Introduction
The ergonomics case study looks at working above shoulder height preparation and finishing tasks that are particularly difficult. Technicians perform the task repeatedly, above shoulder height, lifting the weight of the tool for a long time. The combination of these factors creates the risk of high musculoskeletal disorders (MSDs).
Situation: Work above shoulder height level
Task: Sand, clean and paint
Duration: 1 hour per day
Frequency: Repetitions: More than 4 times per minute
Force exerted: 58.7 lb
Problem: Musculoskeletal pain (MSD) in the shoulder, neck and wrist
Method of Analysis: Cost Analysis of Wrist, Neck, and Shoulder Injuries: $ 2,991,735
Number of workers performing this task: 5 per shift x 3 shifts = 15
Potential cost related to carpal tunnel type injuries for this operation: 67, 248 x 2 (neck, right shoulder) + 64,953 (right wrist) x 15 = $ 2,991,735 (See OSHA calculator below)
Value-added solutions to reduce MSDs for work above shoulder height :
- Exoskeleton
- Modify the handle of the tool to respect the neutral posture
- Use gloves to reduce vibrations
Cost of ergonomic assessment and modifications for working above shoulder height = $ 97,450
- Ergonomist:
- Travel: $ 2,000
- Fees: $ 15,000
- Cost for the purchase of 5 exoskeletons = $ 30,000
- Ergonomic equipment (Anti-vibration gloves): $ 30 x 15 = $ 450
- Development of a more ergonomic handle or tool with the supplier: $ 50,000
Total: $ 97,450
Return on investment solutions: $ 2,894,285
* The costs of ergonomic solutions and evaluation are approximate.
The OSHA Calculator describes the cost of the three identified MSDs for above shoulder height work. https://www.osha.gov/safetypays
3D ergonomic analysis of work above shoulder height
High risks at the elbows and wrists. The biomechanical analysis table below indicates the percentage of the population unable to perform this task, ie close to 25% for the wrists.
1-Work above shoulder height 2-3D ergonomic modeling
3- 25% of employees cannot perform the task as demonstrated
The analysis below uses another method to identify MSD risks. A score was assigned to the postures of each limb according to the degrees of movement that are permissible or risky. We can see that the neck and the arm (shoulder) are also at risk.
4-Postural analysis of the task while working above shoulders height according to predetermined degres of flexion settings based on scientific literature
Conclusion: Value-added solution for the task of working above shoulders height
MSD can be avoided with the right tools and méthods. In this case, using an exoskeleton supporting the arms when the tasks require static postures for a long duration helps reduce muscle fatigue and the weight of the tool. Training users to follow best practices, reducing cultural barriers and resistance to change are elements that can help the adoption of the solutions.
It’s obvious that ergonomics is an Investment, not only at a financial level but also for workers’ wellness et for the smooth operation of the companies. Ergonomics is a fundamental discipline for workers and companies’ health.
This case study refers to a task performed above shoulder,s height when preparing and finishing parts, especially difficult to reach. Technicians perform the task repeatedly, above shoulder height, lifting the weight of the tool for a long time. The combination of these factors creates the risk of high musculoskeletal disorders (MSDs).
