Mental Workload Assessment in Construction Industry with Fuzzy NASA-TLX Method

Abstract

The construction industry is a sector where human resources are used intensively, and work accidents related to falling from height occur mostly. In the construction industry, studies are generally carried out to determine and prevent the physical workload of the work done. However, it is necessary to measure mental workload and make improvements to keep this workload at an optimum level to prevent work accidents and performance losses. In literature, NASA-TLX (National Aeronautics and Space Administration Task Load Index) method is widely used to evaluate the mental workload of workers. Uncertainty arises in the calculation process of NASA-TLX since this method is subjective, and the rating values of workload dimensions included are expressed in linguistic terms. For this reason, to eliminate uncertainties and obtain more accurate results, fuzzy set theory can be used. In this study, the Fuzzy NASA-TLX method is proposed to determine the mental workload of construction workers working at height in a construction site. In addition, to demonstrate the effectiveness of the proposed model and understand the effect of weights, the results of the proposed model are compared with the results of the Fuzzy NASA-RTLX (Raw Task Load Index) method in this study. According to the results of Fuzzy NASA-TLX and Fuzzy NASA-RTLX, the levels of overall mental workloads are 0.624 (62.4%) and 0.612 (61.2%), respectively. Besides, the most important workload dimension for the workers working at height is temporal demand in both models. It is determined that this study will contribute to reducing work accidents that result from the excessive mental workload and protecting workers’ health.