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Pioneers of Survival
All of the safety features you take for granted, from
firefighting gear to seat belts, from airplane chutes to life
rafts, have gone through extensive design and testing, often
with real people serving as guinea pigs. Meet some of the
leaders in the field of safety research—people who, in
some cases, have not hesitated to put their own lives on the
line to improve your safety.
Fire |
Car |
Plane |
Ship
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Professor Edwin Galea
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Professor Edwin Galea, Director of the Fire Safety
Engineering Group at Greenwich University, has worked in
fire safety research for almost 15 years. His work in fire
safety engineering began after the tragic Manchester B737
fire in 1985. Since then, it has expanded to include the
modeling of evacuation, fire and smoke spread, and fire
extinguishment. Professor Galea's work in fire safety
research covers the field of aviation, buildings, rail, and
marine environments.
NOVA: Why do you think it is that people so often
underestimate fire?
Galea: I think most people aren't faced with fire in
everyday life. We no longer have open fires in our houses, we
have central heating. We no longer have fire for cooking, we
have electric cooking ranges, and so on. So most people aren't
faced with fire. The only time they would probably come across
a fire is possibly in a barbecue, or possibly when they have a
bonfire. So when a fire incident happens, they forget about
how quickly fire can spread, and they forget about how
dangerous the actual fire products—the gases and the
smoke—can be. So that certainly doesn't help in people's
response, or their sense of respect for how dangerous a fire
can be.
When a fire broke out during a football match in
England, there was little reaction from the nearby
crowd who watched as it grew.
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NOVA: What have you learned about human behavior in a
situation where there are a lot of people in a building with a
fire, and all those people need to get out?
Galea: The way that people behave in structures is
often misunderstood and misreported. If there is an evacuation
in a building, what generally hits the headlines is that
people panicked, there was a mass stampede, and so on. When
you actually go and analyze what happened in these evacuations
you often find that in fact people have not panicked. The
response that people have to a known fire is to run away from
it. And that's not a panic reaction. That's a natural
reaction. If you have a fire that's about to burn you, you run
away from it as fast as you can. It's a rational response to
threat.
What we find, though, is that in most instances people are not
actually aware that there is a life-threatening situation
developing. They might hear an alarm go off and think, "Well,
that's usually a false alarm, it could be somebody's car
alarm, it could be a burglar alarm," and they tend to ignore
it. So they don't respond immediately to the call to evacuate.
They mill around, they continue doing what they are doing
until they see some sign of a life-threatening situation or
until they start seeing other people actually fleeing. Then
they turn around and escape.
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Soon after it began, the fire in the Bradford
Football stadium transformed into an inferno that
claimed the lives of 53 people.
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NOVA: Can you give an example?
Galea: Well, in the Bradford Football Fire in England,
quite a large fire developed in the stands. People were still
sitting around watching the game, watching the fire, and not
really trying to get away from it as quickly as possible. And
within seconds that small fire developed into a flashover
event which took the entire stand. So that's a very good
example of where people have just forgotten about the impact
of fire, and how quickly fire can spread.
NOVA: What is your advice for how crowds should be
handled in a fire situation?
Galea: I think people need to be made aware of fire
events. I think we should convey information to people on the
scene, rather than just an alarm sounding. We should convey,
for example, a verbal warning—"there is a fire present,
please evacuate"—rather than just a bell going off, or a
siren going off. People will then tend to take that more
seriously, and they tend to react more quickly to those sorts
of responses than just simply hearing a bell.
In 1987, a small fire under an wooden escalator
quickly spread to the rest of the Kings Cross
Underground Station in London.
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NOVA: Can you describe why the Kings Cross Fire in the
London Underground in November 1987, was such a dreadful
fire?
Galea: It started off as quite a small fire under an
escalator and rapidly spread onto the escalator. Once it got
hold of the wooden escalator, the shape of the escalator and
the slope of the escalator caused the rising plume to be
entrained down onto the actual rising escalator. Because of
that the fire had a channel to spread the gases and the heat
and the top products right up into the ticket hall, very, very
rapidly.
On top of all of this you had trains approaching and departing
the actual Underground station itself. Now when a train
approaches a station, it's coming in in a tight tunnel, and
it's pushing in all the air in front of it. As it enters into
the actual platform area all that air is pushed up the
escalators, up the staircases. That fanning effect accelerates
the combustion process and accelerates the spread of flames on
the escalator. That effect spread the fire very, very rapidly.
One of the key things that came out of the Kings Cross fire
was how quickly the fire developed—once it actually
gripped the whole of the escalator—how quickly the whole
fire spread and how quickly it grew to a very large size and
actually spread in the ticket hall.
NOVA: Later on this fire was modeled. What was the
significance of this model?
Galea: The computer model of the Kings Cross fire was
quite pivotal in the development of fire modeling in that we
had a fire at Kings Cross that no one could understand. The
fire experts couldn't explain why the fire was so severe and
why it progressed so rapidly. When the Harwell Laboratory
modeled the Kings Cross fire the model suggested a mechanism
that explained the entire fire development and why it
developed so rapidly. Initially the results were not believed.
Then an experiment, where a model of the escalator was built
and a fire was lit, confirmed what the computer model had
predicted. So here we had for the first time a fire model
explaining the cause of a fire that had baffled the experts.
Usually it happens the other way around. You do the
experiments, you have an explanation, and then you do some
modeling.
NOVA: Could you explain how computer modeling buildings
can help save lives?
Galea: By performing a computer simulation of a
potential fire and how smoke spreads in a structure, we can
get a feel for how the structure will interact with the
generated smoke products and the actual fire itself. We can
get a feel for how rapidly the structure is going to fill with
smoke. We can get a feel for where the smoke is going to go
and how the fire is going to spread. So we can design a
structure so that—rather than causing a fire to spread
more rapidly—it could possibly contain the fire. We can
use a computer model while the structure is still on the
drawing board to hopefully design a safer building.
NOVA: Are these models hard to make?
Galea: Yes. When you run a fire field model similar to
what was used to simulate the Kings Cross fire, you are taking
the volume of the room and dividing it into thousands of
little volumes. And in each one of those little volumes you
are solving the fundamental equations of fire development.
There are only seven or eight of those equations. But they are
very complicated, very difficult equations to solve. And you
are solving them in each one of these thousands of volumes.
So, in fact, you end up with millions of equations to solve.
Those millions of equations need to be solved at each point in
time; you mark your calculation through maybe every second of
the actual fire event. So you not only have millions of
equations to solve at one point in time, you have thousands of
those millions of equations to solve. So you end up with
millions of equations that you have to solve to end up with
your fire simulation. This takes a lot of time even on a very
powerful computer. Even on a supercomputer it could take weeks
to generate a simulation of a fire in a structure, and because
of that, the technique is quite expensive.
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Computer models, such as these, are used with
increasing frequency to study fires.
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NOVA: What are the limitations on fire modeling aside
from the time and expense?
Galea: Fire field modeling is still a developing and
evolving technology, and there are limitations. Predicting the
fundamental fire spread on a solid material surface is quite
difficult and is an area of research at the moment. Predicting
the onset of flashover and also predicting back draft are
other areas that are currently under development. We have
developed our own computer models and are beginning to be able
to simulate flashover and back draft in a fundamental way, but
the models are still in the early days of development, and
they are restricted to very simple types of solid fuel, such
as cellulosic fuels and wood products.
NOVA: You did some interesting analysis on a fire in
1993 in Basingstoke, England. Tell us what you learned from
that.
Galea: The Basingstoke building was a modern structure.
It had only recently been built, and it had been designed to
be more or less fireproof on the inside. They had designed it
using passive fire prevention means, so they had good
insulation on all the walls, they had pressurized stair cases,
the whole structure was fire blocked, which meant that if a
fire started on a floor it would be contained on that floor
and it would not spread to the rest of the structure. However,
on the evening that they had the fire, the fire started on one
of the upper floors, rapidly developed, and engulfed the
entire floor. Eventually the exterior glass panels broke, and
flames emerged from the fire compartment. What the designers
had forgotten to take into account in designing the structure
was that it was possible for fire to spread to higher floors
via the exterior portion of the building. So when the fire
broke the glass, flames emerged from the side of the building
and spread fire to the higher floors.
Professor Galea demonstrates that computers not only
can predict the behavior of fires—they can model
human reactions to a fire.
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NOVA: What does this suggest in terms of the design of
tower blocks and high building? What are you suggesting?
Balconies?
Galea: Yes. You could have a balcony structure—a
fixed permanent structure that is perpendicular to the face of
the building—or you could have a deployable device so
that when a fire breaks out, you have a deployable ledge that
comes out perpendicular to the side of the building and
deflects the upward moving flame. Computer simulations suggest
that this would provide a great deal of protection to the
higher floors. As far as I know, no buildings have purposely
put in this device as a means to prevent fire spreading to
higher floors.
NOVA: In addition to developing fire simulation models,
you've also developed evacuation models. Can you explain how
you predict how people behave in your evacuation model?
Galea: In the Exodus evacuation model, we predict the
behavior of individual people. The model looks at
people-people interaction; how people interact with each
other. It looks at people-structure interaction; how people
react with the actual building itself, and people-environment;
how people respond to the fire, the smoke, the heat, and the
toxic gases. We describe people as unique individuals. They
have their own sets of attributes, how quickly they can walk,
how quickly they're likely to respond to a fire, their
knowledge of the building, which exit they're likely to use,
their drive, and how keen they are to get out of the
structure. So we have a collection of physical attributes that
describes individual people. We even have respiration
rates—different breathing rates—for people as part
of the description of each individual person. All these
parameters then interact to describe how that person is going
to respond to the particular incident that they're faced
with.
NOVA: And how do you use that information?
Galea: Well, we're using the Exodus computer model
while the building is still in the planning phase, to try and
design the structure so that it is more efficient in terms of
evacuating people. For example, where do you have the exits?
What type and how wide should the exits be? What sort of
staircases should you have? How many staircases? What sort of
procedures should you have? Should you have trained staff,
fire marshals in the structure? Where should they be? What
should they be doing? So we're using the computer model to try
and help design structures and also to look at things such as
procedures—how you can train people to manage a fire
situation more efficiently.
NOVA: Do you think it's possible to design a fireproof
building?
Galea: I don't think it's possible to design a
structure that is one hundred per cent fire proof. Any
structure has the capacity to burn. And because it's going to
burn, it's going to produce smoke, heat, toxic gases and so
on. Because of that, you need to make sure that you can get
people out of that structure as quickly and efficiently as
possible, and that's why you need evacuation models to help
design structures so that the evacuation of people is going to
be as efficient as possible.
NOVA: What advice do you have for young people who are
interested in getting involved in this field?
Galea: Fire safety science and engineering is a
fascinating subject, because it brings together many different
disciplines in the pursuit of a safer environment. A good fire
safety scientist/engineer, for example, needs to have an
understanding of math, chemistry, physics, physiology,
psychology, computer science, engineering, economics,
architecture, and many more subjects. This is one of the
reasons it is such an interesting subject: You rarely get
bored doing the same thing over and over again, and there is
always something new to learn.
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| Updated November 2000
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