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I worked 6 am – 6:30 pm at the FD on Friday. I got up at 3:00 am Saturday to drive Rabid and the Os two hours to Hartford to the airport, two hours back, then I worked a 22-hour shift at the FD starting at 8 am Saturday, ending up at 6 am this morning. At 9 am, I started an 8 hour shift at a new place, an ambulance service. I’m looking haggard in this picture; that’s me Saturday afternoon talking to one of the lieutenants.

While on duty Saturday, I attended training hosted by the FD and presented by the Vermont Fire Academy. The training involved recognition of impending flashover. Flashover is ‘the stage of a fire at which all surfaces and objects within a space have been heated to their ignition temperature. Flame breaks out almost at once over the surface of all objects within the space,’ according to the International Fire Service Training Association.

The morning was spent in the classroom learning about flashover. Flashover is not survivable and can come on quickly, so it is crucial that interior firefighters can recognize the signs; increasing heat and dense smoke banking down towards the floor, turbulent smoke flow, tendrils of flame (rollover) as the uncombusted gases start to ignite. At this point the firefighter has moments to react and must immediately aggressively cool the unburnt gases, walls, and ceiling while quickly retreating.

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The centerpiece of the training is a trailer used to demonstrate flashover. A wood fire is set in one raised end of a metal shipping container while firefighters in protective gear watch from a lower level. The firefighters are able to see the smoke production and feel the heat increase. After a while, the burning ‘room’, walls and ceiling lined with plywood, flashes. Using aggressive cooling with a hoseline and venting, the instructors stop the flash and allow it to build again. During the twenty-or-so minutes in the container, the students see ten or fifteen flashovers.

As flashover approaches, the gases start to ignite and snakes of fire flow out into the observation area, at arm’s length over the heads of the students. The effect is like a bright aurora borealis and is quite beautiful. The rollover is incredible to see in this captive setting; a harbinger of death in any other.

After twenty minutes, the students are happy to go outside; the temperature on the floor of the observation area has been approaching 200 degrees F while the ceiling around 600 degrees F. No pictures from inside, of course.

More pictures of the flashover trailer (shot by Mrs. Turquoise with Lt. McClown’s camera) are here.

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