HPD's such as earmuffs and/or earplugs shall be worn in areas and operations where necessary. They shall be provided at no cost to the employee in an accessible location for discretionary use. In locations where high noise levels are identified (above 90 decibels), the area shall be posted as "Caution - Hearing Protection Required" or equivalent signage.
3.5 When earplugs or earmuffs are used, all procedures related to their safe use and care shall be followed as specified in this program.
3.6 To ensure a proper and comfortable fit for HPD's, at least three options shall be made available to employees. Employees shall be given the opportunity to provide feedback on their fit and comfort after receiving training on their use and care. A two-week break-in period shall be used in the assessment of which HPD's.
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3.7 Non-disposable HPD's such as earmuffs will be made available to individuals who must use them. These specific HPD's will be checked to determine whether adequate noise attenuation is being achieved for the environment and operation it is used in. A record of their issuance brand name shall be maintained. A reasonable level of cleanliness shall be maintained for all HPD's that are used in common.
3.8 The selection of appropriate HPD's shall be made by a qualified person adequately trained in interpreting noise exposure data and the determination of noise reduction ratings.
3.9 Any extenuating circumstances, conditions or operating procedures not covered within the City's Hearing Conservation Program shall be handled in accordance with a common sense approach, using accepted industry and safety standards.
3.10 All operations determined to merit the use of HPD's shall be accompanied by the use of hearing protection in accordance with the procedures outlined in this written program.
3.11 Contractors, vendors and all other persons not employed by the City shall comply with NIOSH/OSHA regulations prior to performing any City of ______________ operation where hearing protection is required.
3.12 The City's Hearing Conservation Program consists of the following: components:
3.12.1 A provision allowing employees to observe employee noise monitoring
3.12.2 Discussion of components and time frames for hearing exams
3.12.3 Training of employees and interpretation of hearing tests of those within the Hearing Conservation Program
3.12.4 How followup measures will be handled if an employee experiences a Noise Induced Hearing Loss (NIHL).
3.12.5 Criteria to ensure that audiometric tests (hearing exams) are performed accurately
3.12.6 The provision or requirement of HPD's, their proper use and limitations
3.12.7 Discussion of the choices of HPD's and who is able to make these
choices.
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3.12.8 Training elements in the Hearing Conservation Program
3.12.9 Recordkeeping of hearing tests and noise monitoring information
3.12.10 Retention of records
4.0 Distribution:
4.1 All employees.
Date
CITY OF ______________
HEARING CONSERVATION PROGRAM
CONTENTS
Introduction
How Noise Damages Hearing
Noise Monitoring
Audiometric Testing
Use of Hearing Protection Devices
Procedures
Purpose
Administrative Responsibilities
Noise Exposure Monitoring
Audiometric Testing
Response to Audiometric Exams
Response to a Standard Threshold Shift
Hearing Protection Devices
Employee Training
Recordkeeping
Retention of Records
Appendices
Permitted Exposure Times at Various Noise Levels
Operating Sound Levels of Municipal Equipment
Resources for the Hearing Conservation Program
Employee Feedback on Comfort and Fit of HPD's
Audiometric Testing Criteria
Training Log Attendance Sheet
Employee Recordkeeping Form
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INTRODUCTION
HOW NOISE DAMAGES HEARING
There are a number of ways that hearing loss can occur. Some of these are non-preventable, such as hereditary or prenatal damage or hearing loss due to old age. Other causes of hearing loss include damage from disease, specific drug use, puncturing of the ear drum or exposure to noise due to a major explosion. These items will not be covered in the Hearing Conservation Program. Prevention of hearing loss due to sustained noise exposure will be thoroughly discussed in this program.
Sustained exposure to high levels of noise damages the inner ear, its cochlea and small hairs which line the cochlea. The fine hairs which line the cochlea respond to the various frequencies or pitches of sound and then send signals to the auditory nerve to be interpreted by the brain. These hairs vibrate in accordance with the intensity (loudness) and frequency. As the tongue has different receptors (taste buds) to sense different types of taste, the inner ear has different receptors to sense various frequencies. When too much stimuli in the form of loud noises vibrates these hairs excessively, the hairs lose their resiliency at the frequency ranges it is most commonly subjected to. The hairs do not "bounce back" as they should and the person has lessened ability to hear quieter noise levels at those frequencies. If the exposure is temporary such as a motorcycle race or a rock concert, the hearing loss is temporary. If sustained, the hearing loss may be irreversible and permanent.
Noise Induced Hearing Loss (NIHL) is typically characterized by a lessened ability to hear higher frequencies. It may be more difficult to hear women and children with higher pitched voices. A characteristic "notch" is shown at or around 4000 Hertz (Hz) on an audiogram produced by a hearing exam revealing an NIHL. In a hearing exam, the employee is sent noise impulses at various frequencies (Hz) and levels; decibels (dBA). The employee indicates when they are able to hear the impulses. Hearing acuity or ability is determined by measuring at what decibel threshold the person begins hearing the frequency. For example, if the employee begins to hear an impulse at 4000 Hz at 20 decibels when beginning employment, and then three years later, can only begin hearing it at levels above 50 dBA, the employee may be experiencing a noise induced hearing loss. This shift in hearing acuity from 20 to 50 decibels is called a threshold shift. Those with a threshold shift must wear hearing protection when exposed to an average exposure of 85 dBA, as opposed to 90 dBA for those without a loss in hearing.
Excessive levels of noise are particularly dangerous to your hearing in that hearing loss is a very gradual process. One cannot perceive incremental reductions in their ability to hear. Once it is perceived as a hearing loss, the person has sustained a significant hearing loss that
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is irreversible. A reduction in one's hearing effects your communication abilities, their appreciation of aspects of recreation and your ability to respond to danger when an unsafe situation is present. The best policy is to reduce noise exposure through equipment maintenance and/or hearing protection devices and to track the potential for hearing loss through annual hearing exams as a part of the Hearing Conservation Program.
NOISE MONITORING
In order to determine whether noise levels exist in the workplace that could potentially damage one's hearing, noise monitoring must be conducted. The priority on noise evaluations is given to the noisiest operations where elevated noise is sustained for a large part of the shift. Some operations have very noise levels, yet are performed so infrequently or are of such short duration that the potential for hearing loss is minimal. In these cases, the wearing of hearing protection is advised during the high noise exposure such as jackhammer use, grinding, or use of pneumatic tools and compressors. Other times, equipment is run automatically such as aerators or pumps. If these areas are found to be above 90.0 dBA, the areas shall be posted "Caution - Hearing Protection Required" or equivalent signage. One rule of thumb is that speech is typically around 60 dBA. If one is not having to raise their voice substantially to be heard over an operation, then the threat of dangerous noise levels is minimal.
Noise measurements to characterize these conditions is typically conducted by an Industrial Hygienist or an Acoustical Engineer. Instantaneous sound level readings can be obtained on a sound level meter set on the A-scale at slow response. These are useful for determining areas, such as pump rooms, that may have exposures over 90 dBA. They are also useful in determining the extent that certain pieces of equipment are contributing to overall noise exposure and ways to minimize their contribution. Full shift noise exposures can be determined using noise dosimeters that can be placed on a worker throughout the shift. These dosimeters integrates all of the noise impulses during the shift which are over 1/16 of a second and averages them. The average full-shift exposure is the measurement used to determine whether those involved in a particular operation should be included in the Hearing Conservation Program. The average exposure specified in 29 CFR 1910.95 for inclusion in this program is 85 dBA.
AUDIOMETRIC TESTING
Hearing exams, also known as audiometric tests, are used to determine whether the employee's hearing acuity is being diminished through time. This is typically performed by a physician, audiologist, otolaryngologist or a certified technician at a clinic. Mobile test vans equipped with audiometers are also available to perform testing. A baseline hearing exam is performed within six months of an employee's initial employment involving an operation which exposes the employee to an average noise exposure of at least 85.0 dBA. This is seen as the baseline hearing exam used for comparison with annual exams.
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Hearing exams are performed annually where exposure is greater that 85 dBA to determine whether hearing is being diminished at an abnormal rate, suggesting noise induced hearing loss. If an employee's audiogram indicates that the threshold for hearing a frequency of 2000 Hz, 3000 Hz, or 4000 Hz is shifted up by at least 10 dBA, this represents a standard threshold shift. This condition, if verified by continued testing, suggests that hearing protection or other controls are not entirely adequate to protect the employee's hearing. A number of measures in response to this condition are discussed in the program itself.
THE USE OF HEARING PROTECTION DEVICES
When engineering or administrative controls are not able to reduce a worker's average full shift exposure below 85.0 dBA, then Hearing Protection Devices (HPD's) shall be worn. These devices limit the intensity of noise that passes through one's ear canal. They must be fit properly to achieve an adequate barrier (attenuation) from excessive noise. Beyond proper fit, the HPD should be comfortable to wear and not cause or aggravate any medical pathology of the individual's ear. For this reason, the employee shall have the opportunity to select HPD's from a number of different options.
Three types of HPD's are typically used and listed below:
1. Earplugs; either formable, premolded or custom molded
2. Superaural protectors; bands holding soft, rubberlike material in place.
3. Earmuffs; dome shaped device fitting over entire ear with suitable cushion or pad
Currently, the City of ______________ uses all three types of HPD's depending upon the operation.
Generally, the first two types are disposable and earmuffs are not. Non disposable HPD's must be washed frequently and stored in a sanitary manner to minimize the risk of infection.
All HPD's purchased will have a National Institute for Occupational Safety and Health (NIOSH) approval number and have the noise reduction rating of the HPD clearly shown. HPD's, like other personal protective equipment, are approved by NIOSH as performing its intended function safely. The Noise Reduction Rating (NRR) indicates the amount of decibels the HPD will reduce from the inner ear if properly worn. The noise level that actually reaches the ear when HPD's are properly worn can be estimated in the following calculation:
The employee's full shift average noise exposure minus (-) the correction factor.
The correction factor equals (=) Noise Reduction Rating (NRR) - 7 decibels
The actual level which reaches the employee's inner ear must be below 90 dBA for someone with normal hearing acuity and below 85 dBA for those with a standard threshold shift. Earplugs that are NIOSH approved should accomplish this magnitude of noise reduction.
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Consideration should be given to those who need to hear specific communications or warnings. Hearing protection devices which are easily removed and placed around the neck are appropriate for those who must remove HPD's periodically for safety reasons.