January 14, 2003

Working on Workplace Safety

- A Professor and His Graduate Students Help Furniture Industry Workers in Their Jobs

Gary Mirka demonstrates a glove-and-harness system that allows a worker to operate a sander with a relaxed hand, thus avoiding tendon strain that can lead to injury. (Photo: Roger Winstead)

Carpal tunnel syndrome.  Low back pain.  Arthritis and bursitis.  Unfortunately, these terms have become familiar to many American workers.  But thanks to the work of Dr. Gary Mirka, associate professor of industrial engineering at NC State University, these injuries could someday be a thing of the past.

Mirka’s interest in workplace safety started during his college days at Ohio State University, where he was active in track and field sports.  “As a shotput and discus thrower during my undergraduate days I always had an interest in applying mechanical and physiological principles to the improvement of human performance in athletics,” he said.  “As I progressed through my undergraduate program in industrial engineering I found that many of these same concepts were important in the prevention of injuries to people working in factories.  The term ‘industrial athlete’ reflects this and indicates that we can design an optimal work environment if we consider the workers’ physical capabilities and limitations.”

According to the United States Bureau of Labor Statistics, nonfatal workplace injuries in private industry accounted for approximately 1.7 million days away from work for U.S. employees in 1999.  There were more than 5.7 million work-related injuries reported that year; close to one-half million of these involved back injury.  Mirka is trying to change those numbers through his work with the Furniture Manufacturing and Management Center, an industry-funded group on campus interested in research projects that will help the furniture manufacturing industry. 

One area of interest is ergonomics, the science of equipment design to increase worker comfort and productivity.  Ergonomic research involves observing workplace activity and then developing various modifications that will correct problems.

	Industrial engineering graduate student Gwanseob Shin demonstrates good ergonomic posture using an adjustable table for upholstery application (above).  The raised work table helps the worker avoid injury that can come from the bending posture (below). (Photo: Gary Mirka)

After observing the processes and equipment used in the furniture industry, Mirka and his graduate students began developing new tools and work methods designed to reduce a worker’s exposure to risk factors for various kinds of injuries.  The injuries may be related to force (such as heavy lifting), posture or repetition. 

In the workplace Mirka’s team videotaped workers performing various tasks, analyzed the injury potential, evaluated the company’s record of injuries from the national Occupational Safety and Health Administration (OSHA) data and tracked trends these data revealed.  Following this initial evaluation, the team created and tested several devices designed to address problem areas they had discovered.  The final step was to field-test the devices with actual furniture industry workers;  Mirka’s team asked for the workers’ subjective assessments of the value of the devices and also conducted ergonomic evaluations using instruments that record such parameters as muscle contractions and joint angles.

One device the team developed is an adjustable table that allows a worker who is stapling upholstery fabric on a couch to reduce back strain caused by repeated bending into awkward positions.  Using a pneumatic system like that used for a dentist’s chair, the table moves up or down to allow the worker to vary the position of the couch frame.  Mirka’s group is still working to find the best design for another device for fabric application to frames:  a tool to hold the fabric in place while it’s being stapled. Such a tool is needed so workers can avoid using a “pinch” grip between thumb and forefinger to pull the fabric down for stapling. The first prototype tool was too big and clumsy for the workers to use efficiently, so the team is working on a design that looks like a tiny rake with very sharp teeth.

Other research projects involve “case goods” — non-upholstered furniture such as bureaus, desks and tables.  Sanding these items prior to staining requires the use of a random orbital sander, a circular sander with a handle.  To use this tool the worker must grip the head of the sander in a configuration that is hard on the wrist and finger tendons. Mirka’s team designed a Velcro® glove-and-harness system that allows the operator to relax the hand while working. Varnish sprayers, too, are tools that could be designed more efficiently. Mirka’s team is evaluating a new spray gun design that offers the worker two alternate grips, depending on whether a vertical or horizontal surface is being sprayed.

These improvements are important to relieve stress on workers’ bodies, but ergonomics researchers must remember that furniture industry workers are paid by the piece, so their productivity cannot be compromised by the redesigned tools.  Workers must be willing to use the new tools properly for them to be effective in reducing injuries.  This challenge can be a significant stumbling block for researchers and supervisors trying to prevent work-related injuries.  For example, Mirka’s team has designed a sewing machine table that can be moved up or down so a seamstress can sew while sitting or standing.  Workers accustomed to sitting down to work may be resistant to the idea of standing up for the same task.

One way to overcome this resistance is to try to make the fewest possible changes to a familiar tool.  Therefore, one focus of Mirka’s research is to evaluate tools currently used in the marketplace, with a goal of redesigns that will keep the familiarity of the tool but make it more ergonomic.

Mirka is in the third year of a large project funded by the National Institute for Occupational Safety and Health (NIOSH).  According to Mirka the goal of this multiphased project is to conduct a longitudinal study to gather information from field tests.  “One of the limitations of our current study is that each worker gets to use these prototypes only for about two months,” he said.  “My goal is to give the most promising tools to workers for five years and see how that has an impact on their comfort levels and productivity over the long run.  This will be the subject of future research.”

	Gary Mirka lives in Apex with his wife, Jami, and his two daughters, Taylor and Blair.  The family enjoys sports and outdoor activities, including volleyball, tennis and golf.  He has been at NC State since 1992.

For Mirka, conducting such research is personally as well as professionally rewarding.  The opportunity to work with students at NC State keeps him enthusiastic about his job.  “The part of my job that I find most rewarding is working with bright young students on the solution to some pretty difficult engineering design problems,” he said.  “You have to remember that we are often tasked with ‘fixing’ a job that has been in place for 5, ten, twenty, even forty years.  Beyond that we also have to deal with worker resistance to change and concerns regarding changes in productivity that may come with our solutions.  But if we can come up with just a couple of ideas that can reduce the number of people developing chronic, debilitating injuries, we can have an immeasurable impact on the quality of these workers’ lives.”

Ergonomic research like Mirka’s has the potential to benefit workers in the furniture industry, a major component of North Carolina’s economy.  With such redesigned tools to help them, North Carolina’s furniture workers can look forward to greater comfort and efficiency in their daily tasks.

— rudd —

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