Flashover! : Deadly Phenomenon Bursts to Life Before Eyes of Firefighters in Special Training Chamber

As searing heat started to penetrate their thick protective suits, a dozen firefighters kneeling in the long, narrow training room peered through layers of smoke, searching for the telltale signs that could one day save their lives.

Within minutes, the front of the room took on a hazy orange cast and reached temperatures exceeding 1,200 degrees. In a training chamber designed to mimic conditions in a real blaze, the firefighters from Westminster and Fountain Valley hunkered down and watched for the moment when the air itself would catch fire.

Unlike their fictitious counterparts in the movie “Backdraft,” these firefighters were watching out for a substantially more dangerous phenomenon called “flashover.” Unlike a backdraft--when oxygen-starved fires suddenly reignite after receiving a new source of air--a flashover occurs with much greater frequency when airborne gases trapped in a burning building become so hot that they ignite, simultaneously triggering surrounding materials to burst into flame.

On Monday evening, the team of firefighters went to a special training facility at a Gothard Street fire station to learn how to recognize and avert flashovers with a new technique brought over from Sweden last year.

There are only four such training grounds in the West, with the others in Anaheim, Ontario and Oceanside. Westminster Fire Capt. Craig Campbell said the training rooms are becoming increasingly important because newer buildings often contain synthetic materials that create twice as much heat and combustible gas in fires as other materials and are more likely to cause flashovers.

A flashover is a sight as awe-inspiring as it is deadly, and can happen so quickly that even the most experienced firefighters are taken by surprise. Exact figures have not been compiled, but Campbell said that about 10 firefighters nationwide are killed each year in flashovers. Two died last month in an Indianapolis hotel blaze.

Although most firefighters have textbook knowledge of the phenomenon, many have never seen a flashover up close. The training room, Campbell said, gives firefighters that experience under the watchful eyes of instructors.

“You can sit in classes all day long, but once you get in there and the flames are jumping out at you, this is where the training takes place. Here, under a controlled environment, we can get as close as possible to a real fire. This is state of the art. There’s nothing better than this,” he said.

Developed in Sweden about six years ago, the battleship-gray metal rooms, which cost about $40,000 each, are about the size and shape of a recreational vehicle. Using them to re-create flashovers is a recent development for the facilities. Inside, veteran firefighters learn new techniques for fighting a blaze, in some cases counter to the training they received at the start of their careers.

For example, rather than blast a hallway with a torrent of water, instructors teach the firefighters to spray the air with a heavy mist of water, cooling it and averting a flashover. A direct blast, the instructors note, can create a blinding cloud of superheated steam that can cause serious burns.

“I’ve been in buildings that have flashed over and when it happens, the chances of being burned severely are great,” said Westminster Fire Capt. Gary Carneghi, 43, before his first trip into the chamber. “To be in a controlled environment is phenomenal. We’re actually able to see the fire develop. This should help us in recognizing when flashover is about to happen.”

After a brief review of what to expect in the training room, the nine veteran and rookie firefighters donned thick yellow pants, jackets and black boots, strapped on a mask and tank that fed them compressed air and stepped into the chamber.

There, instructor Bill Crow lit paneling made of wood and particle board at the front of the room and instructed everyone to kneel and wait. Within minutes, smoke blocked out everything but a dull orange glow and the yellow pillars of flame that climbed the walls. As the air grew smokier, the men switched on their air supplies, which hissed with each breath.

Helmeted silhouettes closest to the fire pointed to the air as the first signs of flashover appeared. Like flickering northern lights, streamers of flame called “roll-over” floated through the air toward the back of the room. Immediately thereafter, the layers of smoke that swirled near the ceiling burst into flame.

One by one, team members took turns at the hose, spraying a fine mist into the air, cooling it below critical temperature and extinguishing all but a bit of burning wood and particle board. As the temperature crept back up and the flames returned, the flashover would soon recur.

For Campbell, who coordinated the exercise, the blaze briefly became all too real--it melted his fireproof goggles and slightly blistered his arms. Still, he pointed out, “This was a minimal fire. When it gets hot in there, remember this is nothing compared to what happens in a real fire.”