29 CFR 1910.95: OSHA Summary of Occupational Noise Exposure
Noise levels capable of causing permanent damage to hearing can be generated by a wide variety of sources including construction, machinery, steam generation, concerts and heavy equipment. To protect hearing, people should take measures to limit or minimize all exposures to harmful sound levels. This can be done by either controlling the sound source by reducing the level, by isolating the source or muffling the sound or by the use of personal protective equipment such as ear plugs or muffs.
Employers have a responsibility to determine where hazardous noise exposures may exist, and take steps to protect affected employees.
The PEOSH Occupational Noise Exposure Standard, 29 CFR1910.95, states that “When information indicates that any employee’s exposure may equal or exceed an 8-hour time-weighted average of 85 decibels (dB) the employer shall develop and implement a monitoring program (29 CFR 1910.95(d)).
All University employees whose noise exposures equal or exceeds an eight-hour time weighted average (TWA) of 85 decibels are enrolled in a hearing conservation program. When information indicates that any employee’s exposure may equal or exceed an 8-hour time-weighted average of 85 decibels, the department is to notify the Health and Safety Office to implement a monitoring program.
Applicable Regulations
The following regulations apply to occupational noise exposure:
- 29 CFR 1910.95 - OSHA Occupational Noise Exposure
- Applicable University Policy: Hearing Conservation Program
Summary of Requirements
The Occupational Safety and Health Administration (OSHA) has specific requirements for employers to protect employees from the harmful effects of noise in the workplace. The key components of these requirements are outlined below.
Noise Monitoring
Employers are required to monitor noise levels to identify employees that may be routinely exposed to noise at or above an 8-hour Time-Weighted Average (TWA) of 85 decibels (dB). This noise level is referred to as the Action Level. When is it necessary to implement a noise monitoring program? It is not necessary for every employer to measure workplace noise. Noise monitoring or measuring must be conducted only when exposures are at or above 85 dB.
Typical conditions that would suggest the possibility of overexposure include employee complaints, indications that an employee's hearing capability is diminishing, or noise conditions that make normal conversation difficult. The employer should also consider any information available regarding noise emitted from specific machines.
Additional monitoring must be performed if there are significant changes in machinery, controls or processes that may increase noise levels.
The employee is to be notified when he/she is exposed at or above an 8-hour time-weighted average of 85 decibels. Affected employees are entitled to observe monitoring procedures, and they must be notified of exposure monitoring if levels are measured at or above 85 dB.
The employer must make a copy of OSHA standard 29 CFR 1910.95 available to employees and post a copy in the workplace.
How is noise measured?
Basically, there are two different instruments to measure noise exposures: the sound level meter and the dosimeter. A sound level meter is a device that measures the intensity of sound at a given moment. Since sound level meters provide a measure of sound intensity at only one point in time, it is generally necessary to take a number of measurements at different times during the day to estimate noise exposure over a workday. To estimate employee noise exposures with a sound level meter it is also generally necessary to take several measurements at different locations within the workplace.
After appropriate sound level meter readings are obtained, people sometimes draw “maps” of the sound levels within different areas of the workplace. By using a sound level “map” and information on employee locations throughout the day, estimates of individual exposure levels can be developed.
A dosimeter is like a sound level meter except that it stores sound level measurements and integrates these measurements over time, providing an average noise exposure reading for a given period of time, such as an 8-hour workday. With a dosimeter, a microphone is attached to the employee's clothing and the exposure measurement is simply read at the end of the desired time period. A reader may be used to read-out the dosimeter's measurements. Since the dosimeter is worn by the employee, it measures noise levels in those locations in which the employee travels.
A sound level meter can also be positioned within the immediate vicinity of the exposed worker to obtain an individual exposure estimate. Area monitoring can be used to estimate noise exposure when the noise levels are relatively constant and employees are not mobile.
In situations where personal monitoring is appropriate, proper positioning of the microphone is necessary to obtain accurate measurements. With a dosimeter, the microphone is generally located on the shoulder and remains in that position for the entire workday.
Manufacturer's instructions, contained in dosimeter and sound level meter operating manuals, should be followed for calibration and maintenance.
How often is it necessary to monitor noise levels?
The amendment requires that when there are significant changes in machinery or production processes that may result in increased noise levels, remonitoring must be conducted to determine whether additional employees need to be included in the hearing conservation program.
Where can equipment and technical advice be obtained?
Noise monitoring equipment may be either purchased or rented. Sound level meters cost about $500 to $1,000, while dosimeters range in price from about $750 to $1,500. Smaller companies may find it more economical to rent equipment rather than to purchase it.
Names of equipment suppliers may be found in the telephone book (Yellow Pages) under headings such as: “Safety Equipment,” “Industrial Hygiene,” or “Engineers-Acoustical.” In addition to providing information on obtaining noise monitoring equipment, many companies and individuals included under such listings can provide professional advice on how to conduct a valid noise monitoring program. Some audiological testing firms and industrial hygiene firms also provide noise monitoring services.
Free, on-site assistance may be obtained from OSHA-supported state and private consultation organizations.
Hearing Protection
Hearing protective devices must be available to all workers exposed to noise levels at or above the Action Level. Hearing protective devices must be worn by the following employees exposed to an 8-hour average noise level at or above 85 dB.
Hearing protection must attenuate employee exposure below 85dB TWA. Employers must supervise the correct use of hearing protection.
The University strongly encourages the use of hearing protection devices while working around noisy equipment. For employees who have experienced a standard threshold shift, hearing protectors must attenuate employee exposure to an 8-hour time-weighted average of 85 decibels or below.
Signs are to be posted in areas where noise levels are above 85 dBA stating that hearing protection is required.
Personal protective equipment for hearing protection is of two basic types, ear plugs and muffs, and a variety of each type is available. The choice of hearing protection provided should be based on the sound levels present in the workplace where the hearing protection will be used.
Audiometric Testing
A baseline audiogram (hearing test) must be provided to employees whose 8-hr TWA noise exposure meets or exceeds the Action Level. This baseline testing must be performed within 6 months of the employee's first exposure to noise at or above the Action Level. Mobile test van exception. Where mobile test vans are used to meet the audiometric testing obligation, the employer shall obtain a valid baseline audiogram within 1 year of an employee's first exposure at or above the action level.
The baseline audiogram is established to compare against subsequent audiograms. Employees are to be notified, in writing, of the results of exams. Testing to establish a baseline audiogram shall be preceded by at least 14 hours without exposure to workplace noise.
Annual audiograms must be performed for each employee exposed at or above the Action Level to monitor changes in hearing ability. Annual audiograms are compared to initial baseline levels to identify hearing loss (i.e., Standard Threshold Shift). Each employee's annual audiogram shall be compared to that employee's baseline audiogram to determine if the audiogram is valid and if a standard threshold shift as defined in paragraph (g)(10) of this section has occurred. The audiologist, otolaryngologist, or physician shall review problem audiograms and shall determine whether there is a need for further evaluation.
The functional operation of the audiometer shall be checked before each day's use by testing a person with known, stable hearing thresholds, and by listening to the audiometer's output to make sure that the output is free from distorted or unwanted sounds. Audiometer calibration shall be checked acoustically at least annually in accordance with appendix E: Acoustic Calibration of Audiometers. Test frequencies below 500 Hz and above 6000 Hz may be omitted from this check. An exhaustive calibration shall be performed at least every two years in accordance with sections 4.1.2; 4.1.3.; 4.1.4.3; 4.2; 4.4.1; 4.4.2; 4.4.3; and 4.5 of the American National Standard Specification for Audiometers, S3.6-1969.
If a Standard Threshold Shift is identified, employees must be fit or refitted with hearing protection adequate to attenuate noise levels below the Action Level. Employees must be notified of a Standard Threshold Shift within 21 days of its determination.
Annual audiometric testing is performed by a licensed or certified audiologist, at UNC School of Medicine’s Speech and Hearing department. Audiometric tests are to be pure tone, air conduction, hearing threshold examinations, with test frequencies including as a minimum 500, 1000, 2000, 3000, 4000 and 6000 Hz.
Administrative and Engineering Controls
When employees are subjected to sound levels exceeding 85 dBA TWA, feasible administrative or engineering controls are to be utilized. Types of administrative controls are rotation of employees, limiting time of certain operations, or restricting areas or work operations.
If feasible engineering or administrative controls cannot be accomplished personal hearing protective devices must be provided and used to reduce sound levels in areas above 85 dBA. The hearing protection used will depend on the operation, employee preference and attenuation required. The safety and health officer is to assist in supplying information on attenuation data and supervise the correct use of hearing protectors. Employees are given the opportunity to select their hearing protectors from a variety of suitable hearing protectors.
Training
Employees exposed to noise levels at or above the Action Level must be trained at least annually about:
- The effects of noise on hearing;
- The purpose of hearing protection;
- The advantages, disadvantages and attenuation of various types of hearing protection;
- Instructions on the selection, fitting, use and care of hearing protection; and
- The purpose and procedures of audiometric testing.
An annual training program is provided for each employee included in the hearing conservation program.
Recordkeeping
Noise exposure measurements must be maintained for two years. Employee exposure measurements and assessments are maintained at the office of Environment, Health and Safety. Employee audiometric test records are kept at the University Employee Occupational Health Clinic.
OSHA Standards and Regulations
Employee exposure to occupational noise hazards is addressed in OSHA’s general industry standards and the recording of occupational hearing loss is addressed in OSHA’s injury and illness recordkeeping regulation.
Section 5(a)(1) of the OSH Act, often referred to as the General Duty Clause, requires employers to "furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees". This section may be used to address hazards for which there are no specific OSHA standards, e.g.
State Plans
There are 29 OSHA-approved State Plans operating state-wide occupational safety and health programs.
Note: These are NOT OSHA standards or regulations. However, they do provide guidance from their originating organizations related to worker protection from noise.
Additional Resources
Paragraphs (c) through (o) of 29 CFR 1910.95 and the accompanying appendices contain provisions which incorporate publications by reference. Generally, the publications provide criteria for instruments to be used in monitoring and audiometric testing. It should be noted that OSHA does not require that employers purchase a copy of the referenced publications.
The referenced publications (or a microfiche of the publications) are available for review at many universities and public libraries throughout the country.
Definitions
- Medical pathology-A disorder or disease.
- Sound level-Ten times the common logarithm of the ratio of the square of the measured A-weighted sound pressure to the square of the standard reference pressure of 20 micropascals. Unit: decibels (dB).