The burning issue

Tall buildings have unique challenges when it comes to fires. James Boley finds out how GCC architects can design the supertall to be super safe.

Buildings have to deal with all sorts of stresses. Earthquakes, hurricanes and other natural disasters can demolish an icon in a matter of minutes. There's only so much that a building can withstand when facing the forces of nature.

Other catastrophes, however, are preventable or can be mitigated with greater success. Fire has the potential to cause absolute disaster, but good design can minimise the damage and save lives. While the risk of fire will always exist in a building, architects and engineers have the skills to design buildings so that even if the unthinkable happens, safety can be maintained.

A building's fire defence can be either active or passive. Active fire defences include the use of sprinkler systems and fire extinguishers. Passive defences are when the very fabric and design of the building can help keep people safe during a fire. It's through these passive defences that architects can make the biggest difference.

Although a building is a significant financial, and perhaps emotional, investment, some architects are pragmatic about what is really important.

"You don't really care if a building burns down, as long as the people are out and life is preserved," says Peter Weismantle, associate director of SOM and senior technical architect on the Burj Dubai.

Therefore, the most critical function for a building in a fire is to provide its occupants with both the time and the means to escape to safety. This can be achieved by specifying the right materials, and by designing the interior of a building to make escape both quick and safe.

The great escape

Needless to say, during a fire, the priority is to remove occupants from danger areas. Fire escapes provide safe passage for a building's occupants, so care needs to be taken with their design and specification.

Frequently within tall buildings, fire escapes are located in the core of the structure, away from the premium space at the edge of the building, which affords the best view.

Locating fire escapes in the core means that it can be difficult to naturally ventilate the area. However, there are other solutions to help keep clean air in fire escapes.

"The way around this is to provide pressurisation to those staircases and lobbies, so you can keep those stairs inside," says Andrew McCracken, senior consultant, Bodycote Warringtonfire Consultancy.

Pressurisation also helps eliminate another tall-building-specific issue for fire escapes. Stack effect-where the warm air on the outside of a building is sucked into the building-is a particularly common phenomenon in the Middle East.

"In a home, in a cold climate, you can feel the warm air rushing out the chimney. We have that effect in Dubai but it's the opposite," explains Weismantle.

"The building air is cold, the outside is hot, and the air tends to want to rush out the bottom of the building."