Making the right connection
|By Mary Elizabeth Williams-Villano|
When putting together or repairing a sprinkler system, you need the right fitting for the right type of pipe.Anyone who’s ever done a jigsaw puzzle knows that every single piece fits in one spot, and one spot only, locking into place when the adjacent pieces match its contours precisely. Well, that’s not too different from the way irrigation fittings work. You need the correct connector for the specific situation you’re working with.
Knowing which PVC or poly connector goes where and when and, maybe even more importantly, how it’s attached to a pipe is the sort of puzzle contractors who install sprinkler systems solve every day.
The newest kids in town: push-on fittings
Not a lot changes in this arena, so usually, asking “What’s new in fittings?” is like asking, “What’s the latest on the Earth’s rotation?” Probably the biggest development in recent years was the advent of glueless push-on connectors for PVC and poly pipe.
“It depends on what we mean by the word ‘new,’” says Brent Mecham, CID, CLWM, CIC, CLIA, CAIS, industry development director for the Irrigation Association, Fairfax, Virginia, “Pushon fittings came into the market around 2014-2015. They’re limited to 3/4-inch and 1-inch in size for irrigation, which are the most frequently used pipe sizes. For larger size pipes, like the 3- and 4-inch pipe used for commercial projects, they’re not really an option, but for a lot of residential type projects they certainly are.”
Their major advantage is that, while PVC cemented fittings need time to set up and cure before they are handled or pressurized, push-fittings can be handled and pressurized right away, making them must-haves for repair work.
“Quite often, at trade events, we’ll hear from contractors who say, ‘You saved me X number of hours by having just a few of these on each of my trucks,’” says Matt Baker, vice president of sales operations, Spears Manufacturing Co., Inc., Sylmar, California. “Especially when there’s a bad enough leak that’s causing property damage; these fittings have come to the rescue in many of those situations.”
When I wrote about push-on fittings three years ago, the conventional wisdom seemed to be that push-on fittings were fine for repairs but not for putting together a whole new system. I asked Mecham if that has changed.
“Yes, it has, and for a couple of reasons. Now that they’ve been in the marketplace for three or four years and are still here, that means there’s some field experience with them and they seem to be working. They’re kind of neat, and the price is coming down.”
Mecham says the current labor shortage is helping make these fast fittings a lot more cost-sensible. “You literally just push them on and you’re ready to go. You can probably do three, four times as many as a guy can using the traditional solvent-weld process. When you factor in labor costs, these fittings are now starting to make a lot more sense and are really, truly affordable, despite their slightly higher initial cost.”
Kurt K. Thompson, CIC, CID, CLWM, CLIA, CGIA, CIT, CSWP, an irrigation consultant and educator, owner of Kurt K. Thompson and Associates LLC, Lake Wylie, South Carolina, says push-fittings “are still primarily used for repairs on PVC pipe, partially because of the cost perceptions. Also, the limited variety of fitting configurations — they’re only available for 1/2-, 3/4- and 1-inch pipe sizes — probably contributes to their limited use.”
Quentin Rollins, owner of Rollins Landscaping Inc., Sandy, Utah, is one contractor who has put together entire systems using push-fittings. “We started using PVC-Lock (from Hydro-Rain, Salt Lake City) fittings about two years ago. They’d approached us four or five years ago, but still had some issues with the bite, which they’ve since fixed and cured. We try to use them on all our residential systems.”
Rollins adds, “They’re fast, clean, easy to use. They are a little more expensive, but their added benefits outweigh that.” However, he says they are still not acceptable for most of his commercial jobs.
There are a few new things to report. Hydro-Rain recently upgraded its Blu-Lock (for poly pipe) and PVC-Lock fittings.
“Blu-Lock 3X came out last year,” says Alan Ence, North American sales director. “Where you used to have to use our proprietary pipe with our lateral three-quarter- and one-inch Blu-Lock fittings, they now fit on anyone else’s high-density poly pipe. They are 30 percent faster to put on and can be removed and reused with our new tool. We’ve also added push-fit PVC-Lock valves and a push-fit manifold system that actually push right into those fittings.”
Gluing: a two-step dance
What we call gluing is a two-step process involving two products: primer and pipe dope or pipe glue. Both primer and glue need to do the dance with their partners, as both are vital to a tight, leakproof seal.
The primer softens the plastic pipe a bit, similar to the way a welding torch melts metal so that another piece of metal can be attached to it. When glue is applied afterward, a chemical reaction occurs that tightly weds the fitting to the pipe with a bond that’s stronger than the pipe itself. That’s why the process should really be referred to as solvent welding.
Mecham says, “If you do a poor job with solvent welding, you’ve actually created a very weak spot.” Unfortunately, he’s observed this quite often in the field, when technicians take shortcuts.
“There’s an ASTM (American Society for Testing and Materials, an international standards organization) standard for the solvent-welding procedure,” he says. “If someone doesn’t follow that standard and a problem results, the manufacturer can come back and say, ‘You glued incorrectly, so there is no warranty.’ Every manufacturer follows that standard, and if you don’t, that’s your liability.”
What kind of shortcuts is he talking about? Mecham frequently sees installations where someone’s decided not to use primer and just used the cement, and even a few where someone has used primer but no cement. “That’s crazy,” he says. Equally crazy, or maybe just lazy, is when someone glues the fitting but not the pipe, or the pipe and not the fitting. The standard is you apply cement to both.
Another gluing mistake is waiting for the primer to dry or letting it dry. PVC cement should be applied while the plastic is still wet and soft from the primer. “The cement should go on while the primer is still wet, but a lot of people don’t realize that,” says Mecham. “They think they’re saving time by putting the primer on back at the shop, but that doesn’t work, because the primer becomes too dry to create the chemical reaction.”
Mike White, irrigation service technician at Tri-County Irrigation and Plumbing Inc., Goodfield, Illinois, observes this in the field quite often while making repairs. “We’ve seen fittings you could literally just pull off because the water pressure over time worked them apart. It’s easy to tell if something was glued without primer, especially with purple primer; you don’t see any purple. With clear primer, it’s a little harder.”
Not everyone “gets” this process, apparently. “You hear guys on job sites saying things,” says White. “I had a guy tell me, ‘You know that primer’s just a scam. They used to use the PVC glue alone and it always worked fine.’ I always laugh when I hear that.”
Avoiding push-ups and other pitfalls
Fittings work great when they’re installed correctly. I asked Josh Posthumus, irrigation field service manager at Carefree Lawn Sprinkler, New Lenox, Illinois, “If someone has clamped together a system the right way, would it hold together for the next 30 or 40 years?” He replies, “If done correctly, using stainless steel clamps, it should theoretically last forever.”
However, he often finds insert fittings that haven’t been put on right. “A lot of people will cut the pipe short and won’t bury all of the barbs inside of the pipe,” says Posthumus. “A couple of the barbs will be sticking out, so when you go to clamp it, it’s not set all the way as it should be. It’ll come loose at some point in time, especially under high pressure.”
That happens mostly when someone has been sloppy says Posthumus. “After they measure their cut, they see that they’re a little short and they say, ‘Ah, the heck with it. I’ll just roll with it like that,’ and kind of pound the fitting in as best they can and hope for the best. It might last a couple years, but eventually it’ll give way, and then you’ve got a big problem.”
White wants you to know that spacing is important, and to “avoid push-ups” (sometimes also called “push-outs”). He’s not talking about ducking your Crossfit classes; he’s talking about the tendency glued fittings and pipes have to repel each other, like two magnetic north poles.
“The fitting will start to reject the pipe and try to push itself back out of the coupling. Every so often you’ll see a guy that’ll put things together and then walk away, and you can see it start to push back out. Make sure you keep that pipe pushed into the fitting and hold them together. You only need to do it for a couple seconds.”
White frequently sees new systems that are installed as if it’ll never have to be taken apart or fixed.
“Say it’s a 1-inch line you’re working with, and it’s got a 1-inch tee that comes off it and a valve and a lateral. If the valve is glued right against the tee and you ever have to replace that valve, you’ll also have to cut the whole tee out. It makes what should be a fairly simple repair more of a job.”
There are many, many types of fittings used in landscape irrigation, and we’ve only touched on a few. We hope what we have discussed here will help you put the pieces together the next time you’re puzzling out an irrigation system installation or repair.
THE MOST COMMON TYPES OF FITTINGS
PVC fittings IRRIGATION are the most common FITTINGS type of fittings used in the installing and maintenance of irrigation systems. They include the solvent-weld and threaded fittings used for PVC pipe and the insert fittings used for poly pipe.
Solvent-weld (glued) PVC fittings. The most frequently used type of fitting for connecting PVC pipe up to 2½ inches. Most are Schedule 40 PVC.
Threaded PVC fittings. These are also frequently used, particularly for connecting PVC pipe to a valve. They must be sealed, usually with Teflon tape or pipe dope (pipe thread paste), in order to prevent leaks. Tape is a better choice if the connection should ever need to be taken apart or need to move slightly, as a swing joint might. Paste can leave bits that can clog components. If you must use paste, make sure it’s a Teflon paste. Many of the residential 1-inch valves have an option of either threaded connections or a glued connection; over 1½-inch and larger, they’re all threaded. The next biggest place for threaded connections is going into a sprinkler, whether it’s above ground and fixed or a pop-up.
Insert fittings. Used on poly pipe and so named as they are inserted into pipe rather than vice versa. They’re made of PVC, and though they have barbs inside, should not be confused with the barbed fittings used on swing or Funny Pipe. Once an insert fitting goes into a pipe it cannot be pulled out. They require that the pipe be double clamped on each side of the fitting in order to withstand the water pressure. Stainless steel clamps are used to secure these fittings, either ear clamps, attached with a crimping tool, or screw clamps, that have an attached screw that is turned until it’s fully tightened around the pipe.
PVC gasketed fittings. As the name implies, these have thick rubber gaskets inside the socket that seals against the pipe. These fittings are called o-rings and sometimes are also referred to as push-on fittings, because, like the newer pushfit connectors, they do not need any glue. One of their advantages is that a pipe can move slightly inside the fitting, providing a buffer for water hammer, particularly on long straight lengths of pipe. They require some special installation methods such as thrust-blocking to stabilize fittings such as elbows and tees.
PVC push-fit fittings. The glueless fittings that connect PVC and some special types of poly pipe. You simply push the fitting onto the pipe, and it locks in place via a stainless-steel retainer ring. Double o-rings inside of the fitting seals against the pipe. Many manufacturers make them.
(information courtesy of Kurt K. Thompson, Kurt K. Thompson and Associates LLC)
Solvent welding, the right way
Kurt K. Thompson of Kurt K. Thompson and Associates LLC, says that while push-fit fittings do not need PVC cement, they aren’t foolproof. Push-fit fittings still require the same amount of care to make a solid connection as when you’re making a PVC cement fitting. The proper steps are:
#1 The pipe must be cut square with all burrs removed.
#2 The pipe must be inserted completely to the bottom of the socket.
#3 The pipe and fitting must be relatively clean, free of dirt and oil, to ensure the seal of the fitting makes complete contact with the pipe.
#4 The pipe must align with the fitting to minimize the angle of deflection.
The author is senior editor of Irrigation & Green Industry magazine and can be reached at email@example.com.