Technology for a Quieter America (2010) / Chapter Skim
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4 Control of Hazardous Noise
4 Control of Hazardous Noise
Pages 31-54
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From page 31... ...
Today, be more accepting of hazardous noise than of other dangers concerns include how noise exposure can also impact non- in industrial settings. auditory health, but these effects are beyond the scope of Employers today are responsible for preventing NIHL this report.1 by controlling hazardous noise exposures through the use of Very few studies have been done recently on the number engineering controls, by monitoring the effects of exposure of people exposed to hazardous occupational noise.
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From page 32... ...
ceptable risk of damage from hazardous noise in industry However, it becomes significant for short exposure times, as and government, hazardous noise from consumer products, shown in Table 4-2. research on impulsive noise, engineering controls in industry and the establishment of "buy-quiet" programs, HPDs, and HAZARDOuS NOISE LEVELS IN gOVERNMENT AND the current status of HPD research.
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From page 33... ...
3-dB exchange rate. Because sound pressure levels vary with time, the levels in the table are generally time-weighted Hazardous Levels Hazardous Levels averages (TWAs)
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From page 34... ...
: NAE workshop on Engineering Responses to Hazardous Noise Exposures, Washington, DC, August 14–15.
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From page 35... ...
Presentation at the and associated auditory hazards was the subject of a NIOSH NAE workshop on Engineering Responses to Hazardous Noise Exposures, workshop in 2005 and two presentations at a workshop Washington, DC, August 14–15.
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From page 36... ...
The study committee concluded that damage risk criteria Because impulsive noise can be a series of bursts or con for impulsive noise need further study and that such studies tinuous noise with an impulsive component, the question is and an agreement in the international standards community whether such noise, generally recognized by its high crest on optimal damage risk criteria for impulsive noise should factor, has the same auditory hazard as continuous noise serve as a basis for changing national, European Union, when the two have the same A-weighted sound pressure and international criteria for assessing auditory hazard from level. This question has been raised for more than 30 years.
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From page 37... ...
An Version. Presented at the NAE workshop on Engineering Responses to example of a complex noise source might be a compressor Hazardous Noise Exposures, Washington, DC, August 14–15.
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From page 38... ...
Durability, sound pressure level by at least 10 dB -- which is similar to expense, need for visual observation of the operation, and "halving" the loudness of the sound. need for access to the operation should all be considered Lagging is a noise control treatment that consists of lay in selecting a material.
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From page 39... ...
Presentation at the NAE workshop on Engineering Re of the problem. sponses to Hazardous Noise Exposures, Washington, DC, August 14–15.
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From page 40... ...
This A-Weighted Sound Pressure Speed in Cans/ weak enforcement policy signaled the death knell for the Level at 1 meter (dB) Minute Manufacturing engineering control of noise in all but the most progressive Equipment Before After Noise Reduction Before After and innovative companies.
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From page 41... ...
Responsibilities of Buyers and Sellers Hearing conservation programs incur costs for annual audiometric monitoring, medical follow-up of hearing loss Both supplier and purchaser have responsibilities in cases, monitoring of noise exposure, posting of warning implementing a "buy quiet" program. For individual pieces signs and controlling access to high-noise areas, annual of machinery, such as compressors, motor generators, and training for employees and supervisors, recurring purchases similar equipment, the supplier must make available the of personal hearing protectors, ongoing administration and noise specification for the equipment, usually in terms of record keeping, and inevitable workers' compensation claims the sound power level it emits.
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From page 42... ...
Thus, the connection servation programs appeared in the 1940s and 1950s (Berger, between emission and immission must usually be resolved by 2003b) , hearing protection was not required by law until a professional in noise control engineering who can define May 1971, with promulgation of the Occupational Noise the relationship between the noise emission of equipment Exposure Standard under the authority of the Occupational and the noise levels in the manufacturing environment.
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From page 43... ...
For example, HPDs can reduce countermeasure: noise annoyance in passenger cabins of commercial aircraft and on subways and buses. They can also reduce noise • It is the employer's duty according to the Occupational in sleeping environments, such as traffic noise or snoring Safety and Health Act of 1970 to provide a safe and Source - -- -- -- -- -- -- -- - -- > Path - -- -- -- - -- -- -- -- -- >Receiver Countermeasures: Engineering Controls Engineering Controls Hearing Protection Administrative Controls FIGURE 4-1 Systems approach to reducing noise exposures.
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From page 44... ...
. In addition to conventional passive hearing protectors, Limitations of Hearing Protection Devices which have been available for decades, HPDs styled and If exposures to noise at hazardous levels persist even after sized specifically for children, designed for spectator events noise controls have been tried, HPDs may be the only way to (e.g., earmuffs that incorporate radios for sporting events)
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From page 45... ...
. the ability of the HPD to dampen vibrations of the ear canal wall, and the resonance frequency characteristics and acous HEARINg PROTECTION DEVICES: EFFECTS ON tical impedances of the HPD.
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From page 46... ...
Because their elevated thresholds for FIGURE 4-3 Comparative noise reduction ratings based on manumid- to high-frequency speech sounds are elevated further by facturers' laboratory tests and real-world "field" performance of dif Figure_4-3-G-1.eps the protector, hearing-impaired individuals are usually dis- ferent types of hearing protection devices. Adapted with permission from Berger, 2003b, bitmapsp.
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From page 47... ...
to encourcians than conventional HPDs because they do not distort age the use of hearing protection by producing HPDs that are more acceptable to the user population, amenable to the working environment, and adjustable to the noise exposure and (2) to improve hearing in a protected state, which may also make workers safer.
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From page 48... ...
These HPDs provide both high passive attenua In the past few years several HPD-based devices have tion through very deep insertion, custom-molded earplugs been developed that have multiple objectives, which include coupled with active noise cancellation in the in-canal sound hearing protection from continuous noise, hearing protection field under the earplug, all covered with a tightly fitted earfrom impulsive noise (particularly gunfire) , measurement muff with custom-fitted cushions (McKinley, 2001)
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From page 49... ...
In practice, employers have a hearing conservation program and is currently essential often used technical and/or economic infeasibility as a justito combating the problem of noise-induced hearing loss. fication for not implementing engineering controls.
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From page 50... ...
government agencies, engineering and trade Hazardous Noise societies, and other stakeholders to promote the development Engineering noise controls provide significant long-term and use of engineering controls. advantages over personal hearing protection.
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From page 51... ...
2006a. American National Standard Determination of Occupational gress and Exposition on Noise Control Engineering, Dearborn, MI, Noise Exposure and Estimation of Noise-Induced Hearing Loss.
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From page 52... ...
Document Number 550/9-74-004. of Emission Sound Pressure Levels at a Work Station and at Other Available online at http://www.nonoise.org/library/leels74/leels74.
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From page 53... ...
2003. Speech Communications and Signal for Occupational Noise Exposure; Final Rule.
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