Musculoskeletal Disorders Risk Assessment Using Various Biomechanical and Ergonomics-Based Tools in an Automobile Fuel Tank Installation Workstation

Work-related musculoskeletal disorders (WMSDs) are still a major problem in workers performing manual material handling (MMH) activities as they are most often associated with lower back pain (LBP) or other physical complaints. Awkward postures, incorrect MMH techniques, high frequency of repetitive movements, and manual handling of heavy loads are the most important risk factors that generate excessive loads on body joints. In order to prevent the negative effects and expenses associated with WMSDs, there are various ergonomics (e.g., Mantra, MAC, RULA, REBA, OWAS, QEC, WISHA) and biomechanical (e.g., biomechanical models such as OpenSim, AnyBody Modeling System, Jack, 3DSSPP, Regression equations and HCBCF) tools available for risk assessments. This study was conducted in order to compare the outcomes of these tools to evaluate the musculoskeletal injury risk of sequential lifting, carrying, and holding tasks in the car fuel tank installation workstation of Pars Khodro Company. Results indicated that the work situation of our case study posed a significant risk of musculoskeletal injuries because of the frequent repetitive movements and worker’s improper postures. The lifting and holding (installing the fuel tank) tasks had the highest risk of injury since most biomechanical tools indicated that the compression forces in the lumbar spine discs exceeded the permissible limit of 3400 N based on the NIOSH standard, and the scores calculated by ergonomics-based tools were in the dangerous zone. As a result, job interventions were found necessary. Eventually, three simple interventions, including load height adjustment utilization lift table, improving the lifting technique using linear guide rails and worker training, and employing a hydraulic jack for installing the fuel tank were suggested. After implementing these interventions, the risk of injury was effectively managed based on the majority of assessment tools.