Pay attention! At critical moments, this glass panel on the ceiling of the mall can save lives →

When everyone is shopping in the mall

Did you find the ceiling?

There are always some vertical glass panels

Do you know what it is used for?

Now let Dr. Ko answer the questions for you!

These glass panels are called smoke barriers . The "Public Safety Industry Standard of the People's Republic of China" defines smoke barriers as: smoke barrier separation facilities made of non-combustible materials, installed vertically under the ceiling, beams or ceiling of a building, which can form a certain smoke storage space in the event of a fire.

The materials of smoke barrier walls are usually steel plates, glass, gypsum boards, etc., which can withstand high temperatures when a fire occurs and maintain integrity for a certain period of time, thereby effectively blocking the spread of smoke and buying time for people to escape safely.

Smoke barrier walls are commonly found in subway platforms, building corridors, traffic tunnels and other places. These places have the same structural characteristics, that is, the length dimension is much larger than the height or width dimension, and usually there are only exits at both ends. Therefore, these places are also called narrow passages .

When a fire occurs in a narrow passage, after the smoke hits the ceiling, the lateral diffusion speed is very fast, up to 1 meter per second. In the absence of obstruction, the smoke will quickly spread along the ceiling to the entire building, forming a smoke layer . The diffusion path of this smoke is the same as the route people take for emergency evacuation , which not only increases the difficulty of evacuation, but also brings challenges to fire fighting. In addition, due to the long structure of long-channel buildings, the impact of horizontal shear force is more significant. As the hot smoke flows through, it inhales a large amount of cold air below, which increases the mass flow of smoke, thereby increasing the risk of causing major casualties.

After installing smoke-blocking vertical walls in the passage, the ceiling is divided into multiple small spaces , and a smoke pool is formed above the vertical walls, which effectively prevents the spread of smoke along the axis of the passage . Combined with the use of ventilation systems to exhaust smoke, the harmful effects of smoke can be greatly reduced, allowing people to escape safely. Smoke-blocking vertical walls can not only block the spread of smoke in the early stages of a fire, but also have an impact on the spread of the entire fire smoke flow.

The inconspicuous smoke barrier is only part of the complex fire protection measures in modern buildings. There are other fire protection facilities in the building.

(1)

Firewall

According to Article 2.1.12 of the current national standard "Code for Fire Protection Design of Buildings" GB50016-2014 (2018 edition), a fire wall refers to a non-combustible wall with a fire resistance limit of not less than 3 hours that prevents the spread of fire to adjacent buildings or adjacent horizontal fire partitions.

(2)

Fire shutter

Fire shutter is a fire separation facility, installed in the fire partition location or the location that needs fire separation in the building. It is usually hidden in the shutter box near the ceiling; in case of fire, it will drop at a uniform speed to prevent the spread of fire and smoke.

(3)

Fire Doors

Fire doors can be divided into normally open fire doors and normally closed fire doors according to the opening method.

Normally open fire doors: generally used in passages or corridors in public places . Normally open does not mean that it can play a fire prevention role when it is open, but it allows it to remain in a normally open state. Because it has an electromagnetic release or a linkage door closer, it can automatically close when a fire occurs, buying time for people to evacuate.

Normally closed fire doors: Normally closed fire doors can only effectively block the invasion of thick smoke and flames after a fire occurs when they are in the closed state. Within a certain period of time, fire doors have functions such as fire prevention, smoke isolation, and high temperature blocking.

That’s all for today’s science popularization!

Dr. Ke would like to remind everyone

Emergency exits, evacuation equipment , etc.

In the event of an accident

This is life-saving information!!

This is the end of this issue

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Source: Physical Science Popularization, Guangdong Science Popularization, Jiangsu Emergency Response and Management.

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