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Vertical Ventilation Video - What do your eyes tell you?

The following video clip was sent to me by a reader who was responding to my last post regarding vertical ventilation:
https://youtu.be/iK-ZpPWJIj4
In it, you will see two firefighters vigorously cutting a roof as fire burns below. The provider of this link pointed out the immediate improvement in interior conditions as evidenced by the lift in the smoke layer that occurred as the fire vented. Taking a contrary position, I would point out that the smoke was turning white prior to the creation of the overhead exhaust path, likely due to the application of water by the interior hose team.

Still, instead of engaging in a debate about the actual cause(s) of the changes seen, or whether this example refutes or supports my position that nothing good comes from cutting rooftops, I would suggest that one of the real values of this clip is to demonstrate the importance of performing fire suppression research in a controlled, “laboratory” setting. Despite the limitations of such artificial environments, there is no other way to control variables, time interventions, and monitor conditions, thereby allowing for the accurate determination of the causes and effects of our fireground actions. Otherwise, we’re left arguing about what we’re actually seeing, and likely forever unable to come to a definitive conclusion.

Apart from the debatable effects of the competing actions of applying water and increasing air flow, there are two other observations regarding this video I would like to share: First, the two firefighters demonstrate exceptional skill and ability in cutting the roof. They were in full PPE and on air; had all the tools needed (chainsaw, axe, and pike pole); chose the proper location (near the peak); and exited the roof immediately after completing their task. As much as I believe roof ventilation to be anachronistic, it’s great to watch someone do their job so well (and, if the Smithsonian ever creates a museum of firefighting methods, I would recommend this for the video archives).

The other thing illustrated here is how immensely difficult it is to coordinate ventilation above with water application below. While the roof was opened just after the start of water application, the sequence recommended by even those who are “pro” tactical ventilation, there was no apparent attempt at “timing” these two interventions, nor, given the smokey, noisy, and rather frenetic setting, likely any ability to do so. Also, even these obviously talented firefighters would have been delayed significantly, and missed their Goldilocks moment (i.e., not too soon, not too late, but at just the right time) if they had been unable to stand on the roof and instead needed to work off of a ladder. Watching this expert performance shoots a big h*** in the frequent argument that roof ventilation failures are usually the result of poor technique. I would, again, argue that it’s a complex, dangerous, wast of time. It doesn't help, even when, as in this case, it’s performed flawlessly.

Finally, thanks for all the comments on my last post, be they cheers or jeers. Rather than wasting effort defending my credentials, motives, and reputation (though I’m proud of all of them), and with apologies to any readers who found my writing insulting, inflammatory, or downright cocky (made ya look!), I would direct our attention back to the central issue: careful experiments have demonstrated that increasing ventilation to a structure fire increases the intensity of its burning (not really news, but a good reminder) more than it releases the products of that reaction (actually, revolutionary). Viewing our tactics with those facts in mind, we can either make adjustments, or not. The renewed awareness of how ventilating a fire can worsen interior conditions has lead many in the fire service to emphasize the importance of its delay until after fire control. (There is, of course, much discussion about the actual timing - Ready to start water flow? Already started water flow? Fire is out? - but it is generally agreed that enhancing air flow to a free-burning fire is a bad idea.) Some of us have also taken the next step and decided that eliminating the very purposes for which we were performing a difficult and dangerous action (in this case, cutting roofs) is sufficient reason to abandon that action, allowing us to instead perform others that are actually proven to be helpful.

Many of us disagree - some even passionately - about the interpretation of the results of fire dynamics studies, as well as the relative benefits of different tactics and methods, and even the addition of a letter to our favorite acronyms. The video clip that inspired this post came to me as a result of a discussion with a vertical ventilation advocate in response to my prior post denouncing that practice. It has now been woven into another discussion in which you are all invited to participate. This is but a small example of the ever-expanding, and likely never-ending, evolution of our craft, a process that I am honored to be a part of.

MJC

The writer can be reached at markjcotter@comcast.net

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Comment by Mark J. Cotter on March 20, 2018 at 8:43pm

Nick,

Thanks for taking the time to view the video and comment.  I will concede that the video does not prove my point, but neither does it prove yours nor anyone else's.  Whether the improvement in conditions was due to the vent or the application of water, we will never know, and the key takeaway from the clip that I listed was the importance of research in controlled conditions to be able to separate the variables and determine what works, and what doesn't.  You also make a great point about the limitations of interpreting videos of fireground actions, or any other actions for that matter, as there is no information regarding such factors as that department's SOPs, what orders were given to the vent crew, or, as stated, any radio communication.  My comments were based on what I could see, and that was an apparently expert crew on a flat roof which, with continuous and intense effort, accomplished the opening of the roof just as water was flowing.  

Regarding my interpretation of the research, that was the task of the research panels, consisting of a cross-section of fire service experts, and their recommendation was that ventilation - horizontal or vertical - should not be performed until after water was being applied to the fire.  This has lead to our renewed emphasis on ventilation coordination.  More to your point, the researchers were actually complimentary of vertical ventilation for the removal of products of combustion, describing it as a more efficient method than horizontal, and I would characterize my opposition to that recommendation as a disagreement rather than a misinterpretation.  That is, I think the panel got it wrong.  In my opinion, at a burning building, once the fire is controlled, horizontal ventilation using hoselines or fans is much more efficient in clearing remaining products of combustion than the risks and difficulties, immense or not, involved with cutting roofs.   

I sincerely respect the skills and courage required to perform vertical ventilation, so try not to take offense at my comments; and I am well aware of the respect this tactic holds in the fire service's collective beliefs, so I'll try not to take offense at those sent my way.  My motivation for raising this issue is to cause us to reflect on our long-taught actions in light of the new information that contradicts much of that teaching, and maybe to adjust those actions to everyone's benefit.

Comment by Nicholas Papa on March 20, 2018 at 6:27pm

Mark,

First off, your use of adjectives is a bit excessive/over-dramatic, which to me raises an immediate red flag.  I fail to see how the timing of vertical ventilation is "immensely difficult" (when appropriate resources are available and conditions permit - as is the case in the video).  You say the video exemplifies your claim, but it is in actuality quite the contrary.  While I will agree that radio communications can be difficult, especially for a working engine boss, and transmitting the order to vent [at just the right moment] can be a challenge at times, there are other ways the roof crew can gauge the operational tempo and successfully coordinate opening up.  The roof crew should be monitoring all radio transmissions to identify critical benchmarks: when the engine calls for water, reaches the seat of the fire, has water on the fire, etc.  Furthermore, they should be continually sizing up the conditions to identify any visual and audible cues that would indicate extinguishment has commenced.  This video is a great example of this, as you can see the disappearance of fire in the window and the improvements of the smoke condition (lightening in color/density and reduction in velocity) as they make their cuts.  The roof crew may have also been able to hear the sound (or feel the force) of the stream impacting the underside of the roof.  Even if a roof crew is in position and ready prior to that point, proactive cutting can still take place as long is not finished prematurely.  Once assured the engine is in position/operating, the h*** can be louvered (and the ceiling dropped).  Having not been there and unable to hear the radio traffic, it is easy for you to sit back and say that there was no intentional coordination or purposeful timing in attempts to validate your point of view.  I am sure if you spoke with that roof crew, or better yet the engine crew operating below, their experience would further contradict your assertions.  And this is where I take issue with your commentary as it comes across as myopic and a distortion of reality/fact.  While I optimistically believe you to be well-intentioned, I personally feel your interpretation and depiction of the research data is less than accurate.  While I can appreciate your dedication and zeal, about the only thing I agree with in your entire post is the competency and professionalism displayed by the members in the video.  

Nick Papa  

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