Sprinkler system noise reduction

Discussion in 'Irrigation' started by andersa, Mar 28, 2007.

  1. andersa

    andersa LawnSite Member
    Posts: 30

    Hello experts,

    I have a couple of issues with my residential sprinkler system. I have a couple of ideas of how to remedy those issues, but I would like to run them by you before I attempt to implement them and possibly waist money and well, perhaps make things worse.

    The first issue I have is with noise. No, not water hammer, but just the noise from the water running through the copper pipes in the basement. Although our bedrooms are on the 2nd story, as soon as the sprinkler system starts in the morning, I wake up from the noise. After finding and reading www.irrigationtutorials.com last year when I was researching drip irrigation, I have concluded that the noise is all related to the velocity of the water running through the copper pipes and my thinking is that if I reduce the velocity I also reduce the noise.

    Let me first describe my current setup;

    1” copper pipe enters through the basement floor, followed by a pressure reducer, followed by a 5/8” water meter and then 35’ of ¾” copper to the outside, where a Wilkins 720a ¾” PVB is mounted 4’ of ¾” to copper below ground, into 6’ of 1” PVC to the manifold and valve box.

    Now, the system is under dimensioned. I found out using the bucket filling exercise, that I have roughly 10 GPM and 95 PSI (well, I found out the PSI by using a pressure gauge). But most stations exceed 10 GPM. I have for example a station with 7 PGP heads with the #5 nozzle => 14 GPM. To make matters worse, two heads do 360, 1 head does 90, and the rest do 180. Or at least the used to have the #5, I have messed with it since I discovered this, i.e., I have replaced nozzles and tried to balance the water use a bit, but needless to say, the grass is still not green! The rest of the system is not much better…

    So, on to my first question re the noise;
    As I am in the process of finishing the basement, my window of opportunity for fixing things in the basement is coming to an end. First, I was thinking that to reduce the racket in the basement, I should replace the ¾” copper, from the water meter to the outside PVB with a 1 ½” copper line. But since copper is expensive, I figured a more cost effective solution would be to simply add a second ¾” copper line in parallel from i.e. the water meter to the outdoor PVB. The sum would be of course not be the equivalent of a 1 ½” pipe, (I am assuming, since the square area of 2 x ¾” is 0.88 sqin, vs. 1.76 sqin for the 1 ½”) but would at least hopefully cut the water velocity in half and thus cut down on the noise. Of course, there are now two sources of noise though, i.e. two pipes, so is my theory correct that the noise generated from the water velocity would be reduced, or will it be even noisier?
    Second part of this question is what to do at the end of the parallel lines if I go this route; i.e., should I simply merge them into the a single ¾” copper pipe before leaving the house and allow me to reuse the existing PVB, or should I perhaps join them into a 1 ¼” pipe (1 ¼” because it is slightly larger square – 1.23 than 2 x ¾”) just before leaving the house and upgrade the PVB to a 1 ¼” on the outside, just to make sure that no or at little noisy ¾” pipe/equipment is being part of the system, in case the PVB adds to the noise? I have a feeling it does, but I have no proof. Since large dimension PVBs are fairly expensive, at least the few I have found on the net so far, I really like some expert advice on this. I’m also thinking of upgrading the water meter to a 1” version, just to be on the safe side of noise reduction, as well as hopefully getting some much needed extra capacity.

    OK, so I know that I have to fix the capacity issue too and that bringing down the flow to 10 GPM would probably benefit my noise issue somewhat, and trust me, I am going to address it, by adding stations and re-organizing stuff. The question I have with respect to this is; how do I pull lines over a lot that pretty much is a spider web of poly lines already? I know when trenching there isn’t much option but keep going and cutting the poly when it happens. After installing an 80’ straight drain pipe in the backyard a couple of years ago, I cut the sprinkler poly lines no less than 7 times. In order to add a couple of stations I would have to cross a lot more and possibly cut a lot more lines. How safe is it, i.e. will I even notice, that I cut a line when pulling?

    So why am I not simply calling in the pros and have them deal with it? Well, after installing the drip last year, I have to say that I kind of enjoy the work. I’m behind a desk all day long and being out in the sun messing with the sprinkler system is great fun to me. I’ll have a plumber friend do the copper work though; I don’t want to risk a leak in the basement because of my lack of soldering skills. But I don’t want the sprinkler company that installed the system touch it again, I mean, they screwed it up big time to begin with! A second sprinkler company that a neighbor brought in to winterize all systems on the street didn’t keep the PVB open over winter so that was busted the following spring. 2 for 2 so far unfortunately.
     
  2. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Posts: 2,781

    I would shoot for reducing your output first. That could be a 2" copper supply line to the PVB and you might still hear the noise you are hearing. If all the heads were #5's.........what kind of spacing are we dealing with? #2 corners and #3 halfs and leave the fulls at #5 might drop your output to a more reasonable level. Also, a PRV after the sprinkler tap for the rest of the house might help your noise and you household plumbing. Was the 95 psi an operating number? Even if it was static, I like house plumbing to be closer to 60psi. Your o-rings and seals will last much longer. A gut feeling suggests we are missing some info as well. Any chance there is a valve the water is passing through that is not fully open? Best of luck to you!
     
  3. Flow Control

    Flow Control LawnSite Bronze Member
    Posts: 1,267

    My attention span is not to long, so you lost me after a bit. Great research, so kudos for gaining knowledge in the area. Does the noise sound like a clicking noise or similar?
     
  4. Flow Control

    Flow Control LawnSite Bronze Member
    Posts: 1,267

  5. DanaMac

    DanaMac LawnSite Fanatic
    Posts: 13,156

    East fix - set it to run after you leave for work!!! You'll never hear it again.

    I've got skills baby!!!!!!!!!!
     
  6. LOL....keen observation for the obvious.

    Wear earplugs to bed like I do....
     
  7. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,356

    I remember neighbors of customers with brass impact heads sometimes calling the police to file noise complaints about nighttime watering.
     
  8. 5/8" meter at 95psi should be flowing in the 20-25pgm range. If you did a flow test on a faucet with a 1/4" opening then I could see 10gpm....
     
  9. Some spigots restrict the flow tremendously...and when the flow is reduced and restricted.....and the velocity is high....it is LOUD.
     
  10. andersa

    andersa LawnSite Member
    Posts: 30

    Ha ha, some great advice here. I know I have gotten to the right place for these questions. But seriously, what fun is it to not fix problems like this and only do the watering during daytime or sleep with earplugs? But I do appreciate the suggestions; especially since the latter would also let me sleep through kids requiring attention during the night :)

    bicmudpuppy:

    95 PSI is the static pressure. It may be a little high. The utility recently upped the pressure, since this is part of town is growing. The water main in the street serving my house was recently extended into a brand new adjacent neighborhood, where they are currently in the process of building 350 town homes. So I suspect that my pressure will go down once the people start moving in there.

    Head spacing seems to be an issue, I think the heads are too far apart and not enough head to head action. I think there may be about 30' feet between the heads but I have to double check when I get home tonight.

    I have currently 7 stations, 6 for the lawn and one for the drip. The 6 lawn valves, all Hunter PGVs, all seem to behave the same, i.e. I can't tell that one station is noisier than another. Hopefully all of them aren't stuck.
    I think I can fix the station in my example by splitting it into two stations. About three heads are right next to the flowerbed holding the valve box, so limited digging and no tearing up the grass, i.e. I can run the poly in the flowerbed to those heads.


    ICS:

    Yes, the noise is the same for the duration of each station. I have for example a station with 4 rotor head with #5 nozzle that is less noisy. There may be a slight clicking or ticking sound, hard to describe. I have always thought it was from the PVB, as my previous house did not have a PVB and there the sprinkler didn't generate that ticking sound. Although in that house – a ranch – the racket from running the sprinkler was even worse and I did run it after going to work, couldn't even take a shower while the sprinkler was running.

    Wet Boots:

    Outside the system is very quiet, no complaints there from me or the neighbors.

    Londonrain/sprinklerguy:

    Good point. I did do the bucket test from the hose faucet (w/o a hose). It is right next to the PVB, but not on the same ¾" copper pipe as the PVB, so there is obviously a great risk for variation here between the faucet and the actual sprinkler system. There is no faucet on the sprinkler line itself, although I would add one if I did all those changes I have mentioned.

    Now, and I have to quote Mr. Stryker, as his site is the only source I know of. http://www.irrigationtutorials.com/sprinkler03.htm, lists max GPM for ¾" Copper to 11 GPM. I should really try to increase the copper dimension, reduce the GPM usage or do both (what I was planning to some degree), no?

    It is interesting to note that nobody believes that an increase in copper dimension will reduce the noise, at least not to a level that will make me happy. I am grateful for the advice given. For a while I was contemplating whether perhaps PEX would be a more quiet solution, and I was thinking that I should replace the copper with that, but it seems to be more of a hassle and also seems to be more susceptible to leaks. Leaks in the basement I can live without.
     

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