Flashover

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YOUR CITY -- You?re pushing a hoseline down a hallway or working your way around a room doing a quick search when suddenly the entire area bursts into flames. The temperature has suddenly risen to over 1800 degrees F. Your turnout gear begins to smoke and then catches fire. Your facepiece begins to glaze over and your faceshield or bourke eyeshields start to become a molten sheen. Any exposed skin immediately starts to burn. You frantically try to get away but the fire appears to be everywhere. If you?re not too deep into the room or if you can back out quickly then maybe, just maybe, you?ll survive but you will be burned.

What has happened to you is called flashover. This phenomenon occurs when ALL of the combustible materials within the confines of a room or area have reached their ignition temperatures and total combustion occurs. The temperatures within the space will suddenly escalate from a few hundred degrees to as much as 2000 degrees F. Unlike a backdraft, this event occurs at a point between the growth stage and the fully involved stage. Despite there is no pressure wave associated with this occurrence.

There are clues associated with the development of this situation. They are an advanced stage of burning upon arrival, sudden buildup of heat, and roll over. How well you recognize these clues and how well you determine why you should be in this environment will dictate whether you return safely from the job or become a statistic.

We all need to become more adept at performing size-up. I?m not talking about the 13 point system so often used for exam purposes. I?m talking about what are you seeing upon arrival and what do you know about the building before you received the alarm. How well do you read smoke? Do you know the difference between trapped smoke or smoke which is pushed by high heat?

Can you differentiate between smoke involved with plastics or furnishings, versus materials that involve structural members? Do you know how weather, temperature, and humidity affect the movement and action/texture of the smoke? As you look at flames do you recognize when a fire has plenty of oxygen already or is starving but still plenty hot? If you can?t answer yes to all of the above, get some more training before you respond again.

In more than two hundred years of organized fire protection in this country, only the gear and equipment have changed. We still send our crews down the hall to extinguish the fire. In my thirty years of fire service, the evolution of Personal Protective Equipment, (PPE) has reached high technological levels, perhaps too high. We?ve encapsulated our members to the point that we are actually robbing them of many of their natural senses.

When I began my service career, we wore Cairns metal helmets, the Senator or the Clifton I believe, and these helmets only had earflaps and a chinstrap. We wore ? length boots and the coats were often short. The biggest advantage was when you were laying on your stomach (we wore MSA filter masks or Chemox if it was a basement) and your ears would began to burn when it was time to get out or back up. Now we wear Nomex hoods, full PPE including turn out bunker pants, SCBA and gloves. If you wear Nomex, it fails at approximately 1200 degrees F and if you wear PBI then it fails at 1600 degrees F. But your skin fails at 124 degrees F. So we?ve taken away the first line of defense, the body?s ability to tell you it?s time to regroup or leave the area. We pride ourselves at being aggressive. Getting the wet stuff on the red stuff as soon as possible is the way to prevent the fire from growing has long been the mantra for the fire service. This theory is no longer valid in my opinion.

The modern building construction materials and techniques might have you ambushed before you get into the building. The use of plastics and the use of truss construction lead to quicker failures and fires become more intense in less time. We don?t know when the fire started; we only know when we were called. I?m not promulgating the concept of not going into a structure, I only do that when it involves vacant buildings. I am endorsing the process of slowing down and evaluating the issue before you enter the IDLH where you will see little or nothing at all.

As you advance the line it never hurts to open the nozzle and give a few short bursts of water towards the ceiling as you go down the hall or enter a room. This simple act can very well interrupt the fire growth cycle and prevent a flashover. Another tip for officers is to remove one glove and as you move along on your knees, raise your hand above your head. If you are forced to bring it back down to your side rapidly because of the heat, it might be a good idea to evaluate where you and your crew are. Deciding whether or not your crew really needs to be there. Remember that the fire never calls a timeout just because you?re not ready or unprepared for the fight. Protect yourself at all times and stay safe.

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