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PPV and PPA
Replies to This Discussion
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Permalink Reply by Ben Waller on
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A little necroposting on a good topic.
Regarding Art's #2, I have a rule that I call "Waller's First Law of Tool Confusion". It reads "Never use a PPV fan as a Thermal Imaging Camera. Use the TIC to find the fire, not the PPV fan."
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Permalink Reply by Don Catenacci on
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The TIC while a great tool is also not infallible. Basic skills, without the crutch of technology, still need to be taught. Fires were found and extinguished long before PPV and TICs.
Both PPV and TICs are awesome tools and we should take advantage of them. I just don't believe that we should become so reliant on them that if they fail we are screwed and unable to function.
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I agree that TICs are not infallible, but I wouldn't use PPA/PPV without one.
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I have used PPV/PPA on numerous occasions without a TIC. It does count on a great 360 to know where the fire is and if PPV/PPA is appropriate. If we have any doubts the fan is left off. It is that simple.
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Permalink Reply by Jesse J. Thompson on
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It is like any other tool in your tool box. There is a time and place for it. If you educate yourself with the PPA/PPV class from Kris Garcia, you will have the knowledge necessary to make the correct decision on use. We have applied it on occasion and have been successful. Again it is a tool to be used at the proper time and with the proper training and education, this can be done safely and effectively.
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Permalink Reply by captnjak on
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OK, I know I'm late to the party here but I've got to add my two cents. I've seen Chief Kriska's powerpoint and I've been to Chief Garcia's website. I've also read many an article and seen many a video. I have some major reservations regarding PPA. I have several serious doubts that I'd love to see someone overcome for me
In no particular order:
1) It begins with an outside survey or 360 which is supposed to determine suitability for PPA. How exactly? You can't determine victim location and often can't even determine exact extent of fire. You may locate a room that is definitely involved but what about other interior spaces? How do you determine layout of area? How do you determine which interior doors are open or closed?
2) We are told that exhaust openings should be anywhere from 1 1/2 to 3 times the size of the attack entry (depending on who you listen to). Most rooms just don't have sufficient windows or exterior doors to accomplish this. So now we have to expand the opening, either by getting to roof (assuming there's not a floor above) and taking skylight or cutting a hole, or by cutting the wall under or adjacent to window. This takes TIME and time is not our friend. Plus we can't operate fan until opening is made. Then we have to wait 30-60 seconds (or more) to evaluate PPA before entering. So how much time exactly has passed since our arrival? Really, how much? 4 minutes? 6 minutes? (I'm being generous with those numbers.) And we are now just going in. There's probably a charged line on the lawn waiting to go in by now. What if the manpower that had been dedicated to ventilation had been assigned to forcible entry and primary search? And the line had advanced ASAP? The main body of fire would have already been knocked down and victim(s) very well could have been removed. Proponents of PPA say it makes fire attack quicker. That's only ONCE IT STARTS, which is delayed by venting tactics.
3) We are told that the area above the attack opening should be used as a barometer of conditions and that if smoke or fire exhausts from this point we must turn off fan because conditions are not suitable. So we have to expand exhaust openings. More time goes by and we are still not even entering building. Or we are told to discontinue PPA entirely. Now what? The same conventional attack we could have done IMMEDIATELY UPON ARRIVAL? In addition, if fire/smoke has now moved back to entry point, where else has it now moved to? This sounds like a tactic of trial and error to me, and there's just too much at stake to accept that.
4) One source says to use PPA only during the free-burning stage of fire. With the typical modern contents fire flashover can occur in as little as 3 1/2 minutes after initial ignition. Fires begin to darken down soon after flashover because available air is quickly used up. Unless fire finds a way to self vent, we usually arrive AFTER the free-burning stage has ended.
5) We are told (by some) not to use PPA if fire location is unknown. This is often the case. There are two ways to ascertain fire location. Either enter the building and locate it or wait for it to come to you. If we are going to enter the building to locate fire, why not just bring a line and extinguish it? And if we are just going to wait for fire to come to us, we pretty much defeat the whole purpose of the fire service: to protect life and property.
6) We are told that it is unsafe for a firefighter (in full PPE) to operate in front of an operating fan. What does this mean for occupants in street clothes or less? And you don't really know presence or location of victims just from outside survey (360). A firefighter in full PPE is in no danger from steam generated by hoseline.
7) One source says that occupant survivability in areas adjacent to fire dramatically improve after PPV. The same is true for those areas after application of an adequate water stream. Recent tests by NIST/UL bear this out. Even a firefighter closing a door to an adjacent area prior to extinguishment can make a huge difference. Of course that firefighter would have to get in there quickly to do it.
8) One article actually states the following:
With the exception of water, there is nothing on your apparatus that will more dramatically impact the fire area than a fan." So if water is better, why don't we stick with agressive interior hoseline attack (or transitional attack) combined with a fast primary search and coordinated ventilation?
I'm not saying PPV/PPA does not work. I'm saying it takes too long. I'm saying there are an awful lot of scenarios in which we can't use it (not to mention the time we waste FINDING OUT we can't use it.
Proponents often point to the clear visibility and low temperatures that firefighters get to operate in when PPV/PPA is used. That's fine but it's also a luxury that we and the public can't afford. We have PPE for a reason. To operate in heat. I believe the time spent training on and drilling with PPV/PPA would be better spent practicing advancing lines and searching in low or zero visibility instead of finding a way to enter a fire standing up in clear cool conditions. I suspect that's why many are such big fans of it. The busy departments (paid or volunteer) who have a lot of experience all seem to put their emphasis on agressive interior attack with hoseline combined with fast primary searches. Application of a sufficient stream of water does just about everything a fan can do, but much faster.
Like I said at the top, I'd love to see someone address the issues I've raised. Especially concerning the time factor because that is our biggest enemy. Or the potential victim's biggest enemy.
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Permalink Reply by John Kriska on
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Chief Murphy, thanks for your post and questions regarding the use of PPA. I will address each of your points and give you my opinion:
1. The 360 is in conjunction with your normal Size-Up procedures, one well known method is Laymans Size-Up. Along with Laymans suggestions, if your considering using PPA then you include attempting to determine the area of fire origin. Sometimes this cannot be done. How do you do this? Checking windows looking for visible fire, is the fire in the potential backdraft stage, extent of the fire. As far as victim location, you may obtain information from others who were in the building. You may not know where any victims are. One thought to consider, if there are any victims in the area of fire origin, the chances of making a live rescue are slim, therefore anyone outside of the fire area is a potential live rescue but you don't know this until you get inside and perform a primary search. As far as layout, you don't know. As far as doors being closed, if PPA is used and there is no change in the enviroment at the doorway, in all probability you have a blockage between the attack entry point and the exhaust, a door closed. Remember, the person doing the size-up must make decisions based on what information they have available, sometimes that information is accurate, sometimes it is not. Review slides 61-73 and sildes 77-86 of my PPT. Even if you do not use PPA, there is still set-up time, A size-up should still be performed and an attack line streched, this takes time and couple that with the time it takes to advance thru a builidng in zero visibility. (See question in #2)
2. The reason why the exhaust must be large as you mentioned is because of the BTU levels being put off by the materials burning, ie: synthetics. Additional exhaust openings can be made in adjoining rooms to the area of fire origin. Review slides 46-53. Here is a question that I always ask of my students: How long does it take to make your way thru a builidng in zero visibility conditions, on your hands and knees pulling an attack line, checking the floor in front of you, you don't know the floor plan, you don't know exactly where any trapped victims are? Keep in mind, the longer trapped victims are exposed to the toxic materials generated by a fire, the less chance we have of making a live rescue. Yes, time is our enmy. As far as setting up PPA, it can be done by the initial arriving engine company providing they are well trained and have the necessary equipment. Review slides 77-86.
3. Not using PPA, as firefighters enter the fire building, the opening that they entered through is now an exhaust opening. Why? Fire Positive Pressure, the area outside is a lower pressure that inside the building because of this pressure. As they advance, the smoke over their heads is "fuel" and they are placed at extreme risk of a flashover. The suggestions for using the area above the attack opening is simply a way to guage whether you have enough exhaust. I would rfecommend in a situation that indicates that not enough exhaust exists, that the blower be shut off and enter without PPA.
4. If after size-up, the fire is determined to be in the backdraft mode, then PPA would not be used. Vent high. However, if that is not the case, once the entry door is opened, a flow path is created, smoke (fuel) exiting high and fresh air entering low providing the fire with needed oxygen so you would be right back to free burning again.
5. If PPA is going to part of your operations, then you must locate the fire origin from outside by a good size-up. If you are unable to determine the area of fire origin, then PPA would not be used. I have a different take on using PPA when the area of fire origin cannot be determned, however, I will not include that in this open discussion. I will provide my take privately though if anyone is interested.
6. I'm not sure I understand this point. Uisng PPA, you are operating in front of the fan because the fan is to the back of the advancing attack crew.
7. I refer back to my question about time and operating in zero visbility
8. I would agree with the article, PPA is a tool to use when appropriate. I also believe in the "transitional attack method" but that too creates controversy. Regarding "aggressive interior hoseline attack", I refer to the previous question about "time".
Training and education are the keys successfully using PPA. I recognize that all the things I have discussed may not work in your first due area, however, it is still a tool that when appropriate can be used. If performed properly, it can have a positive affect on both firefighter safety and making live rescues. Hope my response sheds some light on your concerns. Stay safe.
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Your reply seems to substantiate most of my reservations. Apparently, PPV/PPA is only to be used in a free-burning fire that is confined to one room which has very large windows.
We appear to disagree on the time factor. I maintain that an agressive interior hoseline attack combined with fast primary search is the most efficient way to protect lives and property. You maintain that taking windows in fire area and then cutting further holes in structure (won't it be very difficult to complete those cuts if fire lights up upon initial venting of window?) to get sufficient size exhaust hole, and then operating fan long enough to guage results is quicker and/or more efficient. And that's only assuming fan worked as desired. If it didn't, ALL OF THAT TIME WAS WASTED (at least as far as fire and victims are concerned). And now you must do what I would have done immediately upon arrival.
Even with proper training, PPV/PPA comes with a lot of "ifs" attached. Fast water on the fire is much more cut and dried.
What I meant when I referenced operating in front of the fan was operating in that area before fan was turned on. Apparently this is a no-no for firefighters in PPE. So what does it mean for occupants who may be in that area? This is no small point. 360 and on scene reports from civilians are rarely reliable in determining exact locations of victims.
To repeat: I don't feel that PPV/PPA does not work. I just feel that it is not the most efficient (fast) way to protect life and property.
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Chief, I don't advocate opening the roof to attain increased exhaust. In my view, vertical ventilation should be reserved for those incidents that require that type of ventilation because it is a very time consuming operation. I learned the use of PPA by doing because back in the 1980s there was not much information except from John Middendorf out of LA and that was basic PPV. Having only a three person engine company, after many hours of testing and experimenting with some very knowledgable folks in my area, we determined that if used properly, PPA enhanced firefighter safety and made our interior operations much quicker than operating in zero visibility. I do believe that the issue of "time" involved of the interior attack in zero visiblity should be considered and compare that to the time it takes for PPA to be set-up and operating. I'm enjoying our professional discussion.
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Also like the discussion. I see where staffing could be a major factor. I'm lucky enought o have sufficient staffing where I am. That's why I can afford to stress agressiveness so much. We can cover all areas of firefighting simultaneously (RIT included) with bodies to spare. I know many departments can't do this, through no lack of dedication or effort on their part. It just is what it is, sadly. Politicians doing what they do best-screwing it up for everybody.
Stay safe.
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