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