[Applause]
each of us who lives in a house
apartment or skyscraper has a carbon
footprint we work in a building or
studying a building and then we do
groceries in another building so many
buildings in our lives cities are like
concrete jungles and they have become
our new natural habitat there is one
problem we use millions of tonnes of
steel and concrete to build that jungles
and the production of steel and concrete
requires so much energy that it consumes
40 percent of the total energy consumed
worldwide leaving behind an enormous
amount of carbon dioxide the primary
cause of climate change this puts the
building industry on top of the list of
the most polluting human activities and
the population is still growing each
year there is 18 million more of us so
more housing is needed more steel and
concrete to build that housing the
problem is only getting worse
but now imagine if we could turn this
polluting industry into the cleanest one
or even better imagine if we could turn
this polluting industry into one that
could reverse climate change maybe maybe
it's time to start using a less
contaminating material maybe timber
today we have the technology to glue
timber planks in infinite ways we can
obtain high-strength beams slabs arches
from a structural perspective timber is
super strong and we are ready to build
timber skyscrapers Norway has just
finished the tallest timber building in
the world with 18 stories the whole
structure is timber
timbre is also much cheaper this opens
great opportunities for developing
countries and of course timber is
beautiful look at this filling above you
so strong cheap and beautiful so many
benefits but still the biggest bonus if
the sustainability of timber as you know
when trees grow the remove carbon
dioxide from the atmosphere and there
with an oxygen in exchange then trees
use this carbon to produce wood and keep
growing this means that the polluting
carbon from the atmosphere is now locked
within the tree trunk forests sequester
the most carbon during the growing stage
once the force is mature this cycle
slows down so ideally we would like to
have continuously growing forests we
should harvest mature trees for
construction purposes and fill the empty
spaces with young trees this way timber
structures can be seen like enormous
carbon storages the atmosphere could
begun to heal and the building industry
could find its path towards a
sustainable future timber skyscrapers
sounds like a fantastic innovative
solution to many of our human problems
we love innovation not like any other
innovation it comes with some hearing
consequences for example everybody
thought that plastic was a great
material 50 years ago and in our food or
smartphones for easier life but
sometimes they explode in airplanes
the Umbra skyscrapers for climate change
maybe I should have said obvious
consequences in this case so after
saying this you can guess who I am
fire safety engineer we can't just build
timber skyscrapers like this that would
be a disaster and I really want to be
done knowing one who puts a break on
innovation but safety is also important
we need to study this let's start with
the chemistry if we have timber as our
fuel an oxygen which we have in air we
just need a small spark to start a
combustion reaction
where the oxygen reacts with the timber
and the products of any combustion
reaction are flames carbon dioxide and
water carbon dioxide this means that
they got timber structure burns all the
carbon that was stored within the
structure is sent back to the atmosphere
not to mention that fire challenges life
safety we don't want to send the
occupants of a timber building to the
atmosphere as well so if a timber
building burns our carbon footprint is
as big as before and we have some
serious lawsuits
not good at all if timber skyscrapers
are to become a reality we have to make
sure that we don't convert them into ash
and that people can evacuate safely
evacuation very very important let's
have a look on this as a fire safety
engineer this is what I see when I look
at a single house a compartment when
there is a fire inside this compartment
the fire safety evacuation strategy
looks like this inside you are not safe
outside you are safe inside you are not
safe outside you are safe it is fast and
simple we are out way before the fire
gets dangerous but we said we want to go
tall this is what I see when I look at a
high-rise buildings lots of compartments
stucked on top of each other connected
with a staircase the prana starts to get
tricky
walking down 20 storeys imagine that you
had a knee surgery after playing soccer
and maybe recurring a kid can easily
take 40 minutes
these gives a lot of time for the fire
to grow the uncontrollable dimensions
and even to spread into the staircase
where the people are evacuating to
prevent that we have the strategy of
containing the fire the compartment
where it started actually we have to
design buildings in such a way that the
fire can't spread this is because a high
res structure can withstand losing one
of these compartments but if we lose
modern this game over to keep the fire
in one compartment
it's called compartment Asian strategy
compared mentation makes sure that a
fire will not spread through the
building it prevents structural collapse
but most important compartment ation
makes sure that the staircase the
evacuation path
is going to be free from smoke and heat
giving people all the time they need to
evacuate the high-rise in one sentence
compartment ation is critical for fire
safe high-rise buildings for steel and
concrete buildings this is doable but
how on earth we achieve compartment
ation if the compartment itself the
floor the wall the ceiling is timber and
it burns they call me let's look for a
solution
how does timber burn by the way timber
doesn't burn at high temperatures timber
decomposes part of the timber the
composes into char which forms a char
layer and the remaining part decomposes
into flammable gases the flammable gases
flow out of the timber mixed with oxygen
and react so when we see flames
it is not timber burning but only the
pliable gases reacting with the oxygen
all these magics happens in the
composing layer which moves like a front
because once it's done here it moves
deeper into the timber to keep
converting more and more timber into
char and cannibal gases but this
decomposing front needs to be hot it
needs energy to be able to transform
timber into channel a noble gases and it
receives this energy from its old flame
at the surface that sneaky Nature has
already decided some time ago that the
char layer is going to be an excellent
insulator which means that it stops the
heat from gumming through and after some
time we built a pretty picture layer so
now we have a really good insulator the
thicker the char layer less unless
from the flame cannot reach the
decomposing front so that the composing
front doesn't have the energy to keep
transforming more timber into charm club
or gasses so the production of the
travel gases stops if there is no more
flammable gases no more fuel to feed the
flame so the flame starts to get smaller
and smaller and eventually it
extinguishes all by its own this is what
we call self extinguishment of timber
this is how nature has designed trees to
withstand raging wildfires by forming
this protective char layer as long as
the tree is thick enough there will be
in that healthy wood remaining when the
flame extinguishes for the tree to
survive and so it is with buildings as
long as a timber member is thick enough
the structure can withstand the charring
of the outer layer while the fire dies
out if you don't believe me look at this
this is a historical picture taken after
a fire we can see a horizontal timber
beam supporting two steel beams that
have completely deformed with the heat
it's true the timber beam is chart all
over but still it is maintaining its
structural performance but the steel
beams have completely failed so in this
case the timber has performed much
better than they still do you remember
compartment ation well for timber
buildings self extinguishment is the
only way to achieve compartment ation is
the only way to prevent structure
collapse so self extinguishment is the
new fire safety strategy for timber
buildings so what is my role in all this
story experiments lots of experiments
I wanted to understand how when and why
different timber structures myself
extinguish or why they may not so close
myself in the fire lab and constructed
hundreds of small timber compartments
and I set them on fire I swear I had
permission to do that and everything was
legal so some of these compartments had
only one timber wolf other compartments
had two timber walls all or had two
timber wall and ceiling all the
configurations you can imagine in the
next videos you will be looking through
the door towards the inside of my
compartments you can see that one of
them sub extinguishes and the other one
kept the burning until it collapsed why
to answer why I had lots of sensors in
my experiment many of them burned by
those but those that survived gave me
really good data I analyzed all this
data and I could answer two questions
such as how many timber wolves can I
have if I want South extinguishment to
happen it is the same to have a timber
wall as a timber ceiling or does the
temperature of my fire change if I have
additional timber walls burning we
basically developed a new fire dynamic
theory for timber buildings then we took
this new theory and moved into the real
world
we designed a full-scale timber
compartment experiment and set it on
fire of course we put all our new
knowledge into this experiment and we
prayed for it to self extinguish you
can't imagine the tension it was burning
like hell
but after some time when the fire
started started to decay the
extinguishment started to happen and
eventually it's not extinguished fully
all by its own the compartment didn't
burn through this means that we achieved
compartment ation thanks to that
extinguishment the test was a success we
push the boundaries of our knowledge and
we showed it is possible
so again timber skyscrapers beautiful
and sustainable we dreamed about
impossible and research connected all
the bits and pieces from evacuation to
compartment a Shinto Sat extinguishment
and made impossible every day a bit more
possible today this kind of research is
used by engineers to design buildings
like the 18-story in Norway all this is
possible because today we understand
better how timber burns but also we
understand better all the hidden
consequences and tricky aspects of fire
safety engineering if we continue
pushing tomorrow
timber skyscrapers will reshape the
skylines of our cities and hopefully
they will change the direction of our
future thank you
[Applause]