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    Default High pressure attack line question

    Hello - I am curious if anyone has any information on the pros and cons of using a high-pressure line during fire attack. We currently have 2 trucks w/ third stage pumps; I personally want to get away from the thought of using a high-pressure attack line. Does anyone have any good reference material or articles/studies?

    Jason

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    High pressure fog was a great idea 30 years ago, when the contents of a house had a HRR of less than 10 kw/lb. Today, when HRR can be three times as much, you need a flow of a lot more than the 20-60 gpm that a high pressure fog line will generate.

    I would be teaching your guys how to use 1 3/4" of 2" handlines and d/c the high pressure pump.

    And please don't tell me about mist fire suppression systems. They are designed to operate on an incipient fire.

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    I agree...I am trying to get away from high pressure...thanx

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    Good luck. If you have have dinosaurs who are staunch advocates of high pressure fog, you are in for a tough fight. You will hear stories about how "one time" they put out a supermarket fire with one fog stream in five minutes and other fanatasies that demonstrate a complete lack of understanding about how water acts to suppress a fire. These will be the same guys, btw, who would advocate wearing cannister masks, riding on the side running board, and not wearing turnout gear because it is too dangerous.

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    George knows how we are few 'gpm' apart in agreeing on this

    High pressure attack lines .... to put it simply, you can, under certain circumstances, get greater fire suppressive performance from a lower flow-rate using high pressure lines than you can from a higher flow-rate using low pressure lines.

    However, whilst there may be distinct advantages in using lightweight high-pressure booster lines, there are strict limitations in their use.

    150' of 3/4" high pressure booster can flow around 30gpm
    150' of one inch high pressure booster can flow around 60gpm and this line may equal the suppressive performance of some low pressure 1 3/4" lines! Booster lines are easy to manage and require less firefighters to advance than low pressure lines. In some circumstances they make ideal primary attack or search lines.

    I would never propose the use of a single booster line for anything more than a one room fire and even then I would attempt to lay-in a secondary support line of greater flow-rate where necessary.

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    Default Volume over pressure

    I have a rule about making an interior attack with absolutley nothing less then 100gpm at the tip. And actually, in my deptartment, we instruct all our pump operators the "150" rule. All our engines run with two 1.75" preconnects of 150' & 200' respectively. The 150 rule implies that your starting point for your PDP is 150psi. Minus friction loss for 150' of 1.75" and a 100psi tip pressure to support the TFT nozzles we use gives an intial max flow of about 150gpm. The nozzle man now has the ability to on open the nozzle 1 or 2 clicks if he believes the fire can be easily knocked down with say 40gpm but if the need for 150 gpm becomes necessary it is only 3-4 clicks away on the nozzle. A good pump operator will instictively pump the 200' line at 160-165 psi PDP to obtain the same flow rate as the 150' line especially if it is the back up line as we always back up our first line with an equal or larger line (that means equal or larger flow too!!). If those flows are falling short PDP can be upped to about 170-175psi and flow rates upped another 20-40 GPM. We also carry a dead bed of 400' of 2" on each engine with a TFT nozzle. The 150 rule works here also. The net result being more gpm at equal lengths to 1.75" or similar flows to 1.75" at longer lengths. A simple rule to remember and starts you off with good flow rates thus the chances of playing catch up down the line becomes much less likely. Sure many a fire can be extingushed with a flow rate of 60gpm but it can be slammed much quicker and safer with a flow double that and likely with less total gallons flowed too. Of course it all means nothing with out good, knowledgable guys on the tip!

    Just my 2 cents

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    The three most dangerous words when talking about the high-pressure fog situation:

    "under certain circumstances"

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    Quote Originally Posted by GeorgeWendtCFI
    The three most dangerous words when talking about the high-pressure fog situation:

    "under certain circumstances"
    Not at all George .... this term can be used for just about every firefighting and rescue operation in the book!

    I use the statement to cover situations like .... for example .... 150gpm at 100psi where low pressure lines will most probably out perform 1" high pressure booster lines from a fire suppression perspective.

    However, fewer firefighters can place a 1" high-pressure booster operating on a fire with greater speed than the 150gpm line. The 1" booster has been seen to equal 125gpm (low pressure) in suppressive performance.
    Last edited by PaulGRIMWOOD; 04-17-2006 at 04:18 PM.

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    Quote Originally Posted by PaulGRIMWOOD
    Not at all George .... this term can be used for just about every firefighting and rescue operation in the book!

    I use the statement to cover situations like .... for example .... 150gpm at 100psi where low pressure lines will most probably out perform 1" high pressure booster lines from a fire suppression perspective.

    However, fewer firefighters can place a 1" high-pressure booster operating on a fire with greater speed than the 150gpm line. The 1" booster has been seen to equal 125gpm (low pressure) in suppressive performance.
    My point is that, in my experience, these types of apparatus are not used in busier urban environments. They are used in rural departments with low fire activity. The average FF in that department probably could recognize a circumstance where hpf might work. But the problem becomes an over-reliance on that line and a failure to recognie the circumstances where it WON'T work. There can be no argument that a "room and contents fire" today has an exponentially higher HRR than a similar fire 30 years ago.

    My FD had two of these apparatus. i have had this argument many times in the past. I have seen it in operation. I have seen it work and I have seen it misused. Thank God it has been deleted from the current apparatus.

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    Well, I have this argument over and over with the old timers in our dept. They alyaws start out by saying we had some huge fires in our day and the high pressure worked great...yeah it worked great to save the foundation...all the buildings that they had huge fires in and used high pressure lines are no longer around.....I am trying to get away from this thinking..its tought to change peoples minds

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    We have a few High Pressure Pumpers. But they are used to supply the standpipes in High Rise building fires. They have special hose that can be pumped up to 700psi. But they operate in volume like all the two stage Engines for "normal" fires.


    They alyaws start out by saying we had some huge fires in our day and the high pressure worked great...yeah it worked great to save the foundation...
    I love this line! Totally true.....
    Last edited by VinnieB; 04-18-2006 at 04:36 PM.
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    Cool

    I would never propose the use of a single booster line for anything more than a one room fire and even then I would attempt to lay-in a secondary support line of greater flow-rate where necessary.[/QUOTE]

    We eliminated the booster lines/reels from our apparatus. That pretty much solves the issue of attacking the fire with anything less than 2, 1.75" lines.
    CAFS is a whole new ballgame. Having used it, I must say it is impressive.

    You can achieve your goal of educating your troops regarding booster lines. It may take some time but in the end it will keep your staff safer and extinguish more efficiently. With practice and modification of your preconnected hose lays, you will achieve water to fire times equal to your booster application.
    Always pull 2, 1.75 lines. If you are in doubt, go bigger.
    "If Prometheus was worthy of the wrath of heaven for kindling the first fire upon earth, how ought all the Gods to honour the men who make it their professional business to put it out?"
    Smokey
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    And please don't tell me about mist fire suppression systems. They are designed to operate on an incipient fire.
    Sorry, going to have to tell you about water mist systems. Actually, just the opposite is true with regard to your comment. Water mist systems are typically tested on 500 kW, 1 MW, and 2 MW fires as test fires. By contrast, a waste basket fire is about 50 kW. A fire of say 400-500 kW in a typical room in a house can be lethal to occupants in a matter of minutes. I don't think by any stretch anyone would consider a 1 or 2 MW fire as incipient by any definition.

    Water mist system extinguish fires primarily by oxygen reduction due to the generation of water vapor/steam created when the heat from the fire evaporates the water mist droplets. Small fires just don't generate enouhg heat to vaporize enough water for the smothering action. Small, shielded fires are difficult to extinguish with water mist while larger fires are actually easier.

    And with regard to GPM, high pressure systems could extinguish say a 2 MW fire with water flow down in the 15- 20 gpm range. I've read fire test reports where water mist at this low flow can extingish fires that water spray (more typically larger droplets) couldn't extinguish at over 100 gpm.

    There is really no question about the effectiveness of water mist (or also called water fog by some) at relatively very low flows. How that relates to water mist/fog for use in manual fire suppression is a different question.

    And with regard to the comment that buildings where high pressure was used are no longer standing - how many bldgs still burn to the ground with those big fancy 2000 gpm pumpers, 1 3/4 on up to 2 1/2" attack lines and then putting those even bigger fancy tower ladders with 2 "highly effective" solid bore master streams pumping out multiple thousands of GPMs - guess what, many of them end up exactly the same way - parking lots.

    I'm not necessarily a big fan of high pressure, but there's a lot more to the issue than high pressure bad, 1-3/4 or 2 1/2' with a solid stream good.

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    Water mist may be great as an internal supression system, but as a means of fire attack the variables are too great. Steam conversion requires heat and enclosure. If you make entry you've already created an opening, now you must introduce the mist and "re-seal the opening." That is if the fire has not created an opening of its own, and there are no victims in the fire area to cook.
    The Fire Service has a hard enough time with other aspects of fire attack: lining up the crosslay bed and the front door, PPV/PPA misapplication, poor ventilation tactics, search as an afterthought, reduced staffing and a plethora of other issues. Why confuse the issue with another method of attack that has so many limitations? What are the benefits of a high pressure handline attack?

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    Quote Originally Posted by RFDACM
    Water mist may be great as an internal supression system, but as a means of fire attack the variables are too great. Steam conversion requires heat and enclosure. If you make entry you've already created an opening, now you must introduce the mist and "re-seal the opening." That is if the fire has not created an opening of its own, and there are no victims in the fire area to cook.
    The Fire Service has a hard enough time with other aspects of fire attack: lining up the crosslay bed and the front door, PPV/PPA misapplication, poor ventilation tactics, search as an afterthought, reduced staffing and a plethora of other issues. Why confuse the issue with another method of attack that has so many limitations? What are the benefits of a high pressure handline attack?
    Well firstly water mist WILL work effectively even where there are openings.

    Secondly, ONE of the major benefits of using high pressure boosters is to support 'reduced staffing'. A 3 person engine can take out a one room fire using a high pressure booster where it might take 4-5 to lay in a larger line. Low flow high pressure attacks can be utilsed effectively to deal with the vast majority of domestic fires, using just the tank supply off the first engine on scene.

    The limitations of booster lines as an interior attack tool are easily documented in SOPs.

    The application of high pressure low flow water fog CAN serve as an effective primary attack line or support a (eg. limited staffed) search crew in some situations.

    I will add that the concept of using booster lines for interior attack is not supported by uncoordinated or uncontrolled venting practice, which may increase the burn-rate beyond the control of a booster line. The performance from a high pressure one-inch booster line can match that of a low pressure inch and a half line. If you consider boosters should not be used for primary attacks then under the same circumstances, neither should lay-flat 1 1/2" lines.
    Last edited by PaulGRIMWOOD; 04-23-2006 at 05:05 AM.

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    Quote Originally Posted by kfactor
    Sorry, going to have to tell you about water mist systems. Actually, just the opposite is true with regard to your comment. Water mist systems are typically tested on 500 kW, 1 MW, and 2 MW fires as test fires. By contrast, a waste basket fire is about 50 kW. A fire of say 400-500 kW in a typical room in a house can be lethal to occupants in a matter of minutes. I don't think by any stretch anyone would consider a 1 or 2 MW fire as incipient by any definition.

    Water mist system extinguish fires primarily by oxygen reduction due to the generation of water vapor/steam created when the heat from the fire evaporates the water mist droplets. Small fires just don't generate enouhg heat to vaporize enough water for the smothering action. Small, shielded fires are difficult to extinguish with water mist while larger fires are actually easier.

    And with regard to GPM, high pressure systems could extinguish say a 2 MW fire with water flow down in the 15- 20 gpm range. I've read fire test reports where water mist at this low flow can extingish fires that water spray (more typically larger droplets) couldn't extinguish at over 100 gpm.

    There is really no question about the effectiveness of water mist (or also called water fog by some) at relatively very low flows. How that relates to water mist/fog for use in manual fire suppression is a different question.

    And with regard to the comment that buildings where high pressure was used are no longer standing - how many bldgs still burn to the ground with those big fancy 2000 gpm pumpers, 1 3/4 on up to 2 1/2" attack lines and then putting those even bigger fancy tower ladders with 2 "highly effective" solid bore master streams pumping out multiple thousands of GPMs - guess what, many of them end up exactly the same way - parking lots.

    I'm not necessarily a big fan of high pressure, but there's a lot more to the issue than high pressure bad, 1-3/4 or 2 1/2' with a solid stream good.
    Let me guess...you're a fire science student, right?

    I have begun to research what you have posted so I can rebut it, but I am going to put the onus on you. Can you provide citations for what you have posted? I am especially interested in the test fire cite. Please also let us know if these are pool fires, crib fires or what.

    Also, please enlighten us on the different types of water mist systems-there are about 4 or 5 of them.

    Then I will rebut you.

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    The application of high pressure low flow water fog CAN serve as an effective primary attack line or support a (eg. limited staffed) search crew in some situations.
    Paul, I have to respectfully disagree with you here. If hpf is such a great idea for fire department suppression, why isn't it being marketed any more? I'll tell you why. Because fighting a structure fire in today's synthetic environment with 30 gpm-regardless of the pressure and regardless of the flow-is simply too dangerous to be worth the potential liability.

    Also, stating that reduced staffing is a benefit of using hpf is foolhardy at best. Stretching a booster line is not all that much different from stretching a dry 1 3/4". It weighs about the same. You still have to have people to hump it in the door and up the stairs and around obstacles. Instead of having your extra line at the door, you now have it on the apparatus many yards away-so you're just changing the position of one of the members.

    And you still have not addressed the fact that it is indisputable that fires in today's residential structures have many times higher HRR's than they did in hpf hey-day-the 50's and 60's. 30 gallons of water can only absorb so much heat-regardless of droplet size.

    Hpf has tremendous benefits in fixed systems. But it has no value or place on the fireground.

    Reduced staffing. That will endear you to the people here.

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    Quote Originally Posted by GeorgeWendtCFI
    Paul, I have to respectfully disagree with you here. If hpf is such a great idea for fire department suppression, why isn't it being marketed any more? I'll tell you why. Because fighting a structure fire in today's synthetic environment with 30 gpm-regardless of the pressure and regardless of the flow-is simply too dangerous to be worth the potential liability.

    Also, stating that reduced staffing is a benefit of using hpf is foolhardy at best. Stretching a booster line is not all that much different from stretching a dry 1 3/4". It weighs about the same. You still have to have people to hump it in the door and up the stairs and around obstacles. Instead of having your extra line at the door, you now have it on the apparatus many yards away-so you're just changing the position of one of the members.

    And you still have not addressed the fact that it is indisputable that fires in today's residential structures have many times higher HRR's than they did in hpf hey-day-the 50's and 60's. 30 gallons of water can only absorb so much heat-regardless of droplet size.

    Hpf has tremendous benefits in fixed systems. But it has no value or place on the fireground.

    Reduced staffing. That will endear you to the people here.
    Well said.

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    High pressure fog is a highly specialized tool that takes training to make sure it is utilized in the proper way at the proper time.

    Having said that I am no advocate of high pressure fog. It leaves zero margin for error. Does not offer enough flow if the fire is bigger than suspected. And a 1 inch booster line is NOT easier to manuever through a structure than a dry 1 3/4 or 2 inch line.

    My volly FD used 1 inch booster lines when I first joined and frankly I thought it was a pain in the *** trying to advance that into a structure. You can't stockpile hose and flake it out like with regular fire hose. You can't shoulder carry it to the point of use like regular fire hose. And you surely can't flow big enough water to effectively fight a free burning multi-room fire, which by the way isn't always easy to see before you enter the structure.

    As for lower staffing preferring the hpf...no thanks. My career FD with 2 person crews on the line routinely move 1 3/4 inch hose inside structrues and my volly FD with 2 or 3 person crews routinely move 2 inch hose around inside structures.

    I guess my final view of this is this: If it works for the London Fire Brigade more power to them. But I think the guys on either of my FD's would not take kindly to the placement of booster lines on our rigs.

    FyredUp

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    Well when I answered this thread I never expected any agreement from firefighters who are traditionally low pressure - high flow stalwarts and naturally so too.

    However, it is clear that despite whatever I say about water-fog, you guys are blind to the benefits in using 1960s arguments against new millenium tactics. We have 112,000 structure fires annually here and 85% of them are dealt with using HP fog lines. We lose less firefighters and victims than the US and more fires are contained within the room of origin .... ok ok I know there are other factors.

    Thing is, we base our approach on fast attack. We get water onto the fire quicker than US firefighters. Contrary to what George says, fires are not burning much hotter than in the sixties fires or the seventies .... and kfactor is spot on with his comments about water mist and water's ability to suppress fires.

    Don't talk to me about laying 'dry' lines! I want to take water in with me as soon as I enter the structure. We are trained to deal with rooms and corridors adjacent to the fire room .... which you are not.

    In respect of limited staffing and resources how can you criticise me your nation's fire protection is strongly biased towards 3 person crews! I am stating that fast attack concepts using lightweight hose, in accordance with strict operating guidelines placing crew safety first, will enhance limited resources and staff.

    Most of you who condemn lightweight high-pressure attack lines have never used them on a 'real' fire .... and if you have, I can assure you it was not in the way we use them here!

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    Eurpoean fire statistics are almost always better than ours .. Maybe there is some value is listening to those from "across the pond" that seem to do a better job than we do.

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    Quote Originally Posted by LaFireEducator
    Eurpoean fire statistics are almost always better than ours .. Maybe there is some value is listening to those from "across the pond" that seem to do a better job than we do.
    Oh but LAEd - I didn't mean it like that bro .... in many ways you do a better job than us! I simply want to place some emphasis on the pros of HP boosters, as that was the original question and I seem to be the only one who is not concentrating totally on the negative aspects!

    I am not in disagreement with many of the points raised. I do not condone HP water-fog for all situations. However, it is a primary attack tool that I know our 36,000 firefighters would not like to lose after 30 years experience. This is in contrast to the brief experience of HP water-fog in the US that was curtailed, probably through mis-applications of the tactics.

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    Quote Originally Posted by PaulGRIMWOOD
    Well when I answered this thread I never expected any agreement from firefighters who are traditionally low pressure - high flow stalwarts and naturally so too.

    However, it is clear that despite whatever I say about water-fog, you guys are blind to the benefits in using 1960s arguments against new millenium tactics. We have 112,000 structure fires annually here and 85% of them are dealt with using HP fog lines. We lose less firefighters and victims than the US and more fires are contained within the room of origin .... ok ok I know there are other factors.

    Thing is, we base our approach on fast attack. We get water onto the fire quicker than US firefighters. Contrary to what George says, fires are not burning much hotter than in the sixties fires or the seventies .... and kfactor is spot on with his comments about water mist and water's ability to suppress fires.

    Don't talk to me about laying 'dry' lines! I want to take water in with me as soon as I enter the structure. We are trained to deal with rooms and corridors adjacent to the fire room .... which you are not.

    In respect of limited staffing and resources how can you criticise me your nation's fire protection is strongly biased towards 3 person crews! I am stating that fast attack concepts using lightweight hose, in accordance with strict operating guidelines placing crew safety first, will enhance limited resources and staff.

    Most of you who condemn lightweight high-pressure attack lines have never used them on a 'real' fire .... and if you have, I can assure you it was not in the way we use them here!
    First of all, I did not say that fires burn hotter. They burn with a higher HRR. I know you know the difference so don't try to make me look stupid.

    I think we have establishe din many other threads that comparing the UK and US fire service is an apples and oranges approach. I'm very happy that hpf works over there. I am very happy that you lose fewr Ff and less property than we do. I have said here befoer that the US can learn much from the UK approach tot he fire service-especially in areas such as research and training.

    But one thing you can't change is the way buildings aer constructed here. It is not a 1960's argument that hpf is ineffective here. It is not a 1960's argument here that most FD's, including the obverwhelming majority of vol. FD's, do not have the consistency or the discipline to use hpf in the proper maner in order to reap the benefits you espouse.

    And kfactor is distorting the facts about hpf. He is using data for deluge orp re-action systems in applications involving pool fires to try to advance a position that hypf is good for structural fire attack. It isn't.

    I've used hpf. I've seen it work. I've seen it fail many mre times.

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    Quote Originally Posted by GeorgeWendtCFI
    High pressure fog was a great idea 30 years ago, when the contents of a house had a HRR of less than 10 kw/lb. Today, when HRR can be three times as much, you need a flow of a lot more than the 20-60 gpm that a high pressure fog line will generate.
    George, no intentions to make you look stupid

    Now firstly kfactor was responding to your comment that water-mist systems are designed to deal with 'incipient' fires. He was right to point out that such systems will also deal effectively with large developing fires. He further explained how small amounts of water are able to deal with large fires. I don't believe he was supporting HP fog tactics in his post.

    Secondly, I am unfamiliar with a HRR measurement related to kw/lb? The effective 'heat of combustion' is recorded in kJ/g. The typical mass burning rate per unit surface area is measured in g/sq.m and the associated energy release rate (HRR) per unit of surface area is measured in kW/sq.m. I am not convinced that HRR has increased over the past 30 years. The ISO tests for room fires are based on oxygen consumption and there is only so much oxygen available in a room fire. Most organic solids burn at a combustion rate of 13.1 kj/g (acurate to 5%). George I am not saying you are wrong .... enlighten me.

    Thirdly, we too have 'volunteer' firefighters who are trained effectively in the use of HP water-fog for room fires. Most fires can be dealt with this way. Where fire is issuing out a window I would normally pull a mainline although some might still use two HP lines.
    Last edited by PaulGRIMWOOD; 04-24-2006 at 10:59 AM.

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    >>Secondly, I am unfamiliar with a HRR measurement related to kw/lb? The effective 'heat of combustion' is recorded in kJ/g. The typical mass burning rate per unit surface area is measured in g/sq.m and the associated energy release rate (HRR) per unit of surface area is measured in kW/sq.m. I am not convinced that HRR has increased over the past 30 years. The ISO tests for room fires are based on oxygen consumption and there is only so much oxygen available in a room fire. Most organic solids burn at a combustion rate of 13.1 kj/g (acurate to 5%). George I am not saying you are wrong .... enlighten me.<<

    I absolutely refuse to believe that you are unfamilar with the works of Nelson, Babarauskas and Quinterre. If you want to discuss this, fine. If you want to play games, I am too busy.

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