1. #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!

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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.

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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.
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  4. #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.

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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

  6. #31
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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?

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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.

  8. #33
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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.
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  9. #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"

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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

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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

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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

  13. #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

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  14. #39
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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

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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

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  16. #41
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    pfd4life....

    Don't put too much faith in the dual pressure nozzles. Remember it is still an automatic nozzle and still needs pressure to open the stem to let water flow. Depending on when you bought them and what model you have they still need eother 50 or 75 psi in order to open up.

    I watched a demonstration of one of these nozzles in a simulation of a pressure reduced standpipe. The pressure at the wye was 45 psi and the hose length was 100 feet of 1 3/4 inch. Initially the nozzle was left at standard pressure and the flow was an amazing 13 gpm. The reach was about 60 feet or so. The nozzle was then turned to low pressure and the flow went up to...are you ready for this? The flow went up to 14 gpm, that's right it gained 1 gpm by going to low flow.

    Depends on your target flow what size of smoothbore to use. My favorites are 7/8" for 160 gpm at 50 psi or 15/16" for 182 at 50 psi.

    Good luck, believe me there are some that voodoo and tradition will outweigh science and hydraulics.

    FyredUp

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    My departments preconnects are 200ft, 1 3/4. 550 to 750ft is way to much for an attack line. Our skid load doesn't even have 750ft of hose. The skid (two handlines 150ft each with a wye and 450ft of 3in). How do they plan to pull a 750ft attack line off the rig? Also friction loss would be a consideration when having to charge the 750ft line to correct nozzle pressure.

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    Quote Originally Posted by remembering911
    My departments preconnects are 200ft, 1 3/4. 550 to 750ft is way to much for an attack line. Our skid load doesn't even have 750ft of hose. The skid (two handlines 150ft each with a wye and 450ft of 3in).
    Just a question what if you need more than 600ft? What if you backstretch from the hydrant?

    How do they plan to pull a 750ft attack line off the rig? Also friction loss would be a consideration when having to charge the 750ft line to correct nozzle pressure.
    It shouldn't be hard...as long as one uses a smoothbore one can easily pump 16 lengths(No more than 6-1 3/4" lengths) up 6-7 flights at 250 psi at the pump. I don't know too many rigs that can't do that.

    FTM-PTB

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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?
    At 155psi on a 250' 1 3/4" line with TFT nozzle, your flow would be around 115 GPM (figured on nearest 5 GPM). That does not include condition of your hose and nozzle, or friction loss in your piping. You may be + or - a few GPMs.

    I get this number right from TFTs own flow chart I printed out from their website a couple years ago. According to TFTs own numbers, you cannot get the full 200GPM with that length of line. The chart shows a max of 195 GPM, and thats at 250 psi engine pressure.

    I got the chart after continued debates with my own Opps Chief over our SOGs for pump pressures. I kept telling him the numbers were wrong (my Akron Fire Calc told me so). He didnt belive me till I handed him a copie of the chart.
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    Just a few comments in regards to the initial post...

    If you are using 1 1/2 hose I'll just assume it's double cotton jacket hose w/ rubber liner. If that's the case, and say the target GPM is a mere 125 GPM, that would equate to about 45 PSI of FL per 100'.

    750' of 1 1/2 is around 335 PSI for the FL plus 100 PSI for those lovely fog nozzles.

    I could understand having a static hosebed of that amount of 1 3/4 hose, assuming the response area won't commonly or hardly ever stretch beyond 300'. But using 1 1/2 and having 750' PRECONNECTED makes no sense.

    BTW, discussing friction loss numbers can be tough considering the number of differnt types of hoses out there today. My dept may factor 40 PSI per 100' for 180 GPM (1 3/4) with our hose, but somebody with some high dollar Angus hose may need to factor a lot less. But either way, get your hands on an inline pressure gauge and do a little math, and there won't be a need to consult 20 different charts anymore.

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    Quote Originally Posted by Dave1983
    At 155psi on a 250' 1 3/4" line with TFT nozzle, your flow would be around 115 GPM (figured on nearest 5 GPM). That does not include condition of your hose and nozzle, or friction loss in your piping. You may be + or - a few GPMs.

    I get this number right from TFTs own flow chart I printed out from their website a couple years ago. According to TFTs own numbers, you cannot get the full 200GPM with that length of line. The chart shows a max of 195 GPM, and thats at 250 psi engine pressure.

    I got the chart after continued debates with my own Opps Chief over our SOGs for pump pressures. I kept telling him the numbers were wrong (my Akron Fire Calc told me so). He didnt belive me till I handed him a copie of the chart.
    Just to add onto my last post, what really only matters as for the friction loss is the hose construction and size. Your EP will be much different in your senarios if you were using 1 3/4" cotton hose from 1970 compared to some Angus "1 3/4" that actually probably expands internally close to 2". Thermo plastic urethane, synthetic rubbers, all that fancy liner stuff I don't know a whole lot about I'm sure plays a big factor. But the nozzle should have no real impact on the FL assuming equal GPM and desired NP. Like others have said, flow testing puts all this theory/speculation to rest.

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    I've gone over our pump chart AGAIN. We are figuring in 22psi/100ft for the FL, at 155psi EP, it makes exactly 55psi for the FL, for 100psi on the knob. GPM is "supposed" to be 150gpm. It makes a bit more sense now, though I still think it's off.
    FF/NREMT-B

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    Quote Originally Posted by pfd4life
    I've gone over our pump chart AGAIN. We are figuring in 22psi/100ft for the FL, at 155psi EP, it makes exactly 55psi for the FL, for 100psi on the knob. GPM is "supposed" to be 150gpm. It makes a bit more sense now, though I still think it's off.
    What brand/model attack line are you using on that line and where is your pump pressure chart from? You may be able to get an accurate chart from the hose manufacture. I know that with our attack line, we figure 30 PSI per 100' on 1 3/4" hose at 150 GPM.

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    Default 2 1/2

    At my department all commercial fires are fought with a 2 1/2. More water the better and two people can handle it if your pump man knows what he is doing. 1 1/2 should be banned execpt for a trash line. 1 3/4 is used for room and contents.

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    The department I work for requires all 33 engine companies be equipped with a 350' preconnect 1-1/2". My company runs a 400', and we extend it often with 100' (standpipe) rack. Our SOG's are set up that 4 of the 5 engines on a box alarm assignment initially run an 1-1/2" preconnect (length between 150-400 ft.). So if we are supplying another company from a hydrant, we will also run an 1-1/2" preconnect from our own piece to the fire building/exposure(usually 250 or 400). One of the reasons for this is to avoid a potential problem if one of the engines has mechanical difficulties while pumping and may need to shut down. That way we still have other water sources available. It works well for us.

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