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Ventilation
In our seminar Residential Ventilation in a rural setting the other night these where some of the comments.
When do you Ventilate?
Where do you Ventilate?
Why do you Ventilate?
Remembering for every action we make on the fire ground there will be a reaction. Do you do a vertical or horizontal vent hole. And where?
One of the things that stuck out in my mind was this and makes perfect sense when you think about it is.
The most important question up here is why are you venting. For Fire or Life.
We vent for fire because we want the fire to do what we want it to do and go where we want it to go.
We vent for life by taking a window and doing a vent-enter search for a suspected or known victim.
This was the commit: If you do not know why your going to vent then you most-likely shouldn't vent at all.
If we vent in the wrong spot by taking a window for the sake of taking a window we will bring the fire right to us. So if we just had a room and content fire; well now we have a whole structure fire. If we have fire blowing out the roof already is there really any reason to put a guy on the roof?
This was just some of the comments made. If any organization is going to put on a 3 hour seminar I would recommend this one.
Replies to This Discussion
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Permalink Reply by captnjak on
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I think too many in the fire service are operating under some hard and fast rules that don't necessarily apply anymore. We all (as far as I know) acknowledge that modern contents fires burn faster and hotter, with more production of smoke/fire gases, than fires of previous generations. Some real oldtimers may not want to hear it but we know it's true.
We all were probably taught at some point about the difference between venting for fire and venting for life. The difference is only in the reason we are doing it. There is no difference in the result. The fire certainly doesn't care what our reasons are. So if we vent a previously darkened down (due to lack of oxygen) fire area, the fire may rapidly light back up and intensify. Combined with an open door and/or other window openings, the opening we make could cause fire to spread not only out the window we vented but into other areas of the structure. The same holds true for openings made remote from the fire area. We are still introducing air to the fire and giving it what it needs to intensify and spread. So we haven't improved conditions for search and we haven't gotten the fire to do what we want (release all or most of it's heat out the window).
I'm sure we were all also taught that venting allowed heat and smoke/fire gases to leave the building, improving interior conditions for search and line advancement. But that is so often not true. The openings we make just aren't big enough to do the job. Even vertical ventilation can be insufficiently sized to do the job. That doesn't mean we sholdn't vent roofs, but that we have to understand that it's not a guarantee of 100% effective ventilation. Fire can still extend horizontally after a roof is opened.
I like the point about knowing why we do things. I think it is underutilized on the fireground. We devote so much time to knowing HOW to do things. First we have to know whether or not we SHOULD be doing some of the things we do.
When it comes to ventilation I still think the where and when questions are most important. Vertical ventilation DIRECTLY OVER THE FIRE as soon as possible and horizontal ventilation of IMMEDIATE FIRE AREA ONLY when a CHARGED line is in place and READY TO OPERATE is the way to go. This is CONTROLLED venting and gives the best chance for success. Rooms remote from fire can be entered and searched from windows only if door to room is closed or can be rapidly closed by firefighter entering that window. This requires experienced firefighters. When in doubt, it probably should not be attempted.
We cannot control fire with ventilation. Even PPV will not control the majority of fires. Proponents of PPV all acknowledge there are very strict guidelines for when to attempt it. And they admit that at some fires the attempt may fail and PPV would have to be stopped. (In these cases time is lost that firefighters and occupants simply cannot afford to lose.)
Aggressive interior attack with a hoseline flowing 180 GPM or more is the best method to extinguish fire. Taking windows may or may not intensify fire. Water NEVER intensifies fire and the window(s) we took in the immediate area can help vent the steam.
I reccomend visiting the various websites (NIST, UL, etc.) that display the results of recent tests on affects of ventilation at fires.
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Permalink Reply by Derek J Sinesi on
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.John, I agree. This was a great class taught by one of your own. Mickey Conboy. I put this up due to the fact that out here in the sticks the response time is much longer and you see guys venting for no apparent reason. When asked they will tell you I don't know why. I find water solves most of our problems. Most of the time when we get on scene the building has already flashed and venting.
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Permalink Reply by Jim Conrad on
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We use ppv most of the time. We are not trained enough to get on a roof and cut a hole, a problem we are working to remedy. What bothers me most is that we always set up the fan and don't always know why, how or when to use it effectively. We just know that we have to set up the fan. However, we worry less about the ventilation and get right to putting water on the fire, so we are USUALLY successful. We often transition from exterior to interior when more people show up and we can mount an interior attack. We are working towards getting better with the when and why of ventilation. Derek, I am envious of your dept. for getting what sounded like a great class, I wish something like that could come to Montana where I live.
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Permalink Reply by John Crabbe on
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Seems like you picked up on things and that is good. Hopefully this spurs some considerations out there. Although, the challenge is that the questions are scenario driven and such decisions will vary by dept, what is found on scene, and resources available. Essentially it comes down to understanding the when and the why and what I have seen here so far, I find that most concerning.
I like the point about knowing why we do things. I think it is underutilized on the fireground. We devote so much time to knowing HOW to do things. First we have to know whether or not we SHOULD be doing some of the things we do.
I agree with John here and it does come down to the crux of the issue. We had seen where a crew was always sent to the roof, bcause that's what we do. Then we seen where windows are busted out because "that's what we do". Now we see PPV fans and even scarier, see the same type of mindset. It really does come down to knowing whether or not we SHOULD be doing something and that gets answered with training.
When looking at the issue, it comes down to the situation you are presented with and what the priorities are. It also comes to sizing up and recognizing immediate threats....such as signs of a backdraft. Is the fire self venting already? What about wind speed..how does that affect tactics? and so forth.
I find these comments from Jim most concerning....
We use ppv most of the time............ What bothers me most is that we always set up the fan and don't always know why, how or when to use it effectively. We just know that we have to set up the fan.
Not to knock the comments because I find such admission beneficial to learn from this. Considering there have been 3 comments so far and each one mentions the aspect of doing something "because that is what we do", shows why firefighters should be asking "WHY" and to address concerns that accompany such lack of information.
Using PPV incorrectly has attributed to FF deaths and many close calls, but just seeing the comments shows that the message is not getting out. If you have a dept setting up a fan and don't know why or how to use it effectively can get someone killed on the fire scene. You are no longer just blowing smoke out, you are giving a fire a lot of fesh air. If not used correctly this can lead to flashover, collapse, etc. Thee has to be adequate and ample exhaust opposite of the fan to be effective. You have to know where the fire is before using a fan. You should NEVER put a fan in operation after personnel have entered.
To me, there is enough examples out there of PPV being used inappropriately that should be learned from. Last year, inproper use of a PPV fan and inadequate exhaust led to the collapse of roofing of a theater and killing a FF in WI. There is a video on Youtube showing a training burn where a fan was put in operation after crews went in and the fire flashed....leading to several close calls.
If anything, at the next training, take a look on youtube of PPV and there is enough to show the reason to be able to answer the "WHY" and should also answer the questions of "WHEN TO" and "WHEN NOT TO".
Personally, I would find it inexcusable for anyone to do something and not know why they are doing it. That means your training has let you down. It is the responsibility of the FF to be able to know "why", if they don't, then learn as to why. That is how one is going to protect themselves and their fellow FFs on a scene.
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John, Thanks I put this up not so much as a training thing on ventilation. But more of a self examining on Why. Why we do Venting, Why we cut a roof of a car. Just plain Why do we do anything we do on the fire ground. These questions hit home because I know the answer most of the time. But I realized that most of the time I do not ask myself these things on a scene just because of the this is what we do mentality. And we do not run many calls that amount to much.
For the most part most of us know how. We forgot the basic's When, Where, and WHY. I hope this will inspire people to start looking at this stuff and maybe realize we are doing just dumb stuff that is getting people hurt or killed. Mostly because of these three words.
I'm not trying make anyone mad or pick on anybody. These are just good questions not only to ask ourselves but to take to our departments and ask. Like Jim stated We place a PPV every time and don't know why but we do. I'm not a big fan of PPV in the first place. Is there a place and a time to use it. You bet. The question becomes When, Where and Why?
So my goal here is maybe make someone else realize crap I forgot about these things too. And we start thinking and doing things a little smarter and safer.
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Jim, 10 years ago a couple on the department I belong to roped me into being a delegate. I was to go to the County firemen's association meetings, state conventions and so on. So my first County meeting I looked around and said to myself no wonder why nobody wants to come to these. It was mostly guys in their 70s with a few younger guys and girls talking about much of nothing. Over the years I have learned a lot from these guys so don't take that last comment the wrong why. after a few of these meetings I decided to run for a directors spot and try to change things. So a long story short I did and one of the changes I helped with is to actually do something for the firemen and woman in our area. We talked to the County Chiefs association and we have a joint training seminar every year. The cost is any place from $1800 to $3000 a seminar. We have a good turn out every year; this year was 210 FF's from 43 different departments from 6 different counties. We do not charge for any of these. We have some that think we are nuts to have these well know speakers and trainers come in. I just tell them there is no value you can put on a follow bothers life and as long as we can raise them monies to put on these types of seminar we are going to at no cost. I would like to think that you most have association's out your way that could put on these types of training seminars. Something you may want to look into.
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We adopted PPV as a means to keep untrained people off of roofs. The downfall is that we do so under the impression that PPV is the be all end all in ventilation. I am not trying to throw any of our people under the bus, but I am now convinced that PPV takes as much training to do properly as making a proper roof cut as far as the when and why is concerned. Some of the officers have training in PPV but don't always show up to the fires. When they don't show up the others set up the fan because they have seen it done before and nothing bad happened. I have been suggesting that if we don't know why we set up the fan we probably should not do it and instead concentrate on getting water on the fire. I have also been harping on the DEPT. to get the state up to train us on PPV, horizontal and vertical ventilation. But the problem for us is staying proficient at those skills and using them in a coordinated manner. I think John Murphy said we can waste a lot of time venting improperly when we could just put water on the fire. Great discussion Derek, I think it all comes down to being a student of fire. The fire service needs more people who are not satisfied with the statement, "Because that is how we have always done it." I want to know why we do it and if it can be done better and safer.
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One of the things that works against us on the fireground is the personality types of those drawn to the fire service to begin with. We are not wired to stand around and watch things unfold. We are "doers" by nature. We want to "fix" things. It is very difficult to develope the individual and team discipline to fight a structural fire. It is even more difficult to develope the discipline to NOT do something right away. Sometimes that is what is needed most.
We always say we should learn from our mistakes. First we have to acknowledge that we made them. The best firefighters, officers and chiefs I've known were always able to talk constructively about what they could have done better or would do differently next time. It's probably one of the things that makes them the best.
As far as PPV goes, it's been exhaustively debated in the fire service for a lot of years. Here are the vital points that supportes of PPV have never explained to my satisfaction:
1) They say never start a fan AFTER firefighters have entered the structure. Would this be detrimental to firefighters in full PPE? If so, what does it mean for UNPROTECTED civilian victims who may be present?
2) They say fan use must be discontinued if smoke/heat/fire gases are seen exhausting out of entry point. Because fan is not being effective. Probably due to insufficient number or sixe of exhaust openings. If fire has been drawn to entry point, where else has it gone? This is basically a trial and error scenario, start the fan and see if it works. If not, fan must be removed and exhaust openings made bigger. Or PPV tactic discontinued entirely. Valuable time has been wasted at this point. A properly operated hoseline could easily have extinguished fire by this point. So why not just start with that from the time of arrival. Delaying the operation of hoseline for 3-6 minutes (I'm being generous here) in order to save a minute or so at best on advance time makes no sense. Average detached single family dwelling just isn't that big. Hose can advance rapidly. That is probably what many departments should be dedicating drill time to as opposed to the (very) fine intricacies of PPV.
3) Once you apply all of the parameters for when PPV can be used, you realize it's only appropriate for a relatively small number of fires. Water is always appropriate and accomplishes all of the things that PPV does.
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Permalink Reply by FETC on
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Micky is a great instructor, you guys are lucky to have him. In my opinion most firefighters are reactive when it comes to ventilation in todays fires due to the expotentially fast curve with todays fuels. So much so that when they realize they are hot, it is too late to self ventilate. Meaning at the point that your gear is no longer protecting you (maximum heat saturation) firefighters are looking to take a window to make things better.
This is a catch 22 because you were not trained in an environment that had the same curve.
That said, and going back to your basic fireground training, either at the academy or controlled burn, NFPA 1403 allows class A fuels that are often hay and pallets. These can produce some decent temperatures for the students, but they will never provide the student with a realistic heat flux / flow path. That said when you ventilate in a NFPA1403 training burn, EVERYTIME you open a window or roof, things ALWAYS GOT BETTER.
But if you take a window in a non-training "real deal" uncontrolled fire tonight, the next 60 seconds post window or door being opened actually makes the room you are "already suffering in" about 100F worse, and thus many times firefighters are burning themselves.
So going back to your comment "vent for life" and "vent for fire"... ventilation must be done correctly for not only the victims but the firefighters themselves. The real question is can we vent now at this moment with the tactic we are about to use, and will it make things better and/or worse. It is all about situational awareness and determine where we are, how hot it is and what is gonna occur when I do ventilate.
I teach a class on this subject as well and many times the training provided in a FF1 or 2 is the bare minimum for a canned program, and often times the material is based off of the fuels and smoke conditions found in the 1960's (CO based 1100F flashover) and not what we are expected to work in tonight with todays synthetic and hydrocarbon based fuels off gassing chemicals like acrolein, toluene, benzene. CO and HCN, for which the low self ingnition temperature of some of the toxic chemicals is in the 400-500F range.
Bill (FETC)
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What do you mean by "when they realize they are hot, it is too late to self ventilate"? I'm not familiar with the term self ventilate. I will assume you are referring to a firefighter taking a window in order to cool the room he/she is in. Any time a firefighter is feeling heat through the PPE, it is time to get out of the area immediately. You only have a few seconds, so there is no time to take a window and as you stated this may make things worse and not better. The 100 degree increase could easily be much more than that. We are seeing temperatures in modern contents fires approach 2000 degrees at times. These are staggering numbers and unheard of in the past.
The only other remedy would be immediate cooling of the fire area by an adequate hose stream. Way too many discussions about ventilation fail to even mention water. (Bill, I notice your reply did not mention water at all.) As if it's an afterthought. This is the most dangerous outlook we can have.
I agree that "live burn training" is a misnomer. You just can't replicate the real thing. I don't see the point in training people to operate in high temperatures. The last thing we want is firefighters feeling comfortable in high heat; there is no reason whatsoever to feel comfortable! Heat is the enemy. When we encounter it we should eliminate it ASAP. The best method is a charged hoseline flowing an adequate stream. What we should be training on instead of high heat is advancing hoseline in low visibility. This would get us better at applying quick water to the fire, which always improves conditions.
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I agree that PPV requires more training than roof ventilation. And once you train you realize that PPV is only appropriate at certain fires (fairly strict parameters). A sufficiently sized roof opening ia always appropriate. Conditions do not deteriorate due to roof opening (except in extreme cases). It is possible for fire to spread horizontally after roof is open. Opening the roof and then waiting to push down the ceiling until charged line is in place would probably get the job done even in these rare instances. A hoseline with an adequate stream is the only thing more consistently reliable than roof ventilation.
As fas as training goes, I would try to drill on vacant properties or properties about to be demolished (with permission of course) and/or mock ups. Smoke and fire are not necessary, at least at first. Get the members used to the saw and it's operation, along with familiarity with cutting motion. Holes should be directly over the fire. Start small and expand. There should be at least three members on roof. One to make cut, one to act as guide and one to keep an eye on overall conditions (fire, structural stability, holes in roof, electrical wires, communication, etc.) There should ideally be two options available for getting off roof. Roof stability must be checked initially and as cutting progresses. Roof ladders are great for footing and spreading out weight.
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John
I agree putting the fire out takes away most of our problems. I didn't speak to that because Derek was speaking towards ventilation specifically. As you know studies from NIST and UL have shown the spike in temps from the onset of taking the window or opening a door.
Most of the fire service fight fires with far less manpower than you are accustomed to, many are trying to be aggressive from the inside with less than 10 on scene. Taking windows from the inside is pretty common tactic to the little guys because there is no ladder company outside or there is rarely roof ventilation being performed. Where I work and we are full time department, I need to strike a 2nd or 3rd alarm to get your initial manpower for a report of fire.
I stated that training in highly controlled environments with hay and pallets has provided a false sense of security to firefighters. In training, ventilation always makes things better... it reduces heat, smoke gases. But in synthetic and hydrocarbon based fuels many of these fires are extremely under-ventilated and firefighters make the aggressive attempt for attack and a short time later when it feels hot through their PPE, they look to ventilate and that is the wrong choice. Back in their training experiences though, they never maxxed out their PPE and the limiting factor for interior time was SCBA air, but now because of the rapid HRR our gear in a good fire only provides 2-3 minutes of protection before it is saturated. Add in a poor stretch, short line, spagetti mess in the street, lack of manpower to make the pull or turns, then you have a delay in getting water actually on the fire and your PPE is maxxed out in no time. If you look at many reports about firefighters "surviving a flashover" lately in the news, often it wasn't a full room and contents flashover it was post taking a window for which these guys spiked the room temperatures by leaning out the rich smoke environment and the PPE was already maxxed out. A rapid fire increase is why they got burned not a true floor to ceiling flashover.
Training on realistic fire behavior, fire attack, and ventilation all are factors, and yes we can't replicate the real world temperatures, that would be too dangerous, but if we don't train them on the environment, how are they expected to work in it? They always fall back on their actual training experiences...
Good discussion brother...
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