Leaks on underground pipe flanges
Leaks on underground pipe flanges
(OP)
I've been recruited to conduct pressure test at a site. During the tests it was clear that we were loosing pressure at all the sections we tested. The was leaks on all flanges (i.e on the bolts). I need to know which method to use in order to stop the leaks permanently. One other problem is that I have no idea what causes the nuts to loosen. NB the flanges are not wlded... Help.





RE: Leaks on underground pipe flanges
"Leaks on underground pipe flanges"
And you wrote:
"I need to know which method to use in order to stop the leaks permanently."
This is really very easy. It is never a good idea to have Flanges buried underground. Cut out all the underground flanges and replace them with pipe butt welded in place.
RE: Leaks on underground pipe flanges
RE: Leaks on underground pipe flanges
RE: Leaks on underground pipe flanges
RE: Leaks on underground pipe flanges
In other words,
All flanges are a necessary evil. Sometimes the evil is above ground, sometimes below. Wishing away the evil usually doesn't work.
RE: Leaks on underground pipe flanges
RE: Leaks on underground pipe flanges
I'm not really sure what has changed in the last near 100 years since this was written, unless it is that gray cast iron pipes have not been furnished in the USA for more than three decades, and some folks have attempted to use in more recent years for buried service some quite expensive stainless steel HHHN bolting in place of old wrought iron etc. (and some of these SS bolts have exhibited thread "galling", characteristic of some such materials, that even exacerbates leakage problems due to imperfect assembly and/or alignment/soil support conditions etc!)
RE: Leaks on underground pipe flanges
No argument, however you appear to assume that there is some choice involved in selecting to use, or not to use, flanged joints under ground and that choice (not to) somehow depends on the difficulty of seeing a leak when they are UG. In my experience, there is not a choice involved when a flanged joint is used underground (or above ground for that matter). You use flanged joints simply because you have no other practical alternative for that particular joint. If you need a flanged joint AG, or UG, then that's where a flanged joint goes, so I think it's kind of irrelavent if its more difficult to determine if a leak exists, no matter where the flange happens to be. I've never put a flanged joint above ground just so I could more easily see it leak ... if you get my drift.
RE: Leaks on underground pipe flanges
I've dug up flanges that have been in the ground for 30+ years without leaking. They have long-lived spiral wound gaskets, but I wouldn't be terribly worried about other sorts of gaskets. I've never repaired a buried flange-face leak on a gathering system (but one time I had a leak that was in the body of a tee that had flanges on two sides, the flanges were fine, the tee was junk). I make sure that the to-be-buried flanges are exposed during the static test, I've found a few that leaked until they were properly made up.
I work with a lot of companies that have hard and fast proscriptions against buried flanges. Their reasoning is always "policy". People don't question policy decisions today like they did in my day, so I bastardize my designs to accommodate the policy and grumble all the way to the bank.
David
RE: Leaks on underground pipe flanges
zdas, Instead of using joining flanges for anchors, use an anchor flange. Its just a double weld-neck flange. No face to face and no bolts.
RE: Leaks on underground pipe flanges
There are a number of portable He detector's on the mark now. We subbed out the Ultrasonic leak detection to a testing service.
http://w
/LeakDetectorSG.html
RE: Leaks on underground pipe flanges
BTW I can't access that link.
RE: Leaks on underground pipe flanges
RE: Leaks on underground pipe flanges