An Evaluation of Manual Lifting Tasks in the Factorics by NIOSH Lifting Equation

Abstract

The objectives of this study are to survey the manual lifting characteristics (e.g., lifting pattern,working condition) and to evaluate the manual lifting task using the NIOSH lifting equation. The studyalso aims to investigate some difficulties underlying the application of the equation. The total of 7factories were surveyed; auto-part manufacturing, auto-part assembly, construction materialmanufacturing, electric appliance manufacturing, ceramic, steel manufacturing, and furnituremanufacturing. This study selects the tasks based on whether they required high degree of manuallifting. Result from the preliminary survey is 31 separated tasks. Total 81 subjects were included inthe study; 78 males and 3 females. Average characteristics of the task being surveyed are weight 17.5kg., vertical height 63.9 cm., vertical distance 37.8 cm, temperature 29.8°C, the relative humidity 58.2%, Recommended Weight Limit (RWL) 13.2 kg., Lifting Index (LI) 1.4 and discomfort score 5 (ratherhigh discomfort or pain).

The conclusion is that most of these tasks (19 tasks) are considered as heavy manual lifting(LI over 1). The major reason is heavy load weight. Another factor is the large reaching distance,which decreases the RWL and therefore increases LI. The study also shows that these liftingrequired workers to work outside the limitation to appropriately use NIOSH equation, such as therequired of short walks (30 tasks), two-persons lifting (13 tasks), exceed temperature and relativehumidity. For further study, to incorporate some aspects of working condition and environmentalfactors would be imperative.

Keywords : Work Load Evaluation / Manual Lifting Task / Survey