Effectiveness of the Manual Lifting Workstation Improvement according to NIOSH Lifting Equation: a Case Study of an Automotive Parts Manufacturing Factory in Chonburi Province

Abstract

This quasi-experimental research was conducted to determine the improvement effectiveness of Toyota Production System workstation using NIOSH lifting equation among automotive parts manufacturing company, Chonburi Province. 60 samples were selected from all male workers of 27 workstation. The instruments were developed by the researcher and adapted from the previous studied including demographic charac[1]teristics, musculoskeletal disorders, job satisfaction and equation of NIOSH lifting. The reliabilities of questionnaire were analysis using Cronbach's alpha coefficient. Descriptive statistic analysis and paired sample t-test were used for data analysis.

The result showed that mean of workers age was 26.3 years old and before improving effectiveness of the 25 workstation, mean of lifting index > 1 was 1.53 (S.D. = 0.75), 44.4% was a lower back pain, and job satisfaction was a low level (81.5%). Improved workstation were adjusted the height of the lifting 90 cm. up, twisted the body less than 60 ํ and reduced working operation less than 25 cm. After improving all workstation, there was not found lower back pain, the mean of lifting index < 1 was 0.81 (S.D. = 0.11) and the job satisfaction (66.6%) is at good level. The t-test statistic was used to compare the values of lifting index, lower back pain and job satisfaction between before and after improvement. The comparison results were significantly different (p < 0.001).

The result of this study suggested that the improvement of the work station using NIOSH lifting equation is given less than 1 being used to prevent lower back pain from work, increasing job satisfaction. Moreover, it will be used as a guideline for improvement to lifting by hand in automotive parts and other industries.