American standard which establishes that employees who are exposed to a possible arc flash should wear appropriate flame resistant garment for the risk level of their workplace. Employers must evaluate an arc flash to determinate the risk of potential energy and the limit of protection against the arc flash. The protective garment should cover the calculated incident energy or risk level, reaching at least its minimum ATPV.

Arc Thermal Performance Value - ATPV

• Level 0: No risk
• Level 1: between 4 to 7.9 cal/cm2
• Level 2: between 8 to 24.9 cal/cm2
• Level 3: between 25 to 39.9 cal/cm2

American standard for garments that protect from flash fire. The standard demands that after being washed a hundred times, the garment is put on a mannequin and exposed to 3 seconds of direct flame. In order to accomplish the standard the result must show less than 50% of body burn.