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  1. #1
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    Default Siamesed or Directly to the Panel?

    I'm looking for some info for effeciency of supplying 4" LDH through siamesed 3" lines to a single 4" line (using 25' pony sections off two pump panel 2 1/2" discharges) versus directly hooking up to a 2 1/2" discharge with an adapter to go from thread to storz.

    It seems in my mind that the direct to panel method is the more efficient, but I'm looking for the concept to attach to why this is. If the friction loss in the hose is the determnining factor (which I believe it is), then I think the direct to the panel method would work better.


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    Quote Originally Posted by MG3610 View Post
    I'm looking for some info for effeciency of supplying 4" LDH through siamesed 3" lines to a single 4" line (using 25' pony sections off two pump panel 2 1/2" discharges) versus directly hooking up to a 2 1/2" discharge with an adapter to go from thread to storz.

    It seems in my mind that the direct to panel method is the more efficient, but I'm looking for the concept to attach to why this is. If the friction loss in the hose is the determnining factor (which I believe it is), then I think the direct to the panel method would work better.
    Mike - When you try to feed a large quantity of water through a single small hole the internal friction loss becomes astronomical. That's even with a discharge right off of the pump and going straight out. In so many cases you will see 2-1/2" valves with 2" waterways (standard flow valves) that add restriction. The more internal plumbing, bends, elbows, etc., the worse the problem.

    It's the same reason as why gated inlets are very inefficient as a way of supplying water to an engine.

    Our '89 Quality/Duplex has what Waterous Co. called a "Pantleg" discharge on the right side. This is a siamese casting behind the pump panel suppled by two 3-1/2" valves. It exits the panel as a single 5" discharge port. It's unbelievably efficient.

    After we got that truck we thought we'd try to improve the efficiency of our '78 Hahn (since replaced by the Toyne). And the Hahn's main discharges had all 3" Hale "B" valves with full 3" waterways. I acquired a piece of 3-1/2 hose, had two 7' pieces cut and coupled with 3" couplings. I gutted the valves out of a 4-1/2 to 2-1/2 wye, and made it into a siamese. We'd connect it to the Hahn's two right side discharges.

    While it's not as efficient as the pantleg discharge, it's significantly better than even a single 3" discharge. I'm looking for a home for it on the Toyne because I've had cases where I needed to supply two 5" lines (we have the water). In the meantime it sits in the firehouse. If you want to borrow it and try it out, come on around. You aren't that far away. I'll even lend you a 5" to 4" Storz adapter. You can test it for yourself and draw your own conclusions. - Sam

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    I agree with the chief. When teaching basic pumps and hydraulics, quite often people are told that the couplings and valves don't affect the loss in the system. This is not the case. 2 of the same size couplings will almost always be better than a single, even if some extra hose sections need to be added.

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    Quote Originally Posted by chiefengineer11 View Post
    I acquired a piece of 3-1/2 hose, had two 7' pieces cut and coupled with 3" couplings. I gutted the valves out of a 4-1/2 to 2-1/2 wye, and made it into a siamese.
    One of the greatest feats of polish-american engineering and you claim the credit for yourself.
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    I understand what CE11 is saying, but I believe that you won't really see any difference. If you have any doubt try them both out with flow meters and see if there is any difference between the PDPs.

    BTW, we use a 3" discharge to pump 5" without any noticable friction loss due to the discharge itself so I don't see a problem with you using a 2-1/2" to pump 4" line.
    I can't believe they actually pay me to do this!!!

    One friend noted yesterday that a fire officer only carries a flashlight, sometimes prompting grumbling from firefighters who have to lug tools and hoses.
    "The old saying is you never know how heavy that flashlight can become," the friend said.
    -from a tragic story posted on firefighterclosecalls.com

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    Quote Originally Posted by IronsMan53 View Post
    I understand what CE11 is saying, but I believe that you won't really see any difference. If you have any doubt try them both out with flow meters and see if there is any difference between the PDPs.

    BTW, we use a 3" discharge to pump 5" without any noticable friction loss due to the discharge itself so I don't see a problem with you using a 2-1/2" to pump 4" line.
    As the flows get increase, the internal friction loss increases dramatically. Granted, in all but the highest flows you can do it, but how much more you have to drive the pump in order to push the GPM through the small openings can be quite a lot.

    It's been many years since we did an experiment at the county fire school, so I don't have the numbers any more. But through our 3" waterway valves with our siamese we supplied a 5" line moving something a little over 1,000 GPM. We shut one of the discharges down and were still able to supply the water. But the increased pressure at that one discharge, and the increased engine RPM needed to achieve it was pretty striking.

    Try it yourself.

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    MG3610: Best advice I can give is to get your head inside the pump panel and examine the piping arrangement for elbows between the pump discharge manifold and the connections on the outside of the panel. Elbows (90 deg) are the equivalent of about 7 feet of pipe. I ran some Hazen-Williams calcs on straight through and elbowed piping (2) just for comparison at 1,000 gpm. Expect the following loss internal to the panel:
    2 1/2" valve straight out (4 ft) @ 1,000 gpm = 32 psi
    2 1/2" valve W/ 2 elbows + 4 ft @ 1,000 gpm = 98 psi
    3" valve straight out (4 ft) @ 10 @ 1,000 gpm = 15 psi
    3" valve W/ 2 elbows + 4 ft @ 1,000 gpm = 41 psi
    I used the 1,000 gpm figure since the 4" has about 22 psi / 100 ft at that flow or a lay of 500 feet without exceeding 180 psi and still providing an incoming relay pressure of about 20 psi.
    The advantage of using siamese lines will reduce these pressure losses to about 1/4 their original value. There is a cost in pressure loss through the 3" - 25' lines of 6 psi at 500 gpm. 3" valves, no elbows, drops to an internal loss of only 4 psi inside the panel, but an increase of 6 psi in the 25' hose or a total of 10 psi compared to 16 psi when feeding directly. A similar comparison for the 2 1/2" valves with 2 elbows will drop the loss from 98 psi to only 31 psi using the siamese. Try a set-up feeding a 2" master stream nozzle using one 25' line and raise the EP until you reach about 72 PSI at the nozzle (1,000 gpm) - record the PDP and rpm. then add the second line and do the same thing. compare pump discharge pressures to understand the advantage of lowering the gpm out a single discharge. Friction loss should decrease to 1/4 of the original value.

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    Thanks for the info so far.

    The specific pump in question has twin 2 1/2" discharges that have about 8-10" pipe from the pump bpdy to the valve, so I'd say the total run of pipe plus valve is about 1'. They are side panel discharges.

    The rig carries supply grade 4" hose.

    The pump is a 2008 Hale Qflo 1000 GPM.

    The 3" pony sections are about 15' long.

    Now, with the hose being 4", is there any advantage of siamesing the 3" lines to a single 4" or are the disadvantages of this size supply hose at high flows such that its simpler just to use an adapter to a single 2 1/2" discharge?

    Its clear to me that a flow of 1500 GPM plus is limited to only a very short lay (250' If I remember right),so our max target flow would probably be about 1000 GPM.

    Seems like the hose is the weak link here?

    FYI, I do plan on doing the expierment, Just need an opportunity.
    Last edited by MG3610; 08-09-2009 at 08:21 AM.

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    I would think that for the very few times in the life of that engine you will need the maximum output I would go the least complicated way and plug in another engine if needed.

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    Quote Originally Posted by RedBaronl32 View Post
    I would think that for the very few times in the life of that engine you will need the maximum output I would go the least complicated way and plug in another engine if needed.
    In the mid '60s, right after I got back from my first pump school at what was then the Fire Service Extension of the University of Maryland, I started talking about figuring out friction loss. But our chief back then said you didn't need any formulae or fancy figures to do it. He said that friction loss was very easy to calculate - just figure 10#/100' of hose. Didn't matter what size hose, just go with those figures and 99% of the time you'd be just fine. Mind you, that's when we laid 2-1/2" (with Jones snap couplings) for supply line and used 1-1/2" for all but the biggest fires.

    I won't say his numbers were right - we all know they weren't. But 99% of the time if you used them you'd be, as he said, "Just fine." It was that other 1% though, that got you.

    Like the time we laid out about 1200' of 2-1/2" supply line for an old school building (my high school, no less!) that was OFF. The newspaper article the next day had the quote that was pretty much standard whenever we burned something down, "Firemen complained of low water pressure."
    Last edited by chiefengineer11; 08-10-2009 at 08:29 AM.

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    I hear you Sam and isn't their motto KISS!

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    Quote Originally Posted by MG3610 View Post
    Thanks for the info so far.

    The specific pump in question has twin 2 1/2" discharges that have about 8-10" pipe from the pump bpdy to the valve, so I'd say the total run of pipe plus valve is about 1'. They are side panel discharges.

    The rig carries supply grade 4" hose.

    The pump is a 2008 Hale Qflo 1000 GPM.

    The 3" pony sections are about 15' long.

    Now, with the hose being 4", is there any advantage of siamesing the 3" lines to a single 4" or are the disadvantages of this size supply hose at high flows such that its simpler just to use an adapter to a single 2 1/2" discharge?

    Its clear to me that a flow of 1500 GPM plus is limited to only a very short lay (250' If I remember right),so our max target flow would probably be about 1000 GPM.

    Seems like the hose is the weak link here?

    FYI, I do plan on doing the expierment, Just need an opportunity.


    If the pumper is a 2008 it should have at least one large diamter hose discharge piped from the pump to the outside of the right panel, likewise on ldh intake.
    Stay Safe and Well Out There....

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    Quote Originally Posted by CaptOldTimer View Post
    If the pumper is a 2008 it should have at least one large diamter hose discharge piped from the pump to the outside of the right panel, likewise on ldh intake.
    Negative, there is none. Don't you think if it did that would have even started this????

    1901 does NOT require a LDH discharge, they simply tell you what each size discharge is "credited for" and state that all discharges larger than2 1/2" shall not be located on the pump operators panel. there are four 2 1/2" discharges and its a 1000 GPM pump. it meets the standard.

    1901: 16.7 and sub sections
    Last edited by MG3610; 08-10-2009 at 08:02 PM.

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    Quote Originally Posted by MG3610 View Post
    Negative, there is none. Don't you think if it did that would have even started this????

    1901 does NOT require a LDH discharge, they simply tell you what each size discharge is "credited for" and state that all discharges larger than2 1/2" shall not be located on the pump operators panel. there are four 2 1/2" discharges and its a 1000 GPM pump. it meets the standard.

    1901: 16.7 and sub sections
    Your dept bought a pumper knowing that your dept used LDH and didn't spec a LDH dicharge?? Make no sense.
    Stay Safe and Well Out There....

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    Quote Originally Posted by CaptOldTimer View Post
    Your dept bought a pumper knowing that your dept used LDH and didn't spec a LDH dicharge?? Make no sense.
    Yup, it makes no sense, so I sent you a PM explaining why I am here explaining it and asking questions.
    Last edited by MG3610; 08-11-2009 at 09:45 AM.

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    Default Siamese for 5"

    We had a similar situation when we first converted to 5" in the 70s. 1000 GPM pump with 2 1/2" discharges. The first experiment was to use a 2 1/2" to 5" Stortz right off the pump but the internal friction loss (30+ PSI at 1000GPM) was unbelievable, even using the discharge closest to the impeller (right rear on a Hale pump). Trying to get the rated capacity of the pump through a single (and very small) port is another part of the problem. We were able to flow the water but it beat up the truck.

    Our solution was similar to CE11'3 using two 3" sections 10' long and a clappered siamese. This worked very well. We changed our spec on the next 5 engines to a manifold fed by two 3" valves from different sides of the pump (top and RH side). This allowed for minimal FL in the pump. We currently use 4" valves on the RH side for LDH with minimal but noticable FL. We loose about 10-15 PSI when flowing 2000 GPM. It starts to increase dramatically above 2000 to about 25PSI at 2400GPM - short lays of 5"

    For second 5" lines we use a 3" full flow valve with a 3" to 5" Stortz or use a 5" by 3-3" gated wye with 2 50' lenghts of 3 1/2" to feed the second line. Our experience with the second line has been relatively low internal FL (10PSI) on the 2000GPM pumps. This is most likely due to the larger waterways in the pum and only forcing 1/2 the capacity of the pump through the small outlet.

    To solve your problem with out re-piping the pump, Kochek makes a number of different siamese conections. The link is below,
    http://www.kochek.com/FireEquipment....id=381-163-149 MES is a local Eastern PA distributor for Kochek.

    Hope this helps. If you would like to take a look at the manifold option we are just north of Philly.

    Mike

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    Quote Originally Posted by Squirt1262 View Post
    We had a similar situation when we first converted to 5" in the 70s. 1000 GPM pump with 2 1/2" discharges. The first experiment was to use a 2 1/2" to 5" Stortz right off the pump but the internal friction loss (30+ PSI at 1000GPM) was unbelievable, even using the discharge closest to the impeller (right rear on a Hale pump). Trying to get the rated capacity of the pump through a single (and very small) port is another part of the problem. We were able to flow the water but it beat up the truck.

    Our solution was similar to CE11'3 using two 3" sections 10' long and a clappered siamese. This worked very well. We changed our spec on the next 5 engines to a manifold fed by two 3" valves from different sides of the pump (top and RH side). This allowed for minimal FL in the pump. We currently use 4" valves on the RH side for LDH with minimal but noticable FL. We loose about 10-15 PSI when flowing 2000 GPM. It starts to increase dramatically above 2000 to about 25PSI at 2400GPM - short lays of 5"

    For second 5" lines we use a 3" full flow valve with a 3" to 5" Stortz or use a 5" by 3-3" gated wye with 2 50' lenghts of 3 1/2" to feed the second line. Our experience with the second line has been relatively low internal FL (10PSI) on the 2000GPM pumps. This is most likely due to the larger waterways in the pum and only forcing 1/2 the capacity of the pump through the small outlet.

    To solve your problem with out re-piping the pump, Kochek makes a number of different siamese conections. The link is below,
    http://www.kochek.com/FireEquipment....id=381-163-149 MES is a local Eastern PA distributor for Kochek.

    Hope this helps. If you would like to take a look at the manifold option we are just north of Philly.

    Mike

    Hey Mike I rather suspect that Chiefengineer11 taught this to Mogensen. And you can tell him that I said that!!!!
    "Loyalty Above all Else. Except Honor."

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    That was before Mogensen joined up with us, was probably still with UGFD at the time (a long time ago). Haven't seen him for a while. He probably still needed the refresher from CE11.

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    Quote Originally Posted by MG3610 View Post
    Yup, it makes no sense, so I sent you a PM explaining why I am here explaining it and asking questions.
    Got it and that answered a lot.

    Stay Safe and Well Out There....

    Always remembering 9-11-2001 and 343+ Brothers

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    I am totally understanding the efficiency differences now of siamesing the lines versus going right to the panel. Now, I'd like to see the math behind it.

    In the time that passes before we actually do the flow test, I'd like to wrap my mind around the concept better.

    We are dealing with 2 1/2" side panel discharges on a midship pump. They have 30 degree turndowns exterior to the panel. They extend about 1' from the pump discharge manifold to pass through the panel.

    With dual 3" lines having very similar to almost idential FL as a single 4", whats the advantage here? I am fairly sure the engine going to do less work with the siamesed layout versus the direct to the panel? Is the "splitting" of the flow between two valves substantial enough to make it worthwhile? But specifically, using 4" hose, is there a MAJOR advantage of taking the extra time to do this?

    KuhShise...good info, I am just trying to digest it and I am having trouble. I suck at math.

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