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  1. #21
    Forum Member backsteprescue123's Avatar
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    Quote Originally Posted by MG3610
    I'm just curious why some of you feel that over 250 PSI isnt safe. Hose bursting at 250 is pretty messy too. Almost all new hose has at least a 400 PSI operating pressure with up to 800 burst pressure. Is it outside the box to think we can pump a little higher on some of these lines or just stupid? Sometimes I think we are just afraid to chart new waters. Just thinking out loud here.
    I believe that around here it is somewhere areound 150 psi.

    Weruj correct me if I am wrong, but aren't 790(engine), 791(tower ladder), 794(engine), all set for 150 psi. I believe that is what 206 told us at drill.
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  2. #22
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    Quote Originally Posted by RFRDxplorer
    I believe that around here it is somewhere areound 150 psi.

    Weruj correct me if I am wrong, but aren't 790(engine), 791(tower ladder), 794(engine), all set for 150 psi. I believe that is what 206 told us at drill.
    Well, 651, 486, 928, and 739 are all set at 475psi! Cuz 104 told me. Kidding..

    Our preconnects are 250ft, we pump at almost 150psi to achieve a decent flow. One more reason I want SMOOTHBORES! We've gone over 300ft before, just happened that we were going downhill with it. Even at 250ft, the stream sucks, perhaps it's the horrible TFT nozzles. Where, or where are my smoothbores..
    FF/NREMT-B

    FTM-PTB!!

    Brass does not equal brains.

    Courage is not the absence of fear, but rather the ability to control it.

  3. #23
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    On the engine at my station and the engine at our HQ we run 2 preconnected 1 3/4" lines. My engine used to be one was 150' the other 200' now they are both 200'. The HQ engine runs the 2 200'. We also have 250' preconnected 2 1/2" on our bed with around 250' more dead load. We also have another 250' of 1 3/4" dead load on the bed. This is standard with both of the main engines. We have done this as long as I have been on the department and it works fine.

    They typically only run the pump up to around 150psi and hold unless they need to boost or decrease pressure. That is what works for us and may not work for you.
    Firefighter/EMT-B
    IACOJ

  4. #24
    Forum Member Bones42's Avatar
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    pfd4life, it ain't the nozzles fault. If you are only pumping 150psi for 250ft of 1 3/4" line, you are losing (general guideline 35psi/100') about half your pressure on just hose.
    "This thread is being closed as it is off-topic and not related to the fire industry." - Isn't that what the Off Duty forum was for?

  5. #25
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    Well, I would LOVE to see pics of this 750' preconnect! Then, I would LOVE to see pics of the fools that thought this idea up! Around here you dont see preconnects of more than 200' of 1 3/4. Most are 150'. My engine runs a street line which is 3 (maybe 4) lengths of 3" with a gated-wye and 3 lenghts of 1 3/4 used for narrow streets the engine cant make. We got rid of crosslays awhile back, all our preconnects are off the back now. This helped reminded the driver to pull past the damn fire building to allow access for the ladder companies and also made for an easier stretch.

    On the issue of the incident that brought about this hairbrained idea anyway. Did these "command" officers ever think of laying in a supply line then stretching off a gate? If the fire was small enough to contain with 1 1/2 this is the way to go. A 750' preconnect is as crazy as yellow fire trucks.
    Just another one of the 99%ers looking up.

  6. #26
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    Hard to believe 1.5" is still out there but then I guess some places truly cannot afford to upgrade. My dept use to run 3 preconnects of 1.75". Two cross lays, 150' and 200' respectively and a 250' off the rear. A number of years ago we upgraded the 250' to 2". More recently we have eliminated the rear 250' 2" preconnect and now leave it as a static bed of 400' of 2" with a TFT nozzle attached along with an extra TFT nozzle in a near by compartment. With the extra nozzle readily availible I have the option for one longer 2" line or 2 average length 2" lines. Along with that we also have a 400' static load of 2.5", again, with a 2.5" TFT nozzle attached. The two 1.75" preconnects handle 95% of the jobs, in both lenght and flow, with no problems. But when you need that 3rd and or 4th line, or the stretch is a little longer then normal, or the fire looks to require just a little higher flow that 400' of 2" comes in very handy. It's not very often we use the 2.5" but that is probably because we don't get many fires that justify its use. In my mind the 2.5" is mainly a exterior blitz attack line when my deck gun cannot get the shot. After initial knock down fallow up with the 1.75" or 2" as they are just so much easier to handle and advance into the interior. As for preconnects over 300' or even 250' for that matter what is the point. I don't get why some think they need a preconnect for every possible scenario. And preconnects of 1.75" or 1.5" over 300' go ahead crank up that pressure and stiffen the line while greatly reducing your pumps capacity. Hope you don't need a 2nd, 3rd or 4th line off that pumper. They make various size hoses for a reason.

    Stay safe!

  7. #27
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    "They make various size hoses for a reason."

    Youre kidding! When did they start doing that?
    Just another one of the 99%ers looking up.

  8. #28
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    Quote Originally Posted by Bones42
    pfd4life, it ain't the nozzles fault. If you are only pumping 150psi for 250ft of 1 3/4" line, you are losing (general guideline 35psi/100') about half your pressure on just hose.
    Wow..talk about a light going on in my head....So a quick calc would mean we have about 62psi on the nob right? See...I knew somthing was not right. I still want my smoothbores though.
    FF/NREMT-B

    FTM-PTB!!

    Brass does not equal brains.

    Courage is not the absence of fear, but rather the ability to control it.

  9. #29
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    Friction loss increases with higher flows. With a 1.75" hose with 35psi/100 ft
    that is at 150GPM.

    At 200 GPM it is about 62 psi/100ft.

    With an automatic nozzle rated at ie. 70 to 200 gpm (TFT) with 250 ft.
    of 1.75" hose and a pump pressure of 150psi you cannot make the calculation. The only way to know what you are flowing is to first measure with a flow meter. But you can be sure it will not be anywhere near 200gpm. On this set-up
    if the TFT is operating as it should, the flow would be around 125 GPM.
    Thats with the gate fully open.

    Also; not all 1.75" hose flows the same. You get what you pay for.
    Hope this helps at bit.

  10. #30
    Forum Member FyredUp's Avatar
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    My volly FD uses 2 inch hose for attack lines. On our main pumper we have 2-200 foot 2 inch preconnests, 1-300 foot 2 inch preconnest, and 1-100 foot 2 inch trashline. We also carry a 400 foot deadlay bed of 3 inch hose with a wye and 100 feet of 2 inch connected to it. There is also a preconnected deluge hooked to 200 feet of 3 inch hose.

    Our new pumper will have 2-200 foot bumper crosslays of 2 inch, 2 mid body 300 foot 2 inch crosslays and beds for 2-500 foot 3 inch dead lays. One for the apartment line and one for a pocket deluge.

    The thing that amazes me is it is really simple through either calculations or field testing to see what your hose lines will prodcue ay any given length or pressure. The best way is a flow meter. But if calcularions say it can't be done...it probably can't be done.

    FyredUp

  11. #31
    Forum Member Bones42's Avatar
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    Before we got our flow meter, we used simple calculations to get a rough idea. Our tank holds 450gal. We tried different pressures until it took 3 minutes to drain the tank. That way, we knew we were getting around 150gpm. That's the pressure we then pumped the lines at. Simple and crude, but effective.
    "This thread is being closed as it is off-topic and not related to the fire industry." - Isn't that what the Off Duty forum was for?

  12. #32
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    TVFD has two crosslay preconnects on E54, one with 150 ft of 1 3/4" and the other with 200 ft. If it's longer than that, there's a pre-connected apartment lay off the back with 350 ft. of 3" wyed to two 150 ft. sections of 1 3/4".

    The major thing that many members of these forums need to understand is that tactics that may work for one FD will not work for another. TVFD will seldom, if ever, pull 2 1/2" or 3" attack line. We are in a rural area with limited water supplies, even with tanker shuttle. 2 1/2" or 3" lines are almost an unviable option for us.

  13. #33
    Forum Member Weruj1's Avatar
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    Quote Originally Posted by RFRDxplorer
    I believe that around here it is somewhere areound 150 psi.

    Weruj correct me if I am wrong, but aren't 790(engine), 791(tower ladder), 794(engine), all set for 150 psi. I believe that is what 206 told us at drill.
    the relief vallves are set @ 150 psi.........there were some automatic nozzles on 790 set for 100 psi. Ther rest are selectable gallonage and need to pump accordingly. longest crosslay is 200 feet of inch and threee quarter hose on all apparatus.
    IACOJ both divisions and PROUD OF IT !
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  14. #34
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    Quote Originally Posted by pfd4life
    Well, 651, 486, 928, and 739 are all set at 475psi! Cuz 104 told me. Kidding..

    Our preconnects are 250ft, we pump at almost 150psi to achieve a decent flow. One more reason I want SMOOTHBORES! We've gone over 300ft before, just happened that we were going downhill with it. Even at 250ft, the stream sucks, perhaps it's the horrible TFT nozzles. Where, or where are my smoothbores..
    TFT means "Toys for Tots"

  15. #35
    Forum Member FyredUp's Avatar
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    I am no fan of automatic nozzles, my volly FD got rid of ours 7 or 8 years ago.

    BUT, having said that the major problems with them really revolve around 2 things:

    1) Lack of knowledge on how they operate.
    2) Lack of manufacturer recommened maintenance.

    Neither of those is the nozzles fault.

    BUT, I still would rather have my single gallonage low pressure Elkhart or a smoothbore than an automatic nozzle.

    FyredUp

  16. #36
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    Quote Originally Posted by FyredUp
    I am no fan of automatic nozzles, my volly FD got rid of ours 7 or 8 years ago.

    BUT, having said that the major problems with them really revolve around 2 things:

    1) Lack of knowledge on how they operate.
    2) Lack of manufacturer recommened maintenance.

    Neither of those is the nozzles fault.

    BUT, I still would rather have my single gallonage low pressure Elkhart or a smoothbore than an automatic nozzle.

    FyredUp
    I agree, though my departmetn will never change as long as current management stays in place. Another question for you, as you seem to be good with quick calcs. I looked over our pump chart again, we are supposed to pump 155psi on our 250ft 1.75 lines with a standard 100psi TFT automatic. We would still be underpumping the line/nozzle combo correct?
    FF/NREMT-B

    FTM-PTB!!

    Brass does not equal brains.

    Courage is not the absence of fear, but rather the ability to control it.

  17. #37
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    Quote Originally Posted by pfd4life
    I agree, though my departmetn will never change as long as current management stays in place. Another question for you, as you seem to be good with quick calcs. I looked over our pump chart again, we are supposed to pump 155psi on our 250ft 1.75 lines with a standard 100psi TFT automatic. We would still be underpumping the line/nozzle combo correct?
    We need the flow range of the TFT( ie. 70 to 200 gpm)

    If it can flow 200gpm it is being under pumped.

    As a general guideline 200gpm-200 ft(1.75")-200psi (theoretically 224psi) pump
    pressure.

    If you were to replace the TFT with let's say 15/16" smooth bore you could
    pump it at about 180psi to achieve approx. the same flow. I've said before
    not all 1.75" hose flows the same.

    Don
    Last edited by don120; 01-14-2006 at 11:41 AM. Reason: adding informatio

  18. #38
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    Quote Originally Posted by don120
    We need the flow range of the TFT( ie. 70 to 200 gpm)

    If it can flow 200gpm it is being under pumped.

    As a general guideline 200gpm-200 ft(1.75")-200psi (theoretically 224psi) pump
    pressure.

    If you were to replace the TFT with let's say 15/16" smooth bore you could
    pump it at about 180psi to achieve approx. the same flow. I've said before
    not all 1.75" hose flows the same.

    Don
    I'm going to be bringing this up to one of our AC's, I've had a theory about this for some time now. And FWIW, our Preconnects are 250ft. We are going to be start some pump training for new drivers this summer. Prime time to make the switch to smoothbores. Thanks for the help guys.
    FF/NREMT-B

    FTM-PTB!!

    Brass does not equal brains.

    Courage is not the absence of fear, but rather the ability to control it.

  19. #39
    Forum Member FyredUp's Avatar
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    PFD4Life...

    If my theoretical calculations are correct you are getting roughly 120 gpm out of your 250 foot 1 3/4 inch lines. Assuming of course your TFT's are 100 psi and not the whiz bang dual pressure ones.

    To flow 150 gpm you would need to pump 187 psi.

    To flow 200 gpm you would need to pump 255 psi.

    Both of the above are by calculation and may be more or less depending on the hose you use.

    With our low pressure Elkhart nozzles and 2 inch hose the engine pressures would be as follows.

    We start out underpumping the nozzle to 55 psi at the tip to get 170 gpm, the engine pressure for a 200 foot preconnect is 100 psi.

    At 75 psi and 200 gpm flowing the engine pressure is 140 psi.

    We also have a 1 1/4 inch slug that flows 290 at 40 psi the engine pressure for that is 175 psi.

    We can flow more water at less pressure and thus less nozzle reaction because our nozzle pressure is less. We have never had a problem with kinking and this works very well for us.

    To flow the same with your 250 foot 1 3/4 inch lines:

    170 at 55 psi at the nozzle would take 167 psi

    200 at 75 psi at the nozzle would take 230 psi

    290 at 40 psi at the nozzle would take 366 psi (Not do able of course)


    The only way to know for sure what you are getting is to get a flow meter and use it on the actual discharge you will use for that line. Some preconnect discharges are horrible for higher flows due to internalk friction loss in the piping.

    I am working hard to get at least a couple 1 inch smoothbores for our 2 inch lines...but the battle still rages.

    FyredUp

  20. #40
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    FyredUp, thanks for the followed info, we do use the dual pressure TFT's, the ones with the emergency mode for low psi. I'm foing to bring it up to one of the AC's, or our Chief come Monday morning. I've been wanting to flow test out preconnects as I don't belive it's ever been done since we recieved our two new engines in early 03, aside from Pierces required test. The line we use I belive is from Angus, by I may be wrong. we just bought 12 new lengths, I never saw the boxes. What would you suggest for a smoothbore size? Stacked tips, or one size?
    FF/NREMT-B

    FTM-PTB!!

    Brass does not equal brains.

    Courage is not the absence of fear, but rather the ability to control it.

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