What is the difference between normally open fire doors and normally closed fire doors?

Many people will wonder why some fire doors are normally open and some are normally closed. In fact, both the normally open fire doors and the normally closed fire doors are designed according to the needs of fire protection.

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Fire doors are usually set in evacuation staircases, front rooms, pipe wells, equipment rooms and other places and parts of the door. The function of fire door is to meet the fire resistance stability and heat insulation within a certain period of time, to prevent the spread and spread of fire, to ensure the evacuation of people, which is an essential equipment in the fire protection work. Fire doors are divided into normally closed fire doors and normally open fire doors. What's the difference between them? To understand the difference between the two, we need to find out how the normally open fire door and the normally closed fire door play a role in fire protection.

Normally open fire door

Normally open fire doors are generally installed in places with large flow of people, such as schools, large shopping malls, hospitals, etc. In these places, it is not convenient to install normally closed fire doors due to frequent access to stairwells. At the same time, if the fire door is often opened, the normally closed fire door will be damaged, which will not play a role in fire prevention and form a fire hazard. Therefore, fire doors are usually installed in these places. The normally open fire door is in the open state under normal conditions, which is convenient for people to enter and exit. When there is a fire, it can be closed automatically by electric control, and the action signal is fed back at the same time. The normally open fire door is not simply to make the fire door open, it must meet the function of automatic control in case of fire. Therefore, the normally open fire door must be equipped with a fire alarm system.

Normally closed fire door

Normally closed fire doors are generally installed in places with few people. Under normal conditions and in case of fire, it should be closed. When someone moves around, it needs to be pushed away, so as to prevent smoke and fire and prevent the spread of fire. For example, in the evacuation stairwell of general high-rise residential buildings, people usually use elevators and few people walk through the stairwell to reach the floor, so the fire door of the stairwell is normally closed. Even if there are people passing through, they can open and close by themselves through the door closer and sequencer (double doors).

No matter the normally open or normally closed fire doors, the newly-built projects generally design the fire door monitoring system to monitor the status of the fire doors. Through the fire door monitor set in the fire control room, real-time master the open and close status of the fire doors in the building.
    Fire doors can be divided into wood fire doors, steel fire doors, steel wood fire doors and other fire doors according to the material classification. The commonly used fire doors are wood fire doors and steel fire doors.

Components of fire door

Fire door leaf and frame

The door leaf and frame of the commonly used wood fire doors and steel fire doors are made of fire-resistant wood and steel respectively. If the door leaf is filled with materials, it will be filled with non-toxic and harmless fire insulation materials.

Fireproof glass on fireproof door

If the fireproof door is inlaid with glass, the fireproof glass shall be used, and its fire resistance performance shall meet the conditions of corresponding fire doors. (the fire-proof glass shall be inspected and qualified by the national authorized testing agency)

Door closer

The fire door shall be equipped with a fire door closer, or a door closing device (except for the use of special parts, such as the pipeline well door) that can automatically close the door leaf when a fire occurs. The fire door closer shall be inspected and qualified by the state approved and authorized testing agency; the door closer device that automatically closes the door leaf shall be inspected and qualified by the state approved and authorized testing agency.

Sequencer

The double fire doors shall have the function of self closing in sequence, which is realized by sequencer.

Fire lock

The door lock with fire door installation shall be fire lock, and the fire lock shall be tested by the national approval and authorization

The organization passed the inspection.

The access door of tube well shall be locked and closed with special fire lock.

Fireproof hinge

The thickness of hinge plate for fire door shall not be less than 3mm.

Fire bolt

Steel fire-proof bolt shall be used and installed on the door leaf on the opposite fixed side of double fire doors or multiple fire doors (if required)

Caulking plate

The double fire doors with flat or stop mouth structure should be equipped with seam board. The joint plate shall be firmly connected with the door leaf; the cover joint plate shall not hinder the normal opening and closing of the door leaf.

Fire seal

The fire seal shall be embedded in the gap between the fire door frame and the door leaf, and between the door leaf and the door leaf. For example: expansion fire-proof sealing tape, etc. (the fire seal shall be inspected and qualified by the national authorized testing agency)

Push rod lock of fire passage (escape lock, fire lock)

Anti passage push rod lock is a door lock used for emergency passage, which can be pushed directly from the inside and can not be opened from the outside. It has certain anti-theft function, and is commonly used in places with large flow such as shopping malls, supermarkets and entertainment.

The warning signs such as "keep the fire door closed" shall be set at the obvious position of the normally closed fire door.

Fire doors are divided into heat insulation / partial heat insulation / non heat insulation fire doors according to their fire resistance performance. Generally speaking, fire doors are all heat insulation fire doors. Based on the fire resistance, they are divided into three types: Class A (1.5h), class B (1.0h) and class C (0.5h).

Publicity of marketing department of Chongqing Youquan doors and windows Co., Ltd