A hazard risk category (HRC) is a rating for FR clothing that indicates the level of protection the garment provides. There are five HRC’s ranging from 0 to 4, with HRC 0 being the least protection and HRC 4 being the most protection. NFPA 70E assigns these categories based on the electrical maintenance task to be performed, and each HRC correlates to a range of ATPV’s.

HRC 0: No minimum ATPV required.
HRC 1: Arc-rated FR garments with a required minimum ATPV of 4 cal/cm2
HRC 2: Arc-rated FR garments with a required minimum ATPV of 8 cal/cm2
HRC 3: Arc-rated FR garments with a required minimum ATPV of 25 cal/cm2
HRC 4: Arc-rated FR garments with a required minimum ATPV of 40 cal/cm2