THE FLASHOVER “PHEHOMENON”
Flashover has been around since people began filling up semitight rooms with combustibles, but it was not until the mid-sixties to early seventies that we began to identify it as such. There’s a lot we still don’t know about it; in fact, there isn’t a concensus, standard definition of this deadly fire occurrence. Some express it in terms of thermal radiation feedback; others see it as a pivotal point in a fire’s growth; still others have attempted to describe it in terms of temperature over time or as a function of burning rate, room geometry, and ventilation. But the simplest, most practical, and most widely accepted way of describing flashover is that it’s what happens when the room gets so hot that all contents ignite simultaneously in a blast of intense fire and heat -full room involvement.
Of course, it doesn’t matter how you try to describe it. Flashover has killed too many civilians and firefighters.
And it’s getting worse. Contents and room construction of the modern home – large, highly synthetic fire loads, heavy insulation, double-pane windows-are combining to produce fires that burn hotter and faster. Time to flashover is getting shorter-just a few minutes after the incipient stage. Too often it traps firefighters who’ve just arrived on the scene.
The fire service is doing what it has to do: You’re educating yourselves on the problem and modifying your strategies and tactics and training accordingly. Funny, though, how it all falls on your shoulders and no one else’s. You’re the ones who have to face the beast. But you accept the grim reality and resolve to work harder.
Well, you’re tackling the problem but you’ve only got ahold of one leg. You’re entering flashover-prone environments better protected than ever before, but you’re changing your armor and not the beast. The beast is still on its feet, carrying you along with it. You’ll never bring it down completely-unless people want to live in well-ventilated concrete houses with steel and concrete furniture -but you can sure change it so that you don’t have to tackle it so often.
Stop using the word “phenomenon” next to flashover. It makes me uncomfortable. Throw away the dictionary: Despite linguistic appropriateness the word conveys a dangerous feeling that the flashover problem is beyond our control, as if it’s an indisputable fact of nature that can be studied but not overcome. Fire is a phenomenon. Heat is a phenomenon. Gravity and inertia and centrifugal force are phenomena. Flashover is what happens when people build boxes out of wood or brick or whatever and cram them full of furniture and furnishings that burn hot and fast when exposed to the heat of fire. And there’s nothing phenomenal about that.
You don’t think people will modify their buying habits for the threat of flashover? I’m not so sure. Before I came to this magazine I had never heard of flashover. It scares the hell out of me now. Fifteen hundred degrees Fahrenheit is a frightening number. I’m conscious of the things in my home that contribute to the problem. I’m not about to start pitching things out the window, but I’m not about to jam my rooms full of unnecessary, high-heat-producing combustibles either.
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Educate the public. Show them the excellent videotapes available on flashover. Explain what it is in common-sense language. Let them know what you’re both up against. Make sure they know that there are fireretardant and flame-resistant home products on the market that could significantly lessen a room’s potential to flash over. Encourage them to buy products that have the best fire-retardant ratings. Money talks: The manufacturers will get the message and the race for better flame-retardant ratings will be on.
Fire-retardant chemicals aren’t a cure-all -there are some serious health and environmental issues at hand (brominated fire retardants, for instance, are suspected of releasing dioxins upon combustion)-but they could have a positive impact on the fire problem in general and the flashover problem in particular.
A news release crossed my desk the other day, announcing an international conference on “environmentally friendly flame-retardant systems.” Its object, said the release, was to bring together a slew of different groups – from regulatory experts to chemical manufacturers to end users. There was no mention of the fire service. I called up the conference sponsor and asked the representative who had written the release the reason for the omission. He said, “I guess I just forgot.”
That’s just wrong, inexcusable. And it’s our own fault. You’ve got to tell these people just how important you are to the equation. You’ve got to voice your concerns about what goes on in that fire compartment and what’s causing it. Yes, wear your best suit of armor and be wary of the beast. But use whatever means available to make sure the beast doesn’t arrive before you have time to put the fire out.