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The fire resistance limit refers to the time for building components to undergo fire resistance test according to the time-temperature standard curve, and the time from the effect of fire to the loss of stability, integrity or heat insulation. According to the fire resistance limit, fire doors in our country are divided into three grades: Class A, Class B, and Class C to meet the needs of different levels of various buildings. The fire resistance rating of Class A fire doors is 1.2h, the fire resistance rating of Class B fire doors is 0.9h, and the fire resistance rating of Class C fire doors is 0.6h.
According to GB50045-95 (Code for Fire Protection Design of High-Rise Civil Buildings) and GB50016-2006 (Code for Fire Protection Design of Buildings) for various types of fire doors The scope of use is specified; when opening doors, windows, and openings on the firewall, Class A fire doors should be installed, and Class B fire doors should be used when opening doors on partition walls with a fire resistance rating of not less than 2.0h. However, the fire resistance limit of the fire door is very different from the fire resistance limit of the firewall. The fire performance of the fire door after its fire resistance limit is unknown, which will cause a fire hazard.
Product standards for fire doors are GB12955-91 (General technical requirements for steel fire doors) and GB14101-93 (Common wooden fire doors Technical conditions) There are also corresponding regulations and requirements for the design and installation of fire doors. Fire doors are produced in accordance with the current national standards for fire doors. Class A fire doors are 45-55mm thick and filled with aluminum silicate fiber cotton, and Class B fire doors are 40-50mm thick with aluminum silicate fiber cotton and rock wool. , The thickness of the door leaf of Class C fireproof door is about 40mm, and the interior is filled with fireproof board and rock wool. The key to the fire resistance of fire doors often depends on the internal filling materials.
Fire doors in the United Kingdom, France, the United States, Japan and other countries generally have a fire protection performance lower than my country’s standards, but Europe and the United States Other developed countries have other advantages in the requirements of fire doors. American standards NFPA and UL10 only require the first 30 minutes of fire resistance and heat insulation for fire doors. The temperature does not exceed 232 degrees, and the integrity is 0.5-3.0h. The inspection method is not only tested in accordance with the standard temperature rise curve, but also passed The actual fire test is carried out to obtain the performance-based fire door design plan, which has more practical value. Malaysian standard MS1073 also has basically similar requirements. British Standard BS476 divides fire doors into fully insulated fire doors and semi-insulated fire doors. The time requirements for the fire resistance and heat insulation of fire doors are not high, such as 20min, 30min, but the fire integrity requirements meet the corresponding design time requirements, such as 2.0h, 3.0h, or even 4.0h.
At present, the Tianjin Institute of Consumer Science and Technology of the Ministry of Public Security is currently revising (General Technical Requirements for Steel Fire Doors) and (General Technical Requirements for Wooden Fire Doors). The revised principle is after revision The standard is more in line with reality. Classify fire doors into Class A fire doors and Class B fire doors. Class A fire doors are also known as fully insulated fire doors. Fire doors that can meet both fire integrity and fire insulation within a specified time are used in more important places, such as fire doors for nuclear power plants and fire doors for important parts. The fire resistance grade of the door can be divided into 1.0h, 1.5h, and 2.0h. Class B fire doors are also called semi-insulated fire doors. Its fire resistance and heat insulation only require 0.5h, and its fire integrity is 0.5h, 1.0h, 1.5h, 2.0h, 2.5h, 3.0h, 4.0h. Because the fire door is an access door, it can basically satisfy the evacuation of people on the fire site within 0.5h after a fire occurs. Generally, no combustible materials are allowed to accumulate nearby. Therefore, the fire door will not be insulated after 0.5h will not cause fire hazards. The door installed on the firewall can prevent the spread of fire and complement the role of the firewall.
