1/2" pipe on residental installs, do you use it?

Discussion in 'Irrigation' started by villagegreenlandscape, Aug 25, 2007.

  1. villagegreenlandscape

    villagegreenlandscape LawnSite Member
    Messages: 69

    I have a friend who takes great pride in the fact that his crew uses 1/2" pipe in his residential installations because it shows how knowledgeable they are. At the supply houses it seems like almost nobody uses 1/2" pipe anymore. They put the valve in the middle of the zone and use only 3/4" pipe (around here we normally use 1" valves in residential). Other than a slight cost difference (we install a 7 zone system on average so the difference I think is about $30) is there any reason to use 1/2" and if that's the case why not just stick with 1" and be really simple? Sure would keep the parts simple.
  2. Mjtrole

    Mjtrole LawnSite Member
    Messages: 226

    My opinion is that its just for speed of the installation, we used to use 3/4" inch but, like you said, it was so much easier to stock only 1" materials.
  3. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,874

    Seems like penny-pinching on a PVC system. On poly, it would almost be weird. I've only pulled half-inch poly twice. It is useful for lines hand-buried in shrub areas, where the small pipe can curve around obstacles.
  4. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    Many years ago... my design instructor stated, "The ONLY reason to size pipe down (to the appropriate size for carrying the amount of required water) is to save money." Smaller pipe also means smaller fittings which translates to savings. However, like you've stated, in a typical smaller residential system install the amount of money may not be that great. BUT... if I downsize a residential to appropriate pipe sizes I can also install our more expensive SCH 80/Marlex swing joints instead of barbed/ha-ha's and the overall cost will be a push.

    Some guys carry the knowledge thing to a snobbish level and maybe that's what this guy is all about.

    Could be a combination of things involved. Some guys just don't have the knowledge base while others are looking to keep the number/type of parts down. There is often no real way to tell. Our use of 1/2" pipe is not that great and is usually only for repairs or renovations where we're moving a sprinkler location off an existing 1/2" final supply to a sprinkler head. On new installs we usually run 3/4" to each sprinkler head and then use a 3/4" x 1/2" slip x thread 90 ell to start our 1/2" swing joints.

    Also, we don't use a bunch of specialty parts and get around by stocking a very good supply of reducer bushings. That way we can readily reduce any fitting down to the size we wish and in the direction we need to go.
  5. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,874

    I think the 'knowledgeable' aspect of the half-inch user's thinking might relate to the 'braking effect' of the small diameter line at the end of a run.
  6. Kiril

    Kiril LawnSite Fanatic
    Messages: 18,335

    Ditto. :)
  7. drmiller100

    drmiller100 LawnSite Senior Member
    Messages: 562

    we stock 1/2 to one inch barbed couplers, and 3/4 to one inch barbed couplers.

    then we stock a bunch of one inch stuff.

    only time i will use 1/2 or 3/4 on an install is for drip systems.
  8. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    As long as one stays within their total zone GPM larger pipe/polly really isn't a bad idea since it leaves a lot more room for renovating a system/zone in the future as things change. I was taught to never max out a zone/system to its full potential because someone may need to make additions/changes later. This has served us well in the school site environment since these types of sites are always in a state of flux. For this same reason we also don't allow any valve smaller than 1-1/2" to be installed even if it is a lot greater than the total zone GPM. Allows for much more future flexibility. Guess this would be akin to installing a 1" valve in a residential situation instead of a 3/4" valve that would be normally installed based on GPM.
  9. villagegreenlandscape

    villagegreenlandscape LawnSite Member
    Messages: 69

    What my friend says is that he's keeping the water speed to 7 feet per second - which is what the rules used to be, I think it's 5 now. He also says he doesn't like trying to repair systems with all 1" pipe because it's too difficult to figure out what's the main line and what's the lateral.
  10. Mike Leary

    Mike Leary LawnSite Fanatic
    Messages: 23,218

    It has been 5' a second for a while, a long while. I used 1/2" years ago, but
    ran into so many jobs where expansion was wanted on the existing zone 1/2"
    would'nt do it. Also, as posted before, the parts & labor to bush down not
    worth it. 1 1/4" or 1" main, 1" to 3/4" laterals. Unless you're "low-flow Hank",
    then it's all 1 1/4".:laugh:

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