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  • #46
    I hate to disappoint those of you who are in a firm stance that a straight stream from a fog is the same as the stream from a solid bore. IT IS NOT!

    All you have to do is look at the quality of streams side by side. Forget the inside of a burning building for a moment, and take two lines one fog and one solid bore, flow them at the same gpm and look at the stream.

    The fog will stream will still have a cone at the point of discharge and the stream will not hold its pattern as well because of the AIR incorporated into it.

    And for those of you who use fog streams on your aerial tips, remember this when wind and thermal drafts from the fire destroy your streams, making them ineffective, and you can't figure out why you can't get any penetration.

    Be Safe.

    Comment


    • #47
      //tell me the last time you have been inside an actual burning building (more than two rooms)that was not a drill.

      Sunday

      // you spew a lot of book crap but have not once told us anything you have learned from actually fighting a fire.

      Oh, I'm sorry, 2 1/2" inch attack lines are stupid with 1 1/8" tips. I'd prefer at 1 3/4" or 2" line with the same tip. There is that better? Oh water is really dumb inside. That is why I use CAFS!

      //you put the fire out from inside the building not outside.

      DUH, you just think that up yourself? Of course there are times to be outside.

      Anything else?

      Comment


      • #48
        All you have to do is look at the quality of streams side by side.

        and

        The fog will stream will still have a cone at the point of discharge and the stream will not hold its pattern as well because of the AIR incorporated into it.

        I don't suppose you'd look at this page and then post which nozzle is producing a tighter stream away from the nozzle, would you?
        http://www.cottrellinc.com/Fdny.pdf

        Comment


        • #49
          Mongo

          You make a good point. A picture is worth a thousand words. However, Fire Engineering has published pictures and my own department has performed tests that contradict what TFT is showing.

          I say perform the tests yourself and decide then. Manufactures make a lot of claims which do not always hold to be true.

          This does bring up a question those of you who do use SB's. Do any of you incorporate a stream straightener into the nozzle? We only use them on Masters.

          Be Safe

          Comment


          • #50
            Mongo:
            Why would you reference a web-site that is not comparing "Apples to Apples"? Do you agree with comparing a 50-psi stream to a 80-psi stream? Yeh they are the same flow rate but not the same exit pressure so why reference it.

            How about you jumping in on this Larry? Any other time you would point out the error in proper comparison but this time your silent? Sorry if I spoke to soon Larry, but I doubt you will agree that Cottrells web-page is not what you would call a proper evaluation or comparison.

            Regardless, Its a law of physics that the stream moving faster will also move more air than the slower stream even in a straight stream. Dont take my word for it, ask Cottrell who agreed on this point in his class at FDIC several years ago.

            To claim that a faster moving stream will go farther and penetrated deeper is not necessarily true.

            The faster moving stream will have more peel-off from the air than a slower moving stream. Again, thats a fact that can not be disputed. If more water is peeled-off from velocity you end up with less water getting where you want it.

            Fact: Larger droplets go farther than smaller droplets!

            I'll stop now because if I get going on this one it will only start a raging battle.

            Beware: What you read on a web-site does not make it right!

            Stay Safe!

            ------------------
            Kirk Allen
            First Strike Technologies, Inc

            Comment


            • #51
              80 psi versus 80 and 50 vs 50 and 100 vs 100 is the proper way. However when the comparison is our 15/16ths out reaches your fog tip then it is a 50 versus 100 and the reach favors the fog in most cases. Smae holds true to a 80 psi SB deck gun versus a 100 psi fog, fog almost always wins. Penetration? The highest NP wins period.

              Comment


              • #52
                This is actually a very good thread if you take the garbage out. This is why I read these posts.

                LHS*,
                You have stooped to a new level insulting an entire department like NYC. THINK BEFORE YOU WRITE!!!

                Comment


                • #53
                  Thanks for posting Larry. Although your post does not point out the error in from Cottrellls web-site you do emphasize proper comparison.

                  However, I disagree that the highest NP wins when it comes to penetration. What I mean by penetration is the ability of the stream to overcome the thermal currents, gravity etc in order to get to the fire.

                  I high NP stream may have velocity on its side but depending on the droplet size it may be a loser when it comes to penetration.

                  Fog nozzles at 100-psi create a much smaller droplet as it rips through the air. THis cuases the mass to decrease which in-turn cuases less penetration. Smaller droplets flash to steam faster and are ate up by the thermal drafts. A great example of this is to take a Low pressure Fog and compare the droplet size of the 100-psi fog. It wont take you long to see which one stands a better chance to penetrate a big fire.

                  A crosswind will also bring out the truth about penetration. Small droplets are more vulnerable to wind. This being the case they do not reach as far as a big dropplet from a SB or a low pressure fog or a ..........(sorry, not supposed to mention it by name)

                  If your talking penetration into a pile of ruble at your feet of 10 feet away, I would agree the higher NP wins regardless of the nozzle.

                  Just adding my two cents.



                  ------------------
                  Kirk Allen
                  First Strike Technologies, Inc

                  Comment


                  • #54
                    -Wouldn't a fog stream, which is made up of smaller water particles have greater surface area than a solid stream?

                    Yes, all hydraulic books speak of this. This is, as we all know why the stream has lower electrical conductive traits. And also why in a controlled environment it absorbs more heat than other streams. It is designed to perform as such.

                    -If a certain Stream had greater surface area than lets say another, wouldn't it hold true that the friction of the water and the air be more than that of a solid stream.

                    -My question is not what the velocity of that water was when it left the nozzle. That is undisputed by the figures...

                    My question would be what is the rate of deceleration on the streams as they are affected by Gravity, Wind and Friction?

                    Basically if the fog stream is slowing down at a faster rate than the smoothbore then it wouldn't have the same punch nor would the majority of the stream hold together as well at the end of the stream.

                    Just as the page says "The basic laws of physics can't be ignored"

                    [This message has been edited by FRED (edited 05-23-2001).]

                    Comment


                    • #55
                      Truckman

                      Do any of you incorporate a stream straightener into the nozzle?

                      We have a stream straightner on a 2.5" nozzle we use on a blitz line.

                      And you are 100% correct, the department should do its own testing.

                      KEA

                      Why would you reference a web-site that is not comparing "Apples to Apples"? Do you agree with comparing a 50-psi stream to a 80-psi stream?

                      In this case yes.

                      I was simply replying to a post stating what I referenced "All you have to do is look at the quality of streams side by side." He references looking at the quality of the streams. There's the pic, which is the better stream?

                      You have the option of posting a pic with a fog nozzle set to a tight straight stream getting beat by the SB at the same flow. With all these folks saying the smooth is better than the fog, there has to be some out there somewhere...

                      I have seen first hand that the stream from a fog does have a better straight pattern away from the nozzle than does a smooth bore. I don't have a pic, but I posted a link to one. As far as apples to apples, they are both flowing 180gpm, I could care less what the reaction is, one firefighter can easily handle them both.

                      To claim that a faster moving stream will go farther and penetrated deeper is not necessarily true.

                      My point was on quality of stream, not penetration. But I'm not so sure I agree with your hypothesis. If I remember, we've been through this before...

                      But this has taken an interesting twist, please post references and studies regarding this.

                      With both flows being equal and teh fog set on its straightest stream, the highest exit pressure wins on the reach and penetration issue.

                      1500# in a 15/16" stream moving at 60mph has how much KE?

                      1500# roughly a 1.25" moving at 75mph has how much KE?

                      Which one has more KE?

                      How much is "peeled-off" of each on the way to the other side of a fire maybe thirty to forty feet away?

                      Here's where the BS in this whole issue comes in.

                      The smooth bore only fans don't think (or know) that a fog nozzle can be operated on a straight stream without disrupting the thermal balance or pushing air into the room.

                      Or, they don't think (or know) the fog has enough penetration.

                      Or, to paraphrase one post, with all the other BS we have to learn and know, we can't be expected to remember how to work a fog in the heat of battle.

                      If any of these situations were actually true, and fogs were so terrible, they would be outlawed. Instead they are used everyday in some of the busiest and slowest departments in the nation, just like the smooths.

                      If the smooths were that much better than the fogs or vice-versa, the firefighter advocacy groups would be beating on congress' door to have the fog nozzles outlawed.

                      And you know what, that ain't happenening.

                      And don't go nuts because I posted a link to Cottrells web page, its handy place to find a picture.

                      Comment


                      • #56
                        Mongo: Who's going nuts. I agree there is way to much BS involved in the SB vs fog argument.

                        /I have seen first hand that the stream from a fog does have a better straight pattern away from the nozzle than does a smooth bore./

                        I gues that depends on your definiation of a straight stream. Not being sarcastic with that statement in any fasion either. Every one has an opinion as to where you should position the bumper on the fog to give what one wants to call a better looking stream.

                        Food for though. For the SB, depending on the the type of ball in the ball valve you may see a huge difference in performance. One manufacute makes a cut out ball on the inlet side and the stream from that type of BV sucks. Use a smooth water way ball valve and the results are much different. Also the type of SB makes a difference as well. These stubby tips may flow the water but there is not enough length in them to stabalize the stream. The little things make a big difference.


                        /I could care less what the reaction is,?

                        So do I! I didnt mention anything about reaction.


                        /But I'm not so sure I agree with your hypothesis./

                        I'm glad to see skepticism. I could post my own testing but all would say those are swayed results. So, try it for yourself.

                        Pick a good windy day and set up a catch tank. Shooting the water into the tank with a crosswind with like flows, one at 100-psi and one at 50-psi and flow water for the same amount of time. You will find that the low-pressure stream will have a better footprint and provide more water into the catch tank at its farthest point. Why? I believe that its because of the velocity of the stream. The faster it goes the more the droplet gets stripped down in size. Smaller size, less mass to carry it.


                        /How much is "peeled-off" of each on the way to the other side of a fire maybe thirty to forty feet away?/

                        Measure what is in you catch tank and you will know the answer to the peel off volume.

                        Most would agree that the bread and butter jobs seen today are handled within that very 30-40 feet your talking about. Yet when the discussion of penetration comes into the conversation most are talking about a much further distance and the results will be noticable different. My reference to penetration stemmed from Larrys comment.


                        /The smooth bore only fans don't think (or know) that a fog nozzle can be operated on a straight stream without disrupting the thermal balance or pushing air into the room./

                        Agreed....although ANY stream does move a small amount of air and the one moving the fastest will move the most. Is it enough to be a problem, not in my opinion as long as the nozzleman knows what he is doing.

                        /Or, they don't think (or know) the fog has enough penetration./

                        Interior I dont think it matters much. Exterior I think it does.

                        /Or, to paraphrase one post, with all the other BS we have to learn and know, we can't be expected to remember how to work a fog in the heat of battle./

                        I would say that we should be tought how to safely and properly use any type of nozzle. Its unfortunate but most academies I have visited teach what they think is right with no regard to the new rookie that has to go back to a department and use something he may have never been trained on. Our academies and instructors should, in my opinion, instruct on the safe operation of all nozzles.


                        /If the smooths were that much better than the fogs or vice-versa, the firefighter advocacy groups would be beating on congress' door to have the fog nozzles outlawed./

                        I dont think its so much a matter of one being better than another as it is recognizing the value of both of them. I must admit it amazes me how heated the nozzle topics are compared to items like SCBA, or TIC. Why is there not the emotional attachement to those types of products?

                        Understanding we only see words on the screen, rest assured my blood pressure is low, my emotions stable and when it comes to going nuts, I'll go for the cashews.




                        ------------------
                        Kirk Allen
                        First Strike Technologies, Inc

                        Comment


                        • #57
                          KEA, I was too lazy to look at Cottrells data, but a test should be equal in all terms. Unless the tester is comparing apples to orages like is so often done on these boards, you know...EP is lower with our SB than your fog. It wold be the same if both had low pressure tips, DUH.

                          One simple reach/pentration test, conducted by Mr Shapiro with my specific guidance was point the SB and the fog straight up side by side. Yeah the fog always wins by a bunch. So, there is a good reach and penetration measurement. In the 10 to 30 foot inside a house range penetration is won by a combo nozzle.


                          Comment


                          • #58
                            Pick a good windy day and set up a catch tank.

                            We'll try it sometime, but I have to wonder....

                            When was the last time we had a good windy day INSIDE a burning house?

                            Comment


                            • #59
                              From Akron Brass:
                              ( http://www.akronbrass.com/products/flowreach.htm )

                              7/8" Solid Bore, 50psi, 160gpm. Effective Reach: 130'

                              15/16" Solid Bore, 50psi, 180gpm. Effective Reach: 142'

                              Akromatic II (Automatic Combination Nozzle),
                              100psi, 150gpm. Effective Reach: 122'
                              100psi, 200gpm. Effective Reach: 142'

                              TurboJet 1724 (Fixed Gallonage Combination nozzle),
                              75psi, 150gpm. Effective Reach: 133'
                              100psi, 150gpm. Effective Reach: 140'

                              See very many rooms 130' wide? Very many halls 130' long? Heck, cut those reaches by a third. Are we putting water on a fire 45' away very often on the inside of building?

                              Even using handlines outside, how far away are we using them that wind would become a concern? Master streams, I could see the arguement. I can't see reach being a legitimate arguement for handlines unless your tying them off to protect a tank against a BLEVE!

                              By the way, I don't mind comparing different nozzles of different psi to each other if what you're comparing is how the nozzles are typically used. 50psi on a SB handline is typical. 100psi on a traditional Auto Combo is typical. Yep, you can compare 50psi SB to 50psi Auto Combo...but then the SB crowd can no longer argue that they have less nozzle reaction, negligent to use it from a standpipe, etc when the nobs are running at the same pressure. Except you still can't pass a mouse through a combo

                              Comment


                              • #60
                                Dalmation:
                                /15/16" Solid Bore, 50psi, 180gpm. Effective Reach: 142'/

                                /100psi, 200gpm. Effective Reach: 142'/

                                If these figures are correct, then are you agreeing that a 50-psi nozzle with less flow reaches the same distance as a 100-psi stream with more flow?

                                This is a perfect example as to why I say dont believe everythhing you read just because its on a web-site.

                                Beware of what you believe! Test things for yourself. It takes all the gobbly-gook out of it.

                                Stay Safe


                                ------------------
                                Kirk Allen
                                First Strike Technologies, Inc

                                Comment

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