Video and Discussion of when to use PPV

[Alpinerunner 61]

I posted a video in the videoshare forum about using PPV at the wrong time. VES PPV Link I got some PM replies because it appears you can't reply in that forum. It's a very educational video and I thought we could have a constructive conversation about when to use what type of ventilation. I always thought you use natural vertical and horizontal ventilation (when possible) during fire extinguishment and forced positive or negative after extinguishment.

My first question is when and why would you used forced negative vs. positive ventilation? Pros/cons?

[JohnnyOV 2]

I posted a video in the videoshare forum about using PPV at the wrong time. VES PPV Link I got some PM replies because it appears you can't reply in that forum. It's a very educational video and I thought we could have a constructive conversation about when to use what type of ventilation. I always thought you use natural vertical and horizontal ventilation (when possible) during fire extinguishment and forced positive or negative after extinguishment.

My first question is when and why would you used forced negative vs. positive ventilation? Pros/cons?

First let me say that we can all use this video to learn from and discuss it in a civilized manor without anyone's panties getting in a bunch. PPV is a very divided topic, and hopefully we can have some constructive discussion there.

That being said, when I first saw this video, the one thing that immediately caught my eye was the thick, black, dense smoke still pushing out the front of the house as the PPV fan was set up. Reading that smoke alone should have been enough for ANY firefighter especially the IC to be aware that the fire was not extinguished, and that there was still heavy, active fire burning somewhere in that house. Regardless of your feelings of PPV, and mine shall stay silent, this was not the time, nor the place for that fan to be set up.

The protocol change in not preforming PPV while firefighters are stll inside, while somewhat effective, does not subsititue for ones ability to actually read, and comprehend the scenario that is playing out in front of them and make the critical fire ground decisions based off of that.

That being said, glad everyone made it out alive, and thanks to the Sandy FD for releasing this video for others to learn from.

[IzzyEng4 427]

There was a city by me a few years ago (not going to mention which one) where they were utilizing a PPV fan while performing suppression operations. The building was an old commercial structure with apartments above it (if I remember correctly). Well the PPV fan was placed in operation to aid in suppression and there was still a hell of a lot of fire in the structure. Needless to say they lost the building as the fire was able to burn more freely with the induction of fresh air.

I'm not saying PPV is not a great tool, it need to be implemented during overhaul after every section of a structure has been cleared of fire and not during fire suppression operations in my opinion. Though you can't really tell from this video due to the way it was edited but it appears that those on scene thought that the main body of fire was concentrated in only one place. It seems this was a complete state of complacency of those commanding the incident that the basement was the only location of the fire. As we know walls, ceilings and floors need to be opened up, furniture and appliances moved, proper vertical and/or horizontal ventilation performed, so on and so forth. Just because you don't see it doesn't mean its not there, always assume the fire has extended to someplace else. Heck, just imagine what would have happened if there was another area that was burning and ended up being starved of oxygen? Now introduce a PPV fan into the mix and bam! We just created a backdraft or flashover situation by introducing fresh air.

Once you know all fire is out, then a PPV operation can be performed and the hot-spots can be knocked down. These firefighters were very lucky and yes this is a good learning experience for all of us on PPV operations. Never assume that the fire is out until you checked the entire structure. We have TICs and IR thermometers to measure heat, salvage and overhaul operations should be performed as soon as you believe the main body(bodies) of fire are knocked down.

PPV operations do have their place but it seems we as firefighters and officers implement it at the wrong time.

[x129K 1,393]

LOL....I was going to start the same topic, but title it, "HAS PPV RUINED THE ART OF VENTILATION?"

Yes...PPV can be VERY effective..and it is too easy to set up and implement....it is a task easily accomnplished by the most junior member...but unfortuneatly, it is a tactic that needs to be well thought out, and you absolutely HAVE TO KNOW when to start that damn fan up!

[wraftery 1,275]

Take another look at this. There are two problems evident to me with PPV on attack in the video.

Since smoke was emanating well from the front door, first due engine correctly chose to attack from the opposite side since the front door was obviously the vent opening. It's horizontal ventilation working nicely.

When PPV was started, however, it not only plugged that vent hole but also blew everything right at the attack company. It is the equivalent of opposing hoselines, another faux pas. PPV also awakened a fire in the walls and blew that towards the attack team also.

PPV requires control of ALL openings in the building and that includes holes in interior walls and ceilings. Picture this video but with a balloon frame dwelling...you'll get vertical ventilation alright...without sending a crew to the roof.

Besides the PPV issue, a little communications on scene would have helped also. The IC also should have noted the front door vent, known where his crews were operating, and put the brakes on the PPV operation. Many IC's have forgotten that overseeing the operation is their job. They tend to concentrate on moving the magnets or velcro tags around their table instead.

[wraftery 1,275]

I guess you're right! How 'bout:

bad IC?

reading smoke?

mayday calls?

tunnel vision?

or

Fire engine photos

[x129K 1,393]

I guess you're right! How 'bout:

bad IC?

reading smoke?

mayday calls?

tunnel vision?

or

Fire engine photos

Ahhhh yes..NOW we are talking! Reading SMOKE is an OUSTANDING TOPIC and underused skill!!!!

[Bnechis 3,961]

I'm not saying PPV is not a great tool, it need to be implemented during overhaul after every section of a structure has been cleared of fire and not during fire suppression operations in my opinion.....Once you know all fire is out, then a PPV operation can be performed and the hot-spots can be knocked down.

While There is clearly a time and place for any tool, one must be very carefull of always and never.

In this thread a number of posts took the "never" (until the fire is out) side. Last year FDNY opened its new high rise simulator and they are now teaching the use of PPV as an attack tool in highrise buildings (they must be of fire resistive/noncombustible construction). They use it to pressurize stiars and hallways as well as removing smoke from different areas.

[wraftery 1,275]

While There is clearly a time and place for any tool, one must be very carefull of always and never.

In this thread a number of posts took the "never" (until the fire is out) side. Last year FDNY opened its new high rise simulator and they are now teaching the use of PPV as an attack tool in highrise buildings (they must be of fire resistive/noncombustible construction). They use it to pressurize stiars and hallways as well as removing smoke from different areas.

That's a whole different use of PPV from the video here.

Here smoke was brown thick ugly venting at front door. You didn't see steam mixed in. Something was still cooking. Let's put our fan on it. That fire was just waiting for some air.

[Alpinerunner 61]

While There is clearly a time and place for any tool, one must be very carefull of always and never.

In this thread a number of posts took the "never" (until the fire is out) side. Last year FDNY opened its new high rise simulator and they are now teaching the use of PPV as an attack tool in highrise buildings (they must be of fire resistive/noncombustible construction). They use it to pressurize stiars and hallways as well as removing smoke from different areas.

I read that article, too. However, you're right that the critical element is the fire resistant stairwells of highrises. No chance of fire burning in concrete walls!

To get a little bit off topic, can someone elighten me as to some factors to consider when choosing negative vs. positive ventallation. To me it seems either would work just as well as long as you control your openings. The only thing I can think of is where the smoke is in relation to the fan. You don't want to put NPV on a first floor when the smoke is on the second floor because you'll pull it through the house before going out, and you wouldn't want to put a PPV on the first floor when the smoke is on the first floor. Am I correct in those assumptions?

[Guest Firediver]

Dave Dodson has a good 30min video on reading smoke with examples. If you cannot get your hands on it Im sure youtube has some clips from his video, check it out.

[Guest Firediver]

youtube has some clips from his video, check it out.

Search youtube for it and I'm sure you can put together close to the 30 mins. And thats free! (Funny how guys will spend over $100 for a gemtor harness and they are the engine chauffeur. JMOb)

[wraftery 1,275]

Re: FDNY and hi-rise PPV

Agreed that multis are more fire resistant. Also, FDNY goes through a pretty involved system of size up by the hi rise co officer and he must get OK from IC before starting PPV. After that, the effectiveness of PPV is evaluated constantly by designated members to insure it is doing what it is supposed to do.

To add to Capt. Benz's post, My Degree says Fire Science but putting out fires is an Art. No two fires are the same and the FF has to change to adapt his strategy and tactics by what the fire is doing or probably will do.

[antiquefirelt 994]

I truly beleive there are some fundamental differences in the places who successfully use PPV vs. those who can't make it work safely and discard it's use. Obviously both sides have good points, the real issues are the "indications" and contraindications".

Without a doubt PPV works and works well in many controlled fireground settings. I say controlled in that we know some basics: where the fire is, the building construction (where the fire is going), the path between the injection point and the exhaust point, and the relative area of any victims.

My FD tried for years to implement PPA/PPV with poor results. Short of some minor training points, I observed a two things that make me feel this may not be as valid a tactic in the Northeast as it is the Southeast or Southwest.

1. Here in the Northeast we have a larger percentage of old housing stock. More woodframe balloon construction, which unless it remains well intact should be a contra indication of PPA. Also basements/cellars are more prevalent and fires below the level of attack should be another contraindication. We seem to have an inordinate number of frame houses converted into multiple dwellings causing numerous ways to block the injection/exhaust pathway leading to pressurization of unanticipated areas.

2. Climate control. The places that see longer hotter summers have central AC or whole house HVAC, while in the northeast many folks only need the A/C a few weeks a year and resort to window opening/closing to cool their homes/units. This leads to buildings where we can't control the exhaust openings to properly utilize the PPA/PPV for superheated smoke and fire for longer periods (spring/summer/fall season). In the winter many old homes are closed up by closing all the doors or even using insulation board to close of whole second/third floors. Again, this blocks the anticipated injection/exhaust pathway.

Look at the bigger proponents of PPA and you'll see Salt Lake City, some Florida FD's, many Cali FD's and many more. Ask yourself how old their housing/building stock is compared to yours. The video provided shows them breaking some of the "rules of PPV" as well as some basic rules some of us beleive in.

My FD subscribes to the residential front door attack. Unlike these folks and WRaftery's FD, we actaully would have chosen the front door 99% of the time. Rather than "push the fire from the unburned to the burned" we choose to make the attack through the point which quickest gets the line between the occupants and/or stairs and the fire. With a few notable exceptions (Shotgun Shacks in TX and single wide trailers) we follow this basic plan of attack. The unburned to burned is in our eyes, a hold over from the days of 1.5" lines where we literally pushed the fire using fog streams and lower flows. Today we bring the correct weapon to the fight and extinguish the fire at the seat, rather than push it at all. I realize this is not how many FD's have been taught or practice, but it works well for us and we find we can get a line into position much faster most of the time. Finding an alternative entrance generally requires more homes, more turns, more time and often fails to secure the interior stairs. So to tie this back to PPA/PPV our fan would almost always be at the front door, but alas we (mostly) only use it after the knock.

[wraftery 1,275]

Sorry, but I stick to my guns about attacking from the rear in this scenario, and your 99% in the front door is bit high. The fire is already venting out the front door, and it is a well established vent.

Yes, my guys would have chosen the rear as did the guy in the video. Why? Many FDs teach that whenever practical, the initial arriving company does a 360 degree walk-around as part of the size up. If you can't do a complete 360, at least do sides A,B, and D. It's easily accomplished by observing one side and front as you approach and driving psat the fire building just far enough to see the far side. If you are an engine company, you have automatically given the front of the building to the truck. Ialso did not say that you could not take your PPV fan to the rear (where it belongs if that is the attack point.)

Other than that, antiquefirelt, I agree with what you said. Good comments especially about HVAC, a major factor. I would have even given you a vote.

[efdcapt115 1,511]

Some might have already seen this video (linked on the page). It's another example of improper use of positive pressure. Honestly, I'm glad we didn't have these when I was OTJ. It adds another puzzle to the already complicated tasks of proper fire attack.

I can see bigger city departments establishing protocols for using PPV in the appropriate settings. Chief Raftery pointed out using it to pressurize a stairwell in a multi-dwelling, with the high rise company officer specifically looking at vent conditions, and others I assume in the stairwells and hallways monitoring if PPV is working.

But too many times we see this; PPV/PPA backfires.

http://www.vententersearch.com/?p=419

I think the Chief from Rockland makes a valid point about construction types more prevelant in different parts of the country, and the effectiveness or lack thereof of PPV as a result of said construction.

Looking at both videos, I see two single story, frame constructions, and I see two attempts at PPA with near disasterous results. Are we looking at change for the sake of change? What was wrong with the fire attacks in either of these videos, aside from the introduction of oxygenated air as "venting"? Why is traditional horizontal and vertical (simpler operations to predict the outcome MOST of the time) being "replaced" with the PPA technique?

I can see understaffed fire departments (that means most depts.) looking for a way to "get around" the manpower required to get the vents done properly. And that's what guys should be leary of in my opinion; a chief who would experiment with PPA as a way to get more with less.

Both these structures could have been handled traditionally, obviously with different outcomes. And the guy lugging around the fan, which is something we always reserved as an "after the fire is out" event, is non effective as a truckie. The seating assignments for a fully staffed truck do not include a "fan man."

As always, just my opinion.

[bad box 371]

Watching many of the youtube fire videos that appear nowadays, it's apparent that many structure fires that years ago would be extinguished using an 'all hands assignment' (1st alarm)in short order now 'get away' often with disastrous results (Mayday's, Firefighters burned and injured while bailing out windows, etc.). Many of these situations can be avoided by adhering to Bread and Butter basics.

*Do a good size up looking for type of construction, visible people trapped, location of the fire, is there a cellar / basement, etc.

*Stretch the correct sized hose lines commensurate with anticipated fire conditions.

*Know the friction loss characteristics of the brand and style hose your department is using as well as the pressure required by the type of nozzle being used in order to provide its maximum flow.

*Vent ahead of the attacking hose team ... don't vent until they have water, are in position and tell you they are ready to move in.

*Vent - Enter- Search for life hazards.

*Ladder the building in multiple locations to give interior firefighters means of egress other than having to jump.

*Put the wet stuff (at that correct GPM's) on the red stuff ... Not over the roof into the neighbor's yard, against a blank exterior wall onto the roof shingles, etc. the goal is to overwhelm the main body of fire. Knock down the heavy fire and many of your problems go away.

Don't be too proud to admit that maybe you aren't doing the job correctly, open your mind, get out and attend good seminars given by guys who have lot's of experience and know what they're talking about. Strive to be the best at what you do ... Your life, the lives of your Brothers and Sisters as well as the public that you protect are all depending on you to do the right thing ...

Be safe ...

[gb17 3]

PPV is another tool in the toolbox for the IC. There are many advantages of using this tactic but you must know WHEN and you must know How to implement PPV. Departments in Europe and in other parts of the United States use PPV in the attack, or precontrol stage of the fire. Most of their SOPs are different from those we use in the northeast, their construction methods are different, and some are currently reviewing these procedures because of incidents similar to the one on the tape.

The use of PPV in a precontrol stage should be extremely limited. As the video shows, if the fire is not completely knocked down, the introduction of air will simply accelerate the combustion process. The FDNY program limits the use of PPV in a precontrol stage exclusively to Fireproof Multiple Dwellings. The fans are set remote from the fire floor and the only objective they have is pressurization of the attack stairwell, replicating the automatic systems found in High Rise Commercial buildings. These units create a static pressure with little air flow. The intent is to gain control of the attack stair, create a clear operating platform, provide egress for occupants, and stop the flow of heat and gasses on the fire floor. The closest an FDNY fan will get to the fire floor is three floors below, and it is usually lower. The department in the video SOPs obviously put the fans a lot closer. As EFDCapt said, standard ventilation practices should not be ignored. We should never forsake the Bread and Butter operations for some fancy new gizmo.

On the other hand, once the fire is under control, the use of PPV can be extremely advantageous. The old fashion way of taking a window and letting it lift should go the way of the back step. The toxins and carcinogens in today’s smoke are so nasty, we should work in clean environments as often as possible. We take bad enough feeds as it is. Taking unnecessary ones don’t make sense. The advantages of PPV over negative pressure are several. When using PPV, firefighters do not have to be in the contaminated area. Because you are not pulling smoke through the fan, the blades stay cleaner and the efficiency of the fan remains high. Also, you can use PPV from outside the building, thereby allowing you to use a gasoline powered fan which will move significantly more cubic feet per minute, increasing the overall efficiency of the operation. It is essential that the fire is under control prior to using the fans; the exhaust opening is large enough to vent the structure; and the wind speed and direction is evaluated and addressed.

If you asked me ten years ago if I thought that PPV was worth looking into I would have laughed and said “Not in my lifetime” without thinking. The reality is however, over the years the dynamics of fire has changed, the methods of construction have changed, the toxicity of smoke has changed. If we in the fire service are unwilling to change, we are destined for failure. This is not to say that every innovation that comes along should be embraced, but it should be investigated, analyzed, evaluated, and if applicable, implemented in a way that your department gets the best advantage from the tool or procedure, and your members operate in a safer atmosphere. After all, that should be our ultimate goal, that everyone goes home. I apologize for the rambling but it is late. Just my opinion.

[antiquefirelt 994]

Sorry, but I stick to my guns about attacking from the rear in this scenario, and your 99% in the front door is bit high. The fire is already venting out the front door, and it is a well established vent.

Yes, my guys would have chosen the rear as did the guy in the video. Why? Many FDs teach that whenever practical, the initial arriving company does a 360 degree walk-around as part of the size up. If you can't do a complete 360, at least do sides A,B, and D. It's easily accomplished by observing one side and front as you approach and driving past the fire building just far enough to see the far side. If you are an engine company, you have automatically given the front of the building to the truck. Ialso did not say that you could not take your PPV fan to the rear (where it belongs if that is the attack point.)

I cannot disagree with your tactic of attacking the fire. It's a proven valid tactic that has worked for nearly ever. We of course employed this routinely as a matter of course until about 10 years ago. Having read many experienced authors on the topic we decided to review our basic residential plan and make the change. Some of the pitfalls we'd encountered in the past were officers always trying to go from unburned to burned and this delayed water on the fire due to extended stretches and more difficult routes to stretch. The amount of fire at the front door, the relative size and compartmentalization of the occupancy both are factors that would have to be considered. In the case on the video, I think we'd have tried to KO the fire at the door if we did not recognize this a basement fire to start (hope so?).

I want to clarify that we do require our officers complete a 360 degree size-up whenever possible or as close as can be completed. The issue is not that we find another way in, as inside the front door of most of our residential occupancies leads to the main egress path of the occupants and stairwells. Rather the walk around is to gain a full grasp on the situation, which is not to say we wouldn't find something to vary from the standard plan, but it would be a variation none-the-less.

For us, an understaffed first alarm FD, getting the initial line in place between the stairs (read chimney) and the fire is huge. This first line very often will not be backed up soon enough and the guys making the search will often do so relying on that line to protect the upper floors. As with anything, there's no "always" or "never's", but our basic tactical plan for residential occupancies is very clear with little room for interpretation of the tactic. On the other hand if the initial officer finds circumstances that lead him to attack from another opening, that of course is his option. After the fire the first question will be "what is our basic residential tactic?" Once he answers this question, proving he did know the expected course of action, he is free to explain why it was not the best option at this particular incident. I've only seen this bite an officer once, where the officer could not explain the proper tactic from the SOG. His choice was valid, but the problem was not failing to follow the "front door tactic" but rather failing to know it.

I'd certainly question attempting PPA/PPV from the opposite side of the house as the attack line. This of course is secondary to using PPV above the fire which can lead to rapid unanticipated fire, smoke and heat travel. In a poorly vented basement the PPV could hold the heat smoke and fire down in the lower level having the exact opposite effect that we're trying for. Another scenario allows the Venturi effect to draw the fire up into the above space in locations not anticipated.

Edited July 20, 2010 by antiquefirelt

[Alpinerunner 61]

A lot of great discussions going on. One thing to consider when discussing front door vs. back door is that we never see the rear door in this video so it's hard to make a judgement call on that. In terms of pushing the fire from the unburned side vs. getting to it quickly, I would think that knowing that a fire doubles every minute, and thinking that how much fire are you going to "push" with water, I would go for the quick attack. However, I haven't worked enough fires to speak on that with authority... but it's something I will pay attention to more in the future.

I think the PPV issue is pretty much settled. It is primarily for overcooked food, Oil burner out of adjustment, or afer overhaul has been completed and confirmed by the thermal camera.

As far as using NPV vs PPV, I would think that wherever PPV should NOT be used, NPV should NOT be used either. If the danger is introducing air into a flamable environment, both are equally dangerous. You have to look at a house as a Control Volume. Flow in = flow out. Houses are not air tight. If PPV is dangerous because it's forcing air into the house, then air is going out somewhere. You can't really pressurize a house to any notable degree, but you do create air flow. Even if a house is closed up everywhere besides the fan door (the issue when PROPER ventilation hasn't happened), air goes out the cracks and eves of a house. Using the same logic, when you turn the same fan around and use negative pressure, you're sucking in air from all these cracks and eves and you're creating a fresh air flow EQUAL to the PPV setup, and therefor it's equally as dangerous.

Edit: Just watched the video that efdcapt115 posted. I didn't not expect those guys to come out alive. That was amazing. I can personally and honestly say that these videos have scared the S out of me and I'm glad I found them because I had not payed much attention to this issue prior, nor do I remember it being covered in FF1/2.

Edited July 20, 2010 by Alpinerunner

[antiquefirelt 994]

I think the PPV issue is pretty much settled. It is primarily for overcooked food, Oil burner out of adjustment, or afer overhaul has been completed and confirmed by the thermal camera.

I'd note that this is far from how many proponents of PPA (Positive Pressure Attack)see this tactic being used. It like so many other tactics is about knowing and controlling the variables.

[wraftery 1,275]

Blow on kindling, you get fire. Don't do it inside your tent.

-New Proverb

-ME

[x129K 1,393]

Some might have already seen this video (linked on the page). It's another example of improper use of positive pressure. Honestly, I'm glad we didn't have these when I was OTJ. It adds another puzzle to the already complicated tasks of proper fire attack.

I can see bigger city departments establishing protocols for using PPV in the appropriate settings. Chief Raftery pointed out using it to pressurize a stairwell in a multi-dwelling, with the high rise company officer specifically looking at vent conditions, and others I assume in the stairwells and hallways monitoring if PPV is working.

But too many times we see this; PPV/PPA backfires.

http://www.vententersearch.com/?p=419

I think the Chief from Rockland makes a valid point about construction types more prevelant in different parts of the country, and the effectiveness or lack thereof of PPV as a result of said construction.

Looking at both videos, I see two single story, frame constructions, and I see two attempts at PPA with near disasterous results. Are we looking at change for the sake of change? What was wrong with the fire attacks in either of these videos, aside from the introduction of oxygenated air as "venting"? Why is traditional horizontal and vertical (simpler operations to predict the outcome MOST of the time) being "replaced" with the PPA technique?

I can see understaffed fire departments (that means most depts.) looking for a way to "get around" the manpower required to get the vents done properly. And that's what guys should be leary of in my opinion; a chief who would experiment with PPA as a way to get more with less.

Both these structures could have been handled traditionally, obviously with different outcomes. And the guy lugging around the fan, which is something we always reserved as an "after the fire is out" event, is non effective as a truckie. The seating assignments for a fully staffed truck do not include a "fan man."

As always, just my opinion.

I saw this video a year or so ago and watched it over and over dumbfounded...I put a link to it on my FD's website,..if that is not an eye opener, i do not know what is!?