www.thebackdraftmagazine.com | A Volunteer Fire Service Publication | Volume 5 | Issue 1 | Backdraft Magazine 9
what our new recruits envision doing--and that is what the
public expects us to do.
The only thing in our way of meeting those lofty rescues is
reality. And fire behavior. And "Survivability Profiling."
Survivability profiling is the art of knowing when a victim
exists and when a body recovery is in order. Too many times
we are rushing into a no-win situation when there is no one
to save. A lot is being written on this topic and makes for a
great follow up article.
The skill and practicality of survivability profiling is rooted
in fire behavior--especially the areas not covered fully in a
typical fire behavior class.
The modern books that academies use to teach fire behavior
are very good at explaining the chemistry of fire behavior.
They also teach how to search and perform rescues in
blinding smoke conditions. Unfortunately, they do not go
quite far enough in teaching the inherent dangers of fire and
its lethal components.
The closest a fire behavior class comes is when they describe
the makeup of smoke and fire rollover--the precursor to
flashover. What they do not do is bring several pieces of the
fire behavior puzzle together for a look at the bigger picture.
One of the largest components to smoke is carbon monoxide.
Carbon monoxide is a highly dangerous gas--we know that it
is a deadly by-product of combustion. What most firefighters
overlook is that is it also highly flammable. It has a flammable
range of 62.5 (12.5% LEL to 75% UEL). Natural gas--the
gas that firefighters fear upon arrival, has a flammable range
of 10.2 (with an LEL of 4.8). With CO having such a high
flammability range, this makes CO part of the fuel load--a
part of the fuel load that very often gets over looked.
The NFPA 704 diamond rates CO's flammability more critical
than its health hazards (4 vs. 3).
Carbon monoxide also has an ignition temperature of around
1100 degrees. When CO starts to ignite, we generally call that
rollover--that eerie precursor to flashover. That 1100 degree
marks another significant number--at 12.5% lower explosive
limit--the parts per million of CO is reaching 125,000!
When rollover starts to occur, that means the entire
compartment is ready to flashover. The much-viewed NIST
video testing a common living room flashover shows this
quite well. For almost 3 minutes, the fire grows unchecked
with smoke slowly banking down. Over the last 30 seconds
of the video, rollover is noted and the smoke rapidly drops to
the floor. Too rapid for firefighters to be able to safely escape.
Survival in this environment is nil. The human body starts to
be altered anywhere from 107° to 124° with burning of the
skin and cooking of the internal organs.
Even before the heat takes its toll, carbon monoxide has
probably already done so. As rollover beings, the parts
per million for carbon monoxide approaches 120,000--
well beyond the 1,200ppm that can take a life in just a few
minutes. The survivability profile shows us that no one can
survive this event.
This leads to the simple question: What are we attempting to
save? Many times fire departments arrive on scene only with
the ominous dispatch in their heads indicating, "There may
be someone inside."
When firefighters hear that, they pull on their superhero
capes (bunker gear, breathing supply) and charge into an
environment that likely has taken any lives in the immediate
vicinity. Moreover, they will do this without properly ventilating.
Without proper ventilation and technique, firefighters are
being exposed to temperatures nearing flashover and CO
that no one can survive.
The 2003 Station Nightclub Fire in Rhode Island claimed
100 lives. According to the testimony of the Chief Medical
Examiner, Elizabeth Laposata MD, 86 of those that died
did so of "inhalation of products of combustion and a super-
heated oxygen-deficient atmosphere." This occured within
4-5 minutes of the initial fire. Video of that night shows an
engine company arriving within 5 minutes--already too late
to save anyone on the inside.