Class B15 single leaf fireproof door is a door specifically designed to provide superior fire performance. It can prevent the flame from passing through at the end of the 30-minute standard fire test, and the class B15 means that the average temperature on the back side of the fire within 15 minutes does not increase by more than 140 °C from the original temperature, and at any point, including any joint, the increase from the original temperature does not exceed 225 °C.