Assessment of manual material handling in a tile and ceramic factory using the National Institute for Occupational Safety and Health‎ equation in 2016

Background: Manual handling, lifting, or carrying of material is responsible for non-fatal injuries among employees in industries. It is the second most prevalent reported risk factor in workplaces that can lead to potential manual handling accidents and longer-term musculoskeletal disorders (MSDs). The aim of this study was the evaluation of manual material handling using the American National Institute for Occupational Safety and Health ‎(NIOSH) equation in a tile and ceramic factory in Tehran, Iran, in 2016. Material and Methods: This cross-sectional study was carried out in a tile and ceramic factory in Tehran, Iran, in 2016. Three tile production lines (A, B, and C) were selected. On each line, cartons were lifted from a conveyor and placed onto a pallet. The task variable data were measured and recorded according to the NIOSH equation. Results: According to the results, composite-lifting index (CLI) value in all three lines exceeded 3 (3.34, 4.53, and 5.99, respectively, for lines C, B, and A). The values of frequency-independent recommended weight limit (FIRWL) and single-task recommended weight limit (STRWL) in all tasks were less than load weight. In addition, values of frequency-independent lifting index (FILI) and single-task lifting index (STLI) in all tasks exceeded 1.0. Conclusions: The results show that CLI value for these jobs exceeded 3, which means that a significant level of physical stress is associated with these jobs for nearly all workers. Both strength and endurance are a problem for many workers. Therefore, the first priorities of job redesign should be the decreasing of the physical demands through modifying the job layout, and decreasing the physiological demands through reducing the frequency rate or duration of continuous lifting.