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  1. #21
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    Default Thank you

    Thank you to all who have posted in a positive manner. If you read any of my posts, they are typically positive and do not offer a critique. The reason that I post on this forum is to learn, because I (unlike George) do NOT know it all. If I am confused about something, I ask. If I've read something somewhere, and I see something different somewhere else, I ask. No I do not have a lot of fire experience. I am in a part of the country that, by the nature of the business, could find myself in a leadership position. This is something that I take to heart, and do not EVER want to walk to the front steps to tell a widow that her beloved firefighter passed because of something I didn't know or didn't know about. The thread was never started with the intent to critique or belittle anyone for any department. If we put ourselves on the internet and turn in pictures for stories, that is a chance we take. I'm only trying to glean from the experiences of others in order to perfect my size-up skills so that no one on my watch is injured or killed.

    George, if you feel that I was trying to make myself look intelligent by posting this, then I am sorry for you. I have always had great respect for your knowledge and what you had to post, and your condescending remarks did, in fact, jab at me a little. Perhaps if you knew me and my passion for the fire service, you would know that I'm just trying to get things right. But, I've been in this line of work long enough to have thick skin, and know that it's easy to hide behind our "internet personas," so I'll just take it.

    I am glad to see that my thread has at least spawned some good discussion (for the most part), and hope that at least my correct spelling shows some signs of "intelligence."


  2. #22
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    Quote Originally Posted by phyrngn
    Thank you to all who have posted in a positive manner. If you read any of my posts, they are typically positive and do not offer a critique. The reason that I post on this forum is to learn, because I (unlike George) do NOT know it all. If I am confused about something, I ask. If I've read something somewhere, and I see something different somewhere else, I ask. No I do not have a lot of fire experience. I am in a part of the country that, by the nature of the business, could find myself in a leadership position. This is something that I take to heart, and do not EVER want to walk to the front steps to tell a widow that her beloved firefighter passed because of something I didn't know or didn't know about. The thread was never started with the intent to critique or belittle anyone for any department. If we put ourselves on the internet and turn in pictures for stories, that is a chance we take. I'm only trying to glean from the experiences of others in order to perfect my size-up skills so that no one on my watch is injured or killed.

    George, if you feel that I was trying to make myself look intelligent by posting this, then I am sorry for you. I have always had great respect for your knowledge and what you had to post, and your condescending remarks did, in fact, jab at me a little. Perhaps if you knew me and my passion for the fire service, you would know that I'm just trying to get things right. But, I've been in this line of work long enough to have thick skin, and know that it's easy to hide behind our "internet personas," so I'll just take it.

    I am glad to see that my thread has at least spawned some good discussion (for the most part), and hope that at least my correct spelling shows some signs of "intelligence."
    Boo-hoo.

    I do not know it all. But I know about this.

    If you think that was condescending, you need a much thicker skin, buddy.

  3. #23
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    George, perhaps when Paul Grimwood sees this thread he'll post his thoughts on a backdraft vs. smoke explosion, and you can then argue with him.

  4. #24
    MembersZone Subscriber Edward Hartin's Avatar
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    Default Backdraft and Smoke Explosion

    Sorry for my late entry into the discussion but I have been on the road.

    First to address the issue of definitions, there are a number of different definitions for fire behavior phenomena. However, I would agree that Karlsson and Quintiere provide a good starting point.

    Flashover: The transition from a fire in the growth state to fully developed stage. Adequate oxygen is required for this to occur (either as part of initial development in the compartment or subsequent to increased ventilation)

    Backdraft: Ignition of flammable products of combustion and unburned pyrolysis products from a underventilated fire. This may occur as autoignition or piloted ignition. However, conditions for a backdraft typically involve high temperature and limited air supply prior to occurance.

    Smoke Explosion: Piloted ignition of flammable products of combustion or pyrolysis products that are premixed with air and within their flammable range (not a common event).

    For a more detailed discussion and case studies, see my series of articles on extreme fire behavior on this web site.

    The difference between a ventilation induced flashover (flashover following an increase in ventilation when the fire is ventilation controlled) and backdraft is the rate of increase in energy release (backdraft generally has a more rapid increase in heat release rate and subsequently is often more violent, particularly when confined). However, a vent induced flashover is also quick and can result in a considerable "push" of hot gases. It is difficult to differentiate between these phenomena on the fireground (and it may not be that important as the initating factor and mitigation tactics are essentially the same).

    Looking at the photos in this incident, I would guess (based on the limited information available) that this was in the what the Swedes would call the "gray area" between vent induced flashover and backdraft. In either case, cooling the gases (i.e. indirect attack) and ventilation (a bit tougher given the fire location) provide two tactics to mitigate the hazards presented.

    The first photos do not show smoke from the basement, but smoke, air track, and heat indicators may have been visible on closer examination (limited smoke under pressure, stained and/or cracked windows, air track into the basement, etc.). It is always difficult to read the fire from a still photo, but looking for critical cues provides good practice and a starting point for discussion.
    Ed Hartin, MS, EFO, MIFireE

  5. #25
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    Default

    Thank you, Mr. Hartin for your explanation. And thank you for maintaining the spirit of this thread, which is to learn. Your answers are extremely helpful.

  6. #26
    EuroFirefighter.com PaulGRIMWOOD's Avatar
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    Quote Originally Posted by GeorgeWendtCFI
    You're right. He documented it. From Page 1:

    "A backdraft is a smoke explosion."

    If we take Chief Dunn's word for it, as I am easily led to do, then it is proof tha tthis thread was started by someone with, how can I say it.....NO KNOWLEDGE of fire science trying to sound intelligent.
    In this case it is clearly GeorgeWendt 'CFI' who is sadly lacking in knowledge! George, you need to get into your fire science books a bit more before you 'testify' at your next case! There are some correct definitions and good analogies of the differences between 'backdraft' and 'smoke explosion' offered in this thread by Ed Hartin; Don120; ROL210 and FireH2O. Perhaps George would like to take some lessons from these guys first before spounting off on here!

  7. #27
    EuroFirefighter.com PaulGRIMWOOD's Avatar
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    Quote Originally Posted by phyrngn

    First of all...was the explosion a true backdraft, or was it a "smoke explosion," where the smoke fell within it's explosive ranges down in the basement? How do we keep ourselves from getting into the same position? Would it have helped to ventilate more prior to the first hoseline entering? From the description, it seemed like it would have appeared to be a fire on the second floor? What other size-up cues can be looked for?

    Again...this is not a critique. It is intended to figure things out from a size-up and tactics point of view to prevent injuries and deaths.

    Stay safe, everyone.
    Phyrngn poses an excellent question that deserves some analysis. Without observing conditions at the actual incident it is always difficult to arrive at a true conclusion based just on the pictures as provided.

    It is certain that 'flashover'; 'backdraft' and 'smoke explosion' are clearly different events that are supported by scientific definitions. These three types of 'rapid fire progress' can be further divided into several other related phenomena that are based upon sound practical experience, yet are not supported at this time by scientific defintion (for example, 'high pressure backdraft').

    The biggest lesson here is .... don't take the location of 'smoke' as a reliable indication for indicating the location of the fire!

    London lost two firefighters in a similar situation two years back where a 'smoke explosion' occurred. Initial response was met with smoke issuing from 4th floor windows and they laddered and opened up there, as well as attempting entry at the front entrance. The fire turned out to be in the basement but it was sometime before this became obvious.

    In picture 2 if I am not mistaken there is fire in the rear basement (window) and the Chief reports that less than one minute after the basement 'flashed' a 'backdraft' occurred on the first floor.

    In truth, we cannot say what occurred. There were under-ventilated conditions apparent throughout the structure but we cannot know the true gas/air mix. Backdrafts can occur either 1-5 seconds, a few short minutes or 30 minutes to an hour (or more) after entry! Smoke explosions can occur both IN the fire compartment itself, or some way from the fire in a room or void appearing completely detached.

    In this case it may have been a backdraft on the first floor following some fire development in the basement or it may have been a smoke explosion as the fire burned through the floor into the first floor.

    This is never an easy one with the fire disguising it's whereabouts. Maybe a quick feel of those basement windows with a hand on doing the initial 360 size up? Never be certain that smoke issuing on the upper floors is ruling out a fire located on lower floors, or in the basement.
    Last edited by PaulGRIMWOOD; 07-06-2006 at 01:18 AM.

  8. #28
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    Hey,
    Here is a short online quiz that covers some of the differences between backdraft, flashover and fire gas ignition.
    Most of the information is based on a research article summarizing some of Paul Grimwood's research.

    http://www.firefloor.com/QUIZRapidFire/RapidQUIZ.htm
    Last edited by firefloor; 07-06-2006 at 01:23 AM. Reason: grammar

  9. #29
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    Default

    George,
    1) You asked for a literature citation. I gave you one.
    2) You stated that I took the definition out of context. How? Please explain.
    3) You stated that Quinter’s “other works don’t support that definition”. What “other works”? Please provide a literature citation so that I can evaluate it.
    4) While you may disagree with my use of the adverb “decidedly”, I still maintain that there is a sufficient difference in the ignition dynamics between a backdraft and a smoke explosion to warrant a distinction in the terminology. RDL210 and don120 have provided the essence of the dynamics. And, yes, it is more complex, but I thought they did it concisely and well enough for this discussion.
    5) “Logic” is defied only because you equate a backdraft with a smoke explosion.
    6) Would you mind sharing the “pre-event” data that you have seen in your investigations. I find this interesting and would like to learn from it.
    7) Please share with us your description or definition of a backdraft/smoke explosion. I, for one, would like to learn more.

    By the way, with all due respect, please have the courtesy to spell Karlsson’s and Quintiere’s names correctly. They are light years ahead of our combined knowledge and thus deserve to have their names spelled correctly, even if you disagree with them.

  10. #30
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    Quote Originally Posted by PaulGRIMWOOD
    Backdrafts can occur either 1-5 seconds, a few short minutes or 30 minutes to an hour (or more) after entry! Smoke explosions can occur both IN the fire compartment itself, or some way from the fire in a room or void appearing completely detached.
    Paul, I am having some trouble with your statements. They are not consistent with my understanding of backdraft and smoke explosion. Can you provide more information?

    Thanks.

  11. #31
    EuroFirefighter.com PaulGRIMWOOD's Avatar
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    Quote Originally Posted by FireH2O
    Paul, I am having some trouble with your statements. They are not consistent with my understanding of backdraft and smoke explosion. Can you provide more information?

    Thanks.
    It is often thought that 'backdraft' generally occurs within a few seconds following the primary openings in a structure are made. This is not always true and a 'backdraft' can occur at any time during a firefight where a fire is allowed to develop under-ventilated conditions in certain parts of the structure and then sourced with a sudden in-flow of air. This has occurred notably in basements and also at the Pittsburgh CHURCH FIRE

    A smoke explosion can occur in the fire compartment itself, even after the main fire has been suppressed. A dangerous smoke layer may form and hang at the ceiling and any subsequent overhaul actions may uncover a burning brand or two. If these rise into a flammable pre-mix then the smoke explosion may occur at the ceiling.

    If the smoke has transported to other spaces or compartments some way from the fire, the same can occur where an ignition source is introduced. Also, auto-ignition of superheated gases may occur both in or away from the fire compartment, where gases are able to dilute with oxygen.

    Does that help?

  12. #32
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    Default Paul

    Paul...Thank you for the great info. I am humbled to have started a thread to which you would reply. Your website is always a great source of scientific info...I look forward to learning more.

  13. #33
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    Case in point.... always check to see whats below you before you move to the next level. This story doesnt make much sense other than there was a big fire below them, firefighters got caught off guard, shards of glass were found 15 to 18 feet away from the house, and they went from an aggressive interior attack to defensive operations.

    I will just assume that the door leading to the basement(in the dining room) failed from the basement fire. Maybe there was some stuff stored in the basement that gave off some booms, the firefighters operating in moderate smoke on the 1st floor suddenly were faced with a violent fire(basement flashed) with no hoseline, jumped into the wall/out the door. Also windows failed as the fire pushed violently out of its contained(basement) area.

    I like this story the best!!

    P.S. i hope they just "regrouped", "got back on the horse that threw them off" and went back inside to put the fire out.

  14. #34
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    Quote Originally Posted by PaulGRIMWOOD
    In this case it is clearly GeorgeWendt 'CFI' who is sadly lacking in knowledge! George, you need to get into your fire science books a bit more before you 'testify' at your next case! There are some correct definitions and good analogies of the differences between 'backdraft' and 'smoke explosion' offered in this thread by Ed Hartin; Don120; ROL210 and FireH2O. Perhaps George would like to take some lessons from these guys first before spounting off on here!
    Paul, please do not insult my intelligence. I asked for a citation. The citation given to me is quoted above. There is nothing wrong with what I posted.

    The definitions posted by Ed make the most sense of anything posted on here so far. I appreciate him doing that. Although I believe that this thread is still a question of semantics, I understand where the differentiation in the two events lies.

    Your posts, however, continue to be arrogant, condescending and insulting. I pray that you show up opposite me in a case some day. But you most likely nmever get dirty, being so busy selling your wares that it is unlikely that it will happen.Thanks for stopping by.

  15. #35
    EuroFirefighter.com PaulGRIMWOOD's Avatar
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    Quote Originally Posted by GeorgeWendtCFI

    If we take Chief Dunn's word for it, as I am easily led to do, then it is proof tha tthis thread was started by someone with, how can I say it.....NO KNOWLEDGE of fire science trying to sound intelligent.
    You see George .... it was YOUR post that was arrogant .... condescending .... and insulting .... to the thread starter. His question was from a tactical viewpoint on the differences between various phenomena and also what actions firefighters might take in this situation.

    It was an excellent case history and and excellent thread .... so if you apologise to him in the first place I will apologise to you!

    BTW what 'wares' am I selling?!

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    Quote Originally Posted by PaulGRIMWOOD
    You see George .... it was YOUR post that was arrogant .... condescending .... and insulting .... to the thread starter. His question was from a tactical viewpoint on the differences between various phenomena and also what actions firefighters might take in this situation.

    It was an excellent case history and and excellent thread .... so if you apologise to him in the first place I will apologise to you!

    BTW what 'wares' am I selling?!
    I told you to stop insulting my intelligence.

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    EuroFirefighter.com PaulGRIMWOOD's Avatar
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    Quote Originally Posted by PaulGRIMWOOD
    You know, awhile back, you could carry on an intelligent debate. Recently, you have adopted the role of troll. That's a shame.

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    Quote Originally Posted by GeorgeWendtCFI
    You know, awhile back, you could carry on an intelligent debate. Recently, you have adopted the role of troll. That's a shame.
    Paul Grimwood, whether you agree with everything he teaches or not, adds much more value to this forum than you ever will by far.

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    Quote Originally Posted by HalliganHook111
    Paul Grimwood, whether you agree with everything he teaches or not, adds much more value to this forum than you ever will by far.
    Wow. Ten posts and you make that judgement call. Bully for you, pal.

    Go back and read a year's worth of posts and see what I mean.

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