Yesterday, we looked at how the 3M® Abrasive Systems Division in Alexandria, Virginia, took a closer look at its hearing conservation program to better characterize worker exposures. It was a first step in reclassifying the “hearing conservation areas” in the plant so that only workers who had actual hazardous exposures would be subject to annual audiograms and recordkeeping. But 3M didn’t stop there—the employer used its detailed data to target its noise control efforts, maximizing its return on investment and demonstrating that eliminating noise exposures doesn’t have to cost more than it’s worth.
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Here’s how 3M eliminated some of its noise exposures at minimal cost.
Manufacturing Quiet
3M considered several factors when deciding where to focus its noise control efforts to achieve the greatest effect, including:
- The extent of the overexposure;
- Worker population;
- Whether the “hearing conservation area” classification could be removed; and
- The likelihood of successful intervention.
In some areas, 3M was simply able to relocate noisy equipment—an intervention with a direct cost of zero. For example, the pressing, slitting, and packaging areas were all classified as “hearing conservation areas” in 2011 when the project began. In each of these areas, some noisy equipment was relocated or isolated. In the pressing area, the press motors were enclosed. The direct cost for all three areas was zero. In the drum slitting and disc converting area, the installation of acoustic enclosures around blower motors cost the company just $600, but reduced noise levels from 85 decibels adjusted (dBA) to 76 dBA. In fact, in 11 of 27 areas that were classified as “hearing conservation areas” at the beginning of 2011, 3M was able to make modifications that reduced noise levels below the Occupational Safety and Health Administration’s 85-dBA threshold at no direct cost.
When it had knocked out this “low-hanging fruit,” 3M started on areas that required more intense intervention. It took $14,000 to install acoustic enclosures and to perform brake modifications in the making area of the plant, but the intervention reduced noise levels from about 88 dBA to about 79 dBA. It took a hefty $65,000 to repair air leaks, replace blower fans and mufflers, and add silencers and acoustic enclosures to noisy machinery in the converting equipment area, but the net result was a reduction in noise levels from 91 dBA to 79 dBA.
Between 2011 and 2015, 3M was able to reduce noise exposures in all areas of the workplace and was able to remove the “hearing conservation area” classification from all but two areas. Between 2013 and 2015, only one standard threshold shift was recorded at the facility out of 186 annual audiograms performed. At the beginning of 2011, 3M had 199 workers enrolled in a hearing conservation program; at the end of 2015, only four workers were still exposed to noise levels requiring their enrollment in a hearing conservation program. By the end of 2016, 3M intends to have implemented noise controls in the two remaining hearing conservation areas, removing those employees from occupational noise exposures, the possibility of noise-induced hearing loss, and the need for annual audiograms and recordkeeping.
Going forward, 3M plans to invest in ongoing maintenance to control noise levels as well as the ongoing validation of noise controls. New equipment coming into the plant will have to meet noise control goals before purchase. By its investment, 3M has saved itself the ongoing cost of a hearing conservation program for nearly 200 employees, as well as having improved working conditions and worker morale.
Need more tips on hearing conservation and noise control strategies? Safety.BLR.com® can help you engineer a quieter workplace.