Simulator gives firefighters a glimpse into an inferno

Buoyed by an influx of oxygen, smoke flows along the top of the simulator to the heat source, creating a flashover


By Christopher Heimerman
The Daily Gazette

DIXON, Ill.  Centimeters in front of our masks, our hands were invisible. Enveloped in viscous gray smoke, we were as good as blind as the heat intensified during a flashover simulation conducted Saturday morning by Lee County fire departments.

“All right guys, imagine you’re in this, can’t see your hand in front of your face, and there’s a baby in there,” Sublette Fire Lt. Nick Dinges said to our mix of City Council members, journalists and firefighters. “This is real life.”

Firefighters partake in the flashover simulator/
Firefighters partake in the flashover simulator/

Dinges, after making sure all of us tourists were OK, told his colleagues to open the back of the simulator. Buoyed by an influx of oxygen, smoke flowed along the top of the simulator to the heat source toward the front of the chamber.

Seconds later, flames slithered back in the other direction mere feet above our heads. Gripping a thermal camera tightly, I watched the temperature reading spike from 200 degrees to 1,169. It was a flashover – as terrifying as it was awesome.

In full gear, with no skin exposed, a firefighter could survive no more than 20 seconds up there, we were told. Unprotected? Unsurvivable.

We laid low to witness and feel the blistering underbelly of five such deadly flashovers, which take about 20 seconds to develop once all the elements are right. That’s with a heat source of pine pallets and the particle board that lines the trailer’s walls – materials that are downright nondescript, flammability-wise.

Most housefires won’t afford firefighters such predictability. When ablaze, plastics in building materials, carpets and other common household items put myriad chemicals into smoke  smoke that is more or less an ignition waiting to happen, as soon as there’s the right amount of fuel, heat and oxygen.

Carbon monoxide and hydrogen cyanide are among the chief chemical concerns, but “honestly, we’re not sure what all [stuff] is in there,” Dinges said.

As we debriefed, Mark Callison, deputy chief of the Dixon City Fire Department, said it used to take 15 minutes for a flashover to occur in a house fire. Today, that timeline is 2 to 3 minutes. Before we entered the simulator, Dinges said smoke is 100 times deadlier than it was 20 years ago.

That’s why simulators such as the one we were lucky enough to climb aboard are so vital to understanding smoke and fire. Dinges said there are only three such simulators in the United States, and that fewer than 50,000 of the nation’s 1.3 million firefighters have gotten to use one. When they do, they learn.

“You’ll be up in the front, and you’ll hear firefighters, guys who have been on the job a while, and who’ve been in a bunch of housefires, commenting on the stuff they see in there,” said Tim Shipman, chief of the Dixon City Fire Department.

With so many known and unknown new factors to combat, studies are constantly being conducted on finding the best firefighting practices.

Previously, among firefighters’ first objectives when they addressed a scene was to open doors and break windows, but opening windows can give a heat source exactly what it’s hungry for: oxygen.

“If you can’t see your hand in front of your face and somebody breaks a window or opens a door, you can be in trouble, and it can come and get you,” Dinges said.

It used to be taboo to put water on anything that wasn’t yet on fire. Dinges said despite the jaw-dropping potency of the smoke within the simulator, the situation could be controlled with just a gallon of water. Although every time he used some droplets to open up a fog pattern and disrupt that daunting thermal layer above our head, it got far more sweltering along the floor.

No matter what best practices are determined, science is only as sound as the communication used to apply it.

“That’s the most important part,” Dinges said. “We always come back to communication and being coordinated.”

Firefighters are working hard to sharpen smoke recognition not only inside buildings, but also before they even enter it. If smoke is brown or green, one can only wonder what volatile chemicals are in it. If it’s moving fast, that means a lot of pressure caused by heat, which can mean a flashover or backdraft could be imminent.

We spent 20 minutes in the simulator. We emerged gassed under our 30 pounds of gear, super-saturated, and appreciative.

“Imagine you had to go back in a second and third time,” Dinges said.

Copyright 2016 the Daily Gazette

McClatchy-Tribune News Service

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