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Since We're Talking Ventilation....
Since posting the video on PPV, I have been sent links to many other videos on PPV, ventilation and flashover. Some were good and some not so good. This one I thought was a good video to sit down and take a look at with your crew.
There are some things that can be learned from this video. We weren’t there from the onset, but valuable information can be taken away from this video.
If you have links for videos or your own that you think would be beneficial, pass them on to us and we will take a look and post them if appropriate.
Take care, stay safe and stay low.
http://firefightersenemy.com
Replies to This Discussion
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Permalink Reply by Jack/dt on
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1) building does not look like it's been prepped to meet NFPA 1403
2) there is an attack crew on the outside flowing water as the interior crew enters
3) doesn't appear to be any ventilation
4) not surprised that it flashed over
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Permalink Reply by Leland Lavender on
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That isn't a flashover. In the art of reading smoke you will see when the changes take place, you get the white then it gets darker... turns into a black super heated cloud....Then brown for unfinished wood (Structure members/frame)
Remember Black fire(smoke....) is a dramatic change you should be aware of because its fuel and its superheated, then sequentially starts to hit the ladder fuels (similiar to wildland....)with smoke being fuel im talking phosgene hydrogen cyanide, carbon di/mon oxide kicking that temperature higher with each one that hits. Wood starts to char at 500 and that's also when you hit your first ladder fuel which then kicks the temp another hundred(s) degrees thus starting flashover. P.P.V should have been out of the question by that time they went in. when you start p.p.a. you vent first pressuring the box then poking a hole in it(either before the fan or after )to get that smoke lift,since air and fire are alike, they'll want to follow the path with less pressure or least resistance, follow that smoke then you attack the fire.
From the looks of this, it turned into black Fire being super heated then the blower introduced a lot of oxygen to the Triangle completing the tetrahedron turning black fire into a smoke explosion... Remember if this were a true flashover NONE of those firefighters would've been able to make it out... let alone stand up and run like one of them did.
Coordinate!!
Here's a link for a P.P.A thread that I posted. have at it
http://www.firefighternation.com/group/enginecompanyfirefighters/fo...
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Permalink Reply by Brian Mackie on
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Ok, I tried to comment, but became so PO'd.. i messed the post up. lol So, I will just say, I am going to be watching this thread very closely. Way too much conflicting info here. Being taught for over 15 years and seeing first hand the do's and don'ts, and reading other 10 and 20 year experienced vets concurring with what I have been taught and experienced, all to be told its wrong.. gets the hair on the back of my neck standing! For the record, I do in fact know of firefighters who have survived a flashover albeit very badly burned. As for running away, well shock does some pretty wonderful things to a human body. ( or so I have been told)....
ok.. watching like crazy to see the information start flowing! I am sure it will!
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How so? I'm not meaning to offend if thats the case.
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Permalink Reply by FETC on
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The following opinions expressed here are my own.
What I have seen is the use of a PPV fan in an effort to lessen the "thermal insult conditions" on the interior attack crew in a tactic known as PPA. Now, what I have been told about this video was it is not the first training fire in this dwelling. Knowing what I learned about live fire training through experience, the conditions are never the same when we use a dwelling for multiple evolutions. The pre-heated conditions from previous evolutions can dramatically change the fires predictibility. These conditions sometimes change the result of a desired evolution.
First off, what you see is the fan being introduced for the first time. Leads me to think they were trying PPA for the first time in this evolution. Secondly, the fan started improperly... Never start a fan pointed into the building. Thirdly the conditions of the building's smoke profile were an underventilated fire in it's natural state (before the fan). By adding PPV or PPA tactics without expandng the dwelling's ventilation exhaust openings, you are in essence charging the building with fresh air and trapping it.
I agree with Leland, that the building was O2 deficient, (even before the fan was started) the conditions for which we see are underventilated, rich in by-product (color of smoke) and yes that smoke is fuel in motion. By adding the increased CFM of fresh air, the firefighter operating the fan, single handedly changed the conditions of the evolution. The smoke profile was rapidly leaned out. This continued until the interior smoke that was trapped, were lowered below their UEL and the smoke exploded in a classic smoke explosion. Ignition source was the training fire.
What you witnessed in my opinion is not a true natural occuring flashover. The interior conditions did rapidly change, the smoke itself flashed and what was burning was the smoke and contents contained within the smokes profile. (Watch the video again) the floor never flashed over, therefore the thermal insult conditions of the entire box never reached their maxximum off gassing temperatures needed for an entire room, natural flashover.
Two reasons to support my point would be the conditions changed again to a more survivable profile when the fan was removed from the equation. Secondly, the interior handline and latter additional lines were able to rapidly knock down the rapid fire increase further supporting the interior conditions (BTU's) never exceeded the temperatures needed to achieve a natural flashover. What occurred was they put the evolution back into the underventilated fire, super rich, above the UEL of the smoke. Which doesn't occurr in a natural flashover.
What did we learn from this? Especially from a PPV or PPA tactic, whenever we choose to pressurize the box, we need to assure the exhaust opening whether horizontal or vertical are sufficient to rapidly expell the CFM, smoke, and not trap it. You see the classic sign of and underventilated box is when the smoke trapped inside the box is forced out of the FANS ENTRY POINT. (watch the video one more time please) the operator has just a few seconds to identify, "Whats up with the smoke blowing back?" and decide to turn the fan off before potentially seriously injuring or killing his or her fellow brothers.
Not to bash the department, because we all make decisions and change tactics dependant upon learning something, but this video is from 2004 and PPA is still a tactic that some in 2010 will say, you do what with a fan? Obviously, everybody was well equipped (PPE) and dressed out, and learned first hand what a rapid fire insult is, and how to evacuate to survive. From that standpoint alone, Kudos.
I am not a adovcator nor bashing the PPA and PPV tactics, just want to say that if used at the right place, right time, it can be very beneficial. There are many factors that need to be considered before I say to my guys, let's use the fan for a Positive Pressure Attack.
FETC
www.fetcservices.com
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Was thinking the same thing
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