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Impact of the UL Study on Ventilation and Fire Behavior

December 10, 2010 UL issued their finding of a study titled "Impact of Ventilation on Fire Behavior in legacy and Contemporary Residential Construction".

There has been a few articles written, on-line training from UL, an excellent class at FDIC 2011 and a few discussions that I have seen read and taken part in surrounding the UL study. Jerry Knapp wrote a good 2 1/2 page article http://www.fireengineering.com/articles/2011/06/ul-vent-study.html urging each of us to read, learn and train off of the data presented by UL from this study.

 

So now that this study was issued just over 8 months ago I have a few questions for all of you regarding this study.

 

Are you aware of the study?

Have you read the executive summary? http://www.ul.com/global/documents/offerings/industries/buildingmat...

Have you read the 405 page study? http://www.ul.com/global/documents/offerings/industries/buildingmat...

Have you discussed the study with your crew at the kitchen table or during training?

Have you changed your tactics based on the study?

Have you trained and practiced getting water onto a fire with 100 seconds for a 1 story home and 200 seconds for a two story home?

Do you feel the fire service will learn from this valuable study and apply the skills learned to ventilate today's fires?

 

I ask these questions in an effort to open the discussion surrounding this report. I would venture to say that many of you have not read the entire report. So my goal with this post is to start the conversation so we can all learn from each other and begin to train and apply the valuable information documented by UL. Please understand that the following discussions can not replace the necessity for you to read the study. Yes, its 405 pages and its allot of information to digest. But we must each read and learn what has been published to keep each of us and our crews safer.

 

So how about it, who's up for some good spirited conversation so we can each learn from each other?

Tags: Behavior, Construction, Contemporary, Fire, Residential, Study, UL, Ventilation

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Mike, do you have the information to post so if anyone is interested in purchasing it?



Michael Dombroski said:

Hi

This is an extremely interesting topic and I am also working my way through the report.  I find it more interesting to engage in these discussions with my North American brothers, as our firefighting tactics differ in so many ways.  We do not have "engine and truck companies". Therefore the first arriving unit decides what the priority tactic is to be.  For house fires it is almost always getting water onto the fire before anything else (unless we see a victim in need of rescue).  Ventilation is an area we consider as secondary to applying water.  In fact often we will employ "anti-ventilation" until hose lines with sufficient flow rates are established prior to making any opening (including the front door).  I have travelled to the USA on a study tour and the greatest difference in our operational tactics is the aggresive ventilation employed in the USA.  I believe we have a lot to learn in that respect.  I'm sure that we can do better at tactical ventilation and I think that the lack of ventilation may have contributed to injury for us in the past in some cases, so I'm certainly not saying we are any better, or even that we have got it right.  I do note however, having examined the different "styles" (in the USA, Europe and at home) I think we can all learn from each other and that perhaps the aggresive ventilation employed by some may also have contributed to injury in the past and that anti-ventilation, or pausing the ventilation tactics may be advantages and prevent injury in some cases as well.

There is a fantastic book available called "Euro Firefighter" written by Paul Grimwood.  He examines this topic in some detail and offers his perspective from experience in the UK and the USA.  I highly recommend his book.  He is truely an expert in relation to fire fighting tactics.

We are a global community and as I have discovered, there is so much to learn by looking outside and having an open mind about what others are doing.  I look forward to following this discussion and learning what I can from it.

Kind Regards

Mike D

Chief, thanks for the comments. I watched your suggested videos and I have an issue with the first one. During the video, its says the window was vented behind the nozzle. I don't think this is correct. The fire was vented when the front door was opened. This caused a flow path of smoke and hot gases towards the front door. When the window was vented, this caused an inrush of air which caused the room to flash and the fire followed the flow path towards the door where the nozzle and search teams were located. If the window was never opened, I believe the results would have been the same but occured later. After reading the UL study (my head really hurts now), it is my belief that venting the window of the fire room prior to opening the front door is best practice on single story residential structures. This causes  the flow path to be out the window, drawing air from inside the house and allowing hose teams to advance towards the fire room quicker and safer. I think convection is the main culprit in heat transfer from one area of the structure to another. This convection of hot smoke and gases primes the pump for flashover and unlimited burning. Control of air movement is the most important idea behind ventilation. Maybe I just said what everybody is already saying.

 

I really can't wait until they do a study on fire remote from the front door. I think this is more real world.

P.J. Norwood said:

Kelly, I agree with Chief Hartin as there are no absolutes. But, I will add that if you are venting ahead of the line as you should always be, you must coordinate with the hose team. Now, this does not mean they must call you on the radio!

Check out this clip from my vent video from Fire Engineering/Penwell's Tactical Perspective Series: http://community.fireengineering.com/video/video/show?id=1219672%3A...

 

When you see or hear signs that the hose team is in place and/or flowing water then open the windows. Check out this excellent video: http://community.fireengineering.com/video/video/show?id=1219672%3A...

You also question should you open the door before the window. This there is definitely no absolutes as you must be able to read the building (construction and fire load) and determine which way the fire is moving or will move and where your hose team is entering. You must remember anything that you open is ventilation and the fire will grow. This is a double edged sword that we must understand and we need to get our FF's and Officers to understand ventilation MUST be coordinated and MUST be ahead of the advancing hoseline.

 

Check out my videos posted on my page in this community also check out this video in its entirety and it may help you with some of the tactical elements you are looking for: http://www.pennwellbooks.com/tapebdvd3ve.html here is a trailer on you tube: http://www.youtube.com/watch?v=E4QxVGBn130



Kelly Wingert said:

I've read a little bit but what I've really been waiting for is someone to do all the work and figure out the tactics. Should I take the window before we open the door to the house? Should I wait until the nozzle is at the fire room before opening a window? Does it matter if it is a single story or multi-storied building?

These are the questions I am looking to be answered.

Kelly, the crew did open the front door start their advance and then the window was taken behind them. This was staged during the filming. You are correct that when the front door was open they did ventilate and yes if the window wasn't take the same condition MAY have occurred just later. Our goal was to show what happens in the hallway when ventilation is not coordinated and done behind the line. Yes, my head hurts too!! I can't say I disagree completely with your tactics on a single story residence. However any ventilation that occurs by taking the window first still must be coordinated because as documented the crew has limited time to get water on the fire!

I am interested in Steve's and Chief Hartin's input is! Thank you for the great exchange!
Kelly Wingert said:

Chief, thanks for the comments. I watched your suggested videos and I have an issue with the first one. During the video, its says the window was vented behind the nozzle. I don't think this is correct. The fire was vented when the front door was opened. This caused a flow path of smoke and hot gases towards the front door. When the window was vented, this caused an inrush of air which caused the room to flash and the fire followed the flow path towards the door where the nozzle and search teams were located. If the window was never opened, I believe the results would have been the same but occurred later. After reading the UL study (my head really hurts now), it is my belief that venting the window of the fire room prior to opening the front door is best practice on single story residential structures. This causes  the flow path to be out the window, drawing air from inside the house and allowing hose teams to advance towards the fire room quicker and safer. I think convection is the main culprit in heat transfer from one area of the structure to another. This convection of hot smoke and gases primes the pump for flashover and unlimited burning. Control of air movement is the most important idea behind ventilation. Maybe I just said what everybody is already saying.

 

I really can't wait until they do a study on fire remote from the front door. I think this is more real world.

P.J. Norwood said:

Kelly, I agree with Chief Hartin as there are no absolutes. But, I will add that if you are venting ahead of the line as you should always be, you must coordinate with the hose team. Now, this does not mean they must call you on the radio!

Check out this clip from my vent video from Fire Engineering/Penwell's Tactical Perspective Series: http://community.fireengineering.com/video/video/show?id=1219672%3A...

 

When you see or hear signs that the hose team is in place and/or flowing water then open the windows. Check out this excellent video: http://community.fireengineering.com/video/video/show?id=1219672%3A...

You also question should you open the door before the window. This there is definitely no absolutes as you must be able to read the building (construction and fire load) and determine which way the fire is moving or will move and where your hose team is entering. You must remember anything that you open is ventilation and the fire will grow. This is a double edged sword that we must understand and we need to get our FF's and Officers to understand ventilation MUST be coordinated and MUST be ahead of the advancing hoseline.

 

Check out my videos posted on my page in this community also check out this video in its entirety and it may help you with some of the tactical elements you are looking for: http://www.pennwellbooks.com/tapebdvd3ve.html here is a trailer on you tube: http://www.youtube.com/watch?v=E4QxVGBn130



Kelly Wingert said:

I've read a little bit but what I've really been waiting for is someone to do all the work and figure out the tactics. Should I take the window before we open the door to the house? Should I wait until the nozzle is at the fire room before opening a window? Does it matter if it is a single story or multi-storied building?

These are the questions I am looking to be answered.

There is an excellent examample of the effects of over venting on a building on YouTube. Wish I could embed the link but I'm on my phone now. Will try later. If you search for "house fire smoke explosion" you will see the video. 
When you watch the video, do a size up yourself. Watch what heppens when the firefighter opens the window on the B side and then how quickly things change. 
The data and conclusions from the study need to be incorporated into our basic ventilation training. We need to be able to identify a ventilation limited fire and know how to attack it to be able to preserve any viable victim...when conditions allow
We also need to ensure that we don't lose our aggressiveness. Aggressiveness, now recklessness. Take this study and become smarter, not shyer at a fire scene. 
http://www.youtube.com/watch?v=15VxYzzjpKM&feature=youtube_gdat...
This is the video I am referring to. 

Trevor Ashe said:
There is an excellent examample of the effects of over venting on a building on YouTube. Wish I could embed the link but I'm on my phone now. Will try later. If you search for "house fire smoke explosion" you will see the video.  When you watch the video, do a size up yourself. Watch what heppens when the firefighter opens the window on the B side and then how quickly things change.  The data and conclusions from the study need to be incorporated into our basic ventilation training. We need to be able to identify a ventilation limited fire and know how to attack it to be able to preserve any viable victim...when conditions allow
We also need to ensure that we don't lose our aggressiveness. Aggressiveness, now recklessness. Take this study and become smarter, not shyer at a fire scene. 

There are one-story dwellings and then, there are one-story dwellings! If the house is small and it is likely that you can access the fire within a minute, taking the window first might be an acceptable tactic. However, if the fire is in a larger house, or it is unclear as to the exact location of the fire, it is likely better to wait until the fire is located. Door control is the other part of this equation. My colleagues from the UK, Europe, and Australia are much more focused on this key concept. How about closing the door after entry with a hoseline to limit intake of air? Door control slows the increase in heat release rate.

One exception to this would be if you determined that the criteria had been met for use of positive pressure attack (PPV prior to entry). In this case you would definitely take the window(s) first to create an exhaust opening two to three times the size of the inlet and then pressurize the inlet with a blower, waiting for 30-45 seconds for ventilation to become effective before entry. The heat release rate increases here as well, but the effects are confined to the area of the fire and outside the vent opening. As a point of clarification, this tactic is good in some circumstances, but should not simply be the default choice.

I agree with the desire to see a study with the fire in a more remote location. The living room was selected as this is the point of origin for a large percentage of civilian fatalities. In the two-story house, the fire was further from the front door in the great room on Side C. Location of the fire further from the front door (entry point) will likely increase the time for changes in fire behavior to occur (with only the front door open), but the time to reach the fire will increase as well.

P.J. Norwood said:

Kelly, the crew did open the front door start their advance and then the window was taken behind them. This was staged during the filming. You are correct that when the front door was open they did ventilate and yes if the window wasn't take the same condition MAY have occurred just later. Our goal was to show what happens in the hallway when ventilation is not coordinated and done behind the line. Yes, my head hurts too!! I can't say I disagree completely with your tactics on a single story residence. However any ventilation that occurs by taking the window first still must be coordinated because as documented the crew has limited time to get water on the fire!

I am interested in Steve's and Chief Hartin's input is! Thank you for the great exchange!
Kelly Wingert said:

Chief, thanks for the comments. I watched your suggested videos and I have an issue with the first one. During the video, its says the window was vented behind the nozzle. I don't think this is correct. The fire was vented when the front door was opened. This caused a flow path of smoke and hot gases towards the front door. When the window was vented, this caused an inrush of air which caused the room to flash and the fire followed the flow path towards the door where the nozzle and search teams were located. If the window was never opened, I believe the results would have been the same but occurred later. After reading the UL study (my head really hurts now), it is my belief that venting the window of the fire room prior to opening the front door is best practice on single story residential structures. This causes  the flow path to be out the window, drawing air from inside the house and allowing hose teams to advance towards the fire room quicker and safer. I think convection is the main culprit in heat transfer from one area of the structure to another. This convection of hot smoke and gases primes the pump for flashover and unlimited burning. Control of air movement is the most important idea behind ventilation. Maybe I just said what everybody is already saying.

 

I really can't wait until they do a study on fire remote from the front door. I think this is more real world.

P.J. Norwood said:

Kelly, I agree with Chief Hartin as there are no absolutes. But, I will add that if you are venting ahead of the line as you should always be, you must coordinate with the hose team. Now, this does not mean they must call you on the radio!

Check out this clip from my vent video from Fire Engineering/Penwell's Tactical Perspective Series: http://community.fireengineering.com/video/video/show?id=1219672%3A...

 

When you see or hear signs that the hose team is in place and/or flowing water then open the windows. Check out this excellent video: http://community.fireengineering.com/video/video/show?id=1219672%3A...

You also question should you open the door before the window. This there is definitely no absolutes as you must be able to read the building (construction and fire load) and determine which way the fire is moving or will move and where your hose team is entering. You must remember anything that you open is ventilation and the fire will grow. This is a double edged sword that we must understand and we need to get our FF's and Officers to understand ventilation MUST be coordinated and MUST be ahead of the advancing hoseline.

 

Check out my videos posted on my page in this community also check out this video in its entirety and it may help you with some of the tactical elements you are looking for: http://www.pennwellbooks.com/tapebdvd3ve.html here is a trailer on you tube: http://www.youtube.com/watch?v=E4QxVGBn130



Kelly Wingert said:

I've read a little bit but what I've really been waiting for is someone to do all the work and figure out the tactics. Should I take the window before we open the door to the house? Should I wait until the nozzle is at the fire room before opening a window? Does it matter if it is a single story or multi-storied building?

These are the questions I am looking to be answered.

I've watched that video a number of times. It is a good (or is it bad) example of venting behind the hose line.

Trevor Ashe said:

http://www.youtube.com/watch?v=15VxYzzjpKM&feature=youtube_gdat...
This is the video I am referring to. 

Trevor Ashe said:
There is an excellent examample of the effects of over venting on a building on YouTube. Wish I could embed the link but I'm on my phone now. Will try later. If you search for "house fire smoke explosion" you will see the video.  When you watch the video, do a size up yourself. Watch what heppens when the firefighter opens the window on the B side and then how quickly things change.  The data and conclusions from the study need to be incorporated into our basic ventilation training. We need to be able to identify a ventilation limited fire and know how to attack it to be able to preserve any viable victim...when conditions allow
We also need to ensure that we don't lose our aggressiveness. Aggressiveness, now recklessness. Take this study and become smarter, not shyer at a fire scene. 

The video provides an excellent example of the effect of ventilation.  The fire had already vented (horizontaly out a B side window).  Why would you want to ventilate between that room and the street where your firefighters are entering?  I think anyone watching that clip would have been able to predict the outcome.  If the window fails in the room of origin, the fire is vented in the right place.  By opening the door we have given it another avenue (depending on wind and a number of other factors).  Door control is the key in this situation, as well as effective overhead gas cooling on the way down to the fire.  Correctly applied, overhead gas cooling utilising a spray pattern to maximise the cooling effect of the water in the gas phase (but that's another whole other debate) is an extremely effective technique to prevent rapid fire events.  Indiscriminant ventilation of windows and doors between the fire room and the point of entry will worsen conditions.

If the the fire has not self ventilated (window failures) then well placed coordinated ventilation at, or as near as possible to the fire room following placement of charged hose lines can assist.  Use of the thermal imaging camera can help identify the fire room if it is not obvious.  As far as I'm concerned it's all about identifying and controlling the air track to ensure the movement is going in the same direction as we are, as well as having an adequate flow rate available for the worst possible scenario.

There are so many variables which makes it so hard to come up with any one way to manage these issues, but at least we are talking about it and learning from each other. 

Mike D 

Kelly Wingert said:

I've watched that video a number of times. It is a good (or is it bad) example of venting behind the hose line.

Trevor Ashe said:

http://www.youtube.com/watch?v=15VxYzzjpKM&feature=youtube_gdat...
This is the video I am referring to. 

Trevor Ashe said:
There is an excellent examample of the effects of over venting on a building on YouTube. Wish I could embed the link but I'm on my phone now. Will try later. If you search for "house fire smoke explosion" you will see the video.  When you watch the video, do a size up yourself. Watch what heppens when the firefighter opens the window on the B side and then how quickly things change.  The data and conclusions from the study need to be incorporated into our basic ventilation training. We need to be able to identify a ventilation limited fire and know how to attack it to be able to preserve any viable victim...when conditions allow
We also need to ensure that we don't lose our aggressiveness. Aggressiveness, now recklessness. Take this study and become smarter, not shyer at a fire scene. 
Mike, I couldn't agree with you more on the following: "it's all about identifying and controlling the air track to ensure the movement is going in the same direction as we are, as well as having an adequate flow rate available for the worst possible scenario.

There are so many variables which makes it so hard to come up with any one way to manage these issues, but at least we are talking about it and learning from each other."

 

Thank you for contributing to the conversation!

 

 



Michael Dombroski said:

The video provides an excellent example of the effect of ventilation.  The fire had already vented (horizontaly out a B side window).  Why would you want to ventilate between that room and the street where your firefighters are entering?  I think anyone watching that clip would have been able to predict the outcome.  If the window fails in the room of origin, the fire is vented in the right place.  By opening the door we have given it another avenue (depending on wind and a number of other factors).  Door control is the key in this situation, as well as effective overhead gas cooling on the way down to the fire.  Correctly applied, overhead gas cooling utilising a spray pattern to maximise the cooling effect of the water in the gas phase (but that's another whole other debate) is an extremely effective technique to prevent rapid fire events.  Indiscriminant ventilation of windows and doors between the fire room and the point of entry will worsen conditions.

If the the fire has not self ventilated (window failures) then well placed coordinated ventilation at, or as near as possible to the fire room following placement of charged hose lines can assist.  Use of the thermal imaging camera can help identify the fire room if it is not obvious.  As far as I'm concerned it's all about identifying and controlling the air track to ensure the movement is going in the same direction as we are, as well as having an adequate flow rate available for the worst possible scenario.

There are so many variables which makes it so hard to come up with any one way to manage these issues, but at least we are talking about it and learning from each other. 

Mike D 

Kelly Wingert said:

I've watched that video a number of times. It is a good (or is it bad) example of venting behind the hose line.

Trevor Ashe said:

http://www.youtube.com/watch?v=15VxYzzjpKM&feature=youtube_gdat...
This is the video I am referring to. 

Trevor Ashe said:
There is an excellent examample of the effects of over venting on a building on YouTube. Wish I could embed the link but I'm on my phone now. Will try later. If you search for "house fire smoke explosion" you will see the video.  When you watch the video, do a size up yourself. Watch what heppens when the firefighter opens the window on the B side and then how quickly things change.  The data and conclusions from the study need to be incorporated into our basic ventilation training. We need to be able to identify a ventilation limited fire and know how to attack it to be able to preserve any viable victim...when conditions allow
We also need to ensure that we don't lose our aggressiveness. Aggressiveness, now recklessness. Take this study and become smarter, not shyer at a fire scene. 
I teach PPV/PPA and have been since 1987.  Because of information in the UL study, I am looking at revising the SOG that I provide in my class to reflect "door control" and "air track" control.  In conjunction with the UL study, I also picked the brain of my friend Ed Hartin.  At this point it appears that the revised procedure will require some additional radio communications between the forcible entry Firefighter and the Officer performing the size-up.  I need to find a place to test it before including it in my class.  As we all know it always looks good on paper until we actually go out and do it. I think UL has done us a huge favor, it's our job now to take that information and make change away from "that's the way we have always done it". 

John, do you teach your PPV/PPA class any where near Misouri? I'm lookin for a class to attend. If PPA is as good as what I've heard, I think it might be something for us.

Right now I am in Michigan but I stay in St Louis during the winter months (Too much snow in Michigan for me).  No classes scheduled at this time.  I do teach at Winter Fire School but as yet no request yet from UMC.  Don't know if I will be at WFS 2012.  Thanks for inquiring.

Kelly Wingert said:

John, do you teach your PPV/PPA class any where near Misouri? I'm lookin for a class to attend. If PPA is as good as what I've heard, I think it might be something for us.

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