Truck company firefighters hang a smoke blocker and while a hose crew prepares to assess conditions with hoseline and thermal imagine camera.
(Photo credit: Jeff Harkey/Project Kill the Flashover)
If we look at the increasing discourse in the U.S. fire service regarding fire science and dynamics, more and more departments should consider changing their tactics based on the practical application of concepts, such as flow path management (controlling the air) and the use of "transitional" attacks. This may mean holding off on opening up the building in the traditional world of the truckie. Having served a number of years on a truck company, I know this article is going to sound crazy to many of you, but I ask that you be open minded.
Letís review some of the basic tasks of the truck company:
Traditional vs. Today
However, some of these activities, when done the traditional way, can adversely affect the growth of the fire. Something as simple as forcing the front door and leaving it open while the engine company readies the attack line and masks up can introduce air into an under-ventilated fire and bring fire over the heads of the crew. This can create the conditions for rapid-fire growth and make extinguishment more difficult. The old "vent for life" tactic of clearing out every window possible does indeed give air for life Ė air for the life of the fire. And if you did not know the location of the fire before then, you soon will. It will be everywhere! Some folks continue to insist that the "lift" achieved is worth this risk. In a building fully charged with hot smoke (example: fuel), the lift is brief at best. The inferno that follows as air mixes with the fuel and brings it into the flammable range creates an environment that is untenable for firefighters and victims alike. The end result of providing new air too often becomes a firefighter-induced flashover.
Lightweight building construction, along with high heat release rate furnishings, present a two-fold problem to roof ventilation. One is determining whether the roof will support the crew. The other is the speed of fire growth with modern fuel packages. By the time a crew can get to a roof to vent and complete the task, the time may have passed for this being an effective tactic. If it has, the crew could remove the entire roof and not provide enough area to effectively ventilate the fire.
A ventilation-limited fire that has gone into decay from a modern fuel package has an enormous amount of potential energy in the form of hot, rich smoke. When that hot smoke (or fuel) is liberated through ventilation openings, it leans out as it leaves the structure and can ignite. Flames can then move back into the structure with great speed and overwhelm a crew with a handline.
Changes in Truck Work
So, what is a truckie to do? The truck company must change its paradigm and operate in a way that can reduce the risk to the crews on the fireground and account for modern fire behavior concepts. In other words, letís think about working smarter and not harder while achieving good results. Just because we have always done something one way does not mean that is the best or safest way.
There are tactics and some new tools that in the hands of a fire behavior savvy truck company can make fire attack and searching potentially less risky endeavors.
If we have a ventilation-limited fire, it is generally safer to leave it in that condition by not introducing a new source of air. A truck company can install a portable smoke blocker at the point of entry prior to forcing the door. The portable smoke blocker allows easy access for crews and a hoseline without introducing a new flow path of fresh air. If a portable smoke blocker is not available, the truck crew or an engine crew member can reduce the air intake aperture by holding the door closed onto the hoseline (and feeding the line) through the narrow opening. Or, they can cut a corner off the bottom of the door to allow hose movement with a closed door.
The use of the thermal imaging camera (TIC) is the next change in tactics. Since we are not going to open up a ventilation-limited building, it stands to reason that the visibility inside will not be good. The truck crew can begin their search using the TIC. Letís throw another bit of heresy into the mix and note that the search crew should have a hoseline for protection with them (Gasp!). They should use the line to cool the area as they search, if necessary. If the TIC registers more than 400ļF at the ceiling, they should use a fog pattern to cool it before advancing. Yes, I am advocating putting water on smoke. Why? Because smoke is fuel. They need to cool the fuel, as this reduces the chance of fire getting behind them over their heads as well as reducing the thermal insult on their protective gear. We could also condition the walls and ceiling with a water additive to slow down or eliminate the off gassing of new fuel.
What about Vent, Enter, Isolate and Search (VEIS)? The issue I have with this tactic is the risk that exists if the firefighter canít access the interior door to isolate the room. Once the entry window is cleared, you canít put it back to limit the air. So, letís take the ventilation piece out and install a portable door over the window to limit the air intake. Oh, and letís take a hoseline in with us in case our isolation plan doesnít work out. Of course, a TIC is along for the ride as well, if available. VEIS in its present form is still a viable tactic in those departments where there is a lot of staffing arriving in a short time span and other important tasks are getting accomplished at the same time. This would include getting water on the fire.
It is time for the fire service to reconsider its tactics and match them to modern fire behavior knowledge. I have only scratched the surface of the changes that need to be considered. To borrow an adage from the medical side of our profession, our actions should not make the situation worse. Too often, our actions allow an under-ventilated fire a breath of fresh air and the situation becomes far more dangerous (i.e. firefighter-induced flashover).
Letís think about employing truck companies to prevent that from happening and encouraging the engine company to use extinguishing techniques that protect the firefighters. (That is another subject altogether.) As my friend Joe Starnes says, ďIf we are not putting the fire into decay, we are not making the situation better.Ē
And remember, when Thomas Kuhn introduced the theory of paradigms, he noted that change canít happen until the old practitioners are gone. In other words, shift happens, but only when new knowledge becomes praxis.
WARREN WHITLEY retired from the Prince William County, VA, Department of Fire & Rescue after 32 years of service. He spent four years as a lieutenant on a truck company and wishes he knew then what he knows now. He has been exploring fire behavior questions since the early 2000s and is involved in the Kill the Flashover project.