Questions are being asked about the fire safety of tall buildings in Dubai after last week’s blaze at the prestigious Address Downtown hotel and residential building became the third such fire in 18 months.
All have followed similar patterns in the way that the external cladding appears to have rapidly spread the fire between the floors of the building.
In some ways the Address building performed in exactly the manner in which it was designed to: the occupants managed to escape; the building did not collapse; and the fire was able to be extinguished. But it still begs the question: is this an endemic problem or an isolated incident?
The fire which broke out in the 63 storey Address Downtown building is believed to have started on the balcony of the 20th floor. From here, the fire appears to have spread devastatingly quickly, jumping between the floors via the cladding panels. It is known that buildings built prior to a regulatory change in 2013 were often built with lighter-weight aluminium sandwich cladding panels comprising aluminium skins with combustible filler in the middle and that this may be the cause of the Address’s rapid descent into an inferno.
Buildings built post 2013 will hopefully not suffer the same fate. However, with an estimated 70% of the building stock in Dubai built with these potentially dangerous facades, is it a matter of time before lives are lost?
In the UAE, buildings are usually designed for a single fire in one location. Internally, sprinkler systems activate, key corridors are vented to remove the smoke and the other corridors are pressurised to prevent the fire spreading. But with multiple fires this system could quickly be overwhelmed.
Explains fire engineering specialist Optimise director Romill Bettany: “There’s a potential for the fire to spread and to start breaking into a number of apartments. The sprinkler systems are only designed for a certain area of operation so if there are a number of fires creeping in from these balconies, a number of sprinkler systems activate on different levels and get overwhelmed by too much water demand.
“You can then see that the sprinkler system becomes ineffective because it can’t deliver the water flow or the pressures required. The fires could then end up not being suppressed and spreading further.”
He says it was to the credit of the Dubai fire team that the event was not more catastrophic.
So what is the solution for the rest of the buildings with this potential tinderbox cladding? Re-cladding all of the affected buildings would be a costly solution and in practice any legislation would be hard to enforce. Insurance companies, who may be the only ones capable of changing the situation, may prefer to hedge the risk, retrospectively replacing cladding on one fire damaged building rather than pro-actively changing it on 50. The future may look understandably bleak for those affected.
But there are solutions to the problem, thinks Bettany.
“If you look at different types of buildings and looked at the way they are used you could tailor retrospective solutions which are performance based, to try and mitigate against this sort of issue happening again. I think there are probably some quite cost effective ways to do it,” he says.
Back in the UK, Bettany’s colleague and Optimise director Markus Cosmann believes that fires in super tall buildings would not be allowed to behave in the same way. Here, cladding panels are required to have non-combustible cores and cavity barriers to create zones within the cladding to stop the fire spreading.
As for the fire in the Address Downtown, the extent of the repairs required are not yet known but the reputation of its brand will surely mean that if the cladding panels are proved to be at fault it will have to undergo a full re-cladding which will be costly. Whether more fires trigger demand for more widespread recladding only time will tell.