What are those vertical glass panels on the mall’s ceiling? Are they advertising spaces that can’t be sold?

As you walk through the mall, don’t stare down at your phone—instead, look up at the ceiling—hey? What are those vertically arranged glass panels spaced a few steps apart on the ceiling?

A mysterious glass panel, located in a shopping mall somewhere in Shanghai | @Guokr Reader Ah Teacher

On closer inspection, you’ll find glass panels like these in the subway as well.

Shot at a subway station in Beijing | @Guokr Reader Penguin

What on earth are these mysterious glass panels used for? Could it be that they’re all unsold advertising spaces?

Deadly smoke, life-saving board.

In fact, these glass panels are called smoke barriers, and they can be incredibly useful when a fire breaks out. They help contain the spread of smoke, giving people valuable time to evacuate safely.

A significant portion of fire-related casualties is linked to smoke. Statistical data show that approximately 40% to 60% of fire-related casualties are attributable to smoke.

Inhaling smoke can cause respiratory burns, carbon monoxide poisoning, and poisoning from toxic gases, leaving trapped individuals feeling short of breath or even falling into a coma and missing their chance to escape.

Image source: Pixabay

Smoke itself can also obscure safety exits and exit signs, disorienting people. Therefore, when a fire has already broken out, it’s crucial to limit the spread of smoke.

How does smoke spread?

To find ways to control smoke, we first need to understand how smoke spreads indoors.

When a fire breaks out inside a building, the scorching smoke rises rapidly and accumulates around the ceiling. Without any barriers, the smoke quickly spreads along the ceiling throughout the entire interior of the building, forming a layer of smoke.

Smoke Control in Shopping Centres | Colt International Ltd

During a fire, smoke spreads horizontally at an extremely rapid rate—up to 1 meter per second. Once the smoke has filled the entire ceiling, it will continue to spread downward along the walls.

Even more frightening is that people instinctively flee in the direction away from the smoke. At this point, the distribution of smoke can mislead those trapped, even causing them to run toward areas that appear to have less smoke—precisely toward the source of the fire.

Smoke Control in Shopping Centres | Colt International Ltd

The smoke curtain has made its move!

To limit the spread of smoke, a simple and effective method is to artificially divide the ceiling into several smaller spaces—this is precisely the function of smoke barriers.

Using fire-resistant and heat-resistant materials to block smoke and prevent it from spreading rapidly throughout the indoor space, combined with the use of ventilation systems to exhaust smoke, can significantly reduce the harmful effects of smoke and enable people to escape safely.

Smoke Control in Shopping Centres | Colt International Ltd

Smoke barriers can also be categorized into fixed types (such as glass panels) and movable types (such as fire-resistant fabric roller shutters).

In public spaces, you might want to take a look above your head—there could be something resembling a rolled-up projection screen up there. That’s most likely an operable smoke curtain, which will deploy when the smoke detectors trigger an alarm.

In general, smoke barriers are suitable for indoor spaces with large areas and lacking natural partitions.

In places with high aesthetic requirements, such as shopping malls, smoke-control curtains made of fire-resistant glass are typically used. In places like workshops and parking lots, smoke-control curtains made of materials such as fire-resistant fabric are usually employed.

The use of smoke barriers also has certain requirements for the floor height of buildings.

According to relevant industry standards, the minimum drop height of smoke barriers must be no less than 50 centimeters. However, fire-resistant rolling shutters, as well as doors, windows, and partition walls that meet fire safety requirements, can also achieve the same effect by preventing the spread of smoke and fire.

The unassuming smoke-control curtains are just one component of the sophisticated fire protection measures found in modern buildings. In your daily life, you should pay more attention to fire safety equipment, emergency exits, evacuation staircases, and other such features in buildings—because in the event of an accident, these elements can be lifesaving.

Of course, the best approach is to do a good job of fire prevention—ideally ensuring that smoke-control curtains never have to be used at all.