Protective clothing guidelines for electric arc exposure

Abstract

Since 1982 when Ralph Lee wrote about "The Electrical Hazard: Electric Arc Blast Burns", industrial and utility engineers have been attempting to better quantify the degree of risk to personnel associated with electric arc exposure and the appropriate protective clothing to wear to mitigate serious injury. Activity, by OSHA, NFPA 70E and ASTM F-18 has further emphasized the need to prefect workers from arc flash burn injuries. This paper discusses the results of multiphase arc testing which has enhanced knowledge about: (1) potential arc energy as a function of prospective fault current, and (2) arc protective clothing designs that are suitable for different levels of incident arc energy. Incident energy levels are correlated with second degree burn criteria for unprotected human skin. Protective clothing systems consisting of flame resistant outer layers in single layer and multiple-layer construction, as well as combination systems of flame resistant outer layers with natural and man-made fiber inner layers are discussed. Protection recommendations for the face, head, hands and feet are also included.