FEATURE
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
THE
BURNING
ISSUE
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MIDDLE EAST ARCHITECT | 06.08 | www.arabianbusiness.com/architect
FEATURE
THE BURNING ISSUE
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.
>
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FEATURE
THE BURNING ISSUE
© Karim Sahib/AFP/Getty Images
1/ DUBAI HAS
SUFFERED SEVERAL
FIRES IN 2008
2/ FOAMGLAS
INSULATION
3/ TALL BUILDINGS
HAVE SPECIFIC FIRE
ISSUES
4/ MATERIALS
CAN BE TESTED BY
ORGANISATIONS
SUCH AS BODYCOTE
WARRINGTONFIRE
YOU DON’T REALLY CARE IF A
BUILDING BURNS DOWN, AS LONG
AS THE PEOPLE ARE OUT AND LIFE IS
PRESERVED.
PETER WEISMANTLE
1/
© Karim Sahib/AFP/Getty Images
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.”
This causes smoke to be sucked back
into the building from the top. Experts
agree that the most dangerous problem in
any fire is less the actual fire itself, than the
smoke generated from burning materials.
“Ninety-nine percent of fire deaths are
caused by smoke, rather than fire,” says
Weismantle. ““If plastic foam catches fire,
it can produce toxic fumes. Many people
[in a fire] die of toxic fumes,” agrees Marco
Thomas Vincenz, general manager of
Foamglas. Pressurisation can prevent this
happening.
Fire escapes also need to be considered in terms of efficient and effective
evacuation. Tall buildings frequently have
a phased evacuation policy, due to the
impracticality of evacuating thousands of
occupants simultaneously.
“You might have the fire floor and two
floors above that would leave,” says McCracken. “The stairs would then be sized
to cater for the number of people involved
in that phased evacuation of those floors.
That means the stairs wouldn’t need to be
sized to evacuate everybody all at once.”
MATERIAL WORLD
A building’s design can significantly
influence the materials an architect
specifies. McCracken says that
depending on how a building is
designed— or fire engineered—can help reduce
the minimum requirements for materials.
“A code might ask for
4-hour fire resistance for
elements of the structure,”
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MIDDLE EAST ARCHITECT | 06.08 | www.arabianbusiness.com/architect
2/
3/
4/
52
Average number of fires
per month in Dubai in 2007
1000°C
Temperature of fire when testing materials
for ASTM (American Society for Testing
and Materials) standard
FEATURE
THE BURNING ISSUE
says McCracken. “Depending on the number of windows in the building and in each
fire enclosure, and how much ventilation
can be provided by those windows breaking…you [may not] actually need 4-hours
fire resistance.”
This can have a massive impact on the
overall budget of a design, since materials
that are fire-rated to last longer, cost more.
“If you’ve a building where the code asks
for a 2-hour fire resistance standard, and it
can be reduced to 60 minutes through fire
engineering, that’s a massive saving on a
tall building,” says McCracken
This reduction can also lead to select© ITP/Dmitry Dolzhanskiy
5/ FIRE ON SHEIKH
ZAYED ROAD IN DUBAI,
MAY 2008
6/ THE SMOKE FROM
A BLAZE AT AL QUOZ
IN DUBAI SPREAD
A CONSIDERABLE
DISTANCE
5/
ing more aesthetically pleasing or sustainable materials. Global aluminium product
supplier Schüco provides aluminium
doors which are smoke and fire-rated for
30 minutes. “For a lobby, [30 minutes] is
adequate escape time,” says Sam Brooks,
Schüco technical manager.
Steel doors and compartments can
provide fire protection for two hours, but
where this has been reduced, through fire
engineering, aluminium can be considered. “If it’s a visual thing, or aesthetic
thing, it’s worth looking at aluminium,”
adds Brooks.
Brooks points out that this technique
is popular throughout Europe, especially in Germany. “In Europe there are
standards that require areas to be rated to
different degrees,” he says.
Developers note that European
standards tend to be higher than those
in the region. “The local codes are very
rudimentary because they really haven’t
experience in the building types, so the local authorities are very pleased to go with
internationally recognised codes,” says
Weismantle.
These codes also place greater emphasis on the quality of insulation in a
building. “If you have a high-rise building,
the insulation should only be of the highest
standards,” says Vincenz. “Some of the
high-rises in the UK and Europe only allow
the top-rated products.”
The Middle East is, to some extent
43
Percentage
of worldwide
fires caused by
negligence
6/
© Mohammed Shamseddine/AFP/Getty Images
IF YOU HAVE A HIGH-RISE BUILDING,
THE INSULATION SHOULD ONLY BE OF
THE HIGHEST STANDARDS.
MARCO THOMAS VINCENZ
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CASEFEATURE
STUDY
THE BURNING
WAVE TOWER
ISSUE
lagging behind the US and Europe with
regard to codes, but in terms of permitting
material, the outlook is very positive.
“All of the thermal insulation needs
material approval from Dubai Municipality. Otherwise it’s not allowed in Dubai,”
says Vincenz. “[The UAE] does that better
than a lot of other countries.”
Suppliers recommend the use of
better fire-rated materials for insulation,
including rock wool or glass foam, which
is relatively new to the region. Glass foam
retains all the fire-resistant properties of
glass as well as all the dynamic capabilities of insulation. “I don’t know any other
insulation that has a zero flame spread index and a zero smoke development index,”
says Vincenz.
Getting the right insulation can
make a huge difference. Materials such
as Foamglas can be used to establish a
secondary fire barrier behind the façade,
thus reducing the spread of a blaze.
Architects also need to bear in mind
the effects of vapour transmission. From
the stack effect, the cold air inside the
building causes air from the outside to
flow into the building.
Non-waterproof insulation needs to
be protected with a waterproof aluminium
skin, otherwise, the material can get wet
from condensation, which ultimately
impairing its fire resistance.
DEMANDING DESIGN
As the construction boom continues
throughout the Middle East, there’s never
been a greater need to ensure that buildings remain fire safe. Supertall projects
like the Burj Dubai are leading the way
to a new standard of fire safety in design.
The better equipped architects are to rise
to the challenge of keeping the supertall
super safe, the better the future for both
buildings and occupants.
7 & 8/ SCHÜCO’S
ALUMINIUM DOORS
CAN BE FIRE RATED
TO UP TO 30 MINUTES
(PHOTOS: SCHÜCO
INTERNATIONAL KG)
9/ THE BURJ DUBAI HAS
ITS OWN CHALLENGES
AND SOLUTIONS WHEN
IT COMES TO FIRE
12
Number of elevators that remain operational in the Burj Dubai in the event of a fire
Image © Steinkamp-Ballogg Photography
7/ 8/
9/
for a minimum standard. “From day one on the
BURJ DUBAI: A case study
As the tallest building in the world, the Burj DubaiBurj Dubai, we put together suggested enhancehas its own unique challenges when it comes to ments that go beyond the code.”
making the building safe in the event of fire. MaterialThe shape of the Burj Dubai has proved benefiselection provides an important part of the brief. cial in terms of providing means of escape. There
are fire escapes in each of the three wings of the
“In the ME, as in many other parts of the
building, instead of being concentrated in a single
world, reinforced concrete is the standard building
method and so there’s very little steel at the Burj core. “We have more capacity than we actually
need,” says Weismantle.
Dubai,” explains Weismantle.
Another important element of the fire escapes
“Reinforced concrete serves us well up to
the top of the occupied floors. We’ve taken the is refuge points. Climbing down the entirety of the
reinforced concrete up to level 154. Above that, world’s tallest building would pose a challenge
even to the super fit, so every thirty floors, the
we’ve introduced steel because the floorplate gets
so small.” The steel on the upper levels is sprayedescape stairs open out into an enclosed, smoke
controlled refuge.
with cementicious fireproofing.
The Burj Dubai uses the International Building “People can go down 30 floors and wait for
the firefighters to contain the fire without having
Code and the US National Fire Prevention Association code 101. “It’s a comprehensive set of codes to go all the way down the building,” explains
and standards for all the systems in the building,Weismantle.
The fire escape also has LED screens at various
specifically focused on fire safety and means of escape.” However, Weismantle points out that codespoints that firefighters can use to send messages
and instructions to people in the building.
are merely a starting point because they are simply
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