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Discussion on several issues about steel fire doors

by:CBM     2021-06-08
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. The main requirements for the product quality of fire doors in China are: 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) Flame appeared on the back side of the specimen and lasted for 10s or more;

b) The cotton pad started to catch fire ;

c) The specimen 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 back surface of the specimen reaches 140°C;

b) The specimen The highest temperature rise of the fire-back surface reaches 180°C;

c) The highest temperature rise of the fire-back surface of the door frame reaches 180°C;

d) The heat radiation intensity of the fire-back surface of the specimen Exceeding the critical heat radiation intensity (persons stay for 5s, the critical heat radiation intensity is 0.96W/cm?;; if the staff stays for 3s, the critical heat radiation intensity is 1.05W/cm?;)

2, building Requirements of fire protection design codes for fire doors

Most of the fire protection design codes have clear requirements for fire doors. The requirements are different according to the different parts of use. The general principle is: fire protection at the opening of the fire partition The doors are Class A; the fire doors in the room and the atrium, the front room of the fire elevator, and the evacuation corridor are Class B; the fire doors on the shaft wall are Class C. For example: GB 50045-1995 'Code for Fire Protection Design of High-Rise Civil Buildings' requires in 5.1: 'The doors and windows between the room and the atrium corridor should be self-closing Class B fire doors and windows'; the requirements in 5.32: 'Inspection doors on the shaft wall' Class C fire doors should be used'. The requirements in 3.5.6 of GBJl6-1987 'Code for Fire Protection Design of Buildings': The front room of the fire elevator room should be equipped with Class B fire doors or fire shutter doors.

3. Common quality problems and inspection points of steel fire doors

In recent years, I have passed the production and production of steel fire doors and the project site management and acceptance experience in the field of construction engineering and use. The following quality problems occur:

1. Raw material problems: 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, and fireproof and heat-insulating materials are not consistent. Filling, or using honeycomb paperboard, rock wool instead of aluminum silicate fiber cotton or filling dissatisfaction, with shoddy filling, reduce its production cost. The focus of the inspection is to check the technical requirements in the test report data. Filling material: one method is Knock and listen to the sound inspection method, the dull sound indicates that there is filling in the door frame and door leaf, the more dull the more solid the filling; the other method is the gap inspection method, that is, from the door frame and door leaf holes (hinge holes, locks) Inspection of holes, bolt holes, door closer sequencer fixing holes, upper and lower ventilation holes, process holes, etc.). At present, the filler for Class A and B fire doors sold on the market 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 Generally, it is smaller than the thickness of the door leaf 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 thickness of the door leaf in the test report.

3. Fireproof glass Problem: Float glass (single-layer or double-layer), hollow glass, thin fire-resistant glass with insufficient grade or fire-resistant glass with poor lighting and excessive air bubbles are often found at the construction site as fire-resistant glass with high fire resistance. Remove a piece of glass randomly, 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. The specifics should be compared with fireproof glass. The data on the test report.

4. The problem of automatic closing: door closers and sequencers are usually installed on the fire door at the project site, and some even only install the door closer. The purpose is to automatically close the fire door when it is opened. Theoretically, it should be no problem to do so. Once a fire occurs, people will be more confused when escaping, resulting in uncertain opening force when passing through the fire door. If the opening angle of the ambassador door is greater than the safe use angle of the door closer, the door closer cannot be reset. In this way, the fire door will not function as it should. 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 the door leaf opened to 135o to eliminate the possibility of failure of the door closer.

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