Chapter 39
NOISE HAZARD ASSESSMENT AND CONTROL

Contents

Approved by Herb Toor
Revised 04/13


39.1 Policy
39.2 Scope
39.3 Applicability
39.4 Exceptions
39.5 Roles and Responsibilities
39.6 Definitions
39.7 Required Work Processes

Work Process A. General Requirements
Work Process B. Noise Monitoring and Hazard Assessment
Work Process C. Controlling Nuisance Noise
Work Process D. Controlling Hazardous Noise
Work Process E. Audiometric Testing and Hearing Conservation Training

39.8 Source Requirements
39.9 Reference Documents

 

NOTE:
. . . . . Denotes a new chapter or section.
. . . . . . . . Denotes the beginning of changed text within a section.
. . . . . . . . Denotes the end of changed text within a section.

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39.1 Policy

The Noise Hazard Assessment and Control Program ensures Berkeley Lab personnel are protected from noise hazards by:

39.2 Scope

Noise levels interfering with verbal communication between people who are only a few feet away from each other may put them at risk of hearing loss. The Berkeley Lab Noise Hazard Assessment and Control Program requires the use of engineering controls, administrative controls, and personal protective equipment to maintain employees' occupational noise-exposure levels below the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV); and requires compliance with Occupational Safety and Health Administration (OSHA) federal regulatory requirements.
The Noise Hazard Assessment and Control Program consists of the following activities:

39.3 Applicability

Berkeley Lab employees, visitors, affiliates, and subcontractors who could be performing work in or around high-noise sources

39.4 Exceptions

None

39.5 Roles and Responsibilities

Role

Responsibilities

Workers

Request an exposure assessment when a concern is present regarding potential noise exposure, and follow all guidance provided in training and work processes to evaluate and control exposures

Supervisors and Work Leads

Request an exposure assessment when a concern is present regarding potential exposure; and ensure that persons within their areas of responsibility comply with this policy and its implementing documents, and have completed the required training prior to beginning work

Industrial Hygienist

Facilitates appropriate noise surveys and/or sampling.

Health Services

Provides audiometric testing and maintains enrollment in the Noise Hazard Assessment and Control Program

39.6 Definitions

Term

Definition

ACGIH

American Conference of Governmental Industrial Hygienists

Audiometric Testing

The measurement of hearing acuity for variations in sound intensity, pitch, and tonal purity, involving thresholds and differing frequencies.  The results of audiometric testing are used to diagnose hearing loss. 

dBA

Decibels, a unit for measuring sound pressure using the “A scale.”  A scale is an expression of the relative loudness of sounds in air as perceived by the human ear.  A weighting filters out the low frequencies and slightly emphasizes the upper-middle frequencies around 2 to 3 kHz.

dBC

Decibels, a unit for measuring sound pressure using the “C scale,” a scale that is unweighted and has no filtering. The C scale is compared to the A scale when calculating hearing protector attenuation of the Noise Reduction Rating (NRR).

Exposure Assessment The process of defining exposure profiles and judging the acceptability of workplace exposures to environmental agents. These assessments may be; quantitative, semi-quantitative, or qualitative. These assessments are generally conducted by an ES&H professional, which may include industrial hygienists or safety engineers. These assessments may be conducted for representative employees and are not required to be conducted for each individual. In all cases, employees have full access to exposure monitoring information, including situations where an individual’s exposure is not monitored.

NRR

Noise Reduction Rating

Nuisance Level Noise

Noise levels below 85 dB (averaged over eight hours) are considered nuisance noise. While nuisance noise does not generally cause injury directly, in some instances it may mask sounds indicative of other developing hazards and may be a source of annoyance.

Threshold Limit Value (TLV)

TLVs for noise refer to sound pressure levels and durations of exposure to which nearly all workers may be repeatedly exposed without adverse effect. These values are developed and published by the American Conference of Governmental Industrial Hygienists (ACGIH).

TWA

Time Weighted Average

39.7 Required Work Processes

Work Process A. General Requirements
Work Process B. Noise Monitoring and Hazard Assessment
Work Process C. Controlling Nuisance Noise
Work Process D. Controlling Hazardous Noise
Work Process E. Audiometric Testing and Hearing Conservation Training

Work Process A. General Requirements

The following work process flow diagram summarizes the Berkeley Lab Noise Hazard Assessment and Control Program’s general requirements. 



Work Process B. Noise Monitoring and Hazard Assessment

  1. The Noise Monitoring Program, administered by the EHSS Industrial Hygiene (IH) Group, identifies employees for inclusion in the Berkeley Lab Noise Hazard Assessment and Control Program. To request noise monitoring, contact HSToor@lbl.gov or CLFlores@lbl.gov of the Industrial Hygiene Group.
  2. Due to high worker mobility and significant variations in noise levels, it is difficult to determine individual noise exposures from noise-monitoring data. Berkeley Lab has identified “exposure groups” at risk of noise exposures exceeding the OSHA action level of 85 dBA. Employees from these exposure groups are also included in the Noise Hazard Assessment and Control Program.
  3. Noise measurements include all continuous, intermittent, and impulsive sound levels from 80 decibels to 130 decibels. Instruments used to conduct sound-level measurements and personal-noise dosimetry are calibrated. Employees are notified of their monitoring results when their eight-hour TWA result is at or above 85 dBA.
  4. Monitoring is to be repeated whenever a change in production, process, equipment, or controls increases noise-exposure levels to the extent that Berkeley Lab employees not enrolled in the Noise Hazard Assessment and Control Program may be exposed to noise at or above the ACGIH-TLV of 85 dBA, or hearing protectors worn by employees for noise attenuation no longer meet OSHA Occupational Noise Exposure Standard requirements.
  5. Berkeley Lab uses the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV) for determining employee noise-exposure levels and for complying with the OSHA Hearing Conservation Amendment to the Regulation on Occupational Noise Exposure. The ACGIH-TLV for an eight-hour time-weighted average (TWA) sound level is 85 dBA. This is the maximum time-weighted average noise level that employees may be exposed to without hearing protection during an eight-hour work shift. The table below lists additional ACGIH noise TLVs adjusted for different time periods. In addition, OSHA requires implementation of noise-exposure controls when noise exposures are at or above 90 dBA as a time-weighted average. Furthermore, OSHA requires that employees be offered hearing protection.
  6. The table below lists the duration in which a worker may be exposed to a given average sound level. (These limits assume that the worker is not wearing hearing protection.)

    Table 4.1 ACGIH Noise Threshold Limit Value Limits

    Duration Per Day (Hours)*

    Sound Level (dBA)

    16

    82

    8

    85

    6

    86

    4

    88

    3

    89

    2

    91

    1.5

    92

    1

    94

    0.5

    97

    0.25

    100

    * Maximum allowable exposure time (without hearing protection) at a given noise level

    1. This relationship is given by:
  7. Duration (T, hours) = 8 x 10(85 – dBA)/10
    or
    Noise Exposure (dBA time-weighted average) = 85 – 10 log(T/8)

  8. Noise-exposure levels above 140 dBC are not permitted for any duration.

Work Process C. Controlling Nuisance Noise

Low-level noise that is not intense enough to cause occupational hearing loss may disturb or interfere with activities such as verbal communication and telephone use. This type of noise is classified as “nuisance” noise.  Various earplugs, headphones or earmuffs are available through vendors to control nuisance noise.  Contact HSToor@lbl.gov or CLFlores@lbl.gov of the Industrial Hygiene Group for assistance in selecting the proper control for nuisance noise. 

Work Process D. Controlling Hazardous Noise

  1. Hearing protectors must be designed and worn to control employee noise exposures to levels below the ACGIH-TLV of 85 dBA.
  2. Noise Reduction Ratings (NRRs) are assigned to all hearing protection devices and are usually displayed on the hearing-protection package. The NRR is a method developed for estimating the adequacy of hearing-protection attenuation. To calculate an employee’s estimated noise exposure while wearing hearing protection, OSHA requires 7 decibels (dB) to be deducted from the NRR as a safety margin. For example, if an employee is working in an area where the noise level is 95 dBA, and the selected hearing protection has an NRR of 22, then the estimated noise exposure would be calculated as follows:

    (Manufacturer’s NRR of 22) – (OSHA safety margin of 7 dB) = Calculated hearing protection attenuation of 15 dB
    (Noise level of 95 dBA) – (Calculated hearing protection of 15 dB) = Estimated employee exposure of 80 dBA

  3. Hearing Protectors: Availability and Criteria. Hearing protection is available from a number of vendors through the Berkeley Lab eBuy system. The EHSS Division establishes minimum-acceptable purchasing criteria for hearing protection and periodically
    1. Earplugs should provide protection when inserted into the ear canal. They may be attached to a cord or cordless, packaged in pairs, or individually packaged for dispenser refilling. They may also be reusable or disposable.
    2. Headband-type hearing protection should provide protection when inserted into the ear canal and should be wearable under the chin or behind the neck. Ear-canal caps should not be used.
    3. Earmuffs should cover the entire ear and should be adjustable. The inner acoustical material should be removable for cleaning and sanitizing.
  4. Contact HSToor@lbl.gov or CLFlores@lbl.gov of the Industrial Hygiene Group for assistance in selecting the proper control for hazardous noise. 

Work Process E. Audiometric Testing and Hearing Conservation Training 

  1. Exposure to high-noise levels may cause temporary or permanent hearing loss. Temporary hearing loss or auditory fatigue may occur after a few minutes of exposure to excessive noise levels; however, normal hearing is recovered after a short period of time away from the noise. Permanent hearing loss may result from repeated exposure to excessive noise levels and limited time away from the noise. Hearing loss typically occurs in the frequency range of 3,000 to 6,000 hertz (Hz). Because affected people are usually unaware of initial hearing loss, audiograms are conducted on potentially exposed employees to determine whether their hearing has been damaged.
  2. Employees exposed to noise at or above the OSHA action level of 85 dBA, as determined through exposure monitoring, must have an initial baseline audiogram within six months of initial noise exposure and an annual audiogram for the duration of the exposure. The EHSS Industrial Hygiene Group and Health Services Group track employees who may be exposed to noise above the OSHA action level. The Health Services Group also provides audiometric examinations. Health Services instructs employees on the proper use of hearing protection, and the Industrial Hygiene Group supplements the training through field surveys and noise survey reports.    

39.8 Source Requirements

39.9 Reference Documents

None

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