Poly Pipe Low Density/High Density

Discussion in 'Irrigation' started by Planter, Apr 4, 2005.

  1. Planter

    Planter LawnSite Member
    from Utah
    Posts: 214

    I looked today at a customer's system to turn it on. It was brand new and installed after the secondary was turned off for the year. Never had water in it.
    I checked the main shut off and noticed the pipe was some of the "green line" poly. I couldn't see any markings on it, but it looked like the thicker low density pipe I've been using on laterals. All all the high density that I have used as main line has been thinner walled and more ridgid that this stuff. Has anyone seen high density poly that has the thicker walls? I'd hate for this customer to have leaks in the main as time goes by. Better to get the installer back to change it out now.

    Nice install, they used a gate valve for the main shut off instead of a ball valve, none of the field wires were connected to the solenoids and I found a spray head in a flower bed that was out of the ground and on it's side. Haven't seen the clock, but I'll bet it's a piece of work if there is one. They ran a piece of poly down on the front of a 10 foot tall rock wall and never covered it. It just goes down and into the gound out in the sun and fully exposed.

    Poor lady had it installed as part of the new home purchase. Nice expensive house, but the install that I have seen makes me wonder.
     
  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,003

    Poly pipe used in deep wells is thick-walled, and usually rated 160 psi or higher. I would be a bit leery of unmarked poly pipe serving as a sprinkler system main line, if it were subject to continuous (no master valve) water pressure. Most, if not all, NSF poly tubing is well marked, although a short length might not show markings. The last roll of 160 psi NSF poly I bought was the high-density type.
     
  3. Planter

    Planter LawnSite Member
    from Utah
    Posts: 214

    I have always used high density for mainline, continuous pressure applicaitons. Low density will leak after time. I have a commecial property I maintain that has two mainline leaks per week. They used low density for the main and high density for the laterials. The owner is too cheap to change out the main.
    I am just wondering if anyone's seen the high density in thicker wall pipe. I have not seen it. This pipe is labeled if I dig enough of it up I'll find it. Just hate to do that.
     
  4. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,003

    Low density is what funny pipe describes itself as. Medium density is what the older standard of poly pipe (PE 2406) was, before the advent of high density (PE 3408) - the density of the pipe is not so important as the pressure rating and NSF certification of the pipe. If you use non-NSF-rated high density pipe in a continuous-pressure application, you have no one to blame but yourself if it springs a leak. There are a bazillion deep wells with NSF-rated medium density poly pipe working leak-free for decades. There is no way to just look at unmarked poly pipe and know whether it is medium density or high density. You have to see the markings on the pipe to know for certain just what it is. I buy high density poly that's as thick or thicker than medium density pipe. What you have to do is try to 'read the mind' of the original installer by looking at the installation. What I think you will find, if you dig up some pipe to see the markings, is that it is probably NSF-rated poly, and with sufficient pressure rating, you should be good to go. I'd still want to see a master valve, if there isn't one already, unless there is a faucet, or lawn hydrant on the main line, as part of the installation. I rather doubt that the pipe would be non-NSF-rated, because nearly all 'utility' grade poly pipe is high density poly, which uses less material, and is cheaper because of it.
     

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