Arc-Rating

Image courtesy of Arc Flash.ie

An arc-rating (AR) is the level of protection offered by a garment against an electrical arc discharge. Higher arc-ratings protect against higher amounts of energy. Arc-ratings are given in calories per square centimeter (cal/cm2). At a minimum, the arc-rating of a worker's ensemble should protect against the estimated incident energy that worker will be exposed to.

An arc-rating is based on its “arc thermal performance value” (ATPV). The ATPV is the amount of incident energy required to cause a second degree burn through the material.

Previous editions of NFPA 70E used the term "FR" or "Flame-Resistant," but this term is no longer applicable. FR clothing CANNOT be used interchangeably with AR clothing. All arc-rated clothing is also flame-resistant but not all FR clothing is arc-rated. Arc-rated clothing or equipment indicates that it has been tested for exposure to electric arcs. FR clothing without an arc-rating has not been tested for exposure to electric arcs.