The effects of protective clothing on worker performance: A study of size and fabric weight effects on range-of-motion.

Abstract

Many workers routinely wear personal protective clothing (PPC) to assure their safety and comfort; however, PPC can detrimentally affect worker performance. To systematically correct the ergonomic problems associated with wearing PPC, it is necessary to identify garment properties that lead to reduced worker comfort and performance, and to quantify their effects. A systematic structure is presented for studying the relationships among garment properties and their effects on worker performance. Previous work was categorized according to garment parameters and dependent measures. Very few studies were found that quantified relationships among PPC properties and specific performance effects other than heat stress. Using this structure, a conceptual Garment Impediment Index model was proposed as an approach for developing predictive models of worker performance that are based on quantifiable garment properties. Three methods were evaluated for measuring range-of-motion (ROM) on clothed subjects, i.e., a universal goniometer, a Leighton Flexometer, and an electrogoniometer. Among these, the goniometer and the Flexometer yielded similar results. The goniometer was found to be less invasive and able to measure a larger set of movements than the Flexometer. The electrogoniometer system that was tested did not perform adequately for measuring joint angles in the types of gross body motions tested. Using the goniometer, the effects of garment size and fabric weight on ROM were quantified for subjects wearing coveralls. Garment size relative to wearer anthropometry affected ROM for all movements tested except shoulder extension, hip extension, and trunk lateral flexion. ROM was least diminished by garments that were oversized and most diminished by undersized garments. Fabric weight had little effect. Subjective and objective assessments of ROM impediment were highly correlated. Two additional pilot studies were conducted. A method was demonstrated for isolating garment weight and measuring the effect of this parameter on arm movement speed, heart rate, and perceived exertion. An approach was also demonstrated for developing a quantitative model of ROM effects based on subject anthropometry and garment dimensions.