Who knows the fire endurance of B-level fireproof doors and windows?
According to the fire endurance, fireproof doors can be divided into A-grade, B-grade and C-grade, whose fire endurance should not be less 1.2h, 0.9h and 0.6h respectively. Fire endurance of fireproof windows: A-grade fireproof windows are not less than 1.5h and B-grade fireproof windows are not less than 1h. The door leaves of A-grade and B-grade fireproof windows should be steel materials, and their glass should be composite fireproof glass whose thickness is no less than 26mm. Monolithic fireproof glass window is not B-grade fireproof window, nor A-grade fireproof glass window. It si called non-insulated fireproof window.
B-grade fireproof windows refer to those fireproof windows whose fire retardant limit is not less than 1 hour. Technical requirements: I. Materials and Accessories (1) Window frame should have a certain strength to ensure the integrity and stability of the steel frame or the wood frame. (2) Steel frame and mound layer can employ galvanized?steel?sheet or stainless steel plate. Its selection criteria should be in line with the stipulation of the Article 5.1 of GB12955 "General Technical Requirements of Steel Fireproof Doors". (3) The selection standard of wood frame and mound layer should be in line with the provision of Article 5.1.1 of GB14101 "General Technical Requirements of Wooden Fireproof Doors". (4) Filling materials inside steel frame and wood frame should be non-combustible materials.
Rock wool board of B-grade fireproof doors keeps 46mm in thickness, doors that are generally used in relatively common fire fighting access, while A-grade fireproof doors are generally used in machine rooms, warehouses, oil depots and other important fire fighting access and flammable and combustible pulbic places. B-grade fireproof doors are more widely used than A-grade fireproof doors.
