Why register? ...To Enhance Your Experience
+ Reply to Thread
Results 1 to 15 of 15
  1. #1
    Junior Member
    Join Date
    Oct 2002
    Location
    Dexter, NY
    Posts
    4

    Question Basic Pumper Operation Question

    I have a basic question that I would like to have answered.

    * How do you hook up double laid 3" (2 1/2" couplings) hose supply line to the pumper for supply operations?

    My answer is you take a siamese ("Y" adapter) with 2 - 2 1/2" intakes on a 5" stortz adapter that connects to the 5" intake on the pumper.

    Is this correct or am I totally wrong. I would like a general idea if this is what people that lay double 3" do. (I know it would be much easier to lay 5")

    I was told by a person to put one 3" supply line in the 2 1/2" intake. (Which is fine, I agree you can do that.) Then take the other 3" supply line and place that on the 2 1/2" discharge and let the pump go, and start pumping. (I guess his idea on doing this was to put more pressure on the hose (intake side) to flow more water?) (I DON'T AGREE WITH THIS.) Am I wrong?

    Please if you could let me know how you would lay double 3" supply line let me know.


  2. #2
    Forum Member
    Join Date
    Apr 1999
    Location
    Maine
    Posts
    212

    Default

    FF17025 - you need to understand the difference between intakes and discharges. An intake is a source of water for your pump. Typical pump intakes are the tank-to-pump plumbing, the old 2 1/2 gated intake present on 99.9% of all engines and the master intake, which might be 4, 5 or 6 inches in diamter depending on your pumps rated capacity. If I were connecting two 3 inch supply lines, I would connect them both to the siamese (hopefully a gated siamese). Connecting a supply line line to a discharge port would be pointless. The discharges are on the outlet side of the pump.
    Remember, it IS as bad as you think and they ARE out to get you!

  3. #3
    Forum Member fflynn17's Avatar
    Join Date
    Aug 2000
    Location
    Finally Vermont!
    Posts
    459

    Default

    I believe that this:
    I was told by a person to put one 3" supply line in the 2 1/2" intake. (Which is fine, I agree you can do that.) Then take the other 3" supply line and place that on the 2 1/2" discharge and let the pump go, and start pumping. (I guess his idea on doing this was to put more pressure on the hose (intake side) to flow more water?) (I DON'T AGREE WITH THIS.) Am I wrong?
    Is supposed to be used when your engine is being used in a long lay as an inline pumper to boost the pressure, not when doing a double lay of 3". The 3" supply line from the hydrant would go into your intake, your pump would boost the pressure and send the water down the line from your 2 1/2 discharge to the next pumper.

    I would think that the answer would depend on the number of INTAKE valves on your truck, I know on ours we have 3 3" intakes and a 5" intake, so if they brought me 2 3" lines from the hydrant, I would connect both to separate intakes.

    I am just now working on my pump ops cert, though, so I could be wrong.
    Last edited by fflynn17; 03-18-2003 at 11:25 AM.
    9/11/01 Never forget Never forgive

    Dusty, working on Crusty IACOJ

  4. #4
    MembersZone Subscriber
    Join Date
    Oct 2002
    Location
    Wisconsin
    Posts
    5

    Default

    It sounds to me like the question should be whether to run both 3" lines into the main intake via a siamese or to run one into the main intake and the other into the 2 1/2" auxiliary intake. If that truly is the question, then assuming both 3" lines originated from the same hydrant (or other source), I would still go with the siamese. This solution will simplify the act of opening/closing intake valves. It will also leave that auxiliary intake free to add another line if you establish another water source (maybe a relay or a different hydrant).

  5. #5
    Forum Member
    Join Date
    May 2000
    Location
    Wisconsin
    Posts
    28

    Default reduce friction loss

    If I understand your question correctly you are using twin 3" lines to supply your pump. As with the other posts I agree that the best situation is to run both supply lines through a siamese into the "steamer" large intake on your pump. The reason for this is that the "steamer" intake will have the lowest amount of friction loss. This is because the water passage will have the largest pipe with the fewest number of elbows. IF you follow the path of the small intake on your truck you will see that this intake uses a smaller pipe with more elbows which results in higher friction loss and less residual water pressure going into your pump. That being said if you put one supply to the steamer and one to your small intake the system will definetely work, but for optimum flow from your water source in this situation you would be best to use the siamese.

  6. #6
    Forum Member
    Join Date
    Nov 2002
    Location
    Nf, Canada
    Posts
    117

    Default

    FF17025
    You said that "you did not agree with this". I hope you can follow what the others have said. Make sure you straighten out your friend.
    when in doubt...post it

  7. #7
    Forum Member Fire304's Avatar
    Join Date
    Jun 2002
    Location
    At the Helm
    Posts
    1,174

    Default

    I guess I would have to say it depends on the way you leave the truck. If you can put a clappered siamese on the steamer intake and leave it there, that's what i'd do. If you could not leave the siamese on the steamer I'd hook the 1st 3" to the 2 1/2" intake and throw a hose clamp on the 2nd until I could get the steamer cap off and throw a 2 1/2" adaptor on to it, that set up would get you water the quickest. Rhino is right about there being more friction loss in the 2 1/2" intake, but give that the pipe is 2 1/2" and only about a foot or two long, I believe the loss would be minimal (especially compaired to the loss over any long run of 3"). Another advantage of my 2nd method would be if a neighboring department is using LDH you could drop one 3" and still flow the other while hooking in to the LDH when mutial aid shows up.

    Your friend's method is certianly a noble attempt at boasting intake pressures, and might work as long as there was no other water flowing from your pumper to the fire ground (tounge planted firmly inside cheek while typing this). If you are supplying from hydrants your local water works director would want to shoot the operator who back feeds and contaminates the drinking water supply. No, it would not work unless you are utilizing some form of jet-siphon device back at the water supply that requires pressure (and even that is doubtful since your 3" is not suction hose), but running from a hydrant or another pumper would be, well for lack of better words, bad.
    ______________________________ __________________
    If you are new to posting please CLICK HERE for an essential lesson
    ______________________________ __________________
    A bad day in the boat is better than a good day in the office. And in my case the office is a boat!

    IACOJ Fire Boat 1

  8. #8
    Forum Member
    Join Date
    Oct 2002
    Location
    Camden County, NJ
    Posts
    7

    Default

    FF17025
    Your idea is probably the most efficient plan for getting the most out of those dual 3's. Your pump should have a second steamer connection that would allow you to hook up an LDH supply later on if it became available. The steamer intakes go directly into the pump and are the ones used to rate capacity of the pump. The smaller intakes do have more friction loss but for the amount of water you are getting from the 3" line, it should be minimal. The only thing to watch out for with a clappered syamese is that if one line has less pressure than the other then the clapper will close off the one line. This should not be a problem however if both lines come off the same hydrant and are the same length. If you are getting the dual 3's from a supply engine make sure that that engine pumps both lines at the same psi.

    As for the other idea that was suggested by that person, forget it. Discharges are for discharging water only. You can not intake water through a discharge on a pump while it is pumping. Really unless your hydrant pressure was greater than your pump discharge pressure, which it wont be because of the other line going into the suction, you will be doing nothing more than pumping back to the hydrant.
    Stay Safe
    Work smarter, Not harder

  9. #9
    Junior Member
    Join Date
    Jan 2003
    Posts
    4

    Default 3" or 5"

    wow!!!,

    confused yet?

    Look I'm not the all knowing, but if I remember right, 5" gives you 1400 GPM.(?) Well two 3" lines will give you 1600, 800 a piece. So 1600 is better than 1400 more VOLUME!!!!!!! But then its just a matter of plug flow, and pump GPM's. Pretty easy I think.

    Remember, Keep it simple.

  10. #10
    Forum Member Fire304's Avatar
    Join Date
    Jun 2002
    Location
    At the Helm
    Posts
    1,174

    Default

    Wookie, you are correct that 3" hose can flow 800gpm, but at that flow rate your friction loss is 53lbs/100ft, meaning that, if the hose is tested to 200psi (as most supply hose is and your max safe working pressure is 180psi) and you want to keep 20psi residual, you cannot lay more than 300ft. By compairison, 5" at 1600gpm has 16psi of friction loss, allowing a lay of 1000ft. This assumes that you have a pumper capable of pushing 1600gpm@180psi.

    2 3" lines are roughly equal to 1 4" line, only you have to pack twice as much hose at the end of the shift. You need 4 3" lines or 2 4" to match 5"'s friction loss, but then do you have 4 intakes on your truck? Or maybe a quad siamese (don't forget the friction loss they create when doing the math)?

    In realistic fire ground use, 3" hose is rarely pushed beyond 500gpm, where its friction loss is about 22psi/100ft. 5" at 2000gpm has about the same friction loss, so you see, it takes 4 3" lines to equal one 5".

    Another way to look at it is to say that for every foot you cover with dual 3" you can lay about 3 1/3 times the distance in 5" with the same friction loss.

    In practical terms, keeping friction loss to less than 25psi/100ft...
    2.5"=300gpm
    3"=500gpm
    4"=1000gpm
    5"=2000gpm

    In case you'd like to see the tables, here's a decent one I found recently... http://www.tamparubber.com/mainpres.htm
    ______________________________ __________________
    If you are new to posting please CLICK HERE for an essential lesson
    ______________________________ __________________
    A bad day in the boat is better than a good day in the office. And in my case the office is a boat!

    IACOJ Fire Boat 1

  11. #11
    Junior Member
    Join Date
    Jan 2003
    Posts
    4

    Unhappy We only use 4"

    See I didnt know 5" could flow 1600 GPM. I thought it was 1400. Nobody uses it around here. We use 4" and 3". I agree, I think 5" is great. I just wish we had it. And you know for our small call load, 4" works. I just like to try to think outside the box and challenge convention. I work on our dept's quint, so I try to see how I can maybe squeeze more water when I can. I just know the basics, So tell me if Im right here,

    The way I figure it is if you are flowing 250 GPM total, and you lay 200' of supply hose in 4" You lose about 8 psi total. I use the real simple, 3psi loss per 200 gpm per 100'

    Follow?

    So that gives me ""APPROXIMATELY" 8 psi loss when we typically have plugs at 50 or better psi.

    Then if I do it in 2 3" lines, I use this) Q=(GPM/100) squared

    So, for you split in half and go 125/100= 1.25, squared is about 1.6

    Times 2 for the other line = about 3 Times 2 for 200' = total loss of
    6 psi.

    This is the way I see it, again I am no great genius, but this is the way that I learned it. It seems like you could just get alittle more with 2 3" lines than 1 4" line. Sorry for my simple logic. I just try to keep it simple. Let me know if there is another way to look at it.

  12. #12
    Forum Member Fire304's Avatar
    Join Date
    Jun 2002
    Location
    At the Helm
    Posts
    1,174

    Default Re: We only use 4"

    My tall furry friend, you are correct in that dbl 3" are functionally equal to one 4". The difference between the two is so small that age has more of a factor than size when compairing friction loss between the two.

    I came from a very rural department where water was always an issue and we used 4" and rural shuttle. Surrounding towns used 5" and they could move a lot more water over much longer distances than we could, since I left that FD they have switched to 5".

    While the 5" can move double the water the 4" can, it really pays off when running at the lower flow rates which are more typical for a rural water supply.

    At 1000gpm you can lay 2300 feet w/o a relay pumper (again assuming 180psi pump pressure and 20psi residual). 3" and 4" over that distance and flow rate would require 4 pumpers (one every 800 feet). If you are running shorthanded this pays off big time, that's 3 trained firefighters who can go to the scene instead of running a pump.

    The down side of 5" is it is big, it takes up a lot more of the hose bed and you end up with less of it one the truck (it's a trade off). Our quint tower could carry 1000' of 4" only carries 800' of 5". Our pumpers each carry 1200' instead of 1500' of 4". I don't know how much 3" they could carry, its been decades since that was standard issue.

    The moral of the story? If you're gonna go LDH, go 5", its not much more money and you lose a little bed space, but it pays off in the long run.
    ______________________________ __________________
    If you are new to posting please CLICK HERE for an essential lesson
    ______________________________ __________________
    A bad day in the boat is better than a good day in the office. And in my case the office is a boat!

    IACOJ Fire Boat 1

  13. #13
    Junior Member
    Join Date
    Jan 2003
    Posts
    4

    Default OK but still...

    I understand but we only have 4" and 3" and our lays are very short typically. So all I am saying is that with a regular, non-gargantuant hose lay, you can get more gpm's out of 2 3" lines than you can one 4" It's not much but I havent been trained enough and nor do I want to sit there and crunch a bunch of stupid numbers while my boys are interior. When it really comes down to it, the 4" is set up to pay out for supply, so screw it 4" it is. If I've gotta flow the stick, I'll get a supply from another truck on another plug. I commend all that can run all the crazy numbers real quick, but I like to keep it simple. I learned the way for calculating FL by the amt. of GPM's you're flowing, it has always worked. Until I can make it to class on the other ways to do it, this works.

  14. #14
    MembersZone Subscriber BVFD1983's Avatar
    Join Date
    Feb 2003
    Location
    IL
    Posts
    434

    Default

    We run 3'' supply lines (hopefully getting 5'' soon) and all of our trucks have at least two intakes. On one engine the intakes are in the rear and one is hidden in a compartment. We don't even have any adapters.

    Double 3'' supply lines sure can't match the 6'' front suction...

  15. #15
    MembersZone Subscriber dmleblanc's Avatar
    Join Date
    Jul 2001
    Location
    Not the end of the earth but I can see it from here...
    Posts
    2,318

    Default

    I got out my trusty Akron "FireCalc" friction loss calculator and I was able to calculate the predicted friction loss in a given length of 5" hose as compared to an equal length of dual 3". Then I entered the figures for what it would cost to replace all our 3" hose and the equation kind of fell apart after that.....
    Chief Dwayne LeBlanc
    Paincourtville Volunteer Fire Department
    Paincourtville, LA

    "I have a dream. It's not a big dream, it's just a little dream. My dream — and I hope you don't find this too crazy — is that I would like the people of this community to feel that if, God forbid, there were a fire, calling the fire department would actually be a wise thing to do. You can't have people, if their houses are burning down, saying, 'Whatever you do, don't call the fire department!' That would be bad."
    — C.D. Bales, "Roxanne"

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts