Soon after dawn on June 7, a fire broke out in London’s 24-story Grenfell Tower. By mid-day, the death toll had reached 79, with tens missing and presumed dead. “In my 29 years of being a firefighter, I have never, ever seen anything of this scale,” said Dany Cotton, the commissioner of the London Fire Brigade. Initially, the cause of the fire was unknown, but two weeks after the tragedy, London police finally confirmed that the fire was started by a fridge, which raised questions about how a fire that began in the kitchen of one apartment spread so rapidly though a 24-story high-rise building with 120 apartments.
In April of this year, a fire broke out in a 72-story skyscraper in downtown Dubai as well, although the reasons were not identified and there were no casualties. We speak with urban security experts working closely with fire disasters about the tense relationship between skyscrapers and fires.
“Grenfell is similar to several of the fires we have seen in the UAE as well as China,” says Robert Solomon, The United States’ National Fire Protection Association‘s (NFPA) building fire protection division manager. “The external façade fires we’ve seen in the UAE likely had a different outcome because those structures were protected with an automatic sprinkler system. The sprinkler system is likely to have activated thus preventing any combustible contents and furnishings on the building’s interior from igniting, thereby allowing the building occupants more time to evacuate and allowing the fire service to focus on the exterior fire.”
After a series of recent fires, Dubai is introducing a new system for tall buildings this year that addresses fire disasters. The municipality encouraged the idea of adding external sprinklers, insisting that full-scale mockups of a building’s façade are fire-tested instead of just the individual materials.
“The difference [between] the Dubai fire and this one is, I believe, in Dubai, only the cladding burned, except for some apartments. The fire rated partitions and floor ratings contained the fire to the exterior. Here it looks like the walls and floor construction did not contain the fire spread,” an urban security veteran who preferred to remain anonymous tells progrss. He adds that that a single staircase was centrally located for the six apartments on each floor, but was certainly undersized for exit units based on the full population load at the lowest level. Although there were no dead-end issues, the stairs were not large enough to meet NFPA-101 criteria, which stipulate that when a building exceeds the population load, a second exit is necessary.
From the video and photographs that have been shared, Solomon explains to progress that the exterior façade of the building obviously had a role in allowing the fire to spread and grow so quickly. “In that particular scenario, as the fire spreads vertically, the heat generated by the fire on the external cladding would ignite the furnishings and contents inside each dwelling unit thus creating a set of fire conditions that would jeopardize the safety of the occupants in a matter of moments,” he adds.
A very typical feature in high-rise building design is the extensive use of what NFPA calls “fire resistive construction,” along with some compartmentation features to subdivide the spaces on the floor. However, Solomon says that NFPA has no knowledge of the presence or absence of any of those features in the Grenfell fire. “It is possible that having so many internal ignition points and fires as a result of the exterior fire simply would have overwhelmed the interior construction features that aren’t necessarily designed for such a challenging fire,” he points out. This point, he adds, is expected to be one of the many elements that will be studied in any official investigations that are conducted.
According to the NFPA report on high-rise fires in the United States, between 2009 and 2013, U.S. fire departments responded to an estimated 14,500 reported structure fires in high-rise buildings annually. In spite of that, NFPA’s building fire protection division manager doesn’t believe skyscrapers are a hazard to urban security. There are tens of thousands of high-rise buildings around the world and they are predominantly extraordinarily safe structures, he says. At least in the U.S., modern era codes, especially in the last 30 years or so, have been updated to layer in multiple systems, features and redundancies to make these buildings safe for the occupants as well as the first responders. Many of these features are even added in retroactively to the stock of existing high-rise buildings constructed prior to some of these code enhancements. “These buildings provide great environments for working, living and entertaining and I believe they really help define many of our cityscapes while improving the overall urban habitat,” he argues.
Automatic fire sprinkler systems, functioning and reliable building fire alarm system and structures that have good quality construction, which may even include wood construction for smaller, shorter buildings, are all good indicators of what may constitute a safe building, illustrates Solomon. “Other features such as a reliable and well-designed exiting system — normally consisting of at least two stairs from multiple story buildings is another important feature that would help make a building safe,” he elaborates. Moreover, one important distinction that’s difficult to detect is how well the building owner conducts the ongoing inspection, testing and maintenance activities for the various safety systems in the building, according to Solomon’s guidelines. With regards to this, the building owner has the ultimate responsibility. “All of the systems and features mentioned here require ongoing checks and balances to make sure they are operational and continuing to perform as intended,” he says.
Adoption, adaptation and enforcement of modern era codes will go a long way to ensure the safety of the occupants, first responders and the building itself, Solomon tells us. “As noted previously, high-rise buildings utilize very conservative construction materials — what we refer to as fire resistive construction. Every high-rise building must be protected with an automatic fire sprinkler system. And every high-rise building needs to have a building fire alarm system that can alert the occupants to an imminent danger as well as allow the on scene fire incident commander to relay real-time information through a voice communication system,” he notes.
Furthermore, Solomon tells us that fire department standpipe systems are another compulsory system required in U.S. codes that allow water delivery to the upper floors of the building in order to permit manual fire suppression operations to be carried out by the first responders.
The kinds of procedures required to prevent fires of this scale from breaking out is not just technical, though. Even after all these years of fires and disasters, there seems to be a knowledge gap for residents of high-rises on basic safety procedures. “I think we need to do a much better job of making sure everybody knows what those procedures are. Even in the U.S., there appears to be some confusion about what the building occupants are expected to do when a fire is reported in a high-rise building,” he says. On NFPA’s High Rise Safety page, the Association discusses the need for clearly defined evacuation procedures for occupants who work or live in high-rise structures. “That information was substantially updated after the September 11 terrorist attacks in the U.S., but it still holds true today.”
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