Assessment of Static Electrical Propensity for Work Clothes Using Human Body Voltage Measuring Methods

Safety quality on the static electrical propensity of work clothes in Japan is confirmed by electrical resistivity or frictional electric charge obtained from the results of test methods specified by International Electrotechnical Commission standard (IEC) or Japanese Industrial Standard (JIS). In practical use, we consider that the hazard related to static electrical charge is dependent on human body voltage caused by various movement of worker during working hours as well as electrical resistance or electric charge amount of work clothes. We thought up two trial movements for determination of human body voltage: one is taking off movement after performing frictional action between work clothes and inner wear during 20 seconds at speed of 90 times per one second, and the other is standing up from the seat of popular use chair quickly after performing frictional action between the back part of work clothes and the back of a chair during 60 seconds at speed of 90 times per one second. Experimental works were performed by using four types of unprotected commercial work clothes and six types of static protected commercial work clothes. As the experimental results, standing up movements from the seat of chair were recorded higher human body voltages than taking off movement. From the almost all work clothes including static protected work clothes, the human body voltage above 3000 voltage which many human felt static electrical shock were detected by the standing up from the chair quickly after performing frictional action.