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Building safetyGrenfell Tower disaster: how did the fire spread so quickly?

By Feng Fu

Published 15 June 2017

In the middle of the night, while most residents were sleeping, a devastating fire started at Grenfell Tower in London. From an engineering perspective, there are a number of factors in the design of the 24-storey tower block that may have contributed to the speed and scale of the blaze. Most of the current guidelines across the world contain detailed design requirements for fire safety such as evacuation routes, compartmentation and structural fire design. But Grenfell Tower was built in 1974. At that time, the rules and regulations were not as clear and well-developed as they are now.

In the middle of the night, while most residents were sleeping, a devastating fire started at Grenfell Tower in London. The emergency response was rapid and robust: more than 200 firefighters attended the scene, with assistance arriving just six minutes after the first calls were made. Emergency services have confirmed that 12 people are dead. More remain missing and dozens are injured. Already, people are asking how the fire spread so rapidly and why it was so difficult for residents to escape.

Doubtless, in time, a thorough investigation will reveal the full details of what caused the disaster. But from an engineering perspective, there are a number of factors in the design of the 24-storey tower block that may have contributed to the speed and scale of the blaze.

Most of the current guidelines across the world contain detailed design requirements for fire safety such as evacuation routes, compartmentation and structural fire design. But Grenfell Tower was built in 1974. At that time, the rules and regulations were not as clear and well-developed as they are now.

Evacuation and compartmentation
The evacuation route is one of the most important design elements when it comes to fire safety. The route should allow occupants to escape the building as quickly as possible, while sheltering them from smoke and flames. Some tall buildings have staircases installed on the outside to prevent people from getting stuck in the corridors and provide access to fresh air while they escape. Other options include installing high-power fans inside buildings, to clear the evacuation route of smoke in the event of a fire. This feature is included in the design of Dubai’s Burj Khalifa, the tallest building in the world.

It’s clear that residents were not happy with the fire safety of the escape route from a blog posted in November 2016 and the design below would suggest there was only one set of stairs for evacuation. Investigators will need to determine what evacuation routes were available.

Another key strategy is to correctly design fire compartments to keep the fire from spreading quickly. This entails placing barriers in the building – such as fire-resistant doors and walls – to confine the fire to a local area, or at least slow the speed at which it can spread. These compartments are designed based on the function of the buildings by architects, so residential and commercial buildings will have different compartment design strategies.