Water main relocating issue.

[LowBoy]

I'm not an expert by any means on water main work, so I have a question pertaining to a job I'm involved in. we have located, and have to reroute a 6" & a 10" main that are 2 feet apart from each other. We're just "horseshoing" around in a 1/2 circle basically to get them out of the way of an addition excavation I'm about to do this week.
We've laid the first 2 lengths of both mains side by side already, with 45's ready to turn the first corner. Next is some straight runs. I recall in the past with this pipe, we used joint restraints at the slip in (gasketed) joints, but this one doesn't call for it. Doesn't the straight runs require some sort of flanges, or megalugs, to hold the straight joints into the hubs? On a few jobs in another state we were required to do so, but I'm assuming it was due to the pressure in the main, and the spec's required by the water authority we were doing it for. Any info? Thanks.

 

[digger242j]

It's been quite a while since I did any water main work, but I'm sure it hasn't changed much.

If I'm reading your question correctly, you're asking if you need something, in a straight run of pipe, over and above just slipping the next pipe into the bell of the last one. My answer would be "no".

Under normal circumstances, any given joint won't deflect far enough to push apart. Now, if you had a run of several pieces exposed, the joints might deflect enough in total for one of them to come apart, but it doesn't sound like that's what you're describing. (I'll qualify that by saying that having two mains that close together would give me some concern, since that means there's more disturbed earth than if each were in its own trench.)

Obviously, any place you put in a bend or Tee, you need a thrust block, or some sort of retaining system in your joint. And I had a very bad experience removing a thrust block from the blind end of a straight run of 8" pipe. (I was told that there was no pipe there to begin with, and since the site was full of buried rubble anyway, I thought the thrust block was just another hunk of buried concrete. Oops! )

Looking forward to hearing the opinion of somebody with more extensive, and recent experience though...

 

[CM1995]

Obviously, any place you put in a bend or Tee, you need a thrust block, or some sort of retaining system in your joint. And I had a very bad experience removing a thrust block from the blind end of a straight run of 8" pipe. (I was told that there was no pipe there to begin with, and since the site was full of buried rubble anyway, I thought the thrust block was just another hunk of buried concrete. Oops! )

Hmmmm... I guess you got a suprise bath and it wasn't even Saturday.

I don't have vast knowledge on the subject but been around it a lot.

I as well would have concerns about putting both mains that close together. Next question - why are there two seperate mains? Is one a fire line or raw water?

The DI pipe we use just slides together in the straight runs, with no other restraining system. Some H2O departments we work with require all thread at FH's, back flows, 90's, end caps and valves. Most fittings I see spec'd use megalugs and a thrust block is always required at bends, T's, 90's, terminations and FH's.

 

[LowBoy]

That's what I was feeling, but I was double checking. I recently worked in a different state where a regional water authority sets the guidelines and strictly policed the work performed. I dug, located and tapped a 10" main and reduced down to 6", then down to 4" into the buildings, or water closets as they referred to them. They required us to use restraints on even the straight push-in gasketed joints.
Why are these 2 mains so close together you ask? Hard to say, except one's definitely fire and one's domestic. No sand around them either, but they'll have it now. They're going just close enough to get the jumping jack between them for compaction.
We're using megalugs on all fittings obviously. The other thing that's bothering me is the young hotshot kid who just was hired to be the water main pro (all of 20 yrs. old,) plans on cutting the 10" main to hook onto it with a 90 about 18"-24" away from a hub, or slipjoint. I'm just keeping my distance, as I'm not going to impose any judgement on him, but if I had a say in it, I would personally eliminate the bell and hook to a clean piece of DI myself to ensure a good fit.

 

[digger242j]

plans on cutting the 10" main to hook onto it with a 90 about 18"-24" away from a hub, or slipjoint.

Do you mean ther's a hub, and then an 18-24" long nipple coming out of that, or do you mean he's going to use a nipple of that length, that has a hub end on it?

The first one I wouldn't be too concerned about. It could actually provide a place to put a clamp behind the hub, and use a couple of allthreads to help retain the 90.

If he's going to use a short nipple that has a hub end to it, I agree--why not eliminate it altogeher, and go to the clean end of the pipe. (Unless of course that 18-24" is critical to have it in the right place.)

I wish I'd done more water main work. It's always interesting...

 

[PipeGuy]

if you have a short length of straight pipe use a "field Lock Gasket" They replace the gaskets in a normal slip joint. The difference is the field lock has teeth that will grip the pipe and will not let it come out. you use field locks for pulling ductile iron while directional drilling. You can pull about 800' of 12" ductile before the pipe pulls out of the field lock. I had an 8" pipe blow out of a bell. When it blew out the pipe was backfilled and it moved an 8" gate valve, fire hydrant with aux valve and the piece of 8" ductile about 8' long. When in doubt restrain the joint. Water hammer blew my pipe apart while flushing the line.

 

[LowBoy]

Do you mean ther's a hub, and then an 18-24" long nipple coming out of that, or do you mean he's going to use a nipple of that length, that has a hub end on it?

The first one I wouldn't be too concerned about. It could actually provide a place to put a clamp behind the hub, and use a couple of allthreads to help retain the 90.

If he's going to use a short nipple that has a hub end to it, I agree--why not eliminate it altogeher, and go to the clean end of the pipe. (Unless of course that 18-24" is critical to have it in the right place.)

I wish I'd done more water main work. It's always interesting...

That is an issue, the length we have currently in place of existing 10" has (or will have rather,) a straight section with an 18"-24" nipple with the bell attached. It does have to be that length for proper configuration, I'd still feel better with a restraint mechanism on it myself.

BTW; Thanks PipeGuy for that. I'll suggest Field Lock Gaskets in the morning to Mr. HotShot and see what becomes of it.:cool2

 

[humboldt deere]

I had a 4' length of 6" c900 completing the main line and even while backfilled I had a hard time putting 120lbs of air to it for test without it slipping off the joint and popping open. My point is on short lengths backfill alone wont always hold it together. When a 6 inch line comes apart its more like an explosion than a pop.

 

[RonG]

Like you need another redundant reply here....LOL.I suspected that the small pipe was a fireline and needs to be tested at about 4 times what the domestic line gets for pressure as I remember.Those fieldlock gaskets are the cats meow and we used to use them whenever we used less than a full length of pipe.Just be sure you want what you got before you install it.)
It seems like there is no standard between water companies......they all seem to have an SAP just to keep you off balance or something.
Be advised that even the wall thickness on ductile iron pipe varies depending on its intended purpose and the thinner pipe is not meant to be tapped but if you do tap it for a test port or something you cannot just put a plug in it,you have to do a major repair by wrapping the pipe with the clamps etc and that has to be tested as well.Again,YMMV depending on who you are working for.Ron G

 

[PipeGuy]

Just remember field lock gaskest are only good for ductile Iron. I don't think they make such a thing for plastic.

 

[bentwrench]

Use mega lugs on the blue plastic, there is a mega lug for ductile iron and one for plastic. The teeth on the plastic lug are wider to keep from damaging the pipe. The blue plastic used in fire mains is the same dimensions as ductile, using the same fittings and allowing the two pipes to join together. Fire mains are tested @ 200PSI for 2 hours per NFPA.

 

[dayexco]

Use mega lugs on the blue plastic, there is a mega lug for ductile iron and one for plastic. The teeth on the plastic lug are wider to keep from damaging the pipe. The blue plastic used in fire mains is the same dimensions as ductile, using the same fittings and allowing the two pipes to join together. Fire mains are tested @ 200PSI for 2 hours per NFPA.

here, we can get ips sized blue pipe..it all depends on manufacturer...i think what you're trying to say, is c-900 and ductile share the same o.d....hence, same fittings....ips sized pipe you must use transition gaskets

 

[bear]

Here's a link to a slightly goofy video about the mega lugs (had to find out what one was) . Pretty neat especially when they lift the dozer with the pvc pipe.

http://www.ebaa.com/movies/dozer.html