Making a difference at Johnson & Johnson: some ergonomic intervention case studies.
Ethicon, Inc. and Johnson & Johnson Health Care are two of Johnson & Johnson's largest domestic companies. Ethicon, Inc. produces wound closure products and Johnson & Johnson Health Care produces consumer health care products. Johnson & Johnson has always been a leader in the concern over health-related issues. One of the philosophies within Johnson & Johnson's governing credo is to provide a safe and healthy work environment for its employees. From this commitment, programs to address ergonomic problems have become a routine part of each business day. Johnson & Johnson's "Live for Life" program provides encouragement and support for employees to practice safer lifestyles, both on the job and at home (smoking cessation, weight control, and a variety of exercise programs). In the same vein, occupational ergonomics programs have been incorporated at many manufacturing centers to identify and eliminate high-risk work practices on the job.
Industrial ergonomics is no place for heroes. The one person who can make it all happen simply does not exist. Many different functions, such as medical, engineering, safety, management and workers must continually interact to resolve ergonomic issues. This level of interaction is necessary because of the complexity of many ergonomic problems. It is generally not difficult to investigate and document a problem; it is often quite difficult to determine an effective solution. There are numerous pitfalls, however, into which many a brilliant ergonomic intervention effort has fallen with frustrating and pitiful results. Truly effective solutions are generally born out of cooperative efforts where outcomes are shaped by the expertise and practical experiences from a wide variety of resources.
Ergonomic initiatives take on many forms, such as engineering design and/or redesign, ergonomic training, comprehensive medical case management and on-the-job exercise programs. Two key focal points of these efforts are to control problems relating to cumulative trauma disorders and manual materials handling injuries. These types of problems are factors in most of the work-related ergonomic medical incidents experienced. The focus of this article is on engineering design and redesign solutions to selected ergonomics problems. Methods changes or modification of the process through engineering redesign is often the only sure way to prevent problem reoccurrence.
Experience has demonstrated that a full-time ergonomics resource is necessary to coordinate an effective ergonomics program. Simple ergonomic training programs for engineers and managers, without the long-term presence of an in-house ergonomics resource person, have yielded little in the way of long-term benefits.
Full-time ergonomics engineers are employed in the industrial engineering departments of Ethicon and Johnson & Johnson Health Care. The job description of an ergonomics engineer is lengthy and requires a rare mix of technical and social skills combined with a good sense of humor. Often, the path leading to the best solution is full of wrong turns and dead ends. The activities of the ergonomics engineer could be broadly classified as problem prevention and intervention. Preventative activities include helping to design all new equipment and processes. The ergonomics engineer is contacted early in the concept phase of the design process and is an active member of the project team. Ergonomic design is very inexpensive, or costs nothing, when built into the project in the early stages before hardware has been built. At Ethicon, this interaction is required, and the ergonomic considerations of machine design must be considered and integrated before the process can be implemented.
"Intervention activities" refers to solving existing problems and generally fall into two categories--job redesign and medical case follow-up. In the job redesign process, existing operations are systematically reviewed, stressful work practices identified, and recommendations made to correct the problems. The process for medical case follow-up is essentially the same, except that close attention is paid to the particulars of the specific medical case to determine all that can be done to speed recovery and prevent symptom re-occurrence.
Many of the specific demands made upon an ergonomics engineer's time are:
* Reviewing current medical incidents.
* Developing medical incidence rate reporting system to determine priorities and evaluate progress.
* Assessing existing jobs to identify high-risk work practices.
nDeveloping recommendations to eliminate or alleviate these work practices.
* Developing specific redesign projects and, unless other resources can be identified, determining costs, selling projects to management, overseeing projects through completion, and evaluating the results.
* Interacting in new equipment design projects from the conceptual through the implementation stages.
* Developing ergonomic guidelines to provide engineers and managers with simple and concise practical guidelines for day-to-day use.
* Developing and conducting ergonomic training programs for workers, managers, and engineers.
A person with formal ergonomics training and experience is necessary to successfully carry on this wide range of activities. It makes little sense to invest substantial time and money in an industrial ergonomics program without providing a dedicated resource to effectively coordinate program activities. Once again, however, the effectiveness of the program generally depends on how effectively resources from other disciplines interact to address ergonomics issues from all directions.
Accomplishments of industrial ergonomics programs take on many shapes and forms. The fundamental objectives, however, are the elimination of high-risk work practices and comprehensive medical case management. Since the ideal situation is to prevent injuries by providing a safe workplace in the first place, the remaining focus will be on the former objective--elimination of high-risk work practices. The following three cases are typical projects.
Case Study 1
A large bandage-making machine combines several wide layers of material and cuts the final product into the final shape. Each component is fed into the machine from separate raw material feed rolls, each of which must be replenished approximately six times per day. While no medical incidents had been reported on this job, the machine operator had submitted a suggestion that the unwind stand for the largest raw material roll be modified to reduce the risk of back strain. This requirement was based upon his feeling that he had experienced several close calls where he felt that he was placing "too much" strain on his back.
The employee's supervisor requested a review of the situation by the staff ergonomics engineer. The job elements required to handle the material rolls were analyzed utilizing the National Institute for Occupational Safety and Health (NIOSH) Work Practices Guide for Manual Lifting. The results verify that a problem exists, particularly when positioning a new roll of material into the unwind stand. The extreme horizontal (H) distance is required for two reasons:
* The roll is 18" in diameter and is lifted using a mandrel inserted through the core. This requires the person to lift in the most stressful manner with the axis of the roll parallel to the front of the body.
* The unwind stand base was built with a piece of angle iron running across the floor right where the person should be standing when positioning the roll. This foot interference substantially increased the required H distance.
Largely based upon input from the machine operator, the unwind stand and mandrel were redesigned such that the roll could be positioned into the unwind stand from the side rather than the end. This required that the mandrel be redesigned and permanently attached to the unwind stand. Elimination of the need to lift the mandrel along with the roll reduced the amount of weight lifted by nineteen pounds (approximately 35 percent of the original lifting requirement). Also, the redesign of the unwind stand allowed the operator to lift the roll positioned with the flat side of the roll against the body. This engineering change reduced the required H distance to ten inches (see graphic, facing page). The allowable weight limit was increased from 25 to 51 pounds, which resulted in a much greater percentage of the weaker population being capable of safely performing this job element. An additional safety benefit was the elimination of two severe finger pinch points where the mandrel slid into slots in the original unwind stand.
A key factor in "selling" this engineering change to management was the use of the NIOSH Work Practices Guide for Manual Lifting to demonstrate the reduction in physical stress gained through the proposed modification. Perhaps the greatest use of the NIOSH Guide and other models is the ability to demonstrate relative improvements which can be achieved through equipment redesign before the change is actually implemented.
This modification was favorably received by the operators, especially two women who are now able to rotate into this job without apparent difficulty.
Case Study 2
The semi-automatic winding (SAW) machine winds sutures in a figure-8 pattern and then folds a paper dispenser around the suture. The machine is a significant labor-saving device which eliminates manual suture winding. The hand-winding department had a high incidence of cumulative trauma disorders (CTDs) of the wrist and hand due to repetitive motions. The SAW machine effectively eliminates the repetitive winding motions and CTDs of the wrist and hand are rare in the SAW Department, but several unanticipated problems were found after the introduction of the machine.
The SAW operator sits at the machine and feeds sutures into the loading area where it is picked up by the machine, wound, and then placed in a folder. On average, the operator will load approximately 10,000 sutures during a shift. This number can vary depending on suture type and length. If the machine jams or if some other event occurs that stops the machine, the operator will clear the jam and then hit a foot pedal to restart the machine. If there are machine or product problems, the operator may hit the foot pedal up to 400 times a shift.
There were numerous complaints from employees about the machine. Large operators complained of the limited leg room; small operators said they had trouble reaching the foot pedal, and all complained about the sharp edges on the work table. There were a number of medical cases in the SAW Department, some of which were OSHA recordable. One case of sciatic nerve entrapment led to a large worker's compensation claim. The injured worker was approximately 5'0" tall and could not reach the foot pedal while sitting in the chair, so she sat at the edge of her chair whenever she needed to reach the pedal.
The working height of the machine is 37 inches. Leg room varies from 11 to 14 inches, and a cut-out is provided for the operator's feet. The foot pedal is mounted on the plate and is located in the cut-out. The foot pedal is seven inches above the floor.
In an attempt to alleviate the problems, the cut-out in the front plate was enlarged to provide more foot room and to accommodate an adjustable foot pedal, the pedal was modified to adjust between seven and fifteen inches, and padding was installed on the edge of the work table to keep the sharp edges from cutting into the operator's forearms.
The idea of increasing the leg room depth was investigated, but was later dropped because it could not be accomplished without almost total redesign of the machine.
At seven inches above the floor, the stationary foot pedal could be reached by fewer than five percent of the workforce while in a normal seated position. With the adjustable pedal, 95 percent of the work force can reach the pedal. Since the modifications have been made, smaller operators can sit in their chairs and reach the pedal and no longer have to sit at the edge of their chairs. The padding has also been a popular change, and complaints about the work table digging into workers' forearms have stopped. To date, the changes have been made only in one plant but are scheduled to be implemented at all locations due to employee acceptance of the changes.
Case Study 3
Ethicon manufactures and markets a wide variety of medical stapling devices for both external skin closure and numerous surgical procedures. Disposable, sterile skin staplers are relatively simple, low-cost devices and are produced in high volumes compared to some of the more complex internal devices.
Final skin stapler components were assembled on conventional flat tables placed in line with one another. The five component parts were delivered to the line in rectangular tote pans (12" x 19" x 6" deep), and there were a variety of methods used to get components from the pans for assembly.
* With the tote upright on the table, employees would reach into the pan each time and get a single component. This resulted in repetitive wrist flexion and/or ulnar deviation, particularly when the pans were less than half-full and the person had to reach near the bottom of the tote.
* Workers would scoop handfuls of parts and put them on the table for easier access. This resulted in high mechanical force concentrations to the hands and fingers in addition to the high hand force required to dig the parts out. Parts also tended to become spread out over a large area and become intermixed with other components. The result was longer reaches than necessary and difficulty in grasping the parts when intermixed.
* The tote pan would be tipped over on its side in order for the parts to flow out onto the table in front of the pan. This method was probably the best of the three but caused extreme intermixing of parts and a generally congested work area.
After assembly, the devices were placed into a tray to be pushed along a table top to the final weld station.
The final weld operation involved welding the instrument in an ultrasonic welder and then firing it five times to test staple formation and staple feed in the magazine. The job steps were:
* Get one instrument from tray with left hand.
* Position and insert into welder nest using left hand.
* Close manual clamp on welder nest with left hand to secure device into nest.
* Push and hold welder activation buttons to cycle welder.
* Get instrument from weld nest using right hand.
* Fire instrument once by striking trigger forcefully with palm of left hand to break instrument free from any weld flash that may have formed.
* Fire instrument four additional times to observe staple formation and proper staple feed in magazine.
* Place instrument aside to final cleaning station, if acceptable, or destroy instrument and discard if unacceptable.
* Record type of defect on sheet.
The production rate on this line was approximately 4000 instruments per day using a four-man crew (two assemblers, one welder, and one cleaner/packer). Job rotation was not structured and generally, the fastest person ran the welder. As the welder station became backed up, one of the assemblers would swing over and assist the welder by performing the test-firing function. In this mode, the welder would perform only the welding operation and hand the instrument to the temporary helper for test firing. This swing arrangement seemed to be the most efficient way to deal with the inherent line imbalance between the assembly and welder stations. One assembler could not work fast enough to keep the welder continuously supplied, and two assemblers could produce enough assemblies to eventually fill the queuing space.
The ergonomic-related medical incidence rate in this department was extremely high. The main problems were various forms of tendonitis and other hand/wrist related disorders. Many employees were placed on medical restrictions which created job manning problems for department supervisors since few "restricted workload" jobs were available. The ergonomics engineer was called in to assess the problem, and several modifications were made.
* A structured job rotation sequence was started, where employees on this line would rotate job positions every 30 minutes.
* Assembly stations were provided with adjustable V-stands to tilt up tote pans to the most accessible angle without allowing parts to spill out onto the table. Recessed parts trays, placed directly in front of the assembler, provided easy access with minimal wrist bending and eliminated intermixing of parts on the table top. A metal scoop was also provided to scoop parts from tote pans located on a side table to replenish the recessed parts trays.
* New, adjustable ergonomic chairs were purchased for all workstations. The chairs featured easy adjustability of seat height, seat inclination, seat back angle, and seat back height. All adjustments could be made from a sitting position. Before this, each employee had his or her own "personal" chair. When the person rotated to a new position where the working height was different, the old chairs couldn't be adjusted quickly. The new chairs eliminated the need to move individual chairs from station to station, since the people could make quick final adjustment upon arriving at the new workstation.
* Footrests were provided for shorter employees where needed. The long-term goal is to provide adjustable footrests at each workstation which can be adjusted without crawling under the workstation. Several types of adjustable footrests are available, but none is flexible enough in terms of of ease of adjustability and height range. Design of an easily adjustable footrest is proceeding in-house and the finished product will be built by an outside contractor. The goal is to keep the cost of the footrest in the $50-$100 range. The interim solution was to provide simple footstools on with the legs cut off to a custom height. The legs on one side were cut off about 1" lower to provide a slight tilt of about 10[degrees]. This temporary solution still required that employees take their footstools with them as they move from position to position.
* Activation buttons on the ultrasonic welders were a problem, since they are small in diameter (1 inch) and were located at the front of the base of the welder and oriented toward the worker at an extreme angle (60[degrees]-70[degrees]). The buttons were usually activated using the thumbs. High repetition, along with the small, poorly positioned buttons that required a lot of pressure, were believed to be a significant factor in the high incidence of thumb tendonitis.
The most effective solution, considering both cost and function, was a presence-sensing activation button system. The target contact area on the "buttons" was 3" in diameter and required no activation force. Both hands simply had to touch the buttons. The system also was available with a built-in, anti-tiedown feature, which was a safety requirement. An adjustable angle mounting bracket was developed to attach the activation buttons to the sides of the welder. The angle of the buttons could easily be changed from horizontal to approximately 20[degrees] angled up toward the worker. Original button separation was only 12", center to center. The separation on the new buttons was approximately 18", which was preferable from both safety and ergonomics standpoints, since this more closely approximates normal shoulder separation.
* The instrument is now automatically clamped into the welder with a pneumatic clamp that activates when the instrument is put into the weld nest. This eliminated the repetitive striking of a manual De-sta-co clamp to retain the instrument for welding. The manual clamping method also involved rotating the forearm of more than 90[degrees] while sustaining a fairly long reach. This combination of risk factors was felt to be significant in the development of a variety of hand/wrist, elbow, and shoulder problems.
* The final engineering modifications, which is still under consideration, is to provide a conveyor to automatically transport trays of assembled instruments between the assembly and welding workstations. The current method requires the assembler to lift the trays of assemblies off the assembly station surface and to place the tray onto a series of connected tables which go to the welder. The assembler also must continually push the trays along on the table top, which forms the queue of trays to the welder. The welder must also get up occasionally to pull trays over to the welder station if trays are not pushed into position. This arrangement is clearly bad from an efficiency standpoint. With the conveyor arrangement, the assembler would simply slide the trays over the work surface top directly onto the conveyor. At the welder end of the conveyor, as the welder operator removes an empty tray from the end position, a full tray is automatically pushed into position.
From an ergonomic view, however, the positive influence of a conveyor is not as clear. It is true that eliminating tray handling at the assembler station is good, but the full trays of instruments weigh only about five pounds, so there certainly are no critical biomechanical problems. In fact, simply performing this occasional tray handling task may provide a short break from the tedious and repetitive assembly process. At the welder station, the task of getting up to retrieve a new tray of assemblies, although inefficient, is probably beneficial from an ergonomic standpoint for the same reason.
If not for the new 30-minute job rotation process, the conveyor project would probably not be pursued for purely ergonomic reasons. In light of less repetition through job rotation and considering the obvious productivity improvements, the conveyor project is still under consideration. However, due to the relatively high cost of the conveyor-approximately $8,000 per line-and due to the questionable ergonomic impact, justification remains in question.
Employee response to the modifications has been extremely positive. There has been a 10-12 percent increase in productivity, and new medical problems have greatly diminished. Unfortunately, there are still the employees who developed problems before the changes were made. Plant medical personnel are continually working with these employees on programs of rest from repetitive work, physical therapy and medication. Through this combined approach of engineering process changes and comprehensive medical case management, medical incidence rates in this department are expected to continue to decrease.
Arthur R. Longmate received a BSIE in Industrial Engineering, and a MSIE in occupational safety and health engineering. He was a senior research associate at the Center for Ergonomics at the University of Michigan for four years and has had extensive consulting experience. Mr. Longmate is currently a staff industrial/ergonomics engineer at Ethicon, Inc., a Johnson and Johnson company, in Cincinnati, Ohio and has been employed as an ergonomist with Johnson and Johnson for seven years. He is a senior member of the Institute of Industrial Engineers, the Human Factors Society, and the American Industrial Hygiene Association. Mr. Longmate served for five years on the President's Committee for Employment of the Handicapped.
Timothy J. Hayes received a BS in psychology in and an MS in industrial engineering from the University of Wisconsin-Madison. He has been employed as an ergonomics engineer at Ethicon, Inc. in Somerville, New Jersey for three years. Previously, he worked as a human factors engineer at F.M.C. in San Jose, California for two years. He is a member of the Institute of Industrial Engineers and the Human Factors Society.
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|Title Annotation:||Johnson and Johnson Health Care; Ethicon Inc.|
|Author:||Longmate, Arthur R.; Hayes, Timothy J.|
|Date:||Mar 1, 1990|
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