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What size preconnects do you prefer?

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  • #16
    My preference is 2" with a Smoothbore or a low pressure 200/75*. I can live with a 150/75* or a 15/16" smoothbore on a 1.75". For a trash line, I like a good old APN (that's a navy ifn ya don't know) on a 100/150' of 1.5". 2.5" with a 1 1/4" tip. Reason for the APN is all those applicator's.

    I know the guy's in Charleston. I call Rusty Thomas a friend. BUT I disagree with using 1" Booster line on an occupied structure. My 2 Cents. Flame on.

    [This message has been edited by John_Ford (edited 01-25-2001).]

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    • #17
      Buck,
      You and LHS keep questioning the fire growth rates that are brought up in the Forums. In fact, I think LHS called them "urban myths." And you ask for a credible source.

      There are plenty of credible sources, but are you willing to learn something, or are you going to just keep playing games?

      Go to NFPA 72, Appendix B. NFPA 72 is the National Fire Alarm Code. It allows for either the perscriptive spacing of fire detection systems or the engineering design of such systems. The guidelines for engineering design are found in Appendix B. Go to Figure B-2.3.2.3.1, Power law heat release rates. It has been well established that ordinary combustibles grow according to a power law of time^2 and those fires fit into 4 main types: ultrafast, fast, medium, slow. If you read the graph, you will see that the fire size doubling times are 16 seconds for ultrafast, 30 seconds for fast, 60 seconds for medium and 120 seconds for slow.
      NFPA 72 has a long history and is adopted by jurisdictions all over the US and even abroad. The data in NFPA 72 are all based on decades of real fire growth data. If 72 isn't good enough, go to the NIST web site and access .pdf files for many of the reports that have all the background data included in 72. That's how fires grow and it is well established.
      But there are fires that are even faster. Storage or industrial fires can grow based on a power law of time^3 on up to time^9. Time^9 - that's a fire that when you double the time, the fire grows 9X. Go from 20 to 40 seconds for these fires, and the fire grows 9x. These are fires that can out run a standard wet pipe sprinkler system - fires grow faster than sprinklers can open. Fires that you may have to use massive deluge systems to stop.

      Do you want some more real data on fire growth? Go to Table B-2.3.2.3.1 (e). Here's some data on typical furniture. You'll see a number called Tg, that's the time it takes for that fire to get to 1MW. 1 MW is the accepted value for flashover. What are some of the Tg values - 35, 40, 50 seconds. One piece of furniture can create enough fire to get to flashover - in 40-50 seconds. How fast do you think that fire is doubling?
      Or go to Table B-2.3.2.3.1(a). There's some Tg value for warehouse materials - how about polyethylene insulation board - 8 seconds to 1 MW.

      More? Call Viking Sprinkler or Central or any sprinkler manufacturer and start getting some warehouse sprinkler approval fire tests. You'll see fires that grow so fast that a 286 degree F sprinkler in a 30 - 35 ft. warehouse activates in 29 seconds from ignition. 29 seconds from ignition, how fast do you think that fire is doubling.

      How do you think those guys got caught in Worcester? When that fire hit the right combo on fuel and O2, it took off, and was described, that fire changed in mere seconds. Did you see the unburned vaporized fuel being released above the building, hitting air and igniting into a huge fireball. How do you think all that fuel got vaporized? Frank Brannigan's column this one or one back had some myths - one of those - the 15 minutes to flashover myth. Fires grow a lot faster than that.

      Or look on the Firehouse homepage just about everyday - see fully involved structures? How did they get like that? Fully involved on arrival of the FD. Fire goes from ignition to the size of a fully involved house fire before the FD arrives. How do you think that happens?

      I read these posts from you and LHS responding to water supply issues and you respond with all this data on how many 4" supply lines it takes to flow ....., and these mathematical calculations on tanker shuttle water supply. But someone mentions a value for the time for fire growth and you respond with the "urban myth" comments and the like. How about practicing what you preach? If you dispute the values given, where's yours???

      15Hoseman has a pretty perceptive view on fire growth. Ordinary combustible fires can be put out by a single sprinkler flowing 20 gpm. Heavy duty storage fire can be put out by a couple to three storage sprinklers flowing 75-125 gpm. They can do it because they catch the fire early, because they catch it 30-40-50 seconds in. If you catch the fire quick, you can get with a 1 1/2".

      Now back to the original question, my preferred pre-connect is a 2". Same manpower as 1 1/2or 1 3/4 for interior attack, respectable defensive flows with less manpower than a 2 1/2" and a single line so you never pick the wrong line. A major plus for depts or FFs that don't see a lot of fire and have less experience to make a judgment call from or if you don't have the short response times of a dense urban area.

      Comment


      • #18
        ///the smallest line you could use would be the booster. Being that this is mainly used for trash fires and the occasional small car fire, why would you even explore the idea of using this line for anything other than these options.///

        If it is set up to do higher flows it can be used very effectively and a whole lot more maneuverable. But with your mind set being that it will only do 60 gpm at best I have to ask, Why do you use a 1" on the occasional small car fire? NFPA requires you to flow at least 100 gpm.

        **CLARIFICATION TIME: My department does not use 1" on car fires. I was merely stating that I have seen it mainly used on trash fires and small fire in cars. Also since you want to use NFPA as a source of information... go to the IFSTA 4th Edition Essentials Manual and turn to page 525. There it will give you information on hoseline selection. It clearly states that booster is to be used outside and the use of booster line may not only delay extinguishment but may be of insufficient volume to protect firefighters from advancing flame fronts.

        ///why would you even explore the idea of using this line ///

        Why does majority of the fire service stay in the same old box of thinking? Try exploring new ideas and new innovations.

        What new idea have you come up with man! The idea of becoming a statistic. What new idea have you come up with? The use of smaller diameter hoselines?!?! I think that this has been going on for a while. This is the very reason 1.75" was developed. To get a larger volume of water with the nearly the same weight of the 1.5".

        /// you may need bigger water. So why not go with the LARGER preconnect and be done with it.///

        Why not pull a 2.5" if you think you might need more water? It's called experience, you pull a 1.75" because at the time your judgement says that is all of the water I need to put out that fire.

        **My thoughts exactley. I do hope that your "experience" has taught you that one or two well placed 1.75" will do as much if not more damage to a fire than hauling out one 2.5" Every fire is different. You can always scale down on the flow if you dont need it. But when you do find yourself in a bind and you dont have the water then you got a problem.

        /// Then you get into the world of property conservation. ///

        Do you use CAF on house fires? Talk about property conservation.

        **Do you use CAF? It is a good concept, however not everyone has it. I have used it in live burns as well as certain types of wetting agents. However whenyou get into larger departments that have large fleets and run a large number of fires... the cost effectivness of outfitting your rigs with CAFS doesnt mesh with the people who decide the budget. Water is readily available and cheap.

        ///One thing is FOR SURE... and that is it is better to have a larger preconnect and not need it than get your butt in a bind ///

        Why don't you use 2" hose then? It is not much harder to maneuver than a 1.75" and will flow a whole lot more water.

        **Why dont you just go up to a 2.5"?!? I mean it would be not that much harder to maneuver and will flow a whole lot more water! You can compare this stuff all night long... fact of the matter is that larger preconnects work. You do get to a point that you need to think of the wear and tear on your men. In a city department, you may have 3 to 4 men on the first due. You grab 1 or 2 1.5" or 1.75" and go to town. Experience should dictate whether or not you would need to go larger. Generally response time is quicker and you will be able to attack the fire within minutes of ignition. NOW THIS IS NOT TRUE IN ALL CASES! Note I said generally.
        Now a majority of volunteer departments cannot get to a fire as quick. They may have to use a larger line or hit the fire more aggressivley. NOW THIS IS NOT TRUE IN ALL CASES OR DEPARTMENTS!!! Note I said a "Majority of". In either case the fire is most of the time beyond the fire flow capabilities of smaller preconnects! Think about it....

        ///Now I think this matter has been thoroughly disected.... lets go onto another topic.///

        Oh boy,Let's change the subject

        **Why not? This one has been answered. Remember the original question? What kind of preconnects do you prefer?

        ///Do you work or volunteer for a fire department///

        I proudly volunteer my time.
        What does that have to do with this subject?

        **Nothing really, other than what I said above. This generally equals out to a manpower situation. I was just asking what you status you were... dont be offended dude.. sheeeeesh!

        ///and if so what kind of preconnects do you use?///

        Mainly 1.75" and 2.5"

        ///Now if you are with the Magnolia, Texas FD ///

        That is what it says below my name.

        ** Being that Magnolia is just north of Houston, I was wanting to clarify where you worked or volunteered your time.

        /// I am wondering what kind of hose they have on those commercial chassis'.///

        Commercial chassis'- the only commercials we have are six 3000 gal FL/E-ONE tankers and they have 600' - 1.75" / 200' - 1" / 400' - 3" / 2000' - 5"

        But if you really know so much about my fire department you would have asked about our pumpers instead...

        **What is there to know about your fire department. I simply asked what kind of hose you have on your commercial chassis'. I mean the picture I have shows two commercial cab, I am assuming that they are pumpers, and a really nice looking brush truck. Other than that there is NO INFORMATION on your department! You can go to my department by clicking the link below my name. Have a good day!


        ------------------
        Grant Mishoe
        Engineer, Station #4
        North Charleston F.D.
        THENCFD Online!

        Comment


        • #19
          Our dept. uses 2-1.75" (150' & 200') crosslays for most everything. We also have 2-200' 2.5' preconnects handy and 100' of either 1.5" or 1.75" on the front bumper for trash/autos. Each truck carries 1200' of 5" for plug connections. No booster lines at all on pumpers. Our brush truck has 200' of 1" booster reel on it along with 200' of 1" forest service preconnect wyed with 200' each site of 5/8" forest service hose. Truck has a 400 gal tank 20 gal tank for each of Class A&B foam. Also has two 25' preconnects of 5/8" hose with bumper nozzles in front (45 degrees).

          Comment


          • #20
            TO EACH HIS OWN !!!!

            The question was asked " What size line do you prefer and why ?

            My dept uses the following on both the wagon and the pumper;
            2- 1.75" x 150' crosslays w/ TFT Autos
            2- 2" x 200' crosslays w/ TFT Autos
            1- 2" x 300' rear pre-con w/ 15/16" smoothbore
            1- 1.5" x 150' crosslay, trashline (FOR SURE)
            1600" - 5" LDH

            We also use a Yamaha load of 300' of 3" for vertical-horizontal applications in conjunction w/ combinationof the 300' of 2"
            and 200' of 2".

            All work extremely well.

            My personal preference is the 300' of 2" w/ the smoothbore. It gives me flexibility in flow and I've been using 2" for 20+ years and just prefer it.

            You just have to know what you and your crews capabilities are and do a proper sizeup when deciding the size/type line.

            Have fun and stay safe!!!

            ------------------

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            • #21
              the primary line is 150' 1 1/2

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              • #22
                200ft.1 1/2 200ft.2 1/2 in case there's alot of fire and 100ft.1 1/2 for trash fires.

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                • #23
                  Our dept. currently uses 1.75" hand lines on all fire calls from vehicle fires to structure fires. They are much easier to move around inside of a structure and put out a good amount of water with the right auto. nozzle. We do not use booster lines except for "mop up" or a small grass fire, etc. With limited manpower, as it is in my dept., 2.5" lines are to large to move around.

                  Comment


                  • #24
                    We have three preconnected lines on each truck. 1) 250ft. 1.75" smoothbore attack line, 2) 250ft. 1.75" fog nozzle attack line, and 3) 250ft. 2.5" smoothbore attack line. Funny that you mention, up until 3 years ago we also used booster line on structures. Reason being it was always easy to roll up and go home. Wow! Things have really changed.

                    Comment


                    • #25
                      ffeng

                      Thanks for talking to Buck instead of me. You'll find it more effective to talk to me.

                      Sure some fires in certain rare circumstances double or triple in size, but only for a short period of time until they like all interior fires become oxygen limited and rarely are fuel starved like a christmas tree.

                      However they do not double every 30 seconds as the question or statement was posed.

                      NFPA and others you quote support what I'm saying. If the majority of fires that kill citizens the burns for more than 40 minutes before the FD knows there is a fire.

                      How big was the fire to double every 30 seconds at time of ignition? 40minutes allows a doubling at least 80 times.

                      1500 sq ft home 8 foot ceilings

                      12000 cu ft

                      divide that by 2 - 80 times

                      Answer? Put 19 zeros behind the decimel point and that is how big it was. You could put 100,000 on the head of a pin.

                      In 6.6 minutes the fire is less than 1 cubic foot in size.

                      78% of all fire deaths the fires don't double at 30 second intervals. Or if in fact they are it isn't a big deal because the fire is so small when it starts that we've got over 15 minutes before we can see it with the human eye. So maybe we should space our stations further apart to deal with this silliness.

                      I don't think so. I'll refer to you math for clarification. Please give a real world example we can see.

                      And for the gentleman who said 150 gpm through a booster is impossible, it's been going on for years, the average rig in europe uses a 1500 psi reel.

                      Comment


                      • #26
                        My department uses 150' 1.75" preconnects on all apparatus and the Tower has an additional 150' 2.5" preconnect. Our Engine/Tanker also has a Skid Load (200' 3" to a gated wye then 150' of 1.5) for rural structure fires.

                        ------------------
                        **The preceding comments in no way represent the views of my department, its members, or associations that it may belong to.**

                        Comment


                        • #27
                          We use 1 3/4" preconnects. We did use a combo of 1 1/2" and 1 3/4" but the 1 1/2" was phased out.

                          Stay Safe, Stay Alive!!

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                          • #28
                            1 3/4"
                            2 1/2"

                            Comment


                            • #29
                              LHS,
                              You guys want everyone else to quote a source. I gave them to you - it's black and white in NFPA 72, Factory Mutual fire test reports, NIST reports, etc. You don't mention one source I can go to. Like I said, practice what you preach.
                              Let's see some sources. Give us some real sources that we can go to and that will verify what you say.
                              I gave you actual sources of the data. You don't even make mention of those sources and just start making unsubstantiated comments.

                              First, acknowledge the sources I quoted and either recognize their legitimacy or refute them with real data or some other source.
                              Second, if you are then going to make different claims - give us the source of your data/information.
                              There's a sign in the testing lab I work next to. It says "1 test is worth a 1000 expert opinions."
                              I'm not interested in your opinion of fire growth. If you've got real data or a recognized source, let's see it.

                              Comment


                              • #30
                                We have gone to using 2" almost exclusively. We have found that while the 1 3/4" is more manuverable, the knock down potential of the 2" with a nozzle setting of 150 gpm is quicker. We run both sizes on our engines and our quint.

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