Distributions of manual materials handling task parameters

This study is an analysis on 25,291 manual materials handling (MMH) tasks obtained from 2442 reports from industrial locations throughout the US. The tasks consisted of 10,101 lifts, 7461 lowers, 1879 pushes, 1866 pulls and 3984 carries. The purpose of the study was to determine the percent distribution of each of the task parameters, i.e., weight, height, distance, and frequency. Secondly, the study compared the percent of reports from key industrial classifications to percent of compensation costs associated with MMH in those classifications. Analyses of the percent distributions revealed that many basic ergonomic considerations for MMH have been ignored. Redesign strategies should be focused toward minimizing hand distances, decreasing loads of lifts, lowers, and carries, decreasing frequencies of tasks, increasing heights of start of lifts, and decreasing distances of carries, pushes, and pulls. There should also be a continued effort to decrease the number of lifts and lowers which comprise 69% of the tasks surveyed. Ratios of percent of reports in key industrial classifications to the percent of compensation costs associated with MMH in those classifications indicate higher ratios in manufacturing, durable, and non-durable categories and low ratios in service, trucking and construction categories. It is concluded that continued effort should be extended toward redesign of MMH tasks and components of tasks that violate good ergonomic principles.