Elements of Ergonomics Programs A Primer Based on Workplace Evaluations of Musculoskeletal Disorders

NIOSH, as a demonstration project, is assisting an appliance manufacturer in designing a new assembly line that, by incorporating ergonomic factors, can prevent musculoskeletal disorders without limiting production output. Steps in the project include the following:

• Evaluating musculoskeletal injury patterns associated with work on existing production lines, observing related risk factors, and determining engineering solutions for these risk factors

• In-house training of assembly line workers, engineers, and management to recognize, evaluate, and provide solutions to job risk factors

• Applying the above training information in the planning of a new assembly line with the goal of preventing musculoskeletal disorders

• Conducting a symptom survey of the assembly line workers at the beginning of the new line's production to establish baseline morbidity rates

• Fine tuning the production line with ergonomic controls as production increases and as workers become more knowledgeable and skilled in their jobs

• Conducting periodic follow-up symptom surveys to determine injury trends and outcomes

• The design and use of a tool-balanced, in-line screw gun with torque control. The torque control is achieved by attaching an "L"-shaped handle called a "cheater bar" to the tool. This design allows the torque resulting from driving screws with this tool to be transferred to the bar, which is stabilized by holding it against the edge of the metal cabinet of the washer or dryer. In so doing, the torque force is not absorbed by the tool user.

• Using a pneumatic tool to open the hose clamps needed to attach hoses to the drain valves of washing machines. The original task was performed with a pair of pliers. This change reduces the static forces and awkward postures required for attaching the hose to the valve.

• Using height-adjustable worktables and height-adjustable shelving units, allowing workers of different heights and arm lengths to assemble parts with more ease and comfort.

• Using a pneumatic lift and rotation table to lift the washers to the desired standing height of the worker so they can drive in screws without stooping over, and rotating the tables so that all screws can be fastened from one workstation.

• Building an assembly line with these ergonomic workstation features may be less costly than retrofitting existing lines. Another advantage is that the worker is learning to do the job in ways that are more healthful and more productive [Estill and McGlothlin 1994].