Noise pollution in the laboratory, as in any workplace, is a serious health concern. That’s according to the US Occupational Health and Safety Administration (OSHA) whose role it is to enforce the Occupational Noise Exposure Standard (29 CFR 1910.5). Among other requirements, the standard calls for employers to implement a hearing conservation program for workers exposed to a time weighted average noise level of 85 decibels (dBA) or above over an eight-hour work period. The peak permissible exposure level is 90 dBA so for example, a worker may only be exposed to a 95 dBA of noise for four hours over a work period. The National Institute for Occupational Safety and Health (NIOSH) recommends an eight-hour weighted average exposure limit of 85 dBA.
Note: dB and dBA are abbreviations that stand for a decibel, the unit of measure for gauging how loud sound is. It is a logarithmic ratio of the observed level compared to a standard. To see how loud some common everyday sounds are as measured in decibels, refer to Table 1. From looking at these examples it is clear that reaching a non-compliant noise level might happen easily if lab managers are not careful.
Table 1 Typical Noise Levels
|Telephone dial tone||80 dB|
|City traffic (inside car)||85 dB|
|Train whistle at 500', truck traffic||90 dB|
|Jackhammer at 50'||95 dB|
|Subway train at 200'||95 dB|
|Level at which sustained exposure may result in hearing loss||90-95 dB|
|Hand drill||98 dB|
|Power mower at 3'||107 dB|
|Snowmobile, motorcycle||100 dB|
|Power saw at 3'||110 dB|
|Sandblasting, loud rock concert||115 dB|
The Health Risks
Compliance with regulations, of course, is not the only reason lab managers should be concerned about noise. The main reason is that excessive noise is harmful. As far back as 1978, then U.S. Surgeon General William H. Stewart said that:
A number of studies have shown that there are significant health effects from even moderately high noise levels during a single eight-hour shift. Noise-induced hearing loss is an obvious one but others include increased incidence of coronary artery disease, vasoconstriction or narrowing of the arteries, and a statistical rise in blood pressure of five to 10 points as well as an increase in stress.
One of the problems with controlling noise levels in the laboratory is that there are many diverse sources of noise such as fume hoods, automated analyzers, or tissue homogenizers; and their effects are cumulative. For example, two instruments operating at 52 dB produce a noise level of 58 dB. Adding a third instrument operating at 58 dB yields a noise level of 62.5 dB. In the workplace a level more than 55 dB(A) is generally considered noise pollution. Also, about 35 to 40 percent of workers in office settings find levels 55-60 dB irritating.
Clearly, noise pollution is an issue lab managers might overlook, given how “easy” it is to let happen. However, they need to manage it if they are to provide a healthy, safe, stress-free and compliant environment.
This is the first of a three part series on Noise Pollution in the Laboratory.
Why You Should Audit Laboratory Noise Sources - Part 2 of 3
A Quieter Approach to Equipment Design - Part 3 of 3
Peter Froehlich, PhD., was contracted by Parker to author the series and white paper. He was assisted by Kim Myers, Product Manager, Parker Hannifin.