Positive Pressure Attack Challenge

Replies to This Discussion

Permalink Reply by Brian Arnold on June 14, 2009 at 7:01pm

Chief,
I have attended Chief Garcia and Reinhard's class and read their book and they make a strong argument for PPA and do an excellent job of defining the difference between PPA an PPV. However, there are also more conditions for properly implemented PPA that are missing which come directly from the NIST studies themselves. #4 is part of my own guideline.

Do NOT employ PPA unless:
1. You know the locations of victims, not just the exit points.
2. You know the location of fire
3. Your hose team is ready and PPA is applied into the structure for 60-90 seconds prior to entry of hose team. (straight out of the NIST study recommendations, and they even reference 2 minutes 10 sec. of PPA before full reversal in the 2005 study)
4. You have no extension into the attic space or voids where fire could travel upwards.
5. Your structure is not heavily charged with smoke issuing under pressure. NIST calls this Overpressurized Occupancy; most firefighters I know call this "ready to flashover".

NIST is supposedly doing more studies on the effects of PPA in single family dwellings since the past few studies have been specifically in high rise and computer generated fluid dynamic studies. It will be interesting to see what comes out of it. I know of no study that empirically supports or condemns PPA at this point.

In my personal opinion, PPA is fine for a simple room and contents fire when employed absolutely correctly. And that's where the "rub" comes in. Conditions are seldom right for this type of tactic, and firefighters actions when utilizing PPA are usually not inline with the recommended application. I've had two close calls in the past several years when a well intentioned truck company thought to employ PPA and lit the entire house up on us. I prefer my truckie brethren break glass and open roofs when I'm making my attack. We generally follow the A,E, I, O, U acronym for contra-indacations of PPA.

1. Attic Fire
2. Exhaust Opening Too Small
3. Imminent Rescue ( If path of by-products of combustion cannot be 100% controlled)
4. Overpressurized Occupancy (Due to increased interior temperatures from the fire)
5. Unable to Locate the Fire


BIG issues that Kris and Reinhard do not address, but I had rousing lunch discussion with them about, is that PPA initially generates up to 60% more BTU's in the structure before you get a positive outflow. Simply translated, you are putting a billows to the fire and if it wasn't ready to flash when you went in it will be shortly. Thus the recommendation of delaying the attack 1-2 min. (Can you keep the reigns on your guys for 1-2 min. at an open front door while PPA takes hold?) The other issue is ventilation opening. What was once appropriate for a simple room and contents now becomes grossly inadequate when the extra BTU's are generated. And if it happens to flash prior to the entry team making to the seat of the fire, ventilation plan B & C should be carried out expeditiously to get the heat out or you will be cooking your crews.

There is one NIOSH report that I know of which directly cites PPV, which was actually being employed as PPA, as being a leading factor in the death of a firefighter. I will find it and send you the link.

Wanna petition NIST to do a study and I'll take the "con" side and you could take the "pro"? Would be a great chance for me to make it North where it's cool.

Stay safe,
Brian

Permalink Reply by Phil Jose on June 14, 2009 at 7:49pm

Hey Brian,

Thanks for the quick response. Several issues here.

1. The time your truck company "lit the building up on you" were you already inside? If so, classic misuse of PPA. If not I'd be interested to hear about the times a coordinate, properly applied, PP Attack was used and it didn't work out for you.

2. If I have a know victim in a known location I call that a rescue. Anything else is a search. In that case the entire fire ground revolves around the rescue. In the case of a rescue I would use PPA unless they were in the fire room. There is some debate on what would happen to them if we used PPA and they were in the fire room. Personally I believe the odds are it would improve the survivability. Mostly I avoid this in training, or in use, because there is a lack of evidence and the resistance is too strong anyway. Any victim at an exhaust point is a conta-indication. Any victim not in the fire room is a go for PPA, IMHO when properly applied.

3. I believe that having a good understanding of fire location is essential to a safe fire attack whether it is a standard or PPA attack. In this case we are talking about the SFR. Most (virtually all) of the time a well trained, thinking, first in company officer can make a very good assessment of the fire location by reading the building and reading the smoke. Research shows that PPA is effective if you get the exhaust opening close to the fire room. BEST in the fire room but close is good enough to improve overall visibility, decrease temperatures, and assist in a rapid advance to the seat of the fire. Just a question too; If the fire location is unknown what type of ventilation would you recommend and how is it accomplished without knowing the fire location?

4. The recommendation of 60-90 seconds from GK and 120 from NIST is based on the idea that the entire flow of gases will be forced into the room and out the other side before fire attack begins. You and I know that firefighters are loathe to way that long. 20-30 seconds is more reasonable and, based on my experience, and the research, is enough to demonstrate that PPA is working, conditions are improving, and the fire attack will be safer overall. That being said it does not remove the conditions of my challenge which are "properly applied" according to GK. Question on the other side: Are your firefighters waiting for ventilation at all? Vertical takes what 5-7 minutes minimum. Horizontal is part of PPA.
5. I personally am not concerned about the attic fire/extension issue. My priority is getting the smoke and heat out so firefighter can get in quickly to tap the main body of the fire, facilitate a search, and ensure that the civilian life-safety hazard is mitigated as quickly as possible. I can deal with an attic fire and I'd rather have my engines in a clear, cool environment to work on it anyway. We have lots of shiplap or tongue and groove attic floors. It's a lot easer to work when you can see. I have seen no evidence, and have no experience, that demonstrates that using PPA to clear the livable spaces of a building with an attic fire would produce a negative result for victims in the fire building on our arrival. GK in their book and studies thoroughly debunked the notion that PPA contributes to fire spread in a balloon construction building. Again, I am looking for evidence to the contrary.
6. A building charged to the point you reference, IMHO, fits the bill of my restriction based on "backdraft" conditions. The survivability profile of civilians in such a structure approaches zero. Therefore the risk assessment would indicate that firefighters should operate from a position of less risk. This would be a function of making sure that enough ventilation is provided to ensure removal of the "potentially explosive/backdraft/rapid fire spread" gases as necessary to ensure a safe and effective fire attack can be made. Again I pose the question: If you arrive at a building with these conditions what is your current ventilation plan, how is that superior to PPA, and what does the hose crew do while waiting?

If the firefighter fatality report you are referring to is from Contra-Costa county you should review the report relative to the conditions for implementing a PPA attack. Also you should go here:

Otherwise I believe that there are 4 other NIOSH reports that reference PPV. (NIOSH has no distinction between PPV and PPA) i do not believe any represent properly applied PPA.

Just for kicks look at the list of NIOSH reports that indicate other ventilation related issues.

Thanks for the discussion. I understand your approach and appreciate you taking the time to engage. I hope you can tell I'm not taking the issue lightly or without much thought or understanding of the issues. I am a guy who likes to ask questions. Helps me learn. I think that most SFR fires we go to are ripe for PPA. Still looking for evidence to the contrary.

Phil

Permalink Reply by Jeff Schwering on June 14, 2009 at 8:59pm

Chief,
I like Brian have not seen anything that supports or condemns PPA. I have seen good outcomes and nearly tragic outcomes using PPA in my small piece of the Midwest. I think you qualified the question perfectly by saying, PROPER USE! Like many tools we have at our disposal in the Fire Service, PPA used properly is great, but its the person who thinks they know and doesn't that scares me.

Stay Safe
Jeff

Permalink Reply by Brian Arnold on June 14, 2009 at 10:00pm

Chief,

In one instance the PPA was applied completely innapropriately and was severely underventilated by a very small window. The second instance was a classic textbook PPA. Delayed entry, large vent. opening, fire showing from a large bedroom. The only issue that came into play was the size of the house. Long stretch with multiple friction points, slow moving attack line with a fire that lit up the rest of the room and barrelled down the hallway at us. Visibility was improved early in the stretch until we rounded the corner of the hall and there it was floor to ceiling smoke and HEAT then fire. We were never releaved of the heat and took a beating. If a 6' x 8' long window for a 20' x 14 room isn't enough ventilation then I don't know what is?

I would agree with you that a known location of a victim in now a rescue, but in the cases of unknown occupants, especially in SFD we go to the roof to assist with search crews. We also employ VES when indicated. As far as time to pop the top, the truck company at my house's goal is roof open 3 min. after arrival. This is pretty consistent in our single story ranch style homes, sheetrock or lathe and plaster ceilings. We've had two good fires in the past two shifts and this was the case in both of them.

I also agree with you on location of the fire can most often be determined by a good size up. As an engine officer I have the option of taking a window during my size up prior to entry, especially while the truck is going to the roof. Glass is cheap and will most likely fail while making the advance anyway. If the fire location can't be determined what better way than to get the smoke and heat out than opening up the lid?

The waiting time is critical in making the attacks and if you are only waiting 20-30 seconds are you truly employing properly deployed PPA tactics with empirically backed numbers? It's during the initial 30-60 seconds when the BTU production of the fire peaks. If it's going to flash it may possibly do so 30 seconds after your entry. Kinda like all those videos that are floating around the internet showing correct or incorrect PPA or PPV tactics, depending on who you talk to.

Fire above me is always a concern in a SFD, due to the possibility of losing the ceiling and having it come down on me. If PPA is feeding and pushing a fire out an exhaust opening as well as into the attic, a well intentioned FF pulling the ceiling prior to knockdown will open up a blowtorch behind the attack crew. This is another wonderful event I've had the displeasure of witnessing.

As far as conditions being heavily charged and pushing out under pressure, I do not consider these backdraft conditions. I would term them more of "ripe" for a smoke explosion or fire gas ignition. Again, the best approach is to let the fuel (smoke) out the top where it wants to go anyway. Put a fan behind a well placed large h*** in the roof and you'll really get a show of flames shooting out the roof.
As to victim survivability, I've seen too many fires that I thought there was no way a victim could live through come out alive. I will always make the committment whenever possible to get the line in place and protect search crews to make the grab. To me and my crew that's what I signed up for; to assess, progress and evaluate risks that will save lives. The citizens and my crew alike. To my knowledge there has never been a study done that collaborates the victims chances of survival based on proximity to the fire, quantity and quality of smoke, etc. When they did the NIST studies they should of put gas monitors along with the temp. gauges which showed that temp. in adjoining rooms were diminished at floor level with all types of ventilation. Get the smoke out and our victims chances improve.

I have binders of all the NIOSH studies but sometimes they become clouded with the number of ones I've read, my age and too many adult beverages. But I will go and pull them back up and re-read them to see if I've missed something. I can't read the other link you provided for some reason, could you possibly type it in?

Lastly, as to our tactics- we are fairly aggressive and blessed with many well qualified truckies that I enjoy bustin' on from time to time. While my crew is laying a supply line for anything showing (yes, I know but it's our sop), and stretching the initial attack line; our truck crew is usually going to the roof. Second due engine or truck is assigned to search and is most often making entry just prior to initiation of the attack or shortly after depending on condition report of possible victims. We have the luxury of having many people on scene relatively quickly.


Stay safe,
Brian

Permalink Reply by Mike Walker on June 15, 2009 at 12:55pm

To add to what Brian has said. Our goal is to have the h*** cut within 4 minutes from the time we set the brakes on the rig. Most of the time, we achieve that goal. By the time the attack lines have been established the vent team is well on their way of having their job done.

We've used PPV or PPA for the last 20 years and we also routinely vent the roof. I've used both with good success and sometimes I've used both at the same fire. It depended on the situation.

The aspect of your question that I think cannot be avoided is the very large qualifier, "when properly used." If the qualifier is used as a catchall to reflect instances when PPA didn't work, then where does it end? Meaning, a crew applies PPA and a negative result ensues, advocates for PPA can just rely on the statement, "PPA wasn't properly used." Though I understand what you are trying get information about I'm not sure your question can be answered simply because any method of ventilation that resulted in a negative consequence would in fact be the wrong type of ventilation for that particular situation.

Whether we want to admit it or not, ventilation isn't as simple as many would like for it to be. Any method of ventilation applied incorrectly can create a huge problem as you all know.

BTW- I am not trying to be a smart a**

Permalink Reply by Kristopher Holien on June 15, 2009 at 5:07pm

You beat me to it Chief. I was going to ask for the same information and try to have it by July1st for you. I have spoken with a number of fire officers and firefighters who took the class in Seattle. The resounding word I am getting is that PPA works great in study, but the jury is still out on whether or no tit works in real life.

The other point that I have taken so far, is that most of the firefighters I have spoken too feel that the videos and examples shown, weren't cases where PPA was even used. Instead, members I have spoken to say that the real world videos that were shown depict the fan being put into the door AFTER the fire had been hit by water and knocked down. In essence, it was used as PPV, and then labeled PPA.

Once again, I also have to question the fact that LA doesn't use this. LAFD, as far as I am concerned, are the PPV guru's. If anyone knows and understands the benefits of using a fan, it's LAFD. If they have chosen NOT to use it, I feel that as the innovators of PPV, they might have a little insight. It would be curious to see if a member of the SFD, say a battalion chief, was able to get a definitive why or why not from LAFD training bureau.

Finally, I have to agree with the Mike is saying below. The challenge in and of itself disqualifies all cases where PPA fails. The real challenge, should be to find cases where PPA is successful in real life emergencies, and to identify WHY it was successful. Due to the constraints placed on this challenge, I again wonder how many, if ever, the circumstances are conducive to using PPA. The studies and the science seem to be there, but how often do studies based on controlled environments happen during real life emergencies?

By the way, I am still looking for instances that fit the Chiefs challenge. so please, if anyone finds just 1, please post it.

The great thing about Fire Tactics, is that there are always discussions!

Permalink Reply by Phil Jose on June 15, 2009 at 7:11pm

Wow, You guys are on it.

I am not trying to create a situation where any poor outcome is automatically disregarded by the qualifying statement. Guess you'll have to take my word on that. I think that Brian has something up there and I'll ask him some questions about it when I get a little more time.

There are plenty of people using PPA. If it didn't work they wouldn't be using it. The fact that LAFD has not (possibly) come fully on board does not, IMHO, detract from the discussion about the likelihood of it being adopted. Fire departtments don't always do what is best as politics and history come into play. Not detracting from LAFD cause those guys flat rock on vert vent. I just don't know what there PPV procedures are, or are not.

I agree that any form of ventilation can be improperly applied. The difference is that when PPV/A is improperly applied the reaction is to say "let's not use it at all" which you don't hear for bad outcomes with vertical or horizontal. (at least not from what I hear said)

I think having a target for vert vent times is great and perhaps 4 minutes (or 3) is reasonable on a singe story house. Most of our stuff is two-stories and I've seen a lot of truck companies try to prove me wrong but that takes at least 5 minutes, if you wear your PPE, and I'm not interested in the discussion if your not. What do you do when the engine arrives without a truck (or are all of yours co-located in doublehouses. We hve a 3 to 1 ratio and an engine could easily wait 4 minutes for the truck to arrive + your 4 minutes to vent = 8 minute delay. Long time for a civilian to breathe smoke. Do you have the engine stand by till the truck gets the vent done?

More later.

Phil

Permalink Reply by Mike Walker on June 15, 2009 at 7:39pm

Why yes we do wear full PPE... we even have indoor plumin in most of our houses.... :) (Forgive me, I couldn't resist)

If the Engine arrives before the ladder, they horizontally ventilate, remember we're in Oklahoma where the wind comes sweeping down the plains. But in all seriousness, our Engines that are in areas where a Ladder Co. isn't close they have PPA/PPV blowers.

Don't get me wrong Phil, when used for the right situation, PPA/PPV works fine. The issue we were starting to run into here was too many people were just throwing the fan up and calling it good instead of doing a good ventilation size-up and applying the correct method of ventilation for the particular situation. On some of our ladders we are carrying gasoline fans and electric, giving a total of 4 blowers. When do we use which one? Again, it depends on the situation. The electric fans were primarily purchased for High-Rise situations where we didnt' want to fill the stairwell with Carbon Monoxide but guys are using them for other calls as well when they want cleaner air then the gasoline fan provides.

Permalink Reply by Art Zern on June 15, 2009 at 10:54pm

Gents,

As many of you will remember, we had a lengthy PPV/PPA discussion here in this group several months ago. I compiled the responses and I'll add it to this reply for reference.

I have to agree with Chief Walker, your qualification of "properly applied" is the same as bringing a knife to a gun fight. If the American fire service would "properly apply" sound decision making, tactics, incident command, accountability etc...... we wouldn't have any issues. Let's stipulate that there is merit to using PPV/PPA, "properly applied" and following the criteria detailed here and in the summary notes from our previous discussions.

With all due respect Chief, it was not a reasonable challenge to make. Your qualification made the opposing discussions moot. The problem with miss-applied, miss-understood and poorly executed PPV/PPA is that the results can be devastating. There are a great many fire departments in this country that buy a tool such as a PPV fan and apply some vague tactical procedures and adopt PPV/PPA without doing their due diligence and properly training their members. The results have been memorialized in countless videos and through many close-calls and near-misses.

As I said when I introduced the PPV/PPA question several months ago, I know that many departments use PPV/PPA with great success; however, I worry about those departments that didn't do their homework, didn't train their members and don't conduct continuous evaluation and training on PPV/PPA.

Great discussion so far, thanks to all.

Art

Attachments:

• PPVDiscussionSummary.doc, 97 KB

Permalink Reply by Phil Jose on June 16, 2009 at 12:04pm

I guess I should take a mea culpa on my approach with the qualification of "properly applied." With all of you gents already using PPV/A to some extent this may seem odd but, based on previous discussions, I was only hoping to eliminate a regurgitation of "PPV done wrong" and attempt to have a discussion predicated on well trained firefighters using the appropriate technique (damn another qualifier!) at the appropriate time. I agree with the resounding rebuke that ANY fireground tactic, when misapplied, can achieve disastrous results. stretch through the wrong door, stretch short, opposing lines, delayed ventilation etc. but that being said. . . . .

I have had plenty of discussion with folks who would not ever use ppv/a. period. end of discussion. and your insane if you want to try. Thanks for attaching your document Art, I read the whole thing prior to asking Jim Mason if I could post my challenge here. While it was an interesting discussion it did not provide me the insight and guidance I was looking for because it had plenty of ad hoc testimonials of PPV gone bad.

In the spirit of my challenge I'd like to address something Brian added earlier as a response.

Quote
"The second instance was a classic textbook PPA. Delayed entry, large vent. opening, fire showing from a large bedroom. The only issue that came into play was the size of the house. Long stretch with multiple friction points, slow moving attack line with a fire that lit up the rest of the room and barrelled down the hallway at us. Visibility was improved early in the stretch until we rounded the corner of the hall and there it was floor to ceiling smoke and HEAT then fire. We were never releaved of the heat and took a beating. If a 6' x 8' long window for a 20' x 14 room isn't enough ventilation then I don't know what is?"

Brian, Brings up several questions being that this was your experience I am hoping you could shed some light on them. Not trying to be a pain in the a**, just trying to learn. Although, as Holien can attest I do have the ability to be a pain in the a**. Here goes.

1. You mention that visibility improved and yet you had some struggles making the stretch effectively. Can you evaluate the relative positive impact of the increased visibility during a difficult stretch versus the negative impact during when you reached the fire area?
2. Can you assess (guess) what the impact of alternative ventilation methods would have achieved given the delay in the stretch including (possibly) and increased delay due to visibility? In other words, had you chosen a different ventilation strategy how would the fire behaviour have changed and the impact of that change on the brothers?
3. Can you give me an idea what the tenability for civilians was throughout the entire operation? What I am driving at here is that you indicate increased visibility, which I take as less smoke, during the majority of the operation. Were there victims in the building would the ventilation plan, overall, have increased or decreased their survivability profile?
4. What was the outcome? You mention that you took a beating getting to the fire room. I'm interested if this meant you had difficulty applying water, if the flow was insufficient due to the BTU generation (due to the forced vent), If the fire behavior overpressurized the room enough to make progress into the hallway, or just in general, Wha hapen?

Also, thanks Art for stipulating that PPV/A has merit when properly applied. Made me feel warm and fuzzy.

Phil

Permalink Reply by Brian Arnold on June 16, 2009 at 4:37pm

Chief,

Without trying to write a novel on the incident here it goes......
1. Visibility in the entry and formal living room areas improved after PPA, good flow of smoke out the top of the door since you know PPA advocates not sealing the entire doorway. Making it through the Family room required dropping to knees as heavy smoke conditions were encountered. By the time we made the corner near the dining room and started an advance down the hall, heavy heat and dense thick smoke. Rollover less than 5' down an approx. 20' long hall which was driven back by a 15/16 sb. Had to make another corner to push into the actual bedroom to start extinguishment. Conditions reported by OV man was 20' flames blowing out window and causing concern for exposure next door.
2. My opinion is that this was a perfect house for horizontal ventilation followed by vertical ventilation. Low pitch roof, easy access to roof and window. It would have initially let the pressurized room blow for a min. until the roof could have been opened and everything would have flowed up rather than laterally. Fire behaviour-would have initially grown and blown out window until roof was opened then it would have been confined to the room of origin for the next several min.
3. Room of origin and hall had no chance for civilian occupants. The rest of the house was smoke filled with moderate heat in close proximity to fire room. 90% of the home ripe for a grab but no one home to rescue.
4. More than adequate gpm for the line but would have preferred a 2 1/2" on this one since the fan was blowing. One of only a few sfd's that I can say that about. Good nozzleman that worked the line properly and an older officer (me) that humped as much hose as fast as I could. Second engine actually assisted in getting the first line into operation by working our many friction points, then went back for a backup line.

It is my opinion that the PPA created more BTU's than the exhaust opening could handle. We could have cut out half of the wall and been alright but it was initially more than adequate for what is taught as apropriate exit opening. Fuel load was a King size bed, 2 night stands, 2 dressers, some kinda funky love seat, make up table and chair, a piece of exercise equipment, walk in closet door was closed but burned through at top and large bathroom incinerated. For PPA to have worked we probably would have to have waited 3-4 min. to see full reversal. And during that time the rest of the smoke charged hall would have lit up creating even more problems. To me PPA/PPV, vertical and horizontal ventilation are all options we have to choose from our perverbial toolbox. No one method works all the time and some are simpler than the rest. Kinda like the differences between a sb and an adjustible gallonage fog nozzle. KISS method.

Thanks for the great discussion. Hope that answers some questions for ya'.
Brian

Permalink Reply by Jeff Goins on June 18, 2009 at 12:55pm

Good proposal Phil. I'm a Captain assigned to a very busy Truck Company in Atlanta Ga with 19 years experience.

I do a lot and teachung and studying on all aspects of our job and i don't think you'll find a truly documented and accurate account of negative effects of proper PPV usage.

What I guarantee you will find is improper use if the real honest truth comes out. The problem is this technique is all to often done incorrectly resulting in a less than acceptable outcome.

One thing I did notice on your Properly Implemented is ventilation. Ventilation meaning the pressure you introduce to the interior of structure has somewhere to go.

Simple example would be a room and contents job on a 1500 sq ft SFD. The fires origin is located from the exterior and the windows to that room are taken out. The attack line is in place and the fan is started as they enter. The smoke and heat are moved out in front of them as easily go directly to the fire room. This would also help tremendously if viable trapped victims are involved.

Best of luck with this study and again great discussion.

• ‹ Previous
• 1
• 2
• 3
• Next ›
• Page