FR workwear is made of FR fabric, and the main purpose is flame resistance. However, in the case of such disasters as arc flash, the impact is far greater than general fire damage. All AR garments are flame retardant (FR), but not all FR-rated garments are arc-rated. People cannot get proper workwear when the arc rating is not marked. Therefore, flame-resistant fabric needs the arc rating.
In 2018, the NFPA committee revised the standard and name of HRC (Hazard Risk Category) and designed PPE 1~4 according to the degree of risk exposure. Arc-flash explosions due to electrical equipment failure depend on the electrical equipment's energy delivery capability, measured in calories per square centimeter. The ARC rating determines the protective properties of the fabric. The higher the ARC rating, the greater the protection.