Please could the folks that have education, experience and thoughts, take a minute and weigh in on this.
UL and Kerber are putting together the data from the vertical ventilation test houses and are also putting together a possible test plan for PPA. What I got from it, and I could be over simplifying, was that you will not get any improvement to the interior environment from having crews on roofs. We have the work that Chief Garcia and Chief Kauffmann on Horizontal Pressure Ventilation which implies that if used correctly, you can get sufficient improvement to operate and improve victim outcomes. Resources and time spent+potential gains-potential losses=what exactly?
So the question is this; where are we headed with Vertical Ventilation?
While we are getting some great information from these studies there is still a lot ahead. I have heard the information regarding the vertical tests from Steve and I have also heard what has yet to be tested. Information is great and improved understanding is what will make us better. This information on a whole is still in it's infancy, it should be used to further discussion and experimentation not fortify positions.
The tests showed that vertical ventilation did not reduce room temperatures as much as anticipated or prevent flashover and it is important that this is shared. Vertical ventilation utilizes fire's innate need to rise releasing energy from the structure up and out. This is out of our plane of operation and when performed properly the ventilation path is direct as the h*** is cut over the fire.
Horizontal ventilation utilizes pressure differentials (high seeking low) "flow paths". We as firefighters also operate horizontally in structures. These flow paths are heavily influenced by room layout, wind conditions and vent openings this now creates variables in your equation. It may be simple - No wind, easily identified room and contents fire and you take the window in the fire room in coordination with attack. As you bring in wind, two rooms on fire, closed interior door, or how about a commercial structure with limited horizontal options (lack of windows) the decision gets increasingly complicated.
When you begin to add in "Pressure ventilation" which I believe you are speaking of a mechanical positive pressure attack you now add in the variable of a machine to overcome the natural forces of fire heat and pressure. In using Mechanical PPA Chief Garcia and Kauffman stress the importance of everyone on the scene having a complete knowledge of the tactic. They recommend a complete turnover of air in the structure before making an attack (60 to 90 seconds) and they include these cautions of when it should not be used
DO NOT USE PPV with the following conditions-
A- Attic fire
E- Exhaust opening too small
I- Imminent rescue (if path of smoke and heat cannot be 100% controlled)
O- Over pressurized occupancy (due to increased interior temperatures from the fire)
U- Unable to locate the fire
I agree that these studies are forcing us to confront the possibility that what we have been doing for years may not be the best thing going forward. But before we believe that they have brought forth an answer know that Steve Kerber himself will tell you his duty is solely to present information.
I can say that I work for a department that performs vertical ventilation, we train, work to understand it and have had success. My department has not sent all of our firefighters, officers and chiefs to a PPA course; it would be nice if we could. With this in mind I can tell you that where we are headed with vertical ventilation is to continue as trained likely to increase our cuts to the 4x8 as a minimum until more information is presented or we are all trained in PPA but even then it is clear that it is not a panacea.
I have learned in some of my travels and networks that there are many places in this nation that do not perform vertical ventilation and they have not been trained on PPA. Unfortunately I believe that they are going to continue to head away from vertical ventilation by using this information to support their position. The true disservice is that they will also fail to appropriately train and educate their members in PPA or horizontal ventilation to compensate therefore taking the easiest and most complacent path.
"If there are windows we don't need to go to the roof" will kill more civilians and firefighters than any collapse. Read, reread and read the studies again. Practice, train and experiment with your companies in your areas with realistic scenarios and answer this for yourself.
Excellent information added to this post Brian. You are right on track, as I closely follow all your work on ventilation. Taking the the time to train and understand the true science, is much more of a difficult path to follow, than blanket statements of not performing a tactic. As with several of the other hot topics being discussed these days, we need to share information rather stroking our egos.
If anyone else can add constructive information to this topic, please do. Many of us are seeking the truth in knowledge.
I would agree with Mr. Brush. I would have stated a lot of the same things, but not as eloquently. Both ventilation techniques are tools and a tool is only as good as the user's training on it. I have difficulty in using terms such as always, never, and expert. The study is great, but should not hang everything on a study because it can not take into account all aspects. Train the firefighter to be proficient on the different types so they have more tools in their toolbox. I might add that the Officer/BC needs to be trained on them too. Ventilation is dependent on interior conditions. I have been on many fires where PPV is utilized correctly with appropriate exhaust and stayed bad conditions until vertical was accomplished. It's like saying the it has "self vented" when you have zero visibility 5 feet in. There are limitations to fans, they are a good tool, but not an automatic answer to ventilation.
For the record, I'm not staking out a position here. The question was asking was; if the best thing that can happen as a result from an effective vertical vent is that the fire is going to take off (smoke and low O2 lift and 21% O2 moves in) and the worst thing that can happen is that a crew member falls off, over or through, do we need bigger saws, line charges, lasers or something else to get on, get it and get out faster.
Ventilation, by definition, makes the fire worse. How can we change how we work so that we can have our cake and eat it too.