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  1. #1
    Member axman51's Avatar
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    Default 4" supply line connection

    How much pressure would you loose if you connected your 4" in to the 2" side of the hydrant rather than in to the steamer, I am on two departments one hooks in to the steamer and the other hooks in to the 2" side with their 4" supply line.
    "I have no ambition in this world but one, and that is to be a fireman. The position may, in the eyes of some, appear to be a lowly one; but we know the work which a fireman has to do believe that his is a noble calling."

    Edward F. Croker
    Chief 1899-1911
    Fire Dept. City of New York


  2. #2
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    axman,

    Hooking in to the steamer port with 4" hose or onto the side port with 4' hose, you'll find no difference in pressure. Hydrant pressure is hydrant pressure. The difference is volume.

    We use 5" hose and have an adapter that allows us to go directly from the 2 1/2" port to a 5" storz. Flow tests showed our 5" hoses as a rule flow 1700 USGPM. The adapter hooked to the 2 1/2" port flowing into the 5" achieved 1250 USGPM.

    Hope this helps.

  3. #3
    Member axman51's Avatar
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    What would the volume difference be? would it be large or small
    "I have no ambition in this world but one, and that is to be a fireman. The position may, in the eyes of some, appear to be a lowly one; but we know the work which a fireman has to do believe that his is a noble calling."

    Edward F. Croker
    Chief 1899-1911
    Fire Dept. City of New York

  4. #4
    John_Ford
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    Figure a 15% drop in volume from the steamer flow. Ball park, not exact. If you have a choice always go for the big port. Try this, if you have a really monster hydrant, gate the 2.5 ports and run a second and third line. Anything worth doing is worth overdoing.

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    I agree 100% with Mr Ford.

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    I did a series of supply line flow tests with 5"

    *flow tested a 2-1/2" hydrant port 1188 gpm
    *flow tested a 4" hyrant port 2016 gpm

    After hooking 400' of 5" supply line to each I got 1000 gpm from the 2-1/2" port and 1250 gpm from the 4" port. What happened? Friction loss in the hose ,intake valve , and pump plumbing.

  7. #7
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    Close enough, 15%, eh? The guy wants to know how much water he will get and you tell him close enough, 15%, pressure is pressure, 5" hose flows 1700 gpm? You're not even close!

    What is missing in the fire service is firefighters simply saying I don't know instead of trying to BS there way through everything they don't fully understand?

    Now some answers, any pump operator was supposed to know this stuff if he is worth his salt.

    4 inch port versus a 2 1/2" port with an LDH line connected... what is the psi loss and what is the flow loss? It depends on the flow and psi ability of the hydrant and the flow and length of lay your are asking from the hydrant. Simply take the gpm flow and divide by 167 for the 2 1/2" port and 428 for the 4 inch port (541 for a 4 1/2" port). Then take whatever number you come up with and multiply it by itself. That is the loss through the discharge at the given flow.

    Examples:
    2 1/2" 4" Difference 4 1/2" port Difference 2/4"
    500 gpm 8.95 psi 1.35 psi 662% 0.85 psi 1052%/158%
    1000 gpm 35.8 psi 5.44 psi 658% 3.4 psi 1053%/160%
    2000 gpm 143.3 psi 21.8 psi 657% 13.6 psi 1053%/160%

    As you can see the pressure difference is always in the 650% range and 1050% and 158% compared to 2 1/2" and 4" ports to 4 1/2"...it will never change.

    So what does all this mean? You've got 6.5 times more energy to push the water further or push a higher gpm flow. OR ten times further if your city was smart enough to buy 4 1/2" ports on their hydrants for no cost over 4".


    NEXT subtract the NP above from the residual pressure of the hydrant. 60 psi residual hydrant at 1000 gpm leaves 24.2 psi and 54.56 psi respectively to push the water through the hose. So the 1000 gpm will only travel 127 feet using the 2 1/2" port versus 287 feet with the big port in this example. If you lay out 800 feet of hose one will flow 382 gpm and the other 587 gpm. 153% more water. At 400 feet the difference is 153% and at 2000 feet 153%. It is always 53% more.

    1700 gpm with a 5 inch line? That is 18.59 psi loss per 100 feet. With a 20 psi residual at 1700 gpm the water goes how far???? 100 feet. At 500 feet you better have a 100 psi residual pressure hydrant. AWWA and NFPA don't sanction hydrant pressure that high. If you are the 4th in rig odds are a 1000 foot lay is needed and you better have a 200 psi hydrant if not your 1700 gpm line will only bring 775 gpm. There aren't a lot of cute little answers you can throw around and be anywhere close to right. All you do is mislead the reader. The guy with one and 2 miles of 5" ain't getting 1700 gpm. EVER!!!!! Just because two guys agree 100% doesn't mean they are anywhere close to right.

    You know, if your going to speak so matter of fact, at least be right.

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    Larry, Larry, Larry. huh?

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    play,

    I think you'll find that your numbers on friction loss are as a matter of fact a little askew. Angus Hose states the friction loss in 5" hose is 7.57 psi/100 ft @ 2000 gpm. (http://www.angusfire.com/angus/Specs/Angus%205%20Inch%20Hi-Vol%20Spec%20UL.html)

    20 psi residual pressure? Does your city pump to it's hydrants with a Honda trash pump. Try 80 - 100 psi residual.

    10 paragraphs of blah blah to prove what?

  10. #10
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    In support of Mr. Fords statement of having a ballpark difference of about 15% I suggest that you do the flow tests and see for yourself. Numbers based on formulas are extremely acurate for calculations on paper but not always good for reality. There are alot of variable that can make a difference. ( PLAY before you fly off the handle again with your answer read what I just said. " NOT ALWAYS")
    Larry In regards to your figures that you posted on flows, knowing your intelligance(forgive my spelling) I am sure you are correct. Hell I wouldn't know how to disprove your facts if I wanted to. What are you trying to tell us common folk? If you really want to teach I would recomend slowing down or should I say coming down to our level ,take a deep breath and try to explain something to us. I havesaid it before and will say it again, you have alot to share but your delivery sucks.
    Larry, let me ask you a question, If I were to try to tell you something and basicaly said Larry you dumb SOB What the hell is wrong with you . You are so stupid . What do you mean you can't add 12236658365785937275 plus 23657836355785 in your head. I can. This is how you come across. But I know I am not telling you anything new.
    Finally Larry, In regards to the statement I made in this thread about how I like to flow tests hydrant, You dummie, You are slamming something you taught me years ago when you were more approachable. Go figure.

  11. #11
    blackb16
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    I think you'll find that your numbers on friction loss are as a matter of fact a little askew. Angus Hose states the friction loss in 5" hose is 7.57 psi/100 ft @ 2000 gpm.

    Well,ifsta, nfpa, fire engineering, akron and elkhart don't support those numbers. Could it be that Angus sells hose? One upping the competition?

    I suggest that you do the flow tests and see for yourself. Numbers based on formulas are extremely acurate for calculations on paper but not always good for reality.

    The 15% isn't even close based upom 630 hydrants worth of flow testing we have on file. So if what Paul is saying the laws of physics don't apply. If Paul would take his own numbers he posted a few days ago he would see the give 100%, but not with the 15% though.

    Work it out, you'll see!

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    Blackb16 aka?

    The 15% isn't even close based upom 630 hydrants worth of flow testing we have on file. So if what Paul is saying the laws of physics don't apply. If Paul would take his own numbers he posted a few days ago he would see the give 100%, but not with the 15% though.

    I thought I made my self clear that the 15% figure involved flow tests with supply hose conecting hydrant to pump.

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    I by no means have a complete answer for this question but I have made some observations on our hydrant system which is by no means the best system around. One of our hydrants, that happens to be on a looped system like I wish all of our hydrants were. On this hydrant it has a 5.25" riser and a 4.5" steamer w/ two 2.5" side outlets. This is our strongest hydrant within our system and I did note while flow testing this one that I was unable to get down to 20lbs. residual pressure with just one 2.5" outlet open with the hydrant fully opened. I have to open either both 2.5" disharge or the steamer to get the residual pressure down to 20lbs. On our other hydrants which are on the weak side to say the least it doesn't seem to matter as far as this goes. On this hydrant anyway I would have to think it would not get as much flow through one 2.5" discharge as it would through the steamer. On the other hand, some of our plugs do not have steamers on them. I don't really like it but that is what we have. On these hydrants the flow is usually pretty weak anyway and the only option I have been able to come up with other than getting the water company to replace them is to put a 2.5" nst to 5" storz adaptor on them straight to the plug's discharge to reduce friction loss.
    Daron

  14. #14
    blackb16
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    Interesting thing is Big Pauley says the difference is only 15% when his own flawed tests revealed a 25% and 85% differences. Of course ne explanation is offered for the post.

    Just goes to show you can trust what is written on these boards.

    He certainly didn't make a case for pressure loss in the hydrant port or travel distance of the water either.

    Can anyone dispute the post about 600% further lays off the big port versus the small port and 150 percent higher flows with any facts, obviously the so called LDH expert, Paul can't. His own post charts out nicely to support the other position.

    You ask Paul what was the common guy suppose to get from it? That water will go 6 times further or flow 1.5 times more. Pretty simple message. If you have a choice use a big port. Move the tops of your hydrants around town to areas where the ones with big ports will help you if needed.
    If you don't understand the hydraulics just say so, several folks here can explain it to you Paul. There are whole books about PRV's in water systems that function the exact same way as a 2 1/2" to 4" reducer off a fire hydrant.

    [ 08-27-2001: Message edited by: blackb16 ]

  15. #15
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    Larry, one final rebuttal.
    If you look back to what was originally written, the statement "ballpark" was used. I think you know what ballpark means - approximately. Of course, you chose to twist things around, like you always do. You chose to hear only what you wanted to hear, like you always do. You'll get no more replies from me.

  16. #16
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    My apologies for all that read this thread for turning this into a ****ing match with LHS . he got to me, but it will not happen again. This forum is for sharing ideas not bashing.

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