Clothing in arc flash: Four types of arc exposure and the effect of moisture on garment appearance after an arc event

Garments respond differently to four types of arc exposures. Moisture in arc exposed garments can alter their appearance in ways not typically observed in standardized arc flash testing such as ASTM F1959, IEC 61482-1-1, IEC 61482-1-2 or ASTM F2621. Color change commonly seen in garments exposed to standard tests do not occur as expected when garments are moist. This information may be useful in accident investigation and hazard assessment. The four types of arc exposures described herein are: Radiated Arc, Ejected Arc, Arc-in-a-box, and a “Tracking” Arc. Two of these arc exposures can be described as plasma-rich and the other two are only circumstantially plasma-rich depending on equipment configuration, duration, voltage, and fault current level. New methods to reduce arc hazards, such as blankets meeting ASTM F2676 and shields meeting ASTM F2522 and how they relate to potential arc exposures will also be discussed.