A comparison of literature-based design recommendations and experimental capability data for a complex manual materials handling activity

Abstract

The majority of industrial manual materials handling jobs include more than one handling activity. Yet, the bulk of ergonomics research in this area has been focused on manual lifting. It has been presumed that manual lifting activity limits a person's ability to perform manual materials handling activities. This case study demonstrates that such is not always the case. Using a complex manual materials handling task from the railroad industry, it is demonstrated that the capability to perform multiple activity materials handling jobs is limited by different materials handling activities for different people. Capabilities of male volunteers on this complex task are presented. The complex manual materials handling task, which involved lifting, turning, carrying, and pushing activities, was also analyzed using both the old and revised NIOSH lifting guidelines (1981; Waters et al., 1993) as well as the guidelines provided by Mital et al. (1993, 1997). It is concluded that both old and revised NIOSH guidelines are of little use in analyzing jobs such as described here. It is suggested that the failure to study realistic manual handling activities, and the resulting lack of guidelines to design such jobs, is a dominant reason why the hazards of manual materials handling have not been contained. Relevance to industry This work demonstrates that the ability to perform manual materials handling jobs is not always limited by the ability to lift materials. Furthermore, NIOSH guidelines, both old and revised, are of little use in providing practical economical solutions to real-life manual materials handling problems.