Industrial noise, or occupational noise, is often a term used in relation to environmental health and safety, rather than nuisance, as sustained exposure can cause permanent hearing damage. Industrial noise or occupational noise is the amount of acoustical energy (noise) received by an employees auditory system while they are working.
"Twenty-two million workers are exposed to potentially damaging noise at work each year. Last year, U.S. business paid more than $1.5 million in penalties for not protecting workers from noise." - OSHA
Industrial noise is an occupational hazard linked to traditionally loud industries such as ship-building, Mining, railroad work, Welding and Construction. Industrial noise, if experienced repeatedly, at a high intensity, for an extended period of time, can cause noise-induced hearing loss (NIHL). NIHL caused by industrial noise can be classified as occupational hearing loss.
Modern thinking in occupational safety and health further identifies noise as hazardous to workers' safety and health. This hazard is experienced in various places of employment and through a variety of sources.
Noise, in the context of industrial noise, is hazardous to a persons hearing because of its loud intensity through repeated long-term exposure. In order for Noise to cause Hearing impairment for the worker, the noise has to be close enough, loud enough and the listener has to be exposed for long enough. These factors have been taken into account by the governing occupational health and safety organizations as they determine the unsafe noise exposure levels and durations for their respective industries.
National Institute for Occupational Safety and Health (NIOSH), Occupational Safety and Health Administration (OSHA), Mine Safety and Health Administration (MSHA), Federal Railroad Administration (FRA) have all set standards on hazardous occupational noise in their respective industries. Each industry is different, as workers tasks and equipment differ, but most regulations agree that noise becomes hazardous when it exceeds 85 Decibel, for an 8-hour exposure (typical work shift). This relationship between allotted noise level and exposure time is known as an Exposure action value (EAV) or Permissible exposure limit (PEL). The EAV or PEL can be seen as equations which manipulate the allotted exposure time according to the intensity of the industrial noise. This equation works as an inverse relationship. As the industrial noise intensity increases, the allotted exposure time, to still remain safe, decreases.
These above calculations of PEL and EAV are based on measurements taken to determine the intensity of that particular industrial noise. A-weighted measurements are commonly used to determine noise levels that can cause harm to the human ear. There are also special exposure meters available that integrate noise over a period of time to give an Leq value (equivalent sound pressure level), defined by standards.
Hazardous industrial noise can cause a permanent auditory threshold shift as excessive exposure to loud noises can damage the Hair cells in the ear. Please see Occupational hearing loss or Noise-induced hearing loss for more information regarding the physiology of hearing loss.
Noise can also effect the safety of the employee and the safety of others. Noise can be a causal factor in work accidents, both by masking hazards and warning signals, and by impeding concentration. High intensity noise can interfere with vital workplace communication which increases the chance of accidents and decreases productivity.
Noise acts synergistically with other hazards to increase the risk of harm to workers. In particular, noise and toxic materials (e.g. some solvents, metals, asphyxiants and pesticides) have some ototoxic properties may also affect the hearing function.
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There are several ways to limit your exposure to hazardous industrial noise. There is a hierarchy of controls which companies have to abide by if their employees are exposed to a hazardous amount of noise. First, the company can eliminate the noise source. If the noise source can not be eliminated or switched out, the company must try to engineer that noise out. This process is called acoustic quieting.
Acoustic quieting is the process of making machinery quieter by damping vibrations to prevent them from reaching the observer. The company can isolate the certain piece of machinery by placing materials on the machine or in between the machine and the worker to decreases the signal intensity that reaches the workers ear.
Noise decreases as distance from its source increases. When two identical noise sources are side by side producing a recorded noise of, say, 100 dB(A) the reduction in noise from removing one of the noise sources is about 3 dB, resulting in 97 dB(A). When the distance to a noise source is doubled the recorded noise level is reduced by 6 dB, sometimes called the Rule of 6.
The noise attenuation in decibels at a distance from the source , knowing the SPL at distance , is . If the distance is doubled, i.e. , the attenuation becomes 6.02 dB (6 for most practical purposes).Experts have developed a number of standards for noise reduction and isolation of its sources from people.
To decrease the employees exposure to hazardous, the company can take administrative controls limiting the employee's exposure time. This can be done by changing work shifts and switching employees out from the noise exposure area. Lastly, to decrease industrial noise exposure, Personal protective equipment should be used. There are several types of Earplug that can be used to attenuate the noise down to a safe level.
For a more detailed description of the hierarchy of controls, please see Occupational hearing loss.
In the United States, the National Institute for Occupational Safety and Health (NIOSH) and the Occupational Safety and Health Administration (OSHA) work together to provide standards and regulations for noise in the workplace. Industrial noise can also be regulated by legislation. A 2012 Cochrane review found low-quality evidence that legislation reduced industrial noise both immediately and in the long-term.
Since the hazards of occupational noise exposure were realized, programs and initiatives such as the US Buy Quiet program have been set up to regulate or discourage noise exposure. The Buy Quiet initiative promotes the purchase of quieter tools and equipment and encourages manufacturers to design quieter equipment. Additionally, the Safe-In-Sound Award was created to recognize successes in hearing loss prevention programs or initiatives.
- Hearing conservation program
- Buy Quiet
- Protective clothing
- ITU-R 468 noise weighting
- Weighting filter
- Equal-loudness contour
- Safe-In-Sound Award Excellence in Hearing Loss Prevention
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- Johnson and Morata, TC (2010). "Occupational exposure to chemicals and hearing impairment" (PDF). Arbete och Hälsa. 44 (4): 177 pp. Retrieved 27 June 2016.
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- ISO 11690-1:1996 Acoustics - Recommended practice for the design of low-noise workplaces containing machinery - Part 1: Noise control strategies (On Russian)
- ISO 11690-2:1996 Acoustics - Recommended practice for the design of low-noise workplaces containing machinery. Part 2. Noise control measures (On Russian)
- ISO 11690-3:1996 Acoustics - Recommended practice for the design of low-noise workplaces containing machinery - Part 3: Sound propagation and noise prediction in workrooms (On Russian)
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- ISO/TR 11688-2:1998 Acoustics - Recommended practice for the design of low-noise machinery and equipment - Part 2: Introduction to the physics of low-noise design
- ISO/TR 11688-1:1995 Acoustics -- Recommended practice for the design of low-noise machinery and equipment - Part 1: Planning
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- Verbeek, Jos H.; Kateman, Erik; Morata, Thais C.; Dreschler, Wouter A.; Mischke, Christina (2012). "Interventions to prevent occupational noise-induced hearing loss". The Cochrane Database of Systematic Reviews. 10: CD006396. ISSN 1469-493X. PMID 23076923. doi:10.1002/14651858.CD006396.pub3.
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- "Safe-in-Sound:Excellence in Hearing Loss Prevention Award". Safe-in-Sound. Retrieved 2016-07-14.