International Journal of Engineering Research and Advanced Technology (IJERAT) E-ISSN : 2454-6135 DOI: 10.31695/IJERAT.2020.3627 Volume.6, Issue 7 July -2020 www.ijerat.com Page 51 Licensed Under Creative Commons Attribution CC BY Determination of the Optimal Number of Workers Using the NASA-TLX Method in Chemical Company, Indonesia Didi Junaedi 1 , Nyimas Desy Rizkiyah 2 & Deni Bagus Pratya 3 13 Industrial Engineering Department, Faculty of Engineering, University of Mercu Buana Jl. Raya Meruya Selatan, Kembangan, Jakarta 11650 Indonesia _______________________________________________________________________________________ ABSTRACT This study aims to analyze the workload of operators and analyze the optimal number of workers to complete work on the part of the production. The research was conducted at one chemical company in Indonesia and this study uses a method NASA - Task Load Index (NASA-TLX) of the six indicators to measure mental workload with the NASA-TLX method, namely mental needs, physical needs, time requirements, performance, level of frustration, and physical and mental effort obtained mental workload calculations on production operators as many as 4 operators experience mental workload categories very high, 13 operators with mental category workloads are high, 2 operators experience mental workload categories rather high, and 1 operator experiences mental workloads with moderate categories. Of the 4 work shift groups, all experienced a high mental workload so that an additional workforce was needed to reduce operator workload. After adding 1 operator in each group, the level of mental workload decreased to a rather high level. But of the 4 work shift groups, there is still 1 shift group that experiences high workloads despite having added 1 workforce. Key Words: Workload, Mental, NASA-TLX, Indonesia, Optimal Number of Workers, Operators. ______________________________________________________________________________________________ 1. INTRODUCTION Human activities require energy which depends on the amount of workload carried out and the physical abilities of each individual. This is due to the limited ability of humans to cause humans to experience fatigue, both physical fatigue and mental fatigue, which will result in decreased work performance. When humans perform activities that exceed their abilities can cause a person to experience fatigue, both physical fatigue and mental fatigue, which can result in decreased work performance. The workload must consider the conditions of the workers because it could affect the company's both positive and negative influences. Excessive physical burdens can result in complaints to workers such as headaches, backaches, injuries, etc. Whereas mental overload can affect workers such as loss of work motivation, stress, and others. This research was conducted at a company engaged in the field of chemicals in Indonesia. The company issued a policy of an average sales target of 1700 tons per month. The company also limits the amount of production operator overtime, but after the rule has passed there is a problem if one of the group shifts is unable to attend, is attending training, or is sick so that it cannot come to work, thereby reducing the number of production operators. With the reduced number of production operators, the workload is charged to the working production operators. Thus it is necessary to analyze the workload in the production department. The study of workload has been carried out by several methods. The workload can be measured based on the time allotted to complete the work. Workload research that is measured based on total work time using the FTE (Full Time Equivalent) method has been studied in the manufacturing industry to determine the workload in the maintenance department [1]. Whereas another workload study is measuring the workload on a chemical analyst workforce [2]. Another study of workloads is based on the mental burden of operators on a garment industry using the NASA-TLX method. This study also aims to determine the right number of operators to find out the workload on the operator [3]. Research on determining the number of operators using NASA-TLX method workload analysis has also been carried out on Quality Control operators in the manufacturing industry by adding work sampling methods [4].