Following a major fire in the United Arab Emirates, Jane Embury looks at fire safety in tall buildings.
Earlier this month, a major fire engulfed a residential tower block in Sharjah. It’s a city state that makes up one of the seven sheikhdoms of the United Arab Emirates.
The fire in the 49-storey Abbco Tower, built in 2005, caused a number of injuries but no fatalities.
The tower, one of the tallest in Sharjah, contains over 300 apartments.
While no cause of the fire has yet been established, the fire spread rapidly on the outside of the building.
This suggests that external cladding may have had a role to play, and that will be a focus for the enquiry team.
However, the Sharjah fire follows a number of other high-rise fires in the UAE in recent years.
Aluminium composite cladding has been implicated in a number of those fires, a significant concern in a country with so many high-rise corporate, residential and hotel buildings.
Although cladding can be made fire-resistant, in many cases the cladding used has been non-specialist. It’s therefore unsuitable for mitigating against the spread of external fire.
The lesson from such high-rise fires in the Middle East is that complacency has been allowed to determine building design and the specification of building materials.
Certification
It’s the reason why we have publicly raised concerns about how fire regulations were being applied across parts of the Middle East.
We also changed our certification process, so that a fire certification on one of our glazing systems could not be applied on another project.
However, the speed with which the Sharjah fire spread, and the extensive damage it caused, suggest that components in the building may not have had proper fire-safety characteristics.
It’s an area in which we are acknowledged experts, having worked on high-rise projects in the UK and worldwide.
Our experience teaches us that architects and designers should, first, look at the detailed fire characteristics of every building component. For example, a form of cladding might be perfectly suitable for a low-rise building, but not for something super-tall.
Framing system
Second, in terms of the glazed components, specifiers should ensure compatibility between the glass and its framing system.
Simply, in a fire situation, if one of those components fails, they both fail – with potentially catastrophic consequences.
Its again a fire safety strategy that jurisdictions in the Middle East, and elsewhere, should revisit. That’s particularly so in the Gulf and parts of Asia, where the trend towards building higher and higher shows no sign of abating.
The most effective way of dealing with fire in tall buildings is by fire compartmentation: keeping the fire contained in one protected area and preventing it from spreading. A contained fire can be dealt with; an uncontrolled fire can’t.
Compartmentation can be compromised by even minor design faults. For example, inadequately-protected wiring or ducting can allow fire or toxic gases to seep from one compartment to another.
Another potential weakness are fragile external windows, or non-fire internal screens. They can break, allowing oxygen into the building, or to other areas.
Safety
A rule of thumb for fire safety in tall buildings is that any fire should be able to burn itself out, without external intervention, and without building collapse.
This minimises damage to other parts of the building and, of course, the threat to human safety.
Of course, sprinkler systems have a role to play, but they need good maintenance and activation sequences to work properly.
They can also be compromised by low water pressure, a particular consideration in very high buildings. Also, PVC water supply pipes can be rendered inoperable by fire.
In contrast, “passive” fire-rated glazing systems are guaranteed to work – if the right systems have been specified – without maintenance.
Over the years, we’ve seen the good, bad and the ugly of fire safety design. We’ve helped to design the good, and call out the bad.
Every building should have fire safety as its top priority and, if the worst does happen, that it has a fire containment strategy to ensure everyone’s safety.
