Course 159 Hearing Protection: Basic

Hazard Controls and Protective Measures

123rf photo 92134513
Limit exposure excessive noise.

Noise control strategies are the first line of defense against excessive noise exposure. The use of these controls should aim to reduce, eliminate, or replace the sources of excessive noise and to reduce exposure to noise hazards to the point the risk to hearing is eliminated or minimized.

With the reduction of even a few decibels, the hazard to hearing is reduced, communication is improved, and noise-related annoyance is reduced. There are several ways to control and reduce worker exposure to noise in the workplace.

Reduce the Hazard and Exposure

OSHA's hierarchy of controls for noise can be summarized as:

  1. Engineering controls to eliminate or contain the escape of the hazardous noise at its source;
  2. Administrative controls to control exposure by changing work schedules to reduce the amount of time any one worker spends in the hazard area; and
  3. Personal protective equipment (PPE) to control the exposure with barriers between the worker and the hazard.

This hierarchy highlights the principle that the best prevention strategy is to eliminate the source of hazardous noise levels, and if that is not successful, manage exposure to those hazards through scheduling and the use of PPE. When it is not possible to eliminate the noise hazard or relocate the worker to a safe area, the worker must be protected with personal protective equipment.

The use of these controls should reduce hazardous exposure to the point where the risk to hearing is eliminated or at least more manageable.

Click on the button below to see a video about the hierarchy of controls.

1. Which of the following strategies is best to protect employees from workplace hearing loss?

a. Eliminate the source of the noise
b. Eliminate exposure to the source of the noise
c. Place a barrier between the source and the employee
d. Wear approved noise protection devices

Engineering Controls

gsg eng controls
Placing a barrier between the noise and the worker.

For hearing loss prevention purposes, "engineering controls" is defined as any modification or replacement of equipment, or related physical change at the noise source or along the transmission path (with the exception of hearing protectors), that reduces the noise level at the employee's ear.

Typical engineering controls involve:

  1. Reducing noise at the source
  2. Interrupting the noise path
  3. Reducing reverberation
  4. Reducing structure-borne vibration

Simple engineering noise control solutions can reduce the noise hazard to the extent that audiometric testing, a hearing conservation program, and the use of hearing protectors are not necessary. Examples of inexpensive, effective engineering controls that can be applied include:

  • Choosing low-noise tools and machinery (e.g., compressors, grinders, etc.)
  • Maintaining and lubricating machinery and equipment (e.g., oil bearings)
  • Placing a barrier between the noise source and employee (e.g., sound walls or curtains)
  • Enclosing or isolating the noise source

2. Which of the following is defined as any modification or replacement of equipment, or change at the noise source or along the transmission path, that reduces the noise level at the employee's ear?

a. Administrative controls
b. Engineering controls
c. Equipment controls
d. Interim measures

Engineering Control Examples

modifying equipment to reduce the noise level.
Changing a hard bend to a soft bend in a steam line an reduce noise levels.

The diagram to the right shows how installing softer bends in the pipe and increasing the distance between the valves will reduce the turbulence in the line and, consequently, reduce the noise generated. Often, large pressure drops across valves, which cause noise, can be prevented with in-line diffuser silencers, which reduce the pressure upstream of the valve. Installing a muffler on the end of the nozzle is another option. All these methods can help reduce noise from compressed air sources.

Common examples of the implementation of such controls include installing:

  1. installing mufflers;
  2. using acoustical enclosures and barriers;
  3. incorporating sound-absorbing material;
  4. installing vibration mounts;
  5. providing proper lubrication

3. Placing noisy equipment within acoustical enclosures is an example of using _____.

a. administrative controls
b. engineering controls
c. equipment controls
d. interim measures

Next Section

Administrative Controls

Administrative controls, defined as "management involvement, training of workers, and changes in the work schedule or operations that reduce noise exposure," may also effectively reduce noise exposure for workers. Examples include:

Sound versus distance.
Controlling noise exposure through distance is often an effective, yet simple and inexpensive administrative control.
  • Operating noisy machines during shifts when fewer people are exposed.
  • Limiting the amount of time a person spends at a noise source. This is probably the most common administrative control being used today in the workplace.
  • Providing quiet areas where workers can gain relief from hazardous noise sources (e.g., construct a soundproof room where workers' hearing can recover – depending upon their individual noise level and duration of exposure, and time spent in the quiet area).
  • Restricting worker presence to a suitable distance away from noisy equipment.

Controlling noise exposure through distance is often an effective, yet simple and inexpensive administrative control. This control may be applicable when workers are present but are not actually working with a noise source or equipment. In open space, for every doubling of the distance between the source of noise and the worker, the sound level of the noise is decreased by 6.02 decibels. No matter what the scale of measurement, you will get a 6.02 decibels sound level drop for every doubling of distance.

4. No matter what the scale of measurement, you will get _____ sound level drop for every doubling of distance.

a. a 2.06 decibel
b. a doubling of the
c. a 6.02 decibel
d. a 4X reduction in

Hearing Protection Devices (HPDs) - Basic Requirements

Employers must make HPDs available.
Employers must make HPDs available to all employees exposed at or above the action level.

Hearing protection devices (HPDs) are considered the last option to control exposures to noise. HPDs are generally used in conjunction with other hazard controls.

  • Employers must make HPDs available to all employees exposed at or above the action level.
  • Employers must ensure that HPDs are worn by employees as required by Table G-16 of 29 CFR 1910.95 or who are exposed at or above the action level and who:
    • have not yet had a baseline audiogram established or
    • have experienced a standard threshold shift (STS).

HPD Selection and Use

It is essential to the success of the program to have someone responsible for the selection of hearing protection devices and the supervision of their use. They must be able to evaluate and select appropriate devices for each employee, based on proper fit, the employee's noise exposure, hearing ability, communication needs, personal preferences, and other constraints imposed by job tasks or work environment.

Choose the proper hearing protection
A responsible person must be able to evaluate and select the appropriate devices for each employee.
  1. Earplugs come in a variety of sizes, shapes, and materials and can be reusable and/or disposable. Earplugs are designed to occlude the ear canal when worn.
  2. Earmuffs are another type of hearing protector. They are designed to cover the external ear and thus reduce the amount of sound reaching the inner ear. Care must be taken to ensure that the seal of the earmuff is not broken by safety glasses, facial hair, respirators, or other equipment, as even a very small leak in the seal can destroy the effectiveness of the earmuff.
  3. Hearing bands are a third type of HPD and are similar to earplugs, but with a stiff band that connects the portions that insert into a worker's ears. Hearing bands may not provide the same noise attenuation as properly fitting earplugs, as the portions that fit into the ears are stationary and cannot be twisted into place like earplugs.

Earplugs, earmuffs, or hearing bands alone might not provide sufficient protection from significantly high noise levels. In this case, workers should wear double hearing protection-earmuffs with earplugs. Avoid corded earplugs, as the cord would interfere with the muff seal. Additionally, hearing bands cannot be worn with earplugs or earmuffs, as the connected band would interfere with the muff seal, and there is no room to insert earplugs at the same time.

5. What should you do if your earplugs can't provide adequate reduction in noise levels?

a. Wear earmuffs with earplugs
b. Wear hearing bands with earmuffs
c. Wear hearing bands with earplugs
d. Wear two sets of earplugs

Fitting HPD's

When fitting hearing protectors, attention needs to be given to each ear. It is not uncommon for a person to have right and left ear canals that are different sizes and must, therefore, be fitted with earplugs that are separately sized for each ear.

Ear canals should be inspected to assure that no physical problems, such as infections or excessive ear wax, will compromise or complicate the use of hearing protectors. Other employer requirements for providing hearing protection include:

  • Employees must be given the opportunity to select their HPDs from a suitable variety. Generally, this should include a minimum of two devices, representative of at least two different types.
  • The employer must provide training in the use and care of all HPDs provided to employees.
  • The employer must ensure proper initial fitting of HPDs and supervise their correct use.

Program implementers should be alert for common pitfalls associated with use and care of hearing protectors. For example, motorcycle helmets, personal stereo headsets, swimmer's earplugs, and hearing aids cannot be substituted for hearing protectors. Program implementers should be proactive in working with employees to avoid such pitfalls.

6. Which of the following is TRUE regarding the use of hearing protection?

a. Earplugs should be inserted as far as possible into the ear canal.
b. Hair within the outer ear must be removed prior to insertion of earplugs.
c. Employees must generally pay for additional pairs of hearing protectors.
d. Employees must be allowed to select from a variety of hearing protectors.

HPD Attenuation

Attenuation refers to the damping or decrease of noise levels as a result of wearing HPDs. All hearing protectors are provided with an Noise Reduction Rating (NRR). Although earplugs can offer protection against the harmful effects of impulse noise, and some earplugs are designed specifically to reduce this type of noise, the NRR is based on the attenuation of continuous noise and may not be an accurate indicator of the protection attainable against impulse noise. Earplugs are better suited for warm and/or humid environments, such as foundries, smelters, glass works, and outside construction in the summer. Requirements related to attenuation include:

  • The employer must evaluate HPD attenuation for the specific noise environments in which the HPD will be used.
  • HPDs must attenuate employee exposure to at least an eight hour time-weighted average of 90 dBA.
  • For employees who have experienced a standard threshold shift (STS), HPDs must attenuate exposure at or below the action level of 85 dBA-TWA (time-weighted average).
  • The adequacy of the HPDs must be re-evaluated whenever employee noise exposures increase to the extent that they may no longer provide adequate attenuation. The employer must provide more effective hearing protectors as necessary.
  • Employer needs to know and understand the methods for estimating HPD attenuation.

7. HPDs must attenuate employee exposure to at least an eight hour time-weighted average of _____.

a. 80 dBA
b. 85 dBA
c. 90 dBA
d. 95 dBA

Employee Training and Education

Safety Memo - Hearing Loss: Myths & Facts

The employer must institute a training program for all employees with noise exposures at or above the action level and ensure employee participation.

  • Training must be repeated annually for each employee in the hearing conservation program.
  • Information must be updated to be consistent with changes in protective equipment and work processes.

Cultivate a vigilant attitude about hearing protection: Employees should expect their hearing protectors to slip or work lose over a period of time. Throughout their work shift, employees must periodically check to see if they need to readjust or refit their protector in order to maintain a reliable fit.

Be vigilant about hearing protection
Always use hearing protection when you work around hazardous noise levels.

Guard against acquiring a false sense of safety: As the discussion and figures in this section have illustrated, it is easy to misuse hearing protectors and greatly reduce their effectiveness. Employees can be effectively protected from hearing health hazards if they:

  • properly wear their hearing protectors,
  • exercise a commitment to wear their hearing protectors consistently, and
  • maintain their hearing protectors by repairing or replacing them when necessary.

Hearing protectors break and become worn: Employees also need to check their protector regularly and to seek repair or replacement whenever necessary. Lastly, they can help each other by encouraging their co-workers to use hearing protectors and to seek help when they have problems.

8. Annual hearing protection training must be conducted for _____.

a. all employees in noisy work areas
b. all employees who chose to wear hearing protection
c. each employee in the hearing conservation program
d. each employee at in the workplace or worksite

The Hearing Conservation Program

The positives of hearing conservation programs.
A Hearing Conservation Program is required at or above an 8-hour time-weighted (TWA) of 85 decibels.

An effective hearing conservation program can prevent hearing loss, improve employee morale and a general feeling of well-being, increase quality of production, and reduce the incidence of stress-related disease.

The employer should administer a continuing, effective hearing conservation program whenever employee noise exposures are at or above an eight hour time-weighted average (TWA) sound level of 85 decibels or, equivalently, a dose of 50 percent.

Program Elements

As detailed in OSHA’s 1910.95 rule, the elements of an effective hearing conservation program are:

  • Monitoring Program: When any employee's exposure may equal or exceed an 8-hour time-weighted average of 85 decibels, the employer must develop and implement a monitoring program.
  • Audiometric Testing Program: Establish and maintain an audiometric testing program by making audiometric testing available to all employees whose exposures equal or exceed the "action level" - 8-hour time-weighted average of 85 decibels.
  • Hearing Protection Devices (HPDs): Employers must make hearing protectors available to all employees exposed to an 8-hour time-weighted average of 85 decibels or greater at no cost to the employees.
  • Employee Training and Education: The employer must train each employee who is exposed to noise at or above an 8-hour time weighted average of 85 decibels. The employer must institute a training program and ensure employee participation in the program.
  • Recordkeeping: The employer shall maintain an accurate record of all employee exposure measurements.

9. When must the employer institute a hearing conservation program?

a. Whenever employee noise exposures are determined to be more than 85 decibels during any workshift
b. Whenever employee noise exposures are at or above an 8-hour TWA of 85 decibels or a dose of 50 percent
c. Whenever employees are exposed to noise are at or above an 90 decibels or more.
d. Whenever the employer determines employees are exposed to 80 decibels or more during any part of the workshift

Employee Responsibilities

Employees must support the hearing conservation program.
Employees should assist those who make the measurements by sharing their knowledge about the work environment.

Employees who operate or maintain and repair the equipment are often the ones who know most about the processes involved. They need to express their concerns and ideas to management, the program implementer, or the noise-control engineer so that the noise-control devices will be as practical and effective as possible.

  • Employee assistance is especially critical to the success of engineering noise surveys where sound sources within a work process or a piece of equipment need to be evaluated, and only the employee knows the proper operation of the equipment.
  • Employees also need to cooperate by maintaining their normal work routine when asked to wear dosimeters, so that the results will be representative of their actual exposures.

Sound levels often increase when equipment begins to wear or fails to receive appropriate maintenance. Also, changes in equipment placement may cause unintended effects on sound levels.

  • When employees notice such changes, they need to inform the supervisory personnel or the program implementer that a change has occurred. A re-survey will be needed to evaluate the new sound levels and employee exposures whenever equipment or production changes occur.
  • Employees also have the responsibility of learning to operate their machines with the noise controls in place, of maintaining the controls properly, and of notifying the appropriate personnel when additional maintenance is needed.

10. What should employees do to ensure that the results of measurements are representative of actual exposures?

a. Wear dosimeters under work uniforms
b. Turn dosimeters off when moving from the workstation
c. Wear dosimeters during their normal work routine
d. Regularly move the location of the dosimeter on their body

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