I was trying to remove an old gas shut off valve and was having some trouble in a confined space. I backed up the 1/2" pipe with my channel locks but it spun as I tried to remove the valve. I loosened the next joint.... in the wall.

Inside the wall it was one side of a coupling that was loose. I was able to spin it off by hand. The other side didnt look like it turned, it certainly wasnt loose by hand like the other side so I didnt touch it further.

I remade the joint on the one the side of the coupling and soaped everything and it doesnt appear to be leaking.

My question...

If I turned the pipe in the one side of the coupling enough to be able to spin it off by hand, do you think I loosened the other side or any other downstream joint?



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If you had, IT would have come out of the wall.

If you tried to remove iron pipe without backing it up, would the next joint downstream be the one most likely to loosen? Is it possible to loosen both sides of a fitting in this manner?

Im thinking there is only one pivot point if that makes sense.... once the one side is loose enough to spin off by hand its not possible to torque another joint downstream.

correct

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Thanks, heres some photos of the joints i was worried about. Does it appear to you like the joints are loose by the exposed thread count?

The joint with the fresh dope is the one that I accidentally loosened and then remade. It had newish dope on it from a previous owner which is why it probably loosened easily. The other joints have a very hard glue like dope and are much older... i didnt remake those.







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When you twist it, the "loosest" joint will turn first and none of the others will be affected.

can't see the pictures. Fellow DIYer here.

Unless it is a straight run all the way, you are only concerned up till the first elbow. I would think most of the time, the more downstream from you it is, the more likely the pipe sections and fittings will resist being turned loose from strapping, or friction against holes in studs, or years of build up gunk or corrosion around the joints.

I would just make your two joints, then tighten them correctly. If during the tightening process, the pipes beyond those two joints does not turn at all, you should be safe. If they do turn, then may be they were loosened for some reason?

Thanks for the replies...



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Does the coupling look correct? I used 10" and 12" pair of channel locks... thrres 4 threads exposed.

No leaks with both bubbles and electronic sniffer. i hope my wrenches were large enough and my joint will have long term integrity.

The nipple had 11 threads and was approx 3/4" long.

The "exposed threads" have very little to do with whether it is tight enough or not. Did you tighten it as much as possible? If yes, AND, you had the proper tools, ( I seldom consider Channelocks "proper tools" for tightening steel pipes), then it should be leak proof.

Being in a confined space, the channel locks were easiest for me to maneuver. I tightened as much as I could with 10" and 12"and used teflon based dope.

I understand its about whether it leaks or not instead of how many threads are showing but is 4 threads for a 1/2" pipe the standard or should I have them buried into the fitting?

does the use of channellocks make it questionable for the long term?

if you pipe dope the male threads and screw in the nipple by hand you will get an idea of how loose or how tight the joint is. sometimes you get 2-3 full turns by hand and sometimes not. in any case, you have to remember that natural gas is only a few ounces of pressure so unless there is a pinhole in a fitting or you forget to make up a joint, leaks are really pretty rare.
when we test gas for an inspection we are only required to put 5 PSI on the system for the inspector. (MA code)

'Theoretically' for 1/2 & 3/4 NPT (IPS):

14 TPI

'cut' 3/4" long - 11 threads

into fitting 7 turns total = 4 threads showing = perfect make-up


trivia: all fittings 1/8 through 2" have EXACTLY 7 threads female threads = 'perfect' make-up = 7 turns total


tightening further merely wedges the fitting open on the last imperfect threads of the male breaking the tapered wedge seal made by the good threads


ps. my kaka don't stink and my joints don't leak - EVER

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

quote; my kaka don't stink and my joints don't leak - EVER

either both statements are true or they are both false.I will let the readers decide which based on the first one.

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638