Fire door refers to the door that can meet the requirements of fire resistance stability, integrity and thermal insulation within a certain period of time. Class B fireproof door shall have a fire endurance of no less than 1.0h, and shall be used in staircases and vestibules. The fire resistance limit of Class C fireproof door shall not be less than 0.5h, and it shall be used in vertical shafts such as pipe shafts and cable shafts.