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on January 24th a Russian military drone struck a
10-story residential building on the outskirts of
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Kiev Ukraine the drone carried a small explosive
charge nowhere near enough to cause structural
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collapse but that wasn't the real danger the
impact ignited the building's EPS insulation a
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combustible material that fueled a devastating
fire the fire and the toxic smoke not the
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explosion itself led to the deaths and injuries
of civilians in this case the insulation became
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the fire load turning the facade into a weapon
and this is not just the Ukraine problem this
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type of insulation can be found on buildings all
over the world including Europe UK and America
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and it doesn't take a military drone to ignite it
a faulty E scooter battery or discarded cigarette
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when landed on a pile of insulation left exposed
during installation any of these can trigger
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a disaster my name is Eugene Corch i'm program
director for facade engineering at the Institute
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for Architectural Science and Technology and today
we will look into the fire safety risks of EPS or
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expanded polystyrene insulation in render facade
systems how dangerous is it and most importantly
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what can be done to prevent future disasters
deadly high-rise facade fires are nothing new
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they've captured public attention and made
headlines worldwide one of the most recent
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large-scale facade fires happened just a year ago
in Valencia Spain on February 22nd 2024 at around
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5:30 p.m a fire broke out at the 8th floor of a
14story residential building in Campanar District
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it was a windy day and within just 15 minutes the
flames raced up the facade reaching the top floor
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within the next 15 minutes the entire west side
of the tower was engulfed in flames the reason for
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such catastrophic and rapid spread of flame was
the combustible cladding with ventilated cavity
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a combination that acted like a chimney feeding
the fire upwards at an alarming speed by the next
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morning as Valencia woke up to the devastation all
attention turned to this dangerous cladding system
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it was not the first fire caused by ACM type
of cladding however on the very same day just a
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15-minute drive from the company building a new
row of 13story highrises was under construction
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with combustible EPS insulation being installed
despite the widespread media attention on facade
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fire safety the installation went ahead as planned
in the months that followed the work was completed
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without any changes to the insulation material
and if the EPS insulation on these buildings
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leads to another catastrophic fire it won't be the
first time either companar building was covered in
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so-called ACM cladding or aluminium composite
material and just like in the UK in the wake
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of the granful disaster all attention shifted to
these types of facads residents of buildings with
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similar looking facads raised concerns whether
their facade have combustible cladding on does it
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have ventilated cavity and are the cavities fire
barriers installed to remediate existing buildings
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by replacing cladding with non-combustible
one and adding fire barriers is a very good
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strategy to prevent future disasters however not
building unsafe facads is a far cheaper and more
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appropriate preventative strategy so let's look
at what is being built in Valencia now what's
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being installed on this new buildings in Valencia
isn't ACM cladding in fact it doesn't look like a
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cladding at all instead it appears to be as a
smooth seamless white surface this system goes
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by different names around the world in the UK it's
known as EWI or external wall insulation in North
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America it's called ESE or external insulation and
finish system it is also referred as stuckco in
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the US in continental Europe it's known as ethics
or external thermal insulation composite system
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the key word here is composite because despite its
uniform seamless appearance it's actually made up
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of multiple layers of materials in case of our
Valencia building the wall buildup consists of
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the following holo clay block work forming
an infill wall which spans between concrete
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columns and slabs of the superructure then a
layer of adhesive which is needed to pack out
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the insulation layer above in this instance it
is so-called dot and dab salmon based adhesive
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which levels out the imperfect surface of the
block work then a layer of insulation which
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is also fixed back to the block work with
mushroom shaped fixings the insulation is
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covered with the level of acrylic or cement based
coating to which a layer of mesh is applied the
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mesh prevents the movement of the coating and it
prevents the cracking of the finished decorative
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layer the top coat in case of our building EPS
insulation is used yet another boring acronym
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which stands for expanded polystyrene how do
we know that well the site conditions are very
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messy the materials are spread all over the area
adjacent to the building it is easy to collect
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samples of insulation and take pictures of render
system materials used the site conditions could be
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a fire hazard on their own but we will come back
to that later eps insulation on its own rated as E
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to Euro class fire classification meaning that it
is combustible to classify materials in isolation
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an ignitability test is used it is a simple flame
source test and the test looks very similar to a
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cigarette lighter small flame is positioned under
a small sample of material test is designed to
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emulate a reaction of a material if exposed to
a fire lighter or a match or a cigarette e-rated
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PATD systems are not allowed on the high-rise
buildings in virtually all countries around
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the world including Spain and Ukraine so why
this material is allowed in the building and
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the reason for this is that unlike individual
materials the facade systems are classified for
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their reaction to fire according to the different
test which is designed to emulate the reaction of
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fire if the wall is exposed to a small fire like a
paper basket positioned in the corner of the room
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in case of a burning cigarette is disposed in it
this test is monitored for spread of flame from
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B moderate to A2 or A1 limited combustibility or
non-combustible it also monitors the emission and
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amount of toxic smoke and production of flaming
droplets of the material as they burn s stands
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for production of smoke and D for the amount
of droplets in the case of render system EPS
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insulation is covered by two layers of cement
based coats which if exposed to lateral frame
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do not allow E-rated combustible polyyne to ignite
and this allows systems manufacturers to classify
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EPS insulated render system as B-rated making
them seemingly suitable for high-rise buildings
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according to the local building codes which refers
to European classifications for materials when
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um relied on the small scale test and this is how
these types of systems found their way onto the
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facads of the mid to high-rise buildings in Europe
and all around the world needless to say that this
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test is hardly representative of the facade fires
occurring in the real buildings the facade is more
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likely to ignite due to explosion and consequent
fire of electric bike or escooter parked next to
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the building or already well-developed fire can
escape from the window of apartment and ignite
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the external facade in 1990 in Winnipeg Canada
fire started at the ground floor car park soared
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through insulated render facade all the way to
the top of the eightstory building in 1996 Munich
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Germany rubbish container fire spread through the
entire height of the five-story building through
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insulated render facade in 2005 Berlin Germany
fire started at the second floor and spread
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upwards through EPS facade reaching the top floor
of the sevenstory building in 2008 in Las Vegas
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USA the fire originated at 29th floor spreads
via EPS rendered facads horizontally across most
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of the 32nd floor in 2009 in Hungary sixth floor
kitchen fire spreads through EPS insulated facads
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of 11story building killing three people 2010
Dejon France fire spreads through the 10-story
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height EPS render facads killed seven people with
another 11 injured with some occupants reported
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jumping from windows with the most recent fire
happened earlier this year when a small military
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drone hit the building in Ukraine at the sixth
floor level igniting entire building you can see
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that the fire has spread not only upwards from the
sixth floor to the 10th but also downwards and to
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the site around the building perimeter despite
the fact that the system might be classified as
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B-rated iranian-made drone fire load capacity is
very small but far exceeds a paper basket in 2016
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a paper was released by the University of Zagreb
which tasks itself to investigate the reasons for
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spread of flame in EPS rendered facads three large
scale tests were carried out uh simultaneously
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based on the large scale British test BS8414
test it was found that when the burning chamber
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designed to represent a window in a room with the
fire load comparable to a furniture inside of the
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apartment the flame was strong enough to melt the
EPS insulation behind the cementitious coating
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of the render the hard cementicious coating now
hollowed up without rigid insulation supporting
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it cracked releasing hot liqufied polyron right
on the flame gashing from the window below hot
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liquid polyron is highly combustible not only
it fuels the fire below it also produces large
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amount of flaming droplets which fall down and
ignite the EPS render facads below flaming liquid
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polystyrene droplets are also a serious hazard
to firefighters below dealing with the fire
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worse still at this point there is a cavity
above the window between the backing wall
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and the rigid cementitious coating where the
rigid insulation used to be and this cavity now
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works as a chimney propelling the flame fueled by
liqufied porter upwards of the building the flame
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further liquefies the EPS render above further
fueling the fire within the chimney producing more
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droplets and spreading the fire and toxic smoke
in all directions within the newly formed cavity
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you can see that the large scale tests in this
assembly fails dramatically within minutes so
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what is to be done the second test rig had
mineral wool barriers installed right above
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the opening and the slap levels mineral wool is
non-combustible material and is A1 rated on its
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own moreover it has good insulation properties and
this barrier was sufficient enough to prevent the
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EPS insulation above it from melting and because
mineral wool is non-combustible it provided
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support for the cementitious coating on top of
it preventing flame to spread behind the render
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coating above this mineral wool fire barrier was
sufficient enough to manage the spread of fire
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through the facade however this large scale test
is a British test and not necessarily recognized
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in Europe but even in Britain it's not mandated
to be carried out by the system manufacturers and
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with the current building regulations combustible
materials are allowed in buildings lower than 11 m
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and this has resulted in EPS rendered insulation
to be installed on the 3 to five story buildings
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with EPS insulation without mineral wool barriers
above openings and at the slap levels and there
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are taller buildings in the UK covered in similar
system prior to recent building regulation changes
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in case of building in Valencia uh the EPS
insulation was installed on the new buildings
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without any fire barriers we understand that
it is a built to rent development so there is
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likely one client and one facade specialist
contractor responsible for the building and
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the fire safety could be upgraded fairly quickly
should the residents of the building find the in
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materials used in the facads inappropriate even
if the system was deemed to be compliant with the
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current Spanish building code which it appears
to be considering the testing process used and
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by the way the company building appears to be
deemed compliant with the Spanish code at the
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time it was designed just a food for thought the
issue with EPS insulation is more complicated when
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it's used in existing buildings as a retrofitting
strategy eps insulation is to go to material for
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thermal performance upgrade of the existing panel
buildings in the Eastern Europe the EPS insulation
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on the building in the Ukraine was not installed
originally at the time of the construction of the
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building it is common for individual apartment
owners to install insulation locally to improve
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thermal performance of individual flats or group
of flats in these cases EPS insulation only spans
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one floor and may not present that much of a fire
safety risk however if multiple apartments owners
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are to install insulated render cladding at
different times the result will be just as
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dangerous there will be a continuous uninterrupted
EPS insulation system spanning multiple floors
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and this is precisely what has happened on the
block 5 development in Padgoritza the capital of
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Montenegro over the years residents individually
were insulating their apartments by installing
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EPS insulated render on the outside surfaces
of their apartments however when it comes to
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the padorita development things get even more
dangerous eps render system is installed without
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any fire barriers and it is installed while the
building is occupied with the residents staying
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in their apartments at night and to put things
into perspective let's go back to the UK and have
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a look at the another fire that has happened
in Dagenham last autumn the building was in
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the process of remediation having its existing
combustible cladding removed and replaced with
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a non-combustible one allegedly the cause of the
fire was either the combustible materials left on
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the scaffold or the timber scaffolding taking
itself the block 5 in pilgor is exposed to the
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same hazard there are stacks of EPS insulation
at the base of the scaffolding with virtually
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all the EPS insulation boards above the stack
being installed onto the facade without any
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fire barriers and not covered by the cementitious
non-combustible coating yet a cigarette butt or a
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burning match is all needed for the catastrophe
to happen so where does it leave us in the UK
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building regulations do allow B-rated combustible
materials on the facades of certain height and
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because the EPS rendered facads do not have
cavities no cavity barriers could be possibly
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installed fire barriers are not mentioned
in the building regulations at all there
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are industry bodies like Inca who mention the
fire barriers at the slap levels and in party
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wall locations however the guidance on barriers
around openings is vague when it calls for fire
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barriers to vulnerable openings it is not clear
which doors and openings are considered to be
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vulnerable and which ones are not this guidance
and indeed approved document B make reference to
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BR135 guidance which states that the fire barriers
should be considered at floor slap level starting
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from the second floor or with the spacing
determined by the large scale BS8414 test they
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are considered but not mandated the fire bears
around openings are mentioned as a consideration
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only again it is not clear what a vulnerable
opening is cwct technical note 60 on rendered
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cladding systems was issued in 2008 some 17 years
ago and for this reason makes reference to class
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n or class zero but to their credit technical
notes suggest that the large scale fire test
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could be useful and at least one non-combustible
fixing per square meter of system is required
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there is a mention of cavity barriers but no
mention of fire barriers where there are no
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cavities to make sense of all that there should
be a facade or and fire engineers involved on
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the project and with EPS insulated render being
virtually the cheapest facade system neither are
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likely to be involved in the small scale low-rise
buildings building regulations and industries
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guidance require updating and coordinating
and they should be more stringent considering
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how widespread and inexpensive EPS insulation is
they should consider sulfits and areas vulnerable
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to new hazards like electric scooters they also
need to be coordinated and brought in line with
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each other and this will take time and this is the
state of the guidance on these systems in the UK
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the country that in the wake of Granful disaster
has introduced one of the world's stringent fire
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safety regulations and trained itself an army of
facade practitioners specializing in facade fire
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safety by injecting billions of pounds into the
fire remediation projects the state of regulations
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in most countries around the world are less
stringent with more loopholes and vague clauses
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so for right now we at Institute for Architectial
Science and Technology have prepared an
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engineering bulletin as a guidance on design
and installation and location of fire barriers
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in EPS render systems it is publicly available
on facade intelligence website the bulletin is
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predominantly based on diagrams rather than just
text to avoid any vagueness and it is designed
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to be applicable globally not just in the UK or
Europe there's also a dedicated case study based
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on fourstory high residential building which
contains the key interface details 3D models
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and technical documents it is available to the
members of IST and general public for free if you
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are in architecture and construction industry you
should consider joining our community and support
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our cause the key takeaways from the case study
and the engineering bulletin are if a large-scale
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fire test was not carried out for the EPS render
system fire barriers should be installed at the
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base floor slabs and party wall locations and
around the openings all horizontal surfaces
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such as balconies or protruding sophets should
be insulated with mineral wall eps insulation
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should not be used in these locations the use
of fire barriers at lintils only above windows
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could be appropriate but subject to the large
scale fire test results there is guidance on
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locations and quantities of fixings both for
EPS insulation and fire barriers within this
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case study we went beyond just fire safety we have
produced best practice details for interfaces and
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position of windows within the openings backed
up by thermal and condensation risk report
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both the bulletin and the case study are at draft
stages at the moment and will be updated following
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your feedback please leave your comments below
and provide suggestions and feedback through the
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dedicated PAT intelligence form the link to the
case study is in the description of this video
