Ergonomics isn’t just about the office – it is also valuable in reducing the risks for musculoskeletal injuries in industrial environments. EWI Works has extensive experience in industries such as mining, utilities, forestry, food production, and manufacturing plants. EWI consultants have conducted assessments on assembly line workers, meter readers and in a recently, reducing MSI risks in control operators.
The client is involved in steel production. At the workstation requiring an assessment, cooled bars of steel are cut as they arrive along a conveyor where the Operator uses a control panel to manually operate the shear. The control panel consists of several manually operated controls used for every cut and is suspended by a semi-fixed overhead hoist and boom. During operation, the Operator needs to be able to watch the upstream conveyor, as well as downstream after the cut is made. Operators may choose to either sit or stand, or both, throughout their turn at the panel.
The operators are rotated every four hours at this station. Over this time, our ergonomist noted the following awkward postures that were deemed moderate risks for MSIs:
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- Excessive reaches
- Bent/tilted head and neck
- Leaning forward or sideways
- Twisting the back
These risks are mainly caused by both the panel design and the Operators’ work practices. The following is an excerpt from the ergonomist’s report to describe the causes of the risks:
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- Panel design: The panel is semi-fixed and can be turned and swivelled left to right but cannot adjust in height or angle to accommodate a variety of employee statures. As a result, the controls near the top of the panel tend to be at a reach, especially when in a seated posture. This reach is increased further due to the inability to adjust the height of the panel. Workers are generally unable to position the chair with the legs under the panel, due to the overall size of the panel, which is 30” (H) by 30” (W) by 13” (D). The depth particularly creates an inability to position the legs underneath the panel when seated. Therefore, the Operators must sit further away, leading to an increased reach as well.
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- The Operator needs to be able to look into the shear to examine the bars. Depending on the location of the panel relative to the Operator’s position, the Operator may be tilting their head/neck to the side to view around the panel. The panel itself is large and not adjustable and impedes view of the shear (upstream and downstream) from a seated position.
- The Operators also needed to turn to look far upstream on the conveyor to examine the bars prior to arriving to the shear. The Operators have to stand semi-perched on a footstool to raise themselves higher to gain a better view.
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- Position of controls on the panel: Controls used most often are positioned near the top of the panel, which leads to frequent reaching.
- Panel design: The panel is semi-fixed and can be turned and swivelled left to right but cannot adjust in height or angle to accommodate a variety of employee statures. As a result, the controls near the top of the panel tend to be at a reach, especially when in a seated posture. This reach is increased further due to the inability to adjust the height of the panel. Workers are generally unable to position the chair with the legs under the panel, due to the overall size of the panel, which is 30” (H) by 30” (W) by 13” (D). The depth particularly creates an inability to position the legs underneath the panel when seated. Therefore, the Operators must sit further away, leading to an increased reach as well.
Next time, I’ll discuss some of the recommendations the EWI ergonomist made to help reduce the risks for MSIs.
