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Using Fire Dynamics Research to Save Firefighters


>>Daniel Madrzykowski: The
presentation today we’re going to break up into a few parts. We have the background, which
is giving you a little bit of background about NIST and what the Fire Research
Division does, and then we want to talk about what is
fire in the United States, what is the problem,
and then get into the firefighters’ workplace
and how has that changed over the past few decades. Then we try to tie in these
changes with fire dynamics and fire behavior, and this is
usually good for the lay person because most people I don’t
think appreciate just how fast a fire could grow and
spread in their home. And, of course, earlier this
week there was a very tragic fire in New York City where seven children
lost their lives due to a rapidly spreading fire. How are fires in
homes different today, we’ll talk a little
bit about that. And then get to sort of
the meat of the subject, how do we take our
laboratory to the street, how do we take the fine
measurements that are done at NIST and replicate them
in acquired structures that are getting
ready to be torn down and you’ll get a little
insight into that. And then we’ll close with the
lessons learned and how we try to share this information
with the Fire Service. So the Fire Research Division
works on a wide range of issues. Basically we’re trying to focus
on reducing the loss of life and the loss of property
from unwanted fire. It’s not exactly our
official mission statement, but that’s the gist of it. We do that by we’ve developed
smoke alarms and we continue to work on developing new smoke
alarms, doing demonstrations with automatic fire
sprinklers to show how efficient and effective they are,
emergency egress studies, reduced furniture flammability. There’s been great progress
made in the case of mattresses, if you buy a mattress today in the United States it’s a
much more fire safe mattress than it was in say 2005, so
there’s been great gains there. We’re currently working
on things like sofas and upholstered furniture
and what-not. Another way to look
at the problem is if we can’t make the furniture
safer do we try to reduce some of the ignition sources,
and so NIST worked with the tobacco industry and
others to develop standards for the reduced ignition
propensity cigarette. Sometimes inappropriately
referred to as a fire safe cigarette with just reduced
ignition propensity. NIST is a world leader in developing fire
models of all sorts. The one that’s mostly in use, currently the state-of-the-art
is the fire dynamic simulator and its partner program,
smoke view, which is how you
review the results and visualize the results. These fire models
are used in research, design and litigation
around the world. It’s really the standard for
fire models around the world. A new group that we
have started is looking at issues regarding wild
land urban interface fires as that’s becoming more and more
of a problem in a large part of the country that are
suffering from droughts and dry weather and
building more and more suburban urban sprawl,
so to speak, into the wild land, so it’s really not the
trees burning necessarily that are the bigger problem, it’s when the trees
catch the houses on fire that it becomes a
very major problem. And as you watch the news
this summer you’ll see events of that, so we’re
trying to understand how to mitigate that hazard. And currently a large portion
of our team is working very hard to bring online a unique
state-of-the-art National Fire Research Laboratory. It’s an investment that
was made a few years ago of over $27 million and it
will really provide some unique capabilities in terms
of testing structures and structural capabilities
against fire. The group that I lead is the
Firefighting Technology Group, and our main objective is to help firefighters do
their job better and by doing that also help them do
it in a safer manner. Again, we want to
reduce losses from fire, both in terms of
life and property. In addition, we want to
provide data and test methods so we can improve firefighters’
protective equipment. And, last but not least, the
firefighters are the ones going out there every day to deal with
our fire problem and we need to get this information to
them, we need to make it part of their training, we need to
make it part of their education so that they have the
best tools, techniques and knowledge to deal with fire. And this doesn’t do this
alone, we work with a number of other Federal agencies, as
you see the list here – ATF, Consumer Product Safety
Commission, NIOSH, they have the Federal mandate for investigating
firefighter fatalities. We have a group at
NIST that works with the law enforcement side
of the house, National Institute of Justice and others, and
we collaborate with them on a number of issues. The Nuclear Regulatory
Commission is playing a major role in validating and verifying
our fire models right now, so that’s an important
partner that we have. The Department of
Homeland Security and the US Fire Administration,
of course, that oversees a number
of programs with regard to improving the fire
safety in the United States. We also work with a large number
of professional organizations, as you can see there, included
in the list the Association of Fire Chiefs, International
Association of Firefighters, International Society of
Fire Service Instructors, and many others. The partners I’m really thankful
for are these fire departments that we have listed here,
as well as the universities and the private laboratories. These are the folks that
get together with us and actually get
their hands dirty. Actually we’re on
fires together, we’re on experiments
together, and so in the case of the Fire Departments
basically they’re willing to own the fire because the
lawyers at NIST don’t like us to go around the country
lighting buildings on fire so we need to have a
partner Fire Department that has the capability
to control the fire and put the fire out and
basically take a chance on us because they’re investing
resources which are usually in high demand in their town
to continue this work to try to improve firefighter
effectiveness and firefighter safety. So what is the fire problem
in the United States? According to NFPA, the National
Fire Protection Association, in 2003 we had over a
million fires reported, there were approximately
3,000 civilian deaths and almost 16,000
civilian injuries, and $11.5 billion
in property damage. How has this changed over time? Well, this has been an exciting
time to be a researcher, if you will, in fire
or to be a firefighter or to be a codes official
or a fire prevention officer because you can see that some of your work has had quite an
impact in reducing the number of structure fires
in the United States. They decreased by
57% since 1977. Coincidentally I
started at NIST in 1979 so this has been a
pretty good track record. It’s leveled off here toward
the end so we still have to keep at it and push on it. The other thing to note is
that civilian fire deaths in the United States have also
decreased by 56% since 1977 and, again, a very important note. What you see on the yellow
line on the bottom, however, are where people die in fire,
and they typically don’t die in fires at work, they
don’t typically die in fires when they’re shopping, they
don’t typically die in fires when they’re on vacation
at a hotel or something, they typically die in a place where they should feel the
safest, in their own home, and that’s where the majority
of fire deaths have occurred over time and continue to occur. In fact, you can see it’s
becoming a larger percentage as time goes on of
all fire deaths, so that’s really a big
focus for us in terms of improving fire
safety in the home. Now we’ve seen all these
curves that are just on this nice reduction, so
things are going along fine, but there’s one curve that’s
not reducing at the same rate and that’s firefighter
deaths on the fire ground. And, as you can see, that curve
is kind of bucking the trend and it’s a very disturbing
trend. According to Dr. Fahey
[Assumed Spelling] again at FPA in the late 2000s firefighters
due to traumatic injuries on the fire ground
are dying at a rate of three deaths per 100,000
fires, where in the late ’70s when they had less
protective equipment, potentially less training,
the death rate was lower. So what’s going on? Well, what do firefighters wear? In the mid ’80s by that point in time pretty much all Fire
Departments had adopted the use of the self-contained
breathing apparatus or the SCBA, so those are the tanks that you
see on the firefighters’ backs. You see they have
protected helmets, they have protected face
pieces, they have turnout gear, which are very heavy and
specially designed pants, bunker pants and a coat,
they wear very heavy gloves to protect them from the heat,
protect them from abrasions and things like that, so
we’re trying to protect them from a range of hazards
in that structure. Unfortunately, and they also
wear very big and heavy boots. Unfortunately, you can imagine
that when you start to put on 30 pounds of gear and
you start to carry tools, which may add another 10
or 20 pounds to the load that you’re carrying, it
can affect your balance, it can affect your stability, it
can affect how you crawl around and your ability to move around. Also, with the SCAB
may have some impact on limiting your
vision, as well. Well, why is this important? Well, if we look at the
two photos on the bottom and if you live in
the Washington, D.C. area you’ll recognize
that there were a lot of homes like this that were
built in the 1950s and 1960s just inside
the Beltway and just outside the Beltway. You also see some
row homes up there, very common inside Washington,
D.C., very common in Baltimore. And then we have sort of
the little mansion up there in the left-hand corner. So these smaller homes were
about 1,200 square feet or so. The larger home in
the picture there is in excess of 4,000 square feet. That makes a difference
in the size fire that the firefighters may have
to deal with when they arrive. Other things that you
can notice, just looking at the outside of the home
is the pitch of the roof. Firefighters typically want to
get on the roof and make a vent to let hot smoke and gases out. Well, when you have a
relatively small flat roof, like the single story, that’s
not too hazardous an operation. When you have a high pitched
roof that’s now 30 feet above the ground
that becomes more of an interesting opportunity
for the firefighters. The windows are different, the
amount of windows are different, so when they vent they let
in more oxygen that can mix with the fire gases that are
already inside the house. Something you can’t see
from these pictures, but we know from experience
the older homes had more compartmentation to
help limit fire spread. The large rooms in the older
homes might have been 12 by 20 feet, the bedrooms were
typically a big bedroom was 12 by 12, and the more modern
homes use engineered lumber to increase the span. We can now have two-story high
openings inside that home, it could be 40 feet long,
30 feet long, 30 feet wide, very large openings with
no compartmentation, nothing to stop the
spread of smoke. And as we look at the back
of the homes, as well, we see additional windows. We also see there’s
combustible decks on the rear of these
large homes. We’re starting to see a trend
across the United States where many fires are starting
outside on the combustible deck in the wintertime due
to mishandling of ashes from a fireplace, in the
summertime from grilling or using a fire pit of
some sort on a wood deck. The fire gets into the siding of
the house, it runs up the side of the house, gets in the attic. By the time the firefighters
get there if they don’t perform a full
size-up they don’t appreciate where the fire is and can
get caught by surprise and, unfortunately, a fire like
this killed a firefighter in Prince William County
not long ago, Kyle Wilson, and in Lowden County there were
several firefighters that had to literally jump out of
windows to save their lives. What do we wrap our
houses in today? Plastic, we have plastic,
we have a lot of insulation in our homes, and this is a
good thing because we want to save energy, we want
them to be energy efficient. The challenge is
if a fire starts in our home now all the
smoke and heat is going to get stored inside the
home and basically waiting for the firefighters to
arrive and make entry. Our thermal paned windows
are more resistant to failure in terms of heat because glass
is such a great insulator and so the interior pane will
absorb most of the energy and slow down the potential
for failure of that glass. So if the oxygen runs out inside
the structure before the glass breaks, again, it’s going to change what the firefighters
find on the fire ground. When we see these homes burn and
we see all that heavy black soot in the images that means
that it’s a fuel rich fire, that means that the
fire has not mixed with enough oxygen fast enough
in order to have a clean burn. In Fire Department vernacular
the condo project that is there in the upper right-hand
corner would be considered fully vented. The windows are all
out, the roof is off, and yet it’s still
a fuel rich fire. In the ’90s we worked with the
Phoenix Fire Department to look at structural collapse issues, so here is a traditional
construction, older construction, heavy
timber, hardware store that they’re getting
ready to tear down, so they let us burn in it. You notice that we had flames
and then we didn’t have flames, we just have smoke, until
we sent a firefighter to the front door to open up and let more air
inside the structure. Once the firefighter opens up the structure we get
a reemergence of flames at the roof line and
within 10 minutes of them opening the
front door we’re going to have a fairly significant
structural collapse, that if any firefighters
were in there at that time clearly
they’d be injured or killed. So these things happen
pretty fast in the big scheme of things. By the time that somebody
notices the fire, somebody calls in the fire, the Fire Department
responds, the clock is ticking and the fire keeps, the
physics of the fire keep going. It’s not watching the
clock because the fact of the matter is wood, which
is a very sustainable fuel, burns and the worst place to
have wood is up high in a space because when a fire burns the
hot gases go up to that space and start to pyralize the wood. There have been great gains
in property protection and protection for
occupants in some of these large wood structures
that are being built all over the country in the
form of condominiums or mixed use structures
with businesses on the first couple levels
and then wood frame structure above them for residential. The challenge is they don’t
sprinkler the entire building so all that attic
area that you see in the upper right-hand corner
there would have no sprinklers in it, it would be
a mechanical space. And we just had an example
of what happens with that about a month ago in New
Jersey when they burned down a large condominium
complex. Once the fire got up in the
attic there’s no way the firefighters can stop it. And firefighters are getting
additional challenges every day, more people are putting
solar panels on the roof, they’re getting fuel cells in
their home, we have all sorts of different power sources
for vehicles nowadays, hybrid vehicles,
batteries, compressed gas. I understand the hydrogen
car is coming so we’ll see, and that can be very
exciting, as well, from a fire perspective. So, in summary, to look at some
of the data from our brothers in the Census Bureau, houses in the United States have gotten
quite a bit larger on average from the ’70s to the 2000s, the
housing lots are getting smaller so these bigger houses are
getting closer together, again, bad news for fire development. During the past 50
years the fuel loads in our homes have changed
dramatically, they’ve gone from being where our furniture
was principally made of cotton and steel springs and you
needed the steel springs in the cushions because the
cotton would kind of bat down, cotton will smolder,
it’s fairly easy to ignite, but it burns slowly. Polyurethane foam, which
has replaced cotton as the principal foam
plastic in our furniture, is extremely resilient, it
makes a great seating material, it’s hypoallergenic in a sense. So I mean it’s a good material
until it catches fire and then when it catches fire it has a
much higher heat of combustion than the natural materials. It burns with a high amount of
soot so it’s a very dirty fire, and it results in
fuel rich conditions within the home very,
very quickly. This kind of burning, in simple
terms we say it burns hotter and faster, so what
that means is for occupants you have
much less safe time to get out after you hear your
smoke alarm and, of course, if you don’t have a smoke
alarm you’re doomed. As we mentioned, the home
designs, as well, have changed. So fire dynamics, what is it? It’s a relatively new science. The first textbook on fire
dynamics wasn’t written until 1985. People have been studying fire
for a long time, but typically in very separate disciplines,
looking only at the chemistry of the fire or the heat
transfer, the heat release rate of the fire, and
then they started to bring it all together,
the material science, the fluid mechanics, to see
really what it takes for a fire to interact, to ignite,
to spread and develop. So what is a fire? In basic terms it’s a gas phase
exothermic chemical reaction. In other words, it
emits heat and light. So the fire tetrahedron is
composed of we need a fuel, we need some sort
of oxidizing agent. We have 21% oxygen in
the air we breathe, so that’s our oxidizing
agent typically. We need some heat or ignition
source and then for it to have these flames, we have
this uninhibited chemical reaction, but the key
thing is the fuel needs to be in gaseous form. Solids don’t burn and
liquids don’t burn. The oxygen is in gaseous
form and the fuel needs to be in a gaseous form to
mix with it and the heat in order to have a flame. So let’s take a look at
that, let’s take a look at our fire tetrahedron. The heat source will heat up the
fuel, the fuel will pyralize, basically give off a fuel gas, it will mix with
the gaseous oxygen, and then a flame will develop
when all the conditions and the concentrations
are right. And then we have this
chemical chain reaction that sustains the flame
and keeps it going, and there we can see
how that sort of evolves in a very artistic sense. Smoke is a fuel, so a very
simple demonstration you could do to prove that is take
a candle in a safe area and blow it out and then
bring up a lighted match to the fire gases that
are coming off the candle and watch what happens. [ Pause ] The fuel gases ignite and
the flame travels back down to the source of the
fuel, which is the wick, so smoke is the fuel, that’s the
fuel that the firefighters need to manage more than anything. Fuels are very different today. If you take a piece
of wood and ignite it with a candle you’ll see
that it burns fairly clean and that the flame spread on
the wood will be slow relative to say a piece of
expanded polystyrene where you can see it’s a very
sooty flame, a very dirty flame, and the flame spread
will be very quick. The pictures aren’t that
dissimilar from looking at this acetylene torch. In the fuel rich case the
acetylene torch is not being mixed with, premixed
with oxygen, it’s just a diffusion
flame that’s picking up the oxygen in the air. And, as we can see,
we have a weak flame and a very sooty flame,
there’s a lot of unburnt fuel in those soot particles. When we add additional oxygen
we see we get a lot more energy out of the flame and
it burns very clean. So one finding that
was developed at NIST in the early ’80s was this idea
of how much oxygen it takes to generate a certain amount of
heat that it became a constant, it didn’t matter if we were
burning acetylene or gasoline or cardboard on average
for every kilogram of oxygen that’s consumed you
generate 13 mega jewels of heat, so basically no oxygen, no heat. Fuels are different today, so
under the legacy fuel you’ll see that we have a sofa that’s,
again has some cotton batting and older materials in it, and
we light it on fire and we see that the fire doesn’t
grow very rapidly. With the modern furniture
that’s made of polyurethane foam and polyester batting
you can see that the fire growth is much
more rapid and the amount of smoke that’s being
produced is much more intense. Imagine that spreading
through your home. So fuels are definitely
different today. Pyrolysis, we mentioned
this earlier, it’s the chemical decomposition
of a compound in one or more substances, basically
just due to heat alone, heat breaks down the material. So here’s a look
at a common sofa that you might have one
very similar in your home, the seating cushions,
the yellow materials, the polyurethane foam, it’s
about five to six inches thick, the polyester batting
is wrapped around it and then the textile
material that’s covering it in this case is also
made out of polyester. The back cushions you see are
also just pure polyester batting so they’re a lighter weight,
lower density material than the seat cushions. So watch what happens, we burned
the sofa in our laboratory in Gaithersburg, Maryland, when
we put an open flame to one of these sofas immediately you
see heavy black smoke coming off, again an indication
that it’s excess fuel. In this case that smoke is
going into our calorimeter so we can measure the heat
release rate, but in your house that smoke would be collecting
under the ceiling and starting to spread from one
room to another. As the foam plastics start to
burn and melt they begin to drip and spread fire down to the
floor level, this has the impact of now exposing that six-inch
cushion of polyurethane foam from both the top and
the bottom, to the flame as we see the flames start
to pick up under the sofa. That increases the
heat release rate and basically increases
the hazard from this sofa. As the sofa starts to melt away
it allows more air to come in and mix with the fuel and you’ll
see that the fuel is melting at such a high rate that
you’ll actually see it flowing across the board that
we’re using there to protect our load
cell, so flowing fire. If this happened in a highway at a larger scale they
would call it a hazmat. The reality is if
you have a fire in your home today
it’s a hazmat scene. So that sofa by itself, which
only weighs a little more than 100 pounds, has more than
twice the energy needed to flash over a typical scale residential
room with an open door, you need about two megawatts
to generate that flashover. This sofa alone has more
than four megawatts. How many people only have
a single piece of furniture and no carpeting in their home? So we started to get
into compartment fires and we understand that
fire growth is a function of fuel property, quantity,
ventilation, all these things, compartment geometry, location
of the fire in the room and is there any wind. So in a very simple
case, again in our lab, we’re going to put the
friend of the blue sofa, a very similar blue sofa into a
small room with an open doorway and we’re going to
light it on fire. If you remember from the
previous video it took about five-and-a-half
to six minutes to get that entire sofa
involved in flame. Here you’re going to
see what we referred to as a compartmentation affect
because the smoke is being held over the sofa and the smoke
has heat it starts to radiate down on the sofa
preheating the sofa for the flame to spread faster. So we’ll get more of the
sofa involved faster, we’ll eventually get enough
excess fuel trapped in the room that the gases, themselves,
will ignite remote from the sofa and start to spread through
the room and transition into a phenomena
we call flashover. Notice that this is taking place in a little more
than three minutes. So what is flashover? Flashover is the transition
phase where we change from having a hot gas layer
in the top of the room and a cool fresh air layer
in the bottom of the room, to once that hot gas layer
auto ignites the radiation from it auto ignites almost
everything else in the space. We have a well-mixed reactor,
basically, burning from floor to ceiling in excess of 600
centigrade or 1,100 degrees F. So let’s look at
another flashover, again, I’m using my friend,
the blue sofas, and this time we have
a dry Christmas tree. So that’s a natural fuel,
right, there’s no synthetics in the dry Christmas tree, and
what you’ll see is that even that fuel will generate
a fuel rich condition, heavy black smoke will start
to come out of the tree. It’s not mixing well
enough to get it burned, and you’ll see the fire triangle
right in front of your eyes as the flames burn at the
interface of the hot fuel gases and where it’s mixing
with oxygen as those hot gases are
moving across the room. Now we’re going to see a very
clear example of pyrolysis. The radiant energy from the
flames are now heating the sofa and the chair to such a point
that the polyester is turning into a white fuel
vapor and that’s going up into the hot gas layer,
again which will mix and burn at a later time once the
concentration is right and once we have enough oxygen. Again, look at the speed with
which this is developing. We had a tragic case in
Annapolis, again last month, where two grandparents and
their grandchildren were killed. They had a huge tree in a very
large home, a 15-foot tree. NIST burned some 15-foot trees for the Wild Land
Urban Interface Study, a dry tree like that can
generate 30 megawatts of energy or the equivalent of about six
sofas going from zero to maximum in a matter of seconds. Here’s the most common cause
of fires in the United States, unattended cooking, that’s
the number one leader in the number of fires. And they don’t look
so bad initially. Someone walks away for a
little while maybe to go check on the kids, watch television,
some people actually run out, have run out to the store
to get an ingredient and left food on the stove. As you see in this 13-inch
cast-iron skillet I’ve got a little bit of cooking
oil, it auto ignites due to the high temperature
and then the flame grows as energy re-radiates
back into the pan, it extends our combustion zone. We start to see the flames
impinging on the cabinets, which are made out of an
engineered wood product, and they start to pyralize. And what looks like we’re
in almost an empty room, a 12 by 12 room with
no other furniture than what you see there, you say that can’t go to
flashover, can it? Well, let’s take a look. The flames continue to
spread, the off gassing from the cabinets are now
adding to the combustion, which is allowing the flames
to impinge on the ceiling. We’re re-radiating so much
energy back into the pan that the oil that’s left
in the pan is starting to do what we refer to as boil
over, it’s bubbling and foaming and now spilling onto the
surface of the kitchen range. Our high pressure
plastic laminate on our countertops
is now bubbling and popping and pyralizing. And now you see that
we’re starting to get some ghosting flames
or intermittent flames in the hot gas layer
as it starts to move toward the
open vent via the door. So now we’ll take
a look at the door and watch the vinyl flooring
pyralize, auto ignite and quickly we transition
to flashover. So how do the firefighters
interact with this? Well, again, we discussed that they have some very
good protective equipment, but their face piece
is made of a plastic, it’s an industrial plastic,
it’s a high temperature plastic, but it’s still plastic
and it melts at a relatively low temperature, relative to the heat
generated by the fire. Flame temperatures can be
anywhere from 1,400 degrees to 2,000 degrees, and once that
face piece reaches 280 degrees or 300 degrees it
starts to soften and then it will be
liquid pretty much by the time it’s
400 degrees or so. Other equipment that
firefighters carry into the space for their
own safety, such as radios, there’s currently no standard
for firefighter radios in terms of how much heat
they’re required to take. So many of the devices
that they carry in with them currently
could melt at 140 degrees or certainly less than
200 degrees and fail them, where their gear is designed
to take more energy than that. So we’re testing all these
things, trying to work with the appropriate standards
development organizations and improve the products
and improve the materials that the Fire Service has,
but in the meantime we want to make sure that
the Fire Service at least knows what the
limitations of this gear is. Unfortunately, we’re reactive
in this sense in many ways. NIOSH has a program where they
study firefighter fatalities, and they start to
– the whole purpose of them studying
these fatalities is to develop root causes and they
start looking at a trend here where there were a
number of fatalities where firefighters’
face pieces had melted, that that was the first item to
fail, that they still had air in their bottle but yet they
died inside the fire room or inside the fire structure. So NIST took that
information and started to run some experiments to
try to get an understanding of how this phenomena works, what is the face piece
very susceptible to. So here we’re going to light a
fire with a very small burner, it’s about 16 inches on a
side, it’s only about that big. We’re going to fuel
it with natural gas. It’s going to generate a flame
that as it moves up and down, as it pulses, it’s about
three to five feet tall, and it’s about six feet
in front of the manikins. Now the manikins are
very specialized, they actually breathe, they have
a controlled breathing device in them, so they’re breathing
about 40 liters a minute of air. And right now we have a camera
inside the breathing manikin’s head, looking out
through the face piece. And so what you’ll notice as
you look through the face piece at the flame is that you’ll
start to see some crazing and damage occur to the face
piece very early on and we start to see the spidering
coming out now. And then if you watch
closely this is sped up 10 times right now
in the interest of time. We’ll slow it down
to real-time shortly. You’ll notice that the face
piece is pulsing in and out with every breath the manikin
takes, that’s how soft it is. What’s a little difficult to see
right now is that there’s a hole in that face piece and
when we shut the flame down it’ll be very clear to
see the hole in the face piece. So firefighters that
have experienced this in say a training
environment have told me that they were warm,
they didn’t feel too bad, they certainly didn’t feel
a lot of heat on their face, and then all of a sudden it
felt like just a blistering, a burning on their
forehead or on their cheek, wherever that hole had
opened up in the face piece. And there you see how
soft the face piece is, the hole is pulsing and moving with every breath
the manikin takes. So radiation is really one
of the bigger challenges for the plastic face piece, and the reason is plastic
is an excellent insulator and it absorbs thermal
radiation so that you could be in 200-degree air, but
if you have line of sight with a hot fire your face
piece could get to 400 degrees or higher very quickly because
it’s absorbing that radiation. Look at the comparison of
some of the current standards for turnout gear, for
personal alarm safety systems, the pass device for thermal
imagers, things like that, we can see that they’re all
tested to at least 500 degrees, everything except the SCBA, the self-contained
breathing apparatus, and of course the reason is the
plastic face piece cannot take 500 degrees. So the new standard that came
out in 2013 based on work done at NIST now exposes it
to a radiative heat flux of 15 kilowatts per meter
squared for about five minutes, and the idea there is
that it still may soften and develop a hole, but
the breathing manikin has to maintain a positive pressure
seal for 24 minutes afterwards to provide time for someone
to rescue the firefighter. So, again, it needs
to be combined with firefighter training
so that they know not to touch the face piece
because it’s so soft, they need to leave it in place. And just to give you some
reference as we’re talking about all these temperatures
and heat fluxes and what-not, the human skin at about 130
degrees has the potential to receive a second
degree burn injury, in other words start to blister. Pain to exposed skin occurs at about five kilowatts per
meter squared, that would happen within seconds, and
the threshold for rollovers we’re starting
to do that transition of flashovers, about 20
kilowatts per meter squared. When we actually
have flames impinging on things it’s anywhere
from say 160 to 200 kilowatts
per meter squared. So firefighters are
a traditional bunch, they’re good folks,
and every community in America is fortunate
to have a Fire Department that they can rely on
when they’re in trouble, almost any kind of trouble. And Fire Departments nowadays
are pretty much all hazard, whether it’s auto
accident, hazmat, responding to a terrorist
incident, it’s not just all about fire anymore, but they
still need to be prepared for the fire when it occurs. And in the ’90s there was
a big change in tactics and that change was
driven by technology, that change was driven
by the adoption of the self-contained
breathing apparatus. The development and
acceptance of these bunker gear that firefighters wear. And they came up
with some practices that whenever possible
they’re going to attack from the unburned side to the
burned side, and that kind of got reinterpreted
to we’re going to go in the front door every time. Ventilation, it’s defined as
being a systematic removal and replacement of heated
air and smoke and toxic gases from a structure with
cooler air, however, that kind of got
shortened and redefined to venting equals cooling. I’ll show you that’s
not the case. When you vent a fuel
rich environment, a hot fuel rich environment, and give it more oxygen the
fire is going to get bigger. The most aggressive and efficient fire attack
is from the interior. Again, that turned into
aggressive interior attack, and there’s all this discussion
about don’t flow water from the outside, you’ll push
fire, you’ll hurt people. Basement fire attacks
always need to be done from the interior because,
again, we’re not going to flow water from the outside. And, of course, in some circles
when they just don’t want to talk about it they say, well, this is how we’ve
always done it. So one of the first
firefighter fatality incidents that I became involved with
occurred in Vandalia Avenue in New York City, three FDNY
firefighters died December 1998. And to look at the
building, the fire occurred on the tenth floor,
it’s difficult to determine whether
the fire apartment was on the downwind side
or the upwind side or whether there were
two fire apartments based on the soot stains
on the building. As it turned out the fire
was on the upwind side and, unfortunately, the door to the fire apartment was
left open by an occupant. In the open apartment, on
the lower left-hand corner, a gentleman there was
getting smoke in his apartment and so he opened
his windows to try to let some of the smoke out. Unfortunately, because he
was on the low pressure side, the downwind side, the
intensity of the smoke coming in his apartment increased. Then he opened the door to his
apartment and could not get out due to the high amount
of smoke, so he went back in his bedroom, closed the door
and safely rode out the fire. Lieutenant Caveleri
[Assumed Spelling], Firefighter Bohan
[Assumed Spelling] and Firefighter Bop
[Assumed Spelling] went through the smoke door
from the elevator lobby, they were approaching
the fire apartment and basically got caught
between the fire apartment and the open apartment. They were in what we
call the flow path. Once the windows in the
fire apartment failed and a wind-driven fire occurred,
a very high intensity fire in that apartment, basically
the heat dropped them where they stood and they died. This is an image
of the corridor, going from the fire apartment,
looking to the attack stair where the rescuers were coming, trying to respond
to their May Day. This is what was left of
the fire apartment, itself. You can see it was hot enough
to spall the concrete beams that composed the ceiling. And so the fire dynamic
simulator, which wasn’t even called that
at this time, it was very rough and in draft stage, the fire
dynamic simulator wasn’t officially released till
2001, was used to get a sense of what might have
occurred in this fire. So you can see the
little flicks of orange as the fire is developing
in the fire apartment, and then we have smoke
that’s going to start, as the fire increases in
intensity the smoke is going to pour out through the
open door into the corridor. We see it flowing into the open
apartment, and then we’re going to see with the impact
of the window failing and we’ll see a surge of smoke and flame pushing
down the corridor. As the firefighters
radioed their May Day, the other firefighters in the
attack stair opened that door, and then you’ll see that
once they opened that door and it vented through that
yellow vent on the top, the bulkhead vent of the
stair, that flame also came in and burned them and slowed
down their ability to get to the original victims. It took about 10 years to
get the funding together, to get the partnerships
together, and to really take
a look at this by burning actual
experiments instead of just looking at
the fire model. And so we, in our laboratory
at NIST we built an apartment, where we had a bedroom,
a hallway, the bedroom is in the orange there,
the hallway connects to the living room toward
the bottom of the image, they’re both 12 feet by 16 feet,
the hallway is 12 feet wide. They open out into a
corridor that goes 24 feet in each direction, in
one direction it’s closed and in the other direction it
has an open vent simulating a door to an open stairwell. There’s a hollow core
door that’s installed in the target room that’s
in between the bedroom and the living room, so we
call that our target room. Somebody could be
safe there for awhile and we’ll take a look at that. The flow path is basically
composed of the volume or the rooms in the hallway, and then what direction
the flow goes and where it goes is controlled
by the inlets and pressure. So in this case the high
pressure area is going to be in the bedroom and flow
always goes from high pressure to low pressure, and the lower
pressure is going to be the path through the living
room and out the vent. It’s pretty clear just by the
colors I drew in the flow path that the higher hazard area for
firefighters to be operating in is toward the outlet
side, on the exhaust side, between where the fire is and
where the fire wants to go. So we prepared these rooms just
as you’d find in anybody’s home with real fuel, real
synthetic fuels. We measured the heat release
rates of them so we have an idea of what the hazard is,
so you get some idea of the peak heat release rate that a small upholstered
chair is almost two megawatts and the sofa is about
two-and-a-half megawatts, it’s sort of a loveseat
size sofa, and the bed, the king-sized bed
there is four megawatts. We start the fires with
a little waste container and that’s about 30 kilowatts. And the first test we
did is a baseline test and it has absolutely no
wind supplied to it, at all, so all the movement that you’re
going to see is a function of the fire acting as a pump
entraining fresh air in, heating the gases up,
causing them to expand, increasing the pressure in
the fire room and then pushing out to lower pressure
areas through vents. So the fire started
next to the bed. On the upper left-hand
side you’ll see the view of the window that’s
still intact. Once we break that window or
once that window fails due to the fire you’ll see a
dramatic change throughout the space. Currently smoke is now
spreading through the hallway, it’s into the living
room that we see on the left-hand
side lower frame, and we see in the
thermal imager view on the upper right-hand side, the amount of heat that’s now
pouring out into the corridor and moving toward the vent. If firefighters were
in there currently and they were crawling
they would be safe, their gear could protect
them from that thermal load, but once the window gets
vented everything changes and it changes within seconds. So now we have a situation
that if firefighters were in the corridor they would be
exposed to untenable conditions, they within 30 seconds or less
they would have to either change that environment or find
a different place to be if they hope to survive. Notice that at this point in time the target
room is still clear, while all the other rooms
are full of black smoke. The door to the target
room starts to fail in about six minutes. So what’s the impact on
the heat release rate, the amount of energy that
the fire is producing? Well, once we vent the window
it goes from two megawatts to more than 12 megawatts. The bedroom temperatures
you see range from about 1,200 degrees
Fahrenheit near the ceiling to about 500 degrees Fahrenheit
near the floor, that all happens in less than four
minutes, clearly untenable for an unprotected civilian. Once the window is vented notice
how we transition a flashover where we have well
mixed burning, floor to ceiling the
temperatures all increase and they’re all over
1,100 degrees Fahrenheit. What about in the living room? So let’s say a firefighter
was working pretty fast, they wanted to see if they
could affect a rescue, they’re working their way back to the fire room
in that apartment. They’re in the living room,
and then that window fails. It goes from a condition that where they would be
crawling would be 300 degrees or less to a condition where
at a minimum it would be at least 750 degrees. As you might note from the
chart I showed you earlier none of their equipment can
be tested to 700 degrees, it can’t survive 700 degrees,
your skin starts to blister and boil at 130 degrees. So, again, an untenable
situation. The velocity in the hallway,
how fast heat is transferred to people is also not only a
function of the temperature and the energy, but also a
function of the velocity, how that hot gas
is mixed and moving around your body or
around the target. So initially without the window
vented we just have a ceiling jet or the gases near
the ceiling are moving at about six miles an hour,
the red line with the squares. As we get to the green line and
the blue line, the green line is at four feet above the floor
and the blue line is one foot above the floor, notice that
once the window is vented that high pressure pushing to the low pressure is now
pushing a velocity even at the floor level of about
six to nine miles an hour. Anyone that’s bought an
electric oven lately, if you go in to buy an
electric oven they’re going to sell you what type of oven? A convection oven,
the only difference between the old school oven
with the heating element and the convection oven is
the convection oven has a fan to increase the velocity of the hot gas moving
around the turkey. What’s the purpose of that? To cook the turkey faster. Unfortunately, high velocity
hot gases take away the firefighters’ safe
time much faster. What about total
unburned hydrocarbons? This is such a fuel rich
environment in the living room, we’ve got more than 12% of gases
such as acetylene and methane that have been broken down
from the materials pyralizing and getting ready to burn that if we give it more air
that’s the fuel that’s ready to burn. Here’s a case where we
actually impose a wind on it, so again you’re looking
at the inlet, which is where the glass is,
and you’re looking at the exit into the public corridor,
which is where the open door from the apartment is. Once the glass fails
it’s exposed to a 20-mile-an-hour wind
pushing through that apartment. This is playing in
real-time and, again, watch how rapidly conditions
for firefighters would change. Again, going from tenable
for firefighters crawling in that corridor to
untenable within seconds. How do you control it? Well, you don’t want to
give it an inlet or outlet, we have to control
the flow path. One way of doing it is
keeping the door closed. So in this case even though
the window is vented the door to the corridor is closed, and
you can sort of see a steel rod in the image that we
welded to the door in order so that we could open
it safely without having to put firefighters inside that
potentially lethal environment. So, again, things for
firefighters to look for, what’s the wind outside,
can you see with the thermal imager smoke
pushing with a high amount of energy around the door, can you feel energy
coming around the door? In which case don’t line
up in front of that door and open it back out
because if you line your crew up to make the push
that’s what they’re going to be assaulted with. Last one of the lab experiments,
and this one is a good one because it actually
happened to us, the phenomena that we’re look at here happened
to us in experiment three, it wasn’t exactly part of
the plan, it was just sort of something that occurred. And what had happened was that
we generated so much excess fuel that it resided in our
40-foot by 30-foot hood with a six-foot ventilation
duct pulling 90,000 SCFM, enough smoke sat there
that it auto ignited. And now that exposed the top
of our test prop in the lab to a lot of radiation,
and we said, well, that was pretty interesting,
let’s see if we can do that again and be ready for
it so we can get a good video of it, get some good
pictures, and also we want to see what the impact
of putting a hose line through the window would be on this flaming that’s going
all the way from one end of the apartment, through the
apartment, and up into our hood. So now as we watch the stack
video view, which is sort of in the middle there on the
bottom, we’re going to start to see flames coming out of
that and they’re going to pulse up and down for awhile. Now we’ve auto ignited the
gases that are in our hood, our 30 by 40-foot hood,
and now we’re going to flow about 80 gallons per minute of
water, a low amount of water in firefighting terms,
into the bedroom. And you notice what
happened, the fire went away in the stack immediately, and
you might look and say, well, wait a minute, we still
have flames in the bedroom, but as we’re going
to get our view back in the bedroom camera there, the
second one from the left on top, we’re going to see that
we just have a bunch of debris fires basically
going in there, what’s left of the bed,
what’s left of some chairs and dressers and
things like that. These are fires that firefighters gear is easily
designed to withstand the energy and the heat from those and
go in and fight that fire. The key thing is the water from the outside took
away the fire gases. Firefighters’ gear
is not designed and firefighters can’t outrun
when the fire gases auto ignite and spread through
the entire property. So within a month we found
ourselves out in the field in high-rises in Chicago
and New York City looking at wind driven fires, and
the Fire Departments had come up with a number of strategies
that they thought would work to handle these kind of fires,
but they didn’t have any way of testing it, they
didn’t have any way of measuring how
good it would be. So NIST went and instrumented
these high-rise buildings with miles and miles of thermal
couple wire and cable and videos to show this is what’s referred
to as a wind control device, by blocking the wind
you smother the fire, you cut off the pressure
from the air, and you see that the fire in the living room was reduced
significantly, the temperatures in the hallway dropped by
more than 50% within a minute without flowing any
water yet at all. Another idea is the floor below
nozzle or the high-rise nozzle, it’s fairly lightweight,
easy to maneuver. What you see in the
inset there is that we have flames rolling the
floor of the public hallway, clearly firefighters could
not safely make entry into that public hallway. So what we’re going to do is
apply water to the bedroom of this apartment so
fire is going all the way through the bedroom, down the
hall, through the living room and out into the public
hallway, and look at the impact that again flowing water from the floor below
has on that fire. They make an adjustment to
get some water in the window, there we go, and
within seconds the fire in the public hallway is out. Conditions are cooled down,
the threat of a flashover or another flashover is gone,
firefighters can now make entry as they normally would on the
fire floor, do their search, finish putting out the
fire, and affect any rescues for any viable victims. We see things that we
try to help the officers, say here’s when you need to
know how to and when to size up. So we had natural wind this day, the wind is blowing the
flames back into the room. At some point in time the
pressure inside the room gets so large that it basically
shoots out a fireball, so if you’re a firefighter
and you roll up on a scene and shooting out fireballs start
thinking about what Plan B is. You shouldn’t be marching
down that corridor. It was commonly thought
that if the windows vented and flames were coming out the
window then it’s safer to be in the hallway – that’s
not the case, the homes are so fuel rich, we have so much
energy stored in our houses that when it burns, like
in this apartment here, there’s a tremendous
amount of flaming and burning energy
going down the hallway. And this doesn’t just happen
in high-rises, this happens in single family homes, as well. In this case two
firefighters in Houston died. We were asked to
come down and look at the fire behavior
and model it. The victims went
in the front door, which was the downwind
side, the low pressure side. They made it to the
back of the house, that’s where their
nozzle was found, and then their bodies were
found in the front of the house as you can see in the living
room and the dining room. The fire started in the attic, it was well involved before
the Fire Department arrived. They had at least
20-mile-an-hour winds coming from the rear of the structure,
and you can see that’s where most of the
burn damage is. Where the people are standing,
down there in the image, that’s where the front door is where the firefighters
made entry. The occupants had also
opened the garage door because they were
rescuing their cars. We made, again, a fire
dynamic simulator model, what we put into the model
was not only the geometry and the thermal and chemical
properties of the fuels that are there, but
also the timeline of what the firefighter’s
actions were. So you can see where we
have little blue marks where ladder 26 made roof vents. We have another blue vent mark
there just behind the front door where engine 36 was pulling the
ceiling and things like that. The big feature that
happened here were the windows on the back side of
the house failed. When there was no wind,
you can see that the blue, the cooler color, when we
look at a cross section of the house was lifted, so the firefighters have
refuge closer to the floor. Once the wind penetrated
the house it mixed the fire, the fire got hotter and dropped
the heat all to the floor. Just looking at it from the top, down at the front floor view 10
seconds before the glass failed it was relatively safe for
firefighters to crawl in there and make an attack, 10
seconds, within 10 seconds after the glass failed it was
untenable thermal conditions blowing out the front door. So as a fire officer if
you’re ignoring the wind and you send a crew in on the
downwind side effectively you’re taking a chance, you’re flipping
the coin as to whether they live or die based on whether a piece
of glass less than a quarter of an inch breaks or not. And, again, here’s another
image showing the flow path where the intense heat is
and how the firefighters got to a cooler place, but not cool
enough for them to survive. So this brings us
to a difference in what they had been taught. Firefighters for
decades had been taught about the fuel controlled
fire, ignition, growth, fully developed and then decay,
so if we had a pile of pallets in a parking lot and we lit them
on fire or we had a campfire that we would light on fire it’s
going to behave in this manner. As the logs go away,
the fuel goes away, the fire is going to decay. When we put a fire inside a
structure we can create a very different kind of phenomena,
the ventilation controlled fire. And in this case
what we’re showing is that the fire can’t
get to flashover, can’t get fully developed yet
because it runs out of oxygen and then the heat
release rate comes down, the temperatures come down, until there’s a change
of ventilation. There’s no change in ventilation
the fire might smother itself and put itself out. If more oxygen is introduced
to these hot fire gases that are stored in our well
insulated homes the fire can reach fully developed stage
in as little as 30 seconds to 80 seconds, 200 seconds
depending on the size of the box, the size
of the house. So this has happened to
firefighters many times. So let’s look at an
example, again working with the Chicago Fire
Department we had the luxury of burning 20 identical
townhouses. I’m only going to show
you one, but, you know? See, we will have
a beer we can go through all 20, it’s
a good thing. You can see the living room
on the front of the house, the dining room and kitchen on
the first level in the rear, and we had bedrooms on
the second floor, again, furnished one bedroom view that
I’ll show you as at the top of the stairs looking out
to the top of the stairs and then the other bedroom view
is in the front of the house. So we’re looking at the front
of the house, we start the fire in the sofa, you’ll start
to see the flames coming up from the sofa, so the two
bottom images there are the first floor. The top two images
are the second floor. The middle image on the
top is the rear bedroom. And so we see the smoke
coming up the stair and coming in through the open door
of the rear bedroom. Then in the image on the upper
right we see the smoke filling the bedroom that has the
open window on the front. That’s the only opening
to the outside. So smoke goes, follows the
path of least resistance, high pressure goes to low
pressure, that window serving as a low pressure vent. We start to see flames coming up
the stairwell, we see the glow, then we see flames
entering the front bedroom. The velocity and the intensity
of the black smoke coming out that window is increasing, and then it’s just
going to stop. As the oxygen concentration in the house drops below
what the fire needs for flaming combustion the
heat release rate comes down, the temperatures come down,
and it just condenses the gases to the point where it stops
pushing and starts sucking. Once the Fire Department makes
the vent, you can see how that flow path is established
with the air inlet low in the door where we
have a bidirectional vent at the front door and a
unidirectional vent coming out the exhaust of the bedroom. Fire is going to develop
a little bit at transition of flashover within 80
seconds of opening that door. This kind of scenario
is basically a trap for firefighters in the past. They would arrive, they
see nothing but smoke, they think they’re
early in the fire vent. They might commit
resources, people to go search for victims upstairs, and if
the line is not ready to put that fire out, if they don’t
come in and out of there in less than 60 seconds they’re
going to have to jump out windows, jump
for their life. Here’s a scenario in Washington,
D.C., 1999, it’s referred to as the Cherry Road fire. And two firefighters died in
this fire, one firefighter was in front of the sofa that
you sort of see upstairs at that little yellow
block, Firefighter Matthews. And Firefighter Phillips
was by the door, which is the vertical
rectangle you see on the upper level there. The fire started
in the basement, the basement was ventilated. When all the Fire Department got
there all they saw was smoke. Once the basement was ventilated
it flashed over the basement, high momentum, high velocity,
hot gases started coming up the stairs and impacted
the two firefighters and they both died. There was a third firefighter
there that received burns over 65% of his body,
but he survived to sort of tell us his experience. So these phenomena
happen again and again. Funerals were held, but not
a lot of change was going on in the Fire Service
in terms of we need to do something different. The leadership of the FDNY,
the Fire Department of the City of New York, said now we really
need to do something different. They met with their
firefighters, they have 11,000 firefighters,
they had focus groups. They said what’s it
going to take for us to get a better understanding
of this? And they said we need to make
sure that the victims are safe, we need to make sure that
we’re doing the best thing for victims, not just the
best thing for our safety. And so that’s why these
experiments were set up on Governor’s Island, we
conducted these in conjunction with Underwriters Laboratory. And, again, old abandoned
Federal property that they left in very nice shape for us. It used to be a Coast
Guard training base. We had a lot of very
similar structures. We could look at the upstairs
bedrooms and monitor them for gas concentrations, as
well as temperatures to look at how victims would
be affected. Again, we’re using real fuels. The places were left in
wonderful condition for us with the wood cabinets, nice
carpeting and everything, we just had to add the
beautiful furniture. I hope you enjoy the mauves and
the purples there, you know, we got a good price on it. We put a lot of furniture in the
basement for the basement fires, as well, but a lot of the fuel in an unfinished basement is
really in the floor assembly, itself, the exposed
wood at the ceiling. Again, if you look
at your furniture at home you’ll see very similar
warnings, you know, be careful, don’t have this near open
flame, et cetera, et cetera. And being as how I’m from
NIST and the main point of our business is measurement
I had to include a slide there to give you an idea of some of
the instrumentation that we put in these structures – bidirectional probes
measure both the temperature and the pressure so we can get
the velocity of the hot gases, whether they’re coming
out of the door or the cool gasses going in
the door or how that changes over time with the fire. Thermal couples,
we’ve put hundreds of thermal couples
throughout the house so we could see the thermal
gradient, the temperatures from the ceiling down to the
floor in the various rooms in the house and the
hallways and what-not. We have our gas analysis
equipment so we can understand the
tenability of victims. Typically folks in
residential fires die due to smoke before they would get
burned to death or something like that so it’s
important to monitor that. And then, again, we run
miles of video cable and data because that’s how we’re
getting this information out to teach people, to show
them what’s actually going on in the house. So here’s a fairly simple case where in the past folks
were hesitant to put water in a basement window, they
would go inside and try to force their way
down the basement. And the reason was that they
thought they would push fire, they thought that they
would make conditions worse, they might steam somebody
inside, but you can tell looking at the thermal imaging
view at the top of the stairs there’s not a lot
of violent movement of heat, there’s no significant
increase in temperatures. In fact, the temperatures
are going down and they knock the fire out so
float water as fast as possible on the fire and mitigate
the hazard and things will get better, so water through
the basement window. Here’s how we’re trying to share
the data, instead of in the form of graphs, a simple graphic that
shows once we introduce water into the window for about
60 seconds the temperature in the basement in the
front went from 1,700 F. down to 300 F. near the ceiling. At the top of the stairs
near the ceiling it went from 600 degrees Fahrenheit
to 200 degrees Fahrenheit and the heat flux dropped from 14 kilowatts per
meter squared to zero. Even in the bedrooms remote, the open bedroom remote upstairs
the temperature dropped from 225 to 190, so it made conditions
throughout the structure better. And, of course, if we had more
time I could show you graphics where we put water
in the front door, water in the second story
window, move the fire all around the house and we
get very similar results. This is one of the
more recent simulations that we’ve completed
in my group at NIST. It’s available, there’s a nice
narrated version, it’s about 10 or 11 minutes long on YouTube, just go to the NIST YouTube
channel and you can find it on the fire play list. So it happened June 2nd,
2011, and this incident kind of brings a lot of
things together, it brings the equipment, the
failures of the equipment, the failures of the radios, this
occurred to these firefighters. It appears that their
bottles may have heated and they may have ingested hot
air from the bottle possibly. We’re still doing
some research on that. It talks about flow
paths and it talks about appropriate fire attack. You can see this house is on a
nice hillside in San Francisco, two stories on the front,
several stories on the rear. The fire starts in a
lower level on the rear. They call these their
upside-down houses, the living room is
in the basement, the street level
has the bedrooms, and then the upstairs level has
the kitchen and dining room. The fire starts near
the sectional sofa in the living room. The victims are on the
street level, they’re there with their hose line
to protect the stair. Their hose was there,
it was charged, they never seemed to flow it. Between the time that someone,
an officer talked to them and conditions were
fine, they weren’t hot, just a little bit smoky. And left, as soon as that
officer left the house he noticed the conditions
dramatically changed, and the reason they
dramatically changed was because the windows
failed on the bedroom on the living room
level, the lower level, and that level flashed over. The windows were only
held in with vinyl frames, no steel supports or wood frame
supports, so once they started to fail the entire wall of windows failed
within two minutes. So, again, our model
shows things like how much energy can
we get out of this fire. And what you see here from the
heat release rate, we should – and we had a potential of
about 20 megawatts of energy with all the furniture
and the carpeting and everything downstairs. However, notice by the
red dotted line that due to the oxygen limitation we were
only getting about six megawatts out of that fuel package
until the windows failed. Once the windows failed
you notice that we shoot up to more than 30 megawatts. Wait a minute, we only
started off with the potential of 20 megawatts, where did
this other fuel come from? It came from the
accumulated fire gases that were held in the structure. Again, that’s the hazard the
firefighters need to mitigate. So here’s a view of the model. As you can see, it’s
advanced quite a bit since we first modeled
Cherry Road years ago. We started to see the smoke
from the front of the house. Here we’ll get some definition,
so remember the fire is on the basement floor
and the firefighters that died are on
the first floor. As the fire intensifies and the
windows fail they then continue very quickly to fail across
the back of the structure. This doorway here on the
side of the structure at the fire level is where they
ultimately successfully attack the fire. So, again, part of the tactics
and part of the consideration is if you size up this
house and you determine that the fire would be beneath
you don’t put your firefighters in the chimney, don’t
put them above the fire. Make your initial attack on
the same level as the fire is. And, again, we talk about
heat transfer rates, and it’s a function of
not only just the energy, but also the velocity. So the firefighters
are at the bottom of the stairs there
at the street level. It’s currently blue, which means
it’s got about zero velocity, but after the windows
fail we see we clearly get about 10 miles an hour of
movement and that’s even with the flames venting out
the rear of that structure. And then we also look at the
increase in temperature which, again, is another
part of the hazard. So before the windows failed
they’re 200 degrees F. or below, and then after the
windows failed we can see that now they’re between 800
degrees and 1,200 degrees in the area where
they were located. Again, well above what any
of their gear can take. We don’t only work with
large cities and towns, we had a great opportunity
to work with the State Fire Marshal’s
Office down in South Carolina and a number of the
Departments in South Carolina. The burns were actually
conducted with the Spartanburg
Fire Department. And what we tried to show with
these burns is different ways, different alternate means
of attacking a fire. So in this case this is somewhat of a traditional
means of attack. The firefighter just
opened the front door, and in the lower right-hand
corner there’s a thermal imaging view, where we’re looking
from the rear of the house, down the central hall, out
through the front door. The kitchen is just off to the left-hand side
of that hallway view. In the lower left-hand corner
we just popped open the kitchen door. We allowed bout 30
seconds for it to simulate the firefighters
making their way to the kitchen, forcing the door, and then
we have a monitor nozzle, a water nozzle in
there that’s going to flow 150 gallons
per minute of water to simulate an interior
attack on that fire. And we flow water for a
few seconds and we start to see it has a pretty
good impact, but notice there was a
surge of heat that came into the house once
that door was open, it would have been flowing
over the firefighters’ heads and causing damage to the
interior of the house. Interestingly enough,
most of the construction in single family homes has
no fire rating whatsoever, the floors aren’t rated,
the walls aren’t rated, the ceilings aren’t rated. The only exception to that in
most parts of the country is if you have an attached garage
that wall has to be fire rated and that door has
to be fire rated. So in this particular case using
this tactic the firefighters are going in the structure and basically disabling
a fire protection device to fight the fire. Let’s look at it from another
perspective, let’s look at it to say what if they hit
it from the outside first? So the views you’re looking at
on the bottom are a video view, looking at the inside
of the kitchen door and a thermal imaging view
looking inside the kitchen door. We’re not going to open
the front door this time. The first move the
firefighters make is to take the charged hose line
and as soon as possible open it up and flow water in that
garage and knock the fire down. So the officer who
is doing the size up, that’s what the officer
is doing, taking that 360 degree
lap of the house, he doesn’t see any victims
hanging out windows or anything, and he’s telling his
firefighters let’s flow water on that fire. Use the reach of your stream. Notice as soon as the stream
gets into the upper layer, where most of the
hot gasses are, the fire goes out immediately. Now they can move in closer and
continue to knock down the fire. Notice the condition
of the kitchen, the fire door is holding, the
kitchen is in very good shape. To be fair, the Fire Service
has reason to be concerned about exterior attack. They say, Dan, we’ve
seen fire being pushed. I’ve had fire being pushed on me
because part of it is you need to use the appropriate tools
and the appropriate tactics. So what we have in this
building are two rooms that are on fire upstairs. If you look at the lower level
views, video on the left and IR on the right, we’re looking
at the small hallway that’s about four feet, that
connects those two rooms. The hallway has combustible
finish inside, which is why it’s
burning, and in the room that we just attacked
with a straight stream, 150 gallons a minute,
we’re maximizing the amount of water that’s getting
in the room, we’re minimizing the amount
of extra air being entrained in the room and, most
importantly, we’re leaving that vent open so smoke and
heat can come out of it. And, as a result, you
didn’t see much change at the top of the hallways. Now we’re going to do
something bad, watch the impact. There’s your pushing fire,
pushing it down the stairs. We took a fog nozzle
and we covered the vent, so now we have a high
pressure vent instead of a low pressure vent, high
pressure flows to low pressure. We minimized the amount of
water that got in there, so the little bit of water that
got in there converted to steam, it was very inefficient,
and using a fog nozzle like that is the same as putting
a fan in front of that window. You’re entraining a
tremendous amount of air, so you’re making the fire
bigger, you’re pushing it in one direction, and
you see the result. Once even with the fog nozzle
if you step up a couple steps and get water in the window
efficiently that stops the push and shuts everything down. I’ll show you another push. So in this case we did
two different houses with the straight stream
on one side of the street and then I’ll show you the fog because obviously the
fog is more interesting. The straight stream
just puts the fire out. So what we have here are two
rooms that are connected inside by a hallway, and the fire
room has the bigger window and unfortunately for us part
of the window pane slid down and is blocking the air
coming into the room so that really slowed the fire down because it doesn’t
have the oxygen it wants. So we’re going to call a
firefighter with a pike pole and he’s going to clear
that window for us and then the fire is going
to resume its growth rate because now it has
the oxygen it needs to increase its heat release
rate and increase its hazard. You’re going to notice
that the smoke pushing out of the target room or
the attached room that’s not on fire just yet we’re
going to start to see flames in the smoke coming out of
that little window as soon as it gets lean enough and
mixes with enough oxygen as it rolls over the eaves. So we’ll see a little bit of
flame there, it’s going to back up and give us a little
better view here in a second. There you can see some orange
in the smoke there coming out of the small window and now
we’re going to do the bad thing and hit it with a fog line,
and there’s your fireball. So, again, the techniques and
the tactics are very important. So how do we communicate
all this information to the Fire Service? Well, we try to use our
web page as much as we can, nist.gov/fire, and if you’re
taking notes online that’s the website you want to take
because these other websites that I’m going to show you where you can great firefighter
training information are all listed on that web page. Again, you’ll recognize
our partners, ISFSI, where we did the
Spartanburg burns with them, and they have three
different programs online. All these programs are
available to the public for free because they’re funded
by Assistance to Firefighters grants that
come from DHS and FEMA, and so that’s been a great
asset in developing networks to really get this information out to the 30,000
Fire Departments that are in the United States. ULfirefightersafety.com,
they’ve got seven or eight programs online. The basement fires happen to
be an ARR grant that they got from NIST and we
collaborated on that together, so that’s a very
good opportunity. International Association of
Arson Investigators runs CFI, or certifiedfireinvestigator
trainer.net, again, it has information on
fire dynamics and some of the other fire fatalities
that NIST has studied with their models
and experiments. The IFF is the Firefighters
Union, International Association of Firefighters, they have
several good programs on YouTube that reflect this information. We’ve been working
with NYU Poly, FDNY and several other Fire
Departments, including Chicago and now LA and Houston, where they’re using web based
training options or starting to. Every firefighter has got
a Smartphone and the idea of getting somebody to sit
down for an hour at a time or a half hour at a time at a computer terminal is
getting harder and harder to do, but if you can push out training
to them that they can watch for five minutes and come
back to it later or watch in between calls and what-not
that’s a good opportunity. LA County Fire Department, the Home of Hollywood has
really taken that mantle and run with it, so they’ve produced
some very high quality videos for training that
they’re willing to share with other Fire Departments
on their web page. The other interesting thing that they’ve been doing
is they’ve been pushing out this information
for about 10 months, training their entire
Department online, using a learning
management system, as well as getting
some local resources from the company officers
doing hands-on drills. Since they’ve started that training they’ve reduced
their firefighter burn injuries by half, so it is
having an impact. Epstar is run through the
International Association of Fire Chiefs, again, it’s
a portal that’s designed for Fire Chiefs, all the
research is sort of boiled down to a one-pager with
links that they can give to their training officer
or other people to spread through the Department. Modern Fire Behavior
is another website, that’s where all the
Governors Island studies live that were done jointly with UL. The other thing that
we see as a success or that we’re making the turn
is that the organizations that develop training
materials that they sell to the Fire Service, that the
Fire Service use for training for firefighter one, firefighter
two, company officer, et cetera, they’re starting to
adopt this material into their manuals
and sell them. So, again, it is
reaching the core groups that it needs to reach. And, last but not least, NIST used to be called the
National Bureau of Standards because a lot of our
focus is supposed to be on developing standards for
trade, commerce, safety, and we are seeing that the
fire dynamics are moving fairly rapidly now into a number of
standards that are designed to help firefighters train and also firefighters’
emergency equipment, designs for their
fire equipment. So, with that, I don’t know if
we’ve got any questions online or we have a few minutes or?>>Yes, we can take questions. Thanks, Dan, that was
fascinating and scary, and I want to go home and
check my smoke detector.>>Daniel Madrzykowski:
Absolutely.>>I actually have
a question for you, we had Dr. Hunter Fanning
[Assumed Spelling] come and talk about the NetZero House,
they’re working to that – has your group been working
or consulting with their group to try and make sure that what
they are doing is not more flammable than previous
inflammation tactics?>>Daniel Madrzykowski: Well,
there’s a couple of things, number one, it absolutely
is more flammable, but number two it’s a
fully sprinklered home. And so they’ve taken a number of other fire protection
precautions intact with building that, as well. So, again, these things really
need to go hand-in-hand, and I don’t want to let the
opportunity go for that question about the importance of
automatic fire sprinklers. There are two states currently that require automatic
residential fire sprinklers in every home that’s built
and that’s California and Maryland currently. Unfortunately, there
are other states and automatic fire sprinklers
are in the model codes for residential homes
and, unfortunately, there are other states that
are actually passing laws and mandating that the
localities cannot implement the model code to give
their state occupants that level of fire safety. And it’s kind of crazy
as we see these incidents across the United States, and
fire is one of those things and where most people
think that’s not going to happen to me. The number of fires
are going down. We don’t see fires,
we’re more likely to get into a car accident
certainly, but the problem is as we had a tour of
the library earlier and there was some
concern about the fact that there were sprinklers in
the library and what damage that might do to the books. I pointed out to the
head librarian, you know, you can dry stuff off,
but you can’t unburn it. And so sprinklers are a
very important feature, but at a minimum you want
to have smoke alarms. Smoke alarms are inexpensive,
don’t limit yourself, put one in every sleeping
area, have one on every floor. Again, the tragedy that
happened earlier this week in New York perhaps
but for a couple of smoke alarms it might have
been a different outcome.>>Anyone else online or in
the room with anything to ask? Here, okay?>>Two questions. The first is hopefully brief and that’s what impact
does a metal roof have on a residence and
fire behavior?>>Daniel Madrzykowski:
Well, a metal roof, as you might imagine, doesn’t
contribute to the fuel load, so that’s a pretty
positive thing. It’s not made out of tar
or other material there. It’s not made out of
wood shakes, for example. So that’s a good thing. It’s going to seal fairly well. Any heat that’s under it
it’s going to radiate back into the space, and so interestingly enough
there was just a research program conducted by
UL on attic fires. And, again, you want to
coordinate your ventilation, you don’t want to open things
up too much before you’re ready because the attic as long
as it maintains its shape and its compartmentation is
going to limit the amount of air that gets involved and limit
the amount of fire spread. So if you can get water
into that space and start to cool it off early before you
start to vent to let the smoke and the toxic gases out
you’ll be better off. So the metal roof
doesn’t have any, typically the firefighter
saws can cut through that pretty easily
and that sort of thing. The advantage it would have from a fire perspective is it
doesn’t add any additional fuel.>>Okay, and a follow-up
question, I’m sure many of us are thinking the
same thing, what do you do if there’s a fire in your house, what are the steps given
all the new research that people should take?>>Daniel Madrzykowski: You
need to get you and your family out as soon as possible. Don’t, you know, keep your
smoke alarms in good shape, when you hear the alarm
get out of the house, stay out of the house. And, in fact, as you’re leaving
the house you can do yourself a favor form a property
perspective and the firefighters a favor
by closing the door and slowing down the fire growth rate
until they get there. You want to practice
exit strategies so that your family knows
where to meet in case they have to come out different
doors or different windows. And there’s a lot
of information, free information
online from USFA on how to practice exit drills and fire
safety information like that.>>Okay, just to be a little
bit more specific what if the downstairs is on fire and
it’s not safe to go downstairs, what should you do with
the upstairs bedrooms?>>Daniel Madrzykowski: You
want to isolate yourself, if your bedroom door wasn’t
closed to start with and you see that you can’t get downstairs to
get out, close the bedroom door. If you open the bedroom
window keep in mind that you may actually draw more
smoke in, so if you’re going to open the window and get
out you need to do that. Get on the phone, let
people know where you are, and get help there
as soon as possible. The door will protect you for a
limited amount of time, minutes, but you may need to look
at getting out that window.>>Do you happen to
know how structure fires or wild land fires affect
radio wave propagation, the communications devices
that firefighters use?>>Daniel Madrzykowski:
Ah, not so much. We’re working with some folks
out of Boulder, Bill Young and some other people, and
they’re working with us where we’re testing the
radios in terms of heat. They’re looking at how
that impacts the signal and the signal strength. We know that sound is impacted
by heavy amounts of soot and smoke with regard
to like the Pass device, the warning alarm that
the firefighters have. So if they go down and they’re
motionless this Pass device would start to give
off a 95-decibel sound so that their rescuers
could help zero in on them and find them. And there’s been some
research at the University of Texas-Austin and some other
places recently that indicate that does have a pretty big
impact on the sound waves. We don’t know about the radio
waves, but soot has a lot – it’s particulate matter and so potentially could provide
some level of interference.>>Great. One more from the
people on WebEx – what are some of the ways the average
firefighter is using technology to improve operations?>>Daniel Madrzykowski: A lot of Fire Departments
the new technology if you will might be
thermal imaging cameras, and the important thing
with any technology is not to just make the deal with
the mayor and the councilmen and what-not and
get that technology in your firefighters’ hands
or your fire officers’ hands, you really need to train them
on how to use that technology. If they don’t understand
what the capabilities, as well as the limitations of that technology are you
may not gain any improvement in performance or any
improvement in safety. But thermal imagers are being
widely used, there is a lot of training going on, and
they’re extremely valuable for sizing up a house to
locate where the fire is. You really want to locate where the fire is
before you make entry, and then you can make some
decisions then instead of going in the smoke and
searching for the fire try to make some decisions of where
you want to attack the fire. And it may be from the inside,
that may be the fastest way to get water on the fire, in other cases it may be taking
a line around to the rear.>>And unless there are
any other questions I think that sums it up. Dan, thank you so much.>>Daniel Madrzykowski:
Thank you, I appreciate the opportunity.>>Great. And for those asking
online the video will probably be available in a few
days, we will post it to library.doc.gov [Assumed
Spelling], you can click on the view past events link
on our calendar on the left. Thanks, everyone.>>Daniel Madrzykowski:
Great host, thank you. [ Pause ]

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