Thread: PPV - Negative Aspects???
08-12-1999, 07:08 PM #1Paul GrimwoodFirehouse.com Guest
PPV - Negative Aspects???
I first saw PPV in use by LAFD in 1990 with Task Force 3. It was spectacular to see the effects and all were positive. I have since followed the development of such tactics with great interest and everywhere I go, firefighters are quick to put forth the good experiences they have had in using aggressive
pre-attack PPV operations.
However, I would be interested to hear the 'negative' aspects of PPV - the bad experiences; the errors; the mistakes; the problems; basically - some pointers to look out for?
08-12-1999, 07:42 PM #2Dalmation90Firehouse.com Guest
1) If you're gonna use it, don't do it half-heartedly...we had a fire that they began using PPV on and then proceded to open up all available windows and doors, and the only places that got Positive ventilation was the voids...ugly fire.
2) Gotcha #2 was a fire I was at where for a while the front and rear doors of the apartment where open...but instead of the fan blowing in one and out the other, we had fans blowing into both at the same time -- fortunately the fire was already knocked down and we were just removing smoke, otherwise it could have been a more serious situation.
But realize neither incident was a disaster...all it took was for an officer to step back from a minute, take a look at the scene, and say "Whoops, hey folks, what are we doing here?" to get the problems straightened out -- and that's probably the point, just keep your eyes open for what the fire is doing under the ventilation!
As an aside, don't forget it's use as a quick and dirty adjunct to the Rehab area on hot summer days!
Also, if you haven't invested in PPV fans, we used regular smoke ejectors for a couple years when we first started and they worked well enough to prove to us the worth of investing in better fans...but the point is, they still worked!
[This message has been edited by Dalmation90 (edited August 12, 1999).]
08-12-1999, 10:30 PM #3JimDWFDFirehouse.com Guest
My department carries both ppv fans and smoke ejectors. However, we normally only use these to remove smoke from things like burnt food. At structure fires, taking out glass and opening the roof are the norm.
Some of the problems i've seen first hand with using ppv are: setting the fan in the doorway, using it even after ALL the glass in the house was gone, using ppv without an opening, and putting the ppv fan in the building blowing outward. I think most of these problems are due to lack of training and understanding how ppv works.
Using ppv is a great tool. The best way to prevent problems is training, training and more training. Making sure everyone knows how to operate it, position it, and understand the principle behind it will help eliminate future problems.
08-12-1999, 10:38 PM #4KEAFirehouse.com Guest
If your looking for negative issues on PPV may I suggest you contact the University of Illinois Fire Service Institute.
The U of I has taught against the use of PPV for some time. I don't agree with them nor does most of Illinois but they are insistant that it kills people. (Rumor has it that a training fire years ago got out of hand using it improperly and a firefighter got killed.)
My experiences have been positive and I attribute that to good training.
One fire that does come to mind was during some filming for American Heat with Ron Moore in Kankakee, Ill. It was a basement fire, entry was made through the front door and they went through the house to get to the stairs. Unfortunatly right next to the main front door was another entry way. (It was an old migrant workers housing) The Fan was placed in that door instead of the door used for entry. It took about 1-2 minutes before you could see the fire and smoke rapidly build.
Like Dalmation stated, simply staying calm and analyzing the situatioin the fan was repositioned to the proper entry and the results were almost instant. (30 sec.)
08-12-1999, 10:47 PM #5resqcaptFirehouse.com Guest
I think we can all agree that P.P.V. is a wonderful tool IF used correctly. Unfortunately, when used incorrectly it can have devastating effects. The following example is a good case in point of P.P.V. being used incorrectly.
A smoky, hot fire in a townhouse type apartment. Crews inside conducting search and rescue and looking for the seat of the fire. 5 - 10 minutes into the search and crews were still unable to locate the fire.
Someone decided to fire up a P.P.V. fan and place it into the front door. Needless to say interior crews quickly found the fire. Unfortunately the crew performing search and rescue upstairs caught the main brunt of the fire as it raced up the open stairwell. The team became seperated trying to escape the super heated conditions. One of them fell down the stairs through the fire. His partner had to jump from second floor window to avoid being more severly burned.
Both firefighters were wearing full P.P.E. including hood. Both suffered second degree burns to head, face, and arms. Head burns were caused by losing helmet. Luckily both have recovered and are back to duty.
(This happened several years ago before Thermal Imagers were around for our use.)
I have tried to retell this story to the best of my knowledge. Both of the firefighters burned in this fire were friends of mine. I was not on the fire but have discussed it with them numerous times.
Again, P.P.V. is a wonderful tool, however can be very dangerous when used improperly. This accident could have been prevented with proper training.
We rarely use P.P.V. during fire attack. We generally rely on windows and roof work. It seems to me (opinion alert!) that unless you have a good idea where the fire is and where you can vent it, P.P.V. shouldn't be used during initial attack. Of course if fire location is known and can be vented without much difficulty, P.P.V. is a great benefit to the attack crews.
Well, enough of my rambling. Remember, the views expressed here are not necessarily those of the management.
Stay safe out there,
08-13-1999, 03:23 AM #6Paul GrimwoodFirehouse.com Guest
Wow! Great (and honest) responses guys! Keep 'em coming....I think we can all learn from openess and other experiences like this.
Here's one to add. I was told by firefighters
in Dallas and Seattle - to PPV a 'T' shaped structure from the base of the 'T' causes a swirling effect in the smoke at the area where the 'T' crosses (does that make sense)!
It struck me that two groups of firefighters had experienced a noteable effect. The effect
prevented the smoke and gases from leaving the central area of the 'T' shape.
Share your experiences (and views) guys - and no......these are not necessarily the views of the management! Thanks for your responses to date..........
08-13-1999, 09:45 AM #7Dalmation90Firehouse.com Guest
Yep, I can see there being smoke stuck at the "cross" in the T...it's called turbulence, and right angles always increase it whether you're moving water through pump piping or air through a building...
But...if I only would think it would happen if you we're venting from both ends of the top of the "T" at once...seems to me if you vented one then the other, it wouldn't create an eddy (swirling air, water, etc) there.
One more comment...there is more than one "correct" way to fight most fires, but mixing and matching without thinking out the consequences can get you in trouble. Aggressive PPV backed fog attacks can work wonders, and so can FDNY style smooth-bore and search ahead of the line operations. But start PPV after you've already gotten crews deep in the building like FDNY and you're gonna get burned!
08-13-1999, 10:29 AM #8morrissFirehouse.com Guest
Don't forget about the posiibility of CO inside the structure. A few years ago, we were removing smoke from an electrical fire and had our 4 gas meter in the area and it alarmed on CO levels. Now we routinely use the meter to check whenever we use a gas powered PPV. We have also purchased extensions for the exhuast systems to route it away from the fan's suction.
08-13-1999, 05:49 PM #9Truckie from MissouriFirehouse.com Guest
To PPV or Not To PPV...that is the question.
To quote from Captain Steve, OPINION ALERT!! I am NOT speaking on behalf of any organization or anyone but myself.
I agree that PPV is a great tool. It has its uses, and when used properly it does save a lot of effort. We did some experimenting with it on one of my old departments. In one building we were training in, we sealed the building, less the entryway, lit off a room, got it going, and let fire start going above our heads. Then we fired off the PPV fan. The pressure pushed the fire back into the room of origin! That was cool! We then radioed for the vent man to pop the window, and it blew most of the fire out of the house. Easy extinguishing job. Do I recommend that for all fires? NO!! But in a controlled experiment, it sure was fun!
However, I think this tool is NOT for every fire. On my other department, we had numerous older balloon structures. And we frequently had to put them out. We found out the hard way that PPV will cause the building to become a parking lot in a big hurry. For fires in these styles, I strongly urge the traditional, tried and true methods of opening the roof fast and get in and hit it hard, opening the walls and ceilings as you go. I am a firm believer in opening the roof in these buildings. Vent early, vent often.
Frequently, in more modern buildings, the fire has advanced enough that natural openings are already gone, or the fire has burned thru the roof. I noticed that PPV only brings in fresher, cooler air behind you (not that I am complaining) and we still have to use older methods to vent. Placeing a fan in front and back and removing the rest of the windows, skylights, etc. can create a nice draft that'll clear things nicely. HOWEVER, be damn sure that there are enough charged and manned hoses inside to handle things that may flare up...unless you want to be a statistic! I prefer we all go home at the end of our shifts, not having become a statistic.
Proud Member of IAFF Local 3133!
08-14-1999, 05:57 PM #10Capt. EdFirehouse.com Guest
Hi guys! I work with resqcapt. and we have on numerous occasions discussed this topic. As stated, we use our PPV mostly for after the dance clean-up. I can, however, relate to the flash burned interior crews. Had it happen once, but the damage was done with a smoke ejector turned backwards. The simple point is, again, if you don't know where the seat of the fire is, and you have people in the building, please resist the urge the stoke the kettle. This will probably hurt us, and more than likely, the ones we are trying to save.
My two cents worth!
08-14-1999, 09:58 PM #11FREDFirehouse.com Guest
As for the PPV it has its uses just as any other technique but you can't rely on it as a solution to all your problems.
I've had some personal exp. with the PPV and it wasn't all that good.
If not set up correctly it can really ruin your day. If the cone doesn't cover the entire door way and there is insufficent ventilation, the cool air flows in right past you to the fire and the fire races back over above and behind you toward your entry point.
You might break out some windows on the back of the house but you never know.. Are the doors to the rooms you just vented open completely...if not you still don't have an exit for the Pos.Pres. and also is the door to the room open paritally with an uncounicous victim lying behind it passed out after he was able to open the door only a few inches. Now you vent the window behind him and now you are sending super heated gasses and steam(asuming you started the PPV after the ENG. Co. has started attacking the base of the fire) toward the victim who now has even less of a chance of survival.
What it you have crews searching on upper floors and they find it nesesary to vent to aid in the search or as a means of escape... they just have made another vent hole for the PPV
However, vertical ventilation and removing all the glass are still the most effective means.
Based on my observations and experiences is use of the PPV works well if the company setting it up is well practiced in its use and had done live fire training with it and once the Engine Crew has attacked the main body of fire and has knocked down the majority of it. Other wise there are too many variables that cannot be accounted for. And place your men and the citizens you serve in undo risk.
[This message has been edited by FRED (edited August 14, 1999).]
08-14-1999, 11:41 PM #12chief4102Firehouse.com Guest
FRED; I agree with you. I was at a live burn training where the fans were placed and started, the hose crews made entry, but the exhaust vent wasn't made (somebody forgot). The smoke, heat and, soon, flame rolled across the celing over the crew's heads, and out the door where the fan was running. As soon as the vent was made, the situation greatly improved and the lines were able to be advanced. When properly set up and when we are reasonably sure of life and fire location, the PPV is impressive. Training and experience make the difference.
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