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Discussion on several issues about steel fire doors
Performance requirements for steel fire doors
1. Product quality requirements
Product quality requirements are divided into two categories: general door requirements and functional requirements. In the two standards, the product quality of fire-resistant doors is mainly: appearance quality, production accuracy, assembly accuracy, overall strength, etc. Its purpose is to meet the requirements for use as a door. The functional requirements are mainly: material performance and fire resistance, the purpose of which is to play a role in preventing fire and smoke in the event of a fire. This is the most important significance of installing a fire door. In terms of material performance: the insulation material filled in the door leaf and door frame should meet the non-combustibility Class A requirements specified in GB8624-1995 'Combustion performance classification of building materials'; the melting point of locks, hinges, bolts and other hardware should not be lower than 950. The sealing strips between the door frame and the door leaf and in the middle of the door leaf should be non-combustible materials; fire-resistant glass should not affect the fire-resistant performance of the fire door. The fire resistance performance is divided into three levels: A, B, and C according to the standard, and the fire resistance time is 72min, 54min and 36min respectively. The test method is in accordance with GB7633-1987 'Fire Test Methods for Doors and Rolling Shutters'. The determination condition of the fire resistance limit is that when any one of the following determination conditions appears, it indicates that the fire resistance limit of the test piece has been reached.
1) Loss of integrity
a) The flame appears on the back fire surface of the test piece and lasts for 10s or more;
b) The cotton pad started to catch fire;
c) The test piece collapses or the penetrating opening is formed or the mechanical device such as the door lock is damaged. ????
2) Loss of heat insulation
a) The average temperature rise of the fire-back surface of the specimen reaches 140°C;
b) The highest temperature rise of the fire back surface of the test piece reaches 180°C;
c) The highest temperature rise on the back fire surface of the door frame reaches 180°C;
d) The heat radiation intensity of the back fire surface of the test piece exceeds the critical heat radiation intensity (persons stay for 5s, the critical heat radiation intensity is 0.96W/cm?;; When the staff stays for 3s, the critical heat radiation intensity is 1.05W/ cm?;)
The common quality problems and inspection points of steel fire doors
1. The problem of raw materials: The actual raw materials used do not match the materials used in the design or testing. For example, thin plates are used for steel plates instead of thick plates, cold rolled instead of galvanized, fireproof and heat insulating materials are not filled, or aluminum silicate fiber cotton is replaced by honeycomb cardboard, rock wool, or filled with dissatisfaction, which reduces the production cost. The focus of the inspection is to compare the technical requirements in the test report materials. Filling materials: One method is to tap and listen to the sound inspection method. A dull sound indicates that there is filler in the door frame and door leaf. The more dull the more solid the filling; the other is One method is the gap inspection method, which is to inspect from the holes of the door frame and door leaf (hinge hole, key hole, bolt hole, door closer sequencer fixing hole, upper and lower ventilation holes, process holes, etc.). Currently, it is on the market. The filler for Class A and Class B fire doors is white aluminum silicate fiber cotton (different bulk density, Class A is more than 200kg/m3, Class B is more than 160kg/m3), Class C uses yellow rock wool.
2. The thickness of the door leaf: The door leaf actually used at the project site is generally smaller than the door leaf thickness during design or inspection, and it is difficult to achieve the fire protection level required by the building. Check whether the actual door leaf thickness meets the door leaf thickness in the test report.
3. Fireproof glass problem: Float glass (single layer or double layer), hollow glass, thin fireproof glass with insufficient grade or fireproof glass with poor lighting and excessive air bubbles are often found on the project site to pretend to be high fireproof glass. fire-proof glass. During inspection, you can randomly remove a piece of glass, check whether the seal of the fireproof liquid is on the upper corner of the glass, and measure its thickness. The thickness is generally 30mm for Class A, 25mm for Class B, and 20mm for Class C. Compare the data on the fireproof glass test report.
4. The problem of automatic closing: door closers and sequencers are usually installed on the fire door at the engineering site, and some even only install the door closer, the purpose of which is to automatically close when the fire door is opened. In theory, this should be no problem. Once a fire occurs, people will be more confused when escaping, resulting in uncertain opening force when passing through the fire door. Once the force is applied, the opening angle of the ambassador door is greater than the safety of the door closer. Using the angle, the door closer cannot be reset. In this way, the fire door cannot play its due role. There are two types of door closers commonly used in engineering: 105o and 135o. Check whether a door stop device is installed within the range of door opening to 135o to eliminate the possibility of door closer failure.
5. The problem of escape locks: It is often found at the engineering site that ordinary press-bar fireproof locks are used at crowded emergency evacuation openings instead of special escape locks. The special escape lock can open the door by simply touching the lock body with the body when the personnel escape. Even if there is a fire, the fire door can be opened in case of crowded people at the door to achieve the purpose of escape. Check whether this special lock is used and its flexibility. Under normal circumstances, the emergency evacuation escape door is not allowed to open the door frequently from the outside to enter, and it is not allowed to set the sill above the ground to prevent the escape personnel from tripping during the emergency evacuation.
In short, steel fire doors must be produced in strict accordance with standard requirements, and reasonable use in accordance with the requirements of the specification. The supervision and management department should also check from the production process to the scientific use in the project to ensure its good quality status and Reliable performance, only in this way can the steel fire door truly play its due role.