Class A/1 designates the material's surface burning characteristics when tested in accordance with UL723, ASTM E84 and CAN/ULCS102.2. The governing building codes such as IBC, NFPA, UBC, BOCA and SBCCI mandate that all building materials meet the minimum of a Class C/3 rating. Time-hour rating is the appropriate designation for those products applied onto or into equally rated doors, as well as fire rated flush mounted corner guards installed in fire rated walls. Applying a material that is not time-rated to a fire rated door and/or door frame will negate the rating of the assembly.