Swing joint fittings blowing out

Discussion in 'Irrigation' started by Dirty Water, Oct 9, 2005.

  1. Dirty Water

    Dirty Water LawnSite Fanatic
    Messages: 6,794

    I'm starting this thread because I don't want to hijack this thread.

    I have always used either Rainbird MPTxBarb fittings and Marlex elbows or the Lasco Blue twisters (We now use the Lasco ones exclusively).

    We use Hunter swing pipe. I have never personally had any swing joint connection blow out on me. It takes only a few seconds to get the swing pipe all the way over the barb, and then I don't think 1000 psi could get it off.

    I have seen scary things though, thin wall 1/2 tubing like Rainbirds .700 using swing joint barbs and a hose clamp...or hose clamps on swing joint.

    We had one guy who would only get the fitting about a 1/4 over the barbs, and even those didn't blow out (though I caught him early on).

    So basically, what I'm getting at is that I don't believe using a SCH80 nipple and marlex ell's is necessary on 1/2" and 3/4" inlet heads.

  2. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    I concur on residential or small commercial. Guess we're industrial-sized with traffic all over the place on turf areas. We'll stick with our swing joints. We also stick with SCH 80 TOE nipples in/out of valves instead of MAs for the same reason. LOL
  3. Dirty Water

    Dirty Water LawnSite Fanatic
    Messages: 6,794

    I use SCH80 Nipple cut in half instead of a male adapter on 2" and larger valves.

    If you cut out your valvebox you shouldn't have any stress on the fittings.
  4. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,400

    So, the swing pipe thread has been hijacked by TOE nipples? :p

    I would be curious to know what specific combinations of swing pipe and barbed fittings have failed. Maybe sticking to brand names is protection enough. If I were to worry about any swing pipe connections, it would be those using the insert x swing-pipe-barb fittings, with their slightly softer PVC material. But no blowouts yet.

    One advantage to avoiding swing pipe is the pressure loss in those elbows, which is usually where the most pressure is lost, as opposed to the pipe itself.
  5. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    That becomes a TOE (threaded one end) nipple, same as we use. Can't count the number of MAs that aren't sufficiently taped/tightened and end up leaking.

    The SCH 40 MAs are weakest where the transition between the glue collar and threaded extension meet. With SCH 80 nipples you don't have this narrowing area. We always use angle configuration and cut our boxes to reduce potential stress for the lateral line side. We use a lot of 3" and 2-1/2" lines in/out of valves. Saws-all works quickly for cutting the valve boxes out. If we're installing valves in a high traffic area then we switch to Cristy B-9 concrete boxes with cast iron lids that hold up well to vehicular traffic. We install with the maintenance aspect in mind whereas other installers are looking at the cost factor for their customers in order to stay competitive. With the amount of irrigation we're responsible for the fewer points of concern we have to ultimately maintain is a big plus. On the commercial side every maintanance is a potential income source which I'm not quibbling about.

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