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Spin off thread: Auto Fog Nozzles...

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  • Spin off thread: Auto Fog Nozzles...

    Sorry if this is a dead horse, but I did do a search and didn't really find anything...

    In my other thread about 1.5" hose, there was talk about nozzles and auto fog nozzles came up. Like fog v. smoothbore, autos seem to have followers and detractors.

    A few in my department view fixed flow and selectable flow nozzles as old fashioned, and autos are the way to go. As I mentioned in my earlier thread, there are at least 3 low pressure Select O Matics floating around where I am, and if I present a case to do some flow testing with a view of standardizing our nozzles, I could forsee a situation where a push from others to stick with low pressure autos happens.

    Looking at the 'limitations' of autos, in terms of training, what can 'we' do to ensure that the nozzle team is kept safe and we're putting enough water on the fire? I've found the Elkhart pump pressure guide that comes with the Select O Matics, but is there more to it than merely pumping to what it says? Or am I making it more complicated than it needs to be?

    Thanks.
    Two departments, twice the fun...

  • #2
    100% the only way to know what is coming out of the nozzle at any given pump pressure is to use a flow meter and do flow testing. That is the only way to be sure. Pump charts and pressure guides simply do not take into account the multitude of hose types in use. This is far easier to do with a smooth bore nozzle because you can use a pitot gauge instead of needing to find an inline flow meter.

    An additional piece of advice for you. If you are looking for this on a pre-connect then put the flow meter on that line. Why? Because piping leading to that discharge can add to the friction loss and cause you gpms if you don't account for that.

    As for automatic nozzles here are my biggest issues: 1) People do not really understand how they work so they can't use them effectively, 2) A good looking fire stream is not necessarily an effective fire stream. In other words the stream may look great, be easy to handle, and be flowing 50 to 70 gpm. Is that what you want for an interior attack line? 3) Additional maintenance that should be done but rarely is.
    Crazy, but that's how it goes
    Millions of people living as foes
    Maybe it's not too late
    To learn how to love, and forget how to hate

    Comment


    • #3
      Originally posted by FyredUp View Post
      As for automatic nozzles here are my biggest issues: 1) People do not really understand how they work so they can't use them effectively, 2) A good looking fire stream is not necessarily an effective fire stream. In other words the stream may look great, be easy to handle, and be flowing 50 to 70 gpm. Is that what you want for an interior attack line? 3) Additional maintenance that should be done but rarely is.
      So, extra education and training to work around all of the above.

      Two departments, twice the fun...

      Comment


      • #4
        Originally posted by MikeG344 View Post

        So, extra education and training to work around all of the above.
        Yes indeed. But it takes someone that understands how they operate to explain them. Do NOT have a salesman run training on them because most often they are going to slip into a sales pitch.

        I would be happy to help you set up a flow test and training if you'd like.
        Crazy, but that's how it goes
        Millions of people living as foes
        Maybe it's not too late
        To learn how to love, and forget how to hate

        Comment


        • #5
          Originally posted by FyredUp View Post

          Yes indeed. But it takes someone that understands how they operate to explain them. Do NOT have a salesman run training on them because most often they are going to slip into a sales pitch.

          I would be happy to help you set up a flow test and training if you'd like.
          PM sent to you.
          Two departments, twice the fun...

          Comment


          • #6
            Through the years I have found a great resistance to pumping adequate pressures for supplying both automatic and selectable gallonage preconnected lines. Open an inspection door on your engine and count the number of elbows including the chicksan swivel feeding your preconnects. Each 90 degree ell adds about 15 feet of pipe equivalent to the equivalent length of hose for that P.C. line. Secondly, if the piping is 1 1/2" and you are using 1 3/4" hose, the error is even worse. The pressure loss inside the pump panel can easily exceed 50 ft of additional hose. We have made 180 psi. the standard operating pressure for all preconnects on our engines. Proper training of new firefighters includes tossing out the oft quoted State Instructors requirement of fully opening the nozzle bail to apply water. Open the bail and apply as much volume (reaction force) as you can handle under the circumstances you are encountering. footing, stairs, ladders, ice, all contribute to your application rate. As FyredUp says, you should use a flow meter to check how much you are actually delivering. With a properly functioning automatic nozzle, your eye can't really tell how much you are delivering, because the exit velocity will always be the same so the reach will be the same for every different volume from 80 to 220 gpm. With a little experience, however even a new trainee will feel the reaction difference between the first bail notch and fully opened. We have settled upon 180 psi E.P. because we also try to keep the incoming residual pressure on the intake above 30 psi. Because the centrifugal pump takes advantage of the incoming pressure, the engine will be operating at its full flow design point with a 30 psi incoming and a 180 psi discharge. (150 psi nominal increase). Lastly, you must periodically test automatic nozzles for proper operation of the pressure sensitive baffle that adjusts the nozzle flow to maintain 100 psi or other pressure setting of the individual nozzle. We do use low pressure (50 psi) automatics on all high-rise bundles, along with a 2 1/2 x (2) 1 1/2" wye. These are equipped with a gauge in place of a valve handle on one side of the wye. This allows the officer the ability to radio the engine supplying the standpipe and increase the pressure on the wye to 125 psi (standard pressure calculation for 150 gpm on 200 ft of 1 3/4" line plus 10 for the wye). I have seen some departments running automatics at as low as 120 psi on 100 psi automatic nozzles. In these cases the sales pitch convinced the chief that this low pressure and light reaction force was still delivering 150 gpm plus of water out the nozzle. Using a TFT flow meter at the nozzle quickly reveals what is actually happening. Do not be afraid to "Over Pump" an automatic line, but train the nozzleman to open it to where he can just handle the reaction force to maximize the applied water volume.

            Comment


            • #7
              Originally posted by kuh shise View Post
              Through the years I have found a great resistance to pumping adequate pressures for supplying both automatic and selectable gallonage preconnected lines. Open an inspection door on your engine and count the number of elbows including the chicksan swivel feeding your preconnects. Each 90 degree ell adds about 15 feet of pipe equivalent to the equivalent length of hose for that P.C. line. Secondly, if the piping is 1 1/2" and you are using 1 3/4" hose, the error is even worse. The pressure loss inside the pump panel can easily exceed 50 ft of additional hose. We have made 180 psi. the standard operating pressure for all preconnects on our engines. Proper training of new firefighters includes tossing out the oft quoted State Instructors requirement of fully opening the nozzle bail to apply water. Open the bail and apply as much volume (reaction force) as you can handle under the circumstances you are encountering. footing, stairs, ladders, ice, all contribute to your application rate. As FyredUp says, you should use a flow meter to check how much you are actually delivering. With a properly functioning automatic nozzle, your eye can't really tell how much you are delivering, because the exit velocity will always be the same so the reach will be the same for every different volume from 80 to 220 gpm. With a little experience, however even a new trainee will feel the reaction difference between the first bail notch and fully opened. We have settled upon 180 psi E.P. because we also try to keep the incoming residual pressure on the intake above 30 psi. Because the centrifugal pump takes advantage of the incoming pressure, the engine will be operating at its full flow design point with a 30 psi incoming and a 180 psi discharge. (150 psi nominal increase). Lastly, you must periodically test automatic nozzles for proper operation of the pressure sensitive baffle that adjusts the nozzle flow to maintain 100 psi or other pressure setting of the individual nozzle. We do use low pressure (50 psi) automatics on all high-rise bundles, along with a 2 1/2 x (2) 1 1/2" wye. These are equipped with a gauge in place of a valve handle on one side of the wye. This allows the officer the ability to radio the engine supplying the standpipe and increase the pressure on the wye to 125 psi (standard pressure calculation for 150 gpm on 200 ft of 1 3/4" line plus 10 for the wye). I have seen some departments running automatics at as low as 120 psi on 100 psi automatic nozzles. In these cases the sales pitch convinced the chief that this low pressure and light reaction force was still delivering 150 gpm plus of water out the nozzle. Using a TFT flow meter at the nozzle quickly reveals what is actually happening. Do not be afraid to "Over Pump" an automatic line, but train the nozzleman to open it to where he can just handle the reaction force to maximize the applied water volume.
              "Open the bail and apply as much volume (reaction force) as you can handle under the circumstances you are encountering"

              I can't agree that the amount of "reaction force" is the determining factor in operating an effective firefighting stream.

              All that talk of operating pressures with little talk of volume of water applied. The one number you do mention, 150 GPM, is barely sufficient for structural firefighting IMO.

              Comment


              • #8
                Originally posted by kuh shise View Post
                Through the years I have found a great resistance to pumping adequate pressures for supplying both automatic and selectable gallonage preconnected lines. Open an inspection door on your engine and count the number of elbows including the chicksan swivel feeding your preconnects. Each 90 degree ell adds about 15 feet of pipe equivalent to the equivalent length of hose for that P.C. line. Secondly, if the piping is 1 1/2" and you are using 1 3/4" hose, the error is even worse. The pressure loss inside the pump panel can easily exceed 50 ft of additional hose. We have made 180 psi. the standard operating pressure for all preconnects on our engines. Proper training of new firefighters includes tossing out the oft quoted State Instructors requirement of fully opening the nozzle bail to apply water. Open the bail and apply as much volume (reaction force) as you can handle under the circumstances you are encountering. footing, stairs, ladders, ice, all contribute to your application rate. As FyredUp says, you should use a flow meter to check how much you are actually delivering. With a properly functioning automatic nozzle, your eye can't really tell how much you are delivering, because the exit velocity will always be the same so the reach will be the same for every different volume from 80 to 220 gpm. With a little experience, however even a new trainee will feel the reaction difference between the first bail notch and fully opened. We have settled upon 180 psi E.P. because we also try to keep the incoming residual pressure on the intake above 30 psi. Because the centrifugal pump takes advantage of the incoming pressure, the engine will be operating at its full flow design point with a 30 psi incoming and a 180 psi discharge. (150 psi nominal increase). Lastly, you must periodically test automatic nozzles for proper operation of the pressure sensitive baffle that adjusts the nozzle flow to maintain 100 psi or other pressure setting of the individual nozzle. We do use low pressure (50 psi) automatics on all high-rise bundles, along with a 2 1/2 x (2) 1 1/2" wye. These are equipped with a gauge in place of a valve handle on one side of the wye. This allows the officer the ability to radio the engine supplying the standpipe and increase the pressure on the wye to 125 psi (standard pressure calculation for 150 gpm on 200 ft of 1 3/4" line plus 10 for the wye). I have seen some departments running automatics at as low as 120 psi on 100 psi automatic nozzles. In these cases the sales pitch convinced the chief that this low pressure and light reaction force was still delivering 150 gpm plus of water out the nozzle. Using a TFT flow meter at the nozzle quickly reveals what is actually happening. Do not be afraid to "Over Pump" an automatic line, but train the nozzleman to open it to where he can just handle the reaction force to maximize the applied water volume.
                Opening the bail part way and flowing 100 gpm or less will not extinguish a fire requiring a target flow higher than that. While the nozzle reaction is easier to control if the fire requires more flow than a partially open bail the fire will continue to burn. I always taught fully open until the fire darkens down then gate back the flow. There is no reason a firefighter can't control up to 200 gpm while making an interior attack. Kneel on the hose, lay on the hose, or if necessary have your back up man move closer and take more of the pressure.

                I mentioned the additional maintenance that needs to be done but the vast majority never do as yet another issue with automatic nozzles. This alone can render them unreliable and failing to operate properly.

                I'm sorry but any kind of combination nozzle on a hise rise pack is a very bad idea in my mind. The odds of some debris or a pressure governing device on the system rendering them either inoperable or so seriously reducing the flow as to make them worthless is a danger.

                Honestly to me, while automatics do what they are supposed to when maintained properly, and enough training is done so that everyone, officer, MPO, and nozzle person, understand how they work and what needs to be done to maximize efficiency, its just not worth it. A single gallonage nozzle has less working parts, so less maintenance and works at one pressure for one flow. If that flow is underpumped it is obvious, if it is overpumped it is obvious.

                Last edited by FyredUp; 11-12-2018, 12:36 AM.
                Crazy, but that's how it goes
                Millions of people living as foes
                Maybe it's not too late
                To learn how to love, and forget how to hate

                Comment


                • #9
                  Originally posted by kuh shise View Post
                  Do not be afraid to "Over Pump" an automatic line, but train the nozzleman to open it to where he can just handle the reaction force to maximize the applied water volume.
                  Why would you waste your time "over pumping" the line if the nozzleman is only going to gate back the flow?

                  Two departments, twice the fun...

                  Comment


                  • #10
                    This area is one that gets my blood boiling.

                    In this area it is more than common for departments to pump their 200' 1 3/4" crosslay at 120psi at the panel, which means typically about 80 psi at the nozzle. This is done so that the pressure on the line will be more "manageable". What most of them fail to understand is that there is also a corresponding drop in flow. For most of them, that simply isn't an issue as most of them have no clue that the 100 or 125gpm they likely are flowing is simpy no longer adequate for a modern fire.

                    In one o my volunteer departments, we recently placed a 15/16" smoothbore and a 150gpm/50psi nozzled into service on each of our 2 crosslays, so that we can get a higher flow at a pressure that can be managed by a single firefighter. Last year we replaced the combination nozzles on our 2 1/2" with smoothbores for the same reason. Is it the complete answer for higher flows? Probably not, but it's a start.

                    I had never thought to add in the elbows and piping into our friction loss calculations. It looks like I might be redoing pump charts.
                    Train to fight the fires you fight.

                    Comment


                    • #11
                      LaFireEducator,

                      I know what you mean about underpumping to make it easier to handle. I was watching a department do a demo for the public on a car fire. They had one firefighter with a 1 1/2 inch hose with a 50 to 350 gpm TFT nozzle on it. They lit the car and I am watching this horrible stream come out of the nozzle and i walked over to the pump operator and asked what pressure he was pumping at. He said 70 psi, I don't want to beat up the nozzle guy. Okay we have 100 feet of 1 1/2 inch hose, a 100psi automatic nozzle and the discharge pressure is 70 psi. Anyone see a problem here? I guestimated that if the nozzle operator was lucky he was getting 15 to 20 gpm and a horrible looking stream at that. While he valiantly tried to extinguish a raging car fire it essentially burned itself down to the point where the garden hose flow could extinguish it.

                      You have to know and understand your equipment to make it work right. Yes, it is that simple.
                      Crazy, but that's how it goes
                      Millions of people living as foes
                      Maybe it's not too late
                      To learn how to love, and forget how to hate

                      Comment


                      • #12
                        Set your target flow, we use 180 gpm for 1.75" and then test it using a calibrated flow meter. Done properly you can figure out your piping loss and the actual friction loss in your hose. As noted the key is hitting the desired flow rate. I've never been a fan of partially opened bales. I was taught there are only two positions: open/closed. I find that a partially opened bale is far to easily bumped, whereas a fully opened nozzle is easier to keep fully open. Of course there are times when you crack the nozzle, but for the majority of our firefighting the nozzle should be fully open and supplied properly using established training and flow requirements.

                        If you have flow meters on the engine panel it's easier than ever as long as the meters are routinely checked and calibrated. This also helps where you have a mix of nozzles using different pressures. Target the flow and watch for anomaly's.

                        Comment

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