"What is a fire door? What is a normally open or normally closed fire door? What is the difference between them? Under what circumstances should a normally open or normally closed fire door be used? What should I pay attention to when distinguishing between true and false fire doors?" For these and How can we be confused about safety-related issues?
What is a fire door?
Fire doors (also known as fire doors) usually refer to doors located in enclosed areas such as stair walkways, elevators, cable wells, smoke exhaust ducts, and so on. The function of the fire door is to meet the fire resistance stability and heat insulation in a certain period of time. It can prevent the fire from spreading and spreading and ensure the evacuation of personnel. It is an indispensable device in fire protection work. It is common in crowded public places such as large shopping malls, supermarkets, and hotels. It can be said that it is inseparable and closely related to the safety of the people. Fire doors are generally divided into two types: normally open fire doors and normally closed fire doors.
What is a normally open or normally closed fire door?
Normally open, and automatically closed in case of fire, is called a normally open fire door.
Normally kept closed, only authorized personnel can pass, and in emergency situations, the fire door is automatically released to allow people to pass, which is called a normally closed fire door.
Third, the difference between normally open fire doors and normally closed fire doors?
Normally open fire doors are normally open, and close automatically in case of fire. Because it is always open, it is convenient for people to pass, and it is convenient for ventilation and lighting. It can be closed by itself in the event of a fire, which acts as a smoke and fire barrier. Therefore, the inconvenience caused by the normal closing of the fire door to personnel and the artificial damage caused by the frequent opening and closing of the fire door are completely solved, and the fire safety is also guaranteed. Therefore, in some large shopping malls' evacuation staircases, fire doors should be always open and usually open. When a fire occurs, the door closers are controlled by various sensors to close the doors.
Normally closed fire doors are closed at ordinary times and need to be opened when people move around. Normally closed fire doors in this open state have certain shortcomings, because the place where the fire door is installed is usually a passageway where people often move, which creates a certain contradiction. Especially in large shopping malls, there is a large flow of people. If a normally closed fire door is installed in the evacuation staircase inside it, the fire door will be damaged and detached quickly due to frequent opening and closing, thereby failing to prevent fire and form a fire hazard.
4. Under what circumstances is a normally open or normally closed fire door used?
Fire doors that are often used in buildings should be normally opened fire doors. That is to say, the fire doors in the public parts of the building, including the smoke-proof stairwell, the front room of the fire elevator and the shared front room, should be always open fire doors, and always open fire doors should also be set up in the evacuation corridors of the hall.
Except for the positions where normally open fire doors are allowed, fire doors at other positions shall adopt normally closed fire doors. In other words, all fire doors should be normally closed fire doors except those marked as normally open fire doors in the drawings. This requires designers to select fire doors, if the code requires a normally open fire door, it must be indicated in the door and window table, and the reviewer can carry out the review accordingly.
Fifth, a few great tricks to distinguish true and false fire doors:
1. Look at the nameplate. The name of the manufacturer on the fire door nameplate should be consistent with the product type approval certificate and inspection report. The product name should clearly indicate that it is a fire door product, and whether the fire door has a large "S" identification mark on it;
2. Touch the surface. The surface of the fire door should be flat and smooth without obvious dents or mechanical damage. The welding of steel fire doors should be firm and the welding points should be evenly distributed. There should be no false welding, burn-through, or missing welding. The seams should be tight and smooth, and plywood is not allowed to plan through the surface veneer;
3. Explore the sandwich. Remove the "cat's eye", and reach into the hole to test the internal filling, and check whether the type of filling material and corresponding parameters are consistent with the content in the type inspection report;
4. Check the door frame. Fire protection door frame shall be provided with fireproof sealing strips, and the sealing strips shall be straight and without arching;
5, 掂 weight. Regular fire doors are heavier than ordinary steel doors;
6. Listen to the sound. Generally, no hollow sound can be heard when the fire door is knocked;
7. Find attachments. Fire doors should be equipped with fire locks, fire hinges, fire sequencers, fire plugs and other accessories.