Track: Human Factors and Ergonomics Competition

Abstract

With the goal to increase production due to the growing demands in the construction industry, small businesses that manufacture hollowblocks utilize semi-automatic machines (to support the molding and compacting process) which is more financially feasible than adapting large-scale and fully automatic equipment. However, the process still requires intensive manual labor and operators exposed to such tasks experience discomfort often manifesting as muscle pain, fatigue, and stress. Understanding the discomfort experienced by these workers in relation to physical and cognitive workload factors helps in designing work that maximizes productivity while also promoting occupational safety and health. In this study, the researchers used the Cornell Musculoskeletal Discomfort Questionnaire to assess worker discomfort, the Fatigue Assessment Scale and cycle time measurement to describe physical workload, and the NASA-TLX and physiological measurements associated with stress level (pulse rate and blood oxygen level) to describe cognitive workload. Results of the Spearman Rank-Order correlation analysis show that CMDQ scores are higher in those workers with higher physical workload measurements [FAS score with rs=0.465 (p=0.06) and cycle time with rs=0.486 (p=0.048)]. Meanwhile, when correlated against cognitive workload factors, CMDQ scores are found to have a positive relationship with raw NASA-TLX score (rs=0.959; p=0.000) and pulse rate (rs=0.435; p=0.081), and a negative relationship with blood oxygen level (rs=-0.65; p=0.005). To mitigate workplace hazards and ergonomic risks that were found in the semi-automated hollowblock manufacturing sites, the researchers then developed an action plan implementing engineering and administrative controls focusing on modifications on the equipment, workplace layout, and operating procedures.