LONG Water Line Question

[txdon]

The new union installed easily. I used the PVC glue that can be used in water. The new union and line has not leaked a bit. The water meter wheel has been still for seven hours. I think I can finally give this job a thumbs up.

What started out being a question about a long waterline ended up being a long thread about a leak with a bit of tractor thrown in for excitement! /forums/images/graemlins/grin.gif

Thanks for the support!

 

[Bird]

Don't you have to burn the thorns off the prickly pear first before the cows will eat them?

And I've used quite a number of the compression fittings like shown in your first attachment and never had one leak. However, I think inch and a half was the biggest line I ever used any on and it was mostly 1" lines. I don't recall ever seeing the type you used the second time; maybe that's a better one.

 

[txdon]

Bird, these cows have been eating my cactus with the thorns. When they get through they have thorns all over their nose and lips. They did this in the summer also when there was plenty of grass to eat. Their supplement feeder is kept full. I don't know why they do it, they appear to be healthy.

My Dad also said he has had no trouble with PVC compression fittings, but he also has never used them on a LONG 2" slip joint line. Maybe the 4" gap was too large. (but it did seal for a day, not a drop) With the new union the gap can be as long as a foot and the line can expand and contract.

 

[Bird]

I never cease to learn new things, Don. I always thought you had to use one of those big torches and burn the thorns off before the cows would touch prickly pear, and that it was only done during drought conditions such as we've had this year.

And that new coupler looks good. I guess all my experience has been with lines that did not have the slip joints. The summer we spent working in an RV resort and campground in Virginia Beach, I got to repair lots of water leaks. But that was definitely different. The water lines were that thin walled blue PVC (I've forgotten what they call it) and nearly every one of the leaks was due to a joint pulling apart. It was obvious that whoever plumbed it originally did a very poor job. They barely slipped the pipe into the fittings. I don't think I found a single one that was originally pushed in a quarter of an inch and some no more than an eighth of an inch.

 

[tommu56]

Yes the polyetherlene is the black plastic pipe the blue or white and red type is usually pex it is alot newer than the poly pipe.

Did the camp ground blow out the pipes?
The other thing that will push joints apart is freezing the plastic pipe expands with the freezing the buldge acts like a wedge and will push off the joints I have even had copper elbows soldered on push off the pipe. Of corse you dont notice it till the water presure is back on. This year I think I'm going to try and presure it with the compressor and mabe I keem the mess small?

tom

 

[Bird]

Tom, in my part of the country, we don't worry much about anything below ground freezing, but we do sometimes have pipe joints pull apart because of soil expansion and contraction due to drastic changes in the moisture content. My own place in the country would sometimes get cracks in the ground in the summer that you could actually drop a golf club in and lose it. When a joint pulls apart, you can usually, if not always, tell how far it was originally inserted by the dried cement on the parts. That's what I was going by when I said it appeared that they were barely put together. That campground has been there a long time and is a big place. I don't remember how many acres, but it had over a thousand campsites (some with full hookups, some water and electric only, some water only, and even some tent sites with no utilities), two stores, restaurant/bar, 4 swimming pools, their own 3 wells, etc. So I don't know how old the pipes were in the places we fixed leaks, but I assume they'd been there quite awhile.

 

[tommu56]

Bird Our pipe fitter suggested snaking pipe in trench he said the extra saved his but a couple times when lines were hit they just dug a couple more feet of line out and couppled it together. there is an expassion issue with plastic it can grow and shrink 1" in 100' so if its puled banjo tight it might pull apart or put in in the heat of the summer in the "cool" winter it will shrink

tom

 

[Bird]

</font><font color="blue" class="small">( suggested snaking pipe in trench )</font>

Probably not a bad idea. That's the way the Alaska pipeline was built instead of a straight run.

 

[Westonium]

PVC Pipe? In a straight line?

If so you have my sympathy! Seriously because I have 600 feet of the ...stuff... myself. I can't be rid of it sooner, but the poly ethelene stuff I was going to use has been mysteriously removed as a product for water mains.(as far as I can tell anyway) I may go with copper wrapped in plastic sleeves. We'll see. The PVC held this year (so far). Last year it busted jsut before an ice storm. Yay. I got the hole dug before the storm hit, but I had to do the repairs in it. Yay.

</font><font color="blue" class="small">( Expansion and contraction. PVC pipe has a higher expansion and contraction rate than metallic pipe. The rate translates into an expansion of 3.36 inches for every 100 feet with a temperature change of 100 F. Where PVC pipe is subjected to severe temperature fluctuations, provisions must be made for expansion and contraction. This can be accomplished by use of expansion joints or offset piping arrangements.
)</font>
quoted from http://www.vinylbydesign.com/site/page.asp?TrackID=&VID=1&CID=73&DID=80

Okay so that means that for your roughly 2640 feet of line, if you installed it at 80 degrees, at 60 degrees it would want to be about 1.5 feet shorter. Of course where it shrinks and doesn't is up to so many factors as to be impossible to tell.

If you are going to use PVC, you need to find a way to give it some slack. I would suggest making it in zig-zagged sections 4 straight pieces long, then have a piece made of some threaded female and male adapters plus some 90 degrees so that when you are done there is a bit of play both directions. A good wrapping of teflon tape will keep it leak free.

If the pipe chills enough, it will either pull out of your slip couplings. I assume they are glued. The gluing process is very important. Of course, with a straight (or nearly so) long run with good glued joints you'll just snap the pipe in two if it contracts enough...

There are probably many other ways to provide slack for the pipe so it doesn't cause you grief.

Best of luck!

 

[Egon]

Thrust blocks, expansion loops,expansion joints and sliding supports are designed into many piping installations.

Egon

 

[txdon]

<font color="blue">"...3.36 inches for every 100 feet..." </font>

Westonium, I can live with that expansion rate. The 2" PVC has a 5 1/2'" coupling with 4" past the O ring. That means each UNGLUED piece could expand and contract a easy 3" each 20' or 15" per 100'. That gives me an easy extra foot of security per 100'.

When my Dad and I installed the line on one cool morning and finished in the warm afternoon we looked back and saw that the pipe had expanded and looked like a snake and actually was coming out of the trench. We just waited till the next morning when it contracted and was laying flat in the trench and then we covered it up.

When I was checking the slip joints last week, and I checked about 50, they all looked good with no leaks. On several of the joints I could tell that they had slipped about an inch which is acceptable.

The problem is that I had put a big rock at the end and overtime (7 years) the expansion pushed the rock and when the contraction happened only the last slip joint stayed at the expanded position. That is why the last slip joint pulled out past the O ring this December. The moving of the glued joint as I worked the slip joint into place loosened the seal of the glue which cause the leak I discovered last week. A larger thrust block might have prevented the original leak. I'm hoping the 6' galvanized T post, 5' down, will.

The union I put in can slide back and forth about 4" without leaking so there is another expansion/contraction relief place.

I have check the meter about 20 times the last few days after water usage. I can now answer my own question with experience.

The question on a LONG 2" pipe fed by a 3/4" line: How long does the water go though the meter after use before the pressure is equalized?

The Answer: About 10 minutes. The meter wheel will continue to go slower and slower and then will come to a dead stop. /forums/images/graemlins/smirk.gif