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    Default 3D Firefighting - Fog v Solid

    Ok .... rules for posting here

    1. Anyone can post a question and I will try my best to answer.
    2. Your opinion counts
    3. Any logical debate against current scientific knowledge can only be based on 'reliable' personal experience.
    4 Recognise that this is NOT a general smooth-bore versus fog debate!

    3D Water-fog will outperform a straight or solid stream when used to -

    a) Effectively reduce temperatures in the overhead gas layers
    b) Maintain (or even raise) the level of the smoke interface
    c) Suppress volumes of gas-phase flaming combustion

    It can be seen from tests undertaken on live fire that the 4-500 deg C 'spikes' created by bouncing 'pulsed' straight streams off the ceiling create excessive steam in comparison to the 150 deg C spikes on the thermocouple gradient created through 3D water-fog pulsing.
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    Wink

    Paul could you possibly post the temperatures in Farenhiet for us US firefighters who cannot convert readily? This certainly will be interesting, I'm going to find so old clothes and goggles so the mud doesn't ruin my Sunday best!

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    Quote Originally Posted by RFDACM
    Paul could you possibly post the temperatures in Farenhiet for us US firefighters who cannot convert readily? This certainly will be interesting, I'm going to find so old clothes and goggles so the mud doesn't ruin my Sunday best!
    LMAO

    Yes apologies ....

    700 C = 1292 F
    200 C = 392 F
    500 C Spikes = 932 F spikes

    600 C = 1112 F
    450 C = 842 F
    150 C spikes = 302 F spikes

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    The smoothbore cools the thermal layer from 1292 F to 392 F after a quick burst, and the fog mist only lowers it a few hundred degrees F. Am I reading that right? Also, you mentioned more steam was generated using the soild stream. Do you feel the steam generated from the SS would present a problem to firefighters or victims nearby?

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    Hey Halligan .... Yes that can be confusing. The bursts from the straight stream reduce temperatures in the overhead quite dramatically in comparison to the bursts from a fog pattern. However, remember this is just for a few short seconds.

    Straight Stream More water hits the ceiling where greater evaporation occurs. A great deal of steam is created in the overhead and this shows on the gradients as a high cooling rate. However, the temperature quickly returns to its original level within a second or two. The effect briefly forces the smoke layer to descend.

    3D Fog Bursts Hardly any water hits the ceiling and most of the evaporation occurs in the gas layer. This has the effect of contracting the gas layers .... the overhead gases shrink instead of expanding. This has the effect of raising the smoke layer.

    As the process of gas cooling continues, the overhead gas temperatures cool faster and more effectively with a 3D fog pattern compared to a bursting or constant flow straight stream. The steam generated from the straight stream forced firefighters to vent the compartment or temporarily move back.
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    The evaporation of 3D water-fog has the effect of raising the smoke layer and maintaining thermal balance more effectively
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    Last edited by PaulGRIMWOOD; 05-07-2006 at 01:59 PM.

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    The effects on the smoke layer of bursting straight streams at the ceiling ....
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    I do not foresee this thread ending well.

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    Remember the old civil defense drills they taught it school in the 50s? "Duck and Cover" . Might be an ideal idea for this thread. LMAO!

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    Paul...I tip my hat for your continued efforts, but I think its a loosing battle. Firefighters here are a hard-headed bunch (if you didnt figure that out already).
    Fire Marshal/Safety Officer

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    First off I want to make sure I get this straight in my head:

    1.) 3D fog reduces the overall temp. of the upper gaseous layer for longer periods of time than solid streams or straight streams that are pulsed into the upper gaseous layer. Correct?

    2.) Due to the cooling and contraction of the gases in the thermal layer the smoke actually rises when 3D fog attack is used, or at least doesn't bank down. Correct?

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    Dave I was a firefighter in the US for two years and I appreciate what you are saying. I also appreciate that forum posters here are likely to take every opportunity to rebuke what i am attempting to say. However, if we can keep the debate relevant .... to the point .... informed .... based on valid facts or experience .... then maybe we can all learn something.

    I am not debating from the stance that 'my way is better than yours' and neither should anyone else be. This debate should keep to reasoned opinions or hard facts. If I suggest that firefighters are poorly trained in specific subjects and that this lack of training might be causing LODDs that is not meant as a personal attack on anybody. We are ALL facing the same hazards on a day to day basis and any attempt to improve firefighter safety and efficiency should be welcomed.

    If systems of work appear too complex to take onto the fire-ground then let us analyse this belief. This thread is NOT about about High Pressure Fog! It is NOT about smooth-bore versus fog! I am so far simply stating research that supports my practical experience of 35 years. If you want to discuss this research, or the techniques behind it, now is your chance.

    I have a hard head too!

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    Quote Originally Posted by jlcooke3
    First off I want to make sure I get this straight in my head:

    1.) 3D fog reduces the overall temp. of the upper gaseous layer for longer periods of time than solid streams or straight streams that are pulsed into the upper gaseous layer. Correct?
    No not quite .... 3D fog reduces the temperatures in the overhead with less disruption of the gas and smoke layer. The cooling process in a compartment is more gradual .... much less steam. It takes several nozzle bursts to achieve this but over a few minutes the cooling effect is much greater than with a straight stream used in the same way..

    Quote Originally Posted by jlcooke3
    2.) Due to the cooling and contraction of the gases in the thermal layer the smoke actually rises when 3D fog attack is used, or at least doesn't bank down. Correct?
    Quite correct.

    Here is a classic fire gas layer that is in need of some 3D bursts of water fog before the main fire is taken .... it is a natural approach that would be taken as you advance up the stair-shaft.
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    Last edited by PaulGRIMWOOD; 05-07-2006 at 04:12 PM.

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    Quote Originally Posted by PaulGRIMWOOD
    No not quite .... 3D fog reduces the temperatures in the overhead with less disruption of the gas and smoke layer. The cooling process in a compartment is more gradual .... much less steam. It takes several nozzle bursts to achieve this but over a few minutes the cooling effect is much greater than with a straight stream used in the same way..



    Quite correct.
    And during these "few" minutes and multiple 3D fog bursts is the fire
    not still burning and spreading and producing more and more hot gases?

    Don

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    Ok, I believe I have the jist of it.

    Question: 1.) Under what circumstances are you advocating that 3D Fog is better than solid stream?

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    Quote Originally Posted by don120
    And during these "few" minutes and multiple 3D fog bursts is the fire
    not still burning and spreading and producing more and more hot gases?

    Don
    Don .... your point is important here. Once the base of the fire can be attacked then a straight stream should be used. The use of 3D fog bursts are reserved for the approach to a fire (see above example). In this case you would be in position to apply 3D fog bursts as you advance up the stairs, just before taking the main fire room.

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    Quote Originally Posted by jlcooke3
    Ok, I believe I have the jist of it.

    Question: 1.) Under what circumstances are you advocating that 3D Fog is better than solid stream?
    Cooling the gas layers on the approach routes to a fire .... in smoke filled environments ... in corridors .... in adjacent rooms where hot fire gas layers are transporting .... in stairshafts (esp where a burning gas layer exists) .... where a room is bordering on flashover with flaming in the overhead but you haven't located the base of the fire or the main fuel fire. Also to test the heat in the overhead .... burst a straight stream directly above your head and you'll get a lot of water dropping back down whatever the temperature in the overhead right? Do it with a fog pattern (just a brief burst) and the fall back will effectively guide you as to the temperature above your head! If its near flashover you won't see ANY drop back!
    Last edited by PaulGRIMWOOD; 05-07-2006 at 04:30 PM.

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    Cooling the gas layers on the approach routes to a fire .... in smoke filled environments ... in corridors .... in adjacent rooms where hot fire gas layers are transporting .... in stairshafts (esp where a burning gas layer exists) ....
    Doesn't proper and effective ventilation of a fire building do the same thing?

    where a room is bordering on flashover with flaming in the overhead but you haven't located the base of the fire or the main fuel fire.
    A straight stream or solid stream into the overhead area will do the same thing when properly applied. In my expierence, which is not vast but non the less valid, properly apllied short burst of a straight stream or solid stream into the fire gas layer causes little if any thermal layer imbalance, significantly cools the area, does not cause a significant banking down of smoke. I will state for the record that I have never used or trained in 3D Water Fog techniques.

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    Quote Originally Posted by jlcooke3
    Doesn't proper and effective ventilation of a fire building do the same thing?
    You tell me! Are you honestly saying that ALL the smoke and dangerous gases clear from a structure as soon as you vent? Of course correctly applied venting will assist but if the fire is not immediately located the burn rate and smoke production will increase.

    Quote Originally Posted by jlcooke3
    A straight stream or solid stream into the overhead area will do the same thing when properly applied. In my expierence, which is not vast but non the less valid, properly apllied short burst of a straight stream or solid stream into the fire gas layer causes little if any thermal layer imbalance, significantly cools the area, does not cause a significant banking down of smoke. I will state for the record that I have never used or trained in 3D Water Fog techniques.
    OK .... but 3D fog does it more effectively. Now if you don't see drops in the smoke layer or feel steam when bursting a straight stream then maybe the temperature in the overhead is not hot enough to create these effects? I have repeatedly done this in live burns and live fires over a 20 year period. I can repeat the effects for demonstration. If you don't see steam or smoke layers descending when bursting the straight stream .... try it in a room bordering flashover or with a temperature around 1000 F at the ceiling? I am interested in your views in this respect and accept what you say. I am interested in the reasons why you don't see the same as me though?

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    You tell me! Are you honestly saying that ALL the smoke and dangerous gases clear from a structure as soon as you vent?
    Nope, not at all. I think everyone knows that while proper ventilation has immediate effects, I don't believe anyone is delusional enough to believe that the effects of ventilation are instantaneous. In the same regard though, are you saying that your tactic of 3D Water Fog immediatley renders the fire gas layer inert and stops the burning process? No I don't believe so. I believe that ventilation and 3D Water Fog accomplish the same thing by using two different methods.

    I am interested in the reasons why you don't see the same as me though?
    See what the same, that 3D Water Fog does it better or the smoke banking down and descending steam? I didn't state that there was no banking of smoke or steam production I stated that it was minimal when properly applied.

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    Quote Originally Posted by jlcooke3
    are you saying that your tactic of 3D Water Fog immediatley renders the fire gas layer inert and stops the burning process? No I don't believe so. I believe that ventilation and 3D Water Fog accomplish the same thing by using two different methods.
    No I am not suggesting that the base fuel fire is suppressed. I am saying that the overhead is secured more effectively. I am also saying that in certain respects (eg stair-shaft fires) the use of 3D fog is far superior to a straight stream in dealing with flaming volumes of fire gases. Ventilation does not inert or cool the overhead effectively in fact it often has the reverse effect as the fire intensifies.


    Quote Originally Posted by jlcooke3
    See what the same, that 3D Water Fog does it better or the smoke banking down and descending steam? I didn't state that there was no banking of smoke or steam production I stated that it was minimal when properly applied.
    Ok so you do see some steam and smoke banking down when bursting a straightstream but not excessive? As I say, the extent of this effect depends on the density of the smoke layer and the amount of heat at the ceiling. In some cases the smoke is so dark in the overhead, firefighters are crawling in under a flaming gas layer without knowing it! The use of 3D fog into smoke will increase safety and enable firefighters to take greater control over their working environment.

    Look at this superheated BLACK SMOKE gas layer forming and igniting on meeting air .... This is just what happens INSIDE a room occupied by firefighters if a window breaks providing some 'unplanned' ventilation. This is the type of gas layer that firefighters have frequently encountered inside a structure and then called for venting .... only to see it light up above their heads! By dealing with this layer prior to venting, using bursts of 3D water-fog you will cool and 'inert' the gases and make the venting action safer.
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    Ok, let me take a step back here. First off, 3D water fog tactics are to be utilized when approaching, entering, and extinguishing compartment fires safely. Correct? And that the 3D Water Fog tactic is superior to utilizing a straight stream or solid stream in this regard. Correct? And that this tactic works with/without adequate and proper ventilation. Correct?

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    Quote Originally Posted by jlcooke3
    Ok, let me take a step back here. First off, 3D water fog tactics are to be utilized when approaching, entering, and extinguishing compartment fires safely. Correct? And that the 3D Water Fog tactic is superior to utilizing a straight stream or solid stream in this regard. Correct? And that this tactic works with/without adequate and proper ventilation. Correct?
    The tactical approaches associated with 3D water-fog start at the point of entry. As soon as an unsecured door is encountered we will initiate an entry procedure that attempts to take control over the entry. As we appraoch a fire yes we may utilise 3D tactics, depending on conditions.

    Extinguishing compartment fires .... nearly always with a straight stream. If there are volumes of gases burning off on the interior we may get some knock-back with 3D fog, especially if the fire base is shielded. If there is a heavy hanging superheated smoke layer we will always deal with that using 3D fog as we approach the fire base. 3D fog is superior to straight stream applications as shown in the initial graphics on the first page.

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    Okay two out of three answered. What role does ventilation play in 3D Water Fog tactics?

    Also what is your definition of an unsecured door?

    I'm thinking its one in which fire maybe on the other side of.

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    Paul, got any videos of live burns where it is used?
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