Continuing Education: Real-Time Data Evaluation at a Bag-Emptying Operation: A Case Study

Abstract

Abstract A variety of tasks are performed during the brief time required to open and empty a bag of powdered material. Each task creates a potential source of dust exposure for the workers performing these tasks. In this study, 50-pound bags of powdered lead chromate were emptied at a ventilated bag-dumping station. Continuous, real-time measurements of dust exposure were recorded, and the worker's actions were videotaped while emptying 65 bags in a 24-minute period. Using a computer program, a representation of the instantaneous dust exposure was overlaid onto the videotape of the worker's actions. Study of this videotape identified seven specific tasks and the relative contribution of each to the worker's overall dust exposure. It was found that pushing empty bags into barrels for subsequent disposal was the major dust source; cutting open bags and lifting them to the emptying shelf of the dump station were lesser but significant dust sources. It was also observed that the bag disposal unit within the dump station control system was awkward for the worker to use; therefore, workers disposed the empty bags in barrels outside the control system. It is estimated that redesign of the disposal system and modification of work practices can reduce worker exposure by about 35 percent. The videotape with the overlay of the dust exposure information can also be used as a training aid for improving work practices. Workers viewing this tape can observe which tasks cause the greatest exposures and understand the need to modify these activities.