In everyday life

You might often see a door that is frequently closed.

They are—the normally closed fire doors.

As the name implies,

Fire doors should remain in a closed state for an extended period.

Some of our friends might have questions.

In the event of a fire,

Shouldn't the door be open for easy evacuation and escape?

Why must fire doors remain in a closed state?

Xiao An

Fire-rated doors are a type of fire-resistant door, and fire-resistant doors generally refer to doors installed in enclosed spaces such as stairways, elevator shafts, cable wells, smoke shafts, and other similar areas. The role of fire-rated doors is to maintain fire resistance and thermal insulation for a certain period of time, preventing the spread and diffusion of fire, and ensuring the safe evacuation of personnel. They are an indispensable piece of equipment in fire safety work.

Fire doors only effectively block the invasion of thick smoke and intense flames when they are in the closed position during a fire. For a certain period of time, fire doors provide fire prevention, smoke isolation, and high-temperature resistance functions.

Fire doors should remain closed to prevent the chimney effect hazard.

Approximately 60% of smoke inhalation fatality victims are found in evacuation corridors, hallways, or even homes, which are farther from the fire source, according to incomplete statistics. This is due to the fact that the direction of smoke flow is the path of fire spread, and the spread of smoke is extremely fast.

Experts note that the flow speed of smoke vertically is 3 to 5 meters per second, which is 8 to 10 times faster than horizontally, and exceeds the spread speed of the fire by 5 times. Taking a 33-story building as an example, without any obstructions, smoke can spread from the ground floor to the top floor within about 30 seconds through the evacuation stairs.

Here's what we need to know!

In accordance with the national building design fire safety regulations.

Fire doors should be kept closed at all times.

Upon opening and passing through, the door closer on the fire door automatically closes it. Such fire doors can effectively block the invasion of thick smoke and fierce flames only after a fire occurs. If a normally closed fire door remains open for an extended period, it may fail to return to its normal position, and in severe cases, it could damage the door frame and panel, rendering it ineffective in smoke and fire prevention.

If the fire door fails to function,

In the event of a fire,

It's all too easy for a small fire to turn into a major disaster.

Xiao An reminds everyone:

Closed fire doors must not be left open or locked in place.

Do not seek temporary convenience.

Keep it open often!