When I say illegal, I'm refering to gas company specs. I don't think homeland security or the FBI really knows nor cares : ) DOT pipeline specs may.
I've never seen or heard of a pipeline owner (I'm excluding gathering/distribution) allowing a hand made fitting on 1800-2000 psi line pipe since maybe when I was in the second grade or so. At least that's what the vintage hands I know "claim" to remember.
Never seen a blowdown stack in line pipe (except for temporary construction aids, where they hot tap a line using an engineered manufactured fitting, and release, say, the argon that drove the pig), maybe in a station yes.
What they do in stations can be quite a bit different, treatment facilities as well. I speak of actual cross country pipelines as that's what I'm familiar with. My time working in facilities is very limited.
Correct me if I'm wrong here, but a blowdown stack is open ended by definition, so it never see's operating pressures?
Still I don't think there's a pipeline operating company in the US that has allowed hand made fittings in a mainline application for a long time now. Correct me if'n I'm wrong because I'd like to know about any hand cut branches used at operating pressures.
The branch test is what it is, relation to real world conditions is tenuous at best. My opinion only. It IS a sacred tradition. And it does weed out many.
J
And yes, a 12 on 12 is a full size branch : )
I've seen them used in a lot of lower pressure applications like hot/chilled water, etc. Not yet in a main line.
JTMcC,
To say that the branch test has no relation to “workplace fittup” of factory fittings is incorrect sir. The branch test is a fillet weld test, and any time there is an olet there is a fillet weld, and according to 1104, a change in joint design is an essential variable meaning that the welder can’t weld a fillet weld if he has only been tested on a butt. The principles of the branch test can be applied to the installation of an olet. I’ve seen welders that can make a pretty good branch but don’t know how to install an olet correctly. Meaning they didn’t get full penetration.
No one said that taking a branch test makes a welder a fitter. But to layout a branch by hand does require some pipefitting skills, such as understanding circumference, division, and the use of a tape measure. It also shows the welder’s cutting abilities. There are welders out there that can’t add fractions and can’t cut straight with a torch but can weld a butt fairly well if it was fit for them. I believe this test would weed out those welders. I mean a length of pipe can become scrap if an olet is not put in the right place or if the hole isn’t cut right. E.g. Oops I cut the hole too big.
Also fairly recently I saw a 6” on 36” branch with reinforcing saddle. This was a modification to an existing line, and it saw full line pressure of around 1500 psi. This was inside of a station.
Well everbody gets an opinion, mine is quite different than yours.
Pipe fitting world (in the workplace) revolves around the basis of plumb, square, and level. Plus some offset work at 45 degree, etc.
None of that is involved with an inverted branch test. Only stone age layout methods (that no company trying to actually make a profit would use on site), torch and grinding patience. The only real advantage is putting a stringer bead in a joint with varying fittup. That directly applies to tie in welds.
A factory fitting is fit up to be straight, square, plumb, level, and 2 holed. The welder takes whatever space is the result of that. That's the opposite of fitting up an inverted branch where the space is set as good as possible and nothing else comes into play.
You can find stations that still have old orange peels and bull plugs in use, but it would be hard to find an owner willing to accept that in new install, or a contractor willing to pay hands to build such things.
My opinion, feel free to dissagree. And don't call me "sir" ;)
J
JTMcC
Why would level, plumb, and square not apply to the inverted branch test? 1104 says: "the welder shall layout, cut, fit, and weld a full-sized branch-on-pipe connection." Did you notice that the word fit was in that sentence. So if an inspector wanted to test the welder's fitting ability, he/she could check the level, plumb, and square of the fit up of the branch along with the root opening. All of those attributes can be checked on an inverted branch. Do you still believe that this test would not weed out some welders. And if you are concerned that the company will not make a profit, a time limit of say two hours seems fair to layout (by hand), fit, and tack. I'm not trying to be a smart ass. I'm just saying that some of the skills that apply to pipefitting do apply to the branch test. Sure laying out a branch by hand is not used very often anymore, but the skills that are used in doing it can be applied in the field. Hey if you don't want to agree that laying out a branch by hand requires math and that pipe fitters use math then go ahead. That's your prerogative. The 6" on 36" branch I referenced in my last post was a new install. Just wait till I get a hold of my pictures. They're in my old computer.
Getting a 6X36 to fit tangentially takes some skill many pipeliner's would have difficulty with.
cwipg25,
I made my point as clear as I can and don't care to repeat myself. You obviously disagree with my take.
You are putting words in my mouth, and clearly missed a few sentences I wrote. Can't fight that via keyboard.
So anybody that wants to see my view can simply read what I personally wrote.
Have a day.
J
I'm sorry I must have missed what you wrote. Could you please repeat yourself?
A system owner will typically own and operate their transmission system, storage, gathering and distribution natural gas. The owner probably will have a couple thousand miles of transmission main. To install a new main extension they will most likely contract this work out due to the high volume of dedicated workers needed. When using smart pigs to identify anomolies they will encounter sections that will need to be removed/replaced, often referred to as remediation or rehabilitation. When replacing this section you identify valves as near as possible to each end (sometimes miles). You install blow downs at each valve site, release the gas, attach air movers to remove any sitting gas. Complete the cut out and replacement. The blow downs on our system remain in place, with full operating pressure potential. Typically this work is not done by contractors but by the owners direct employees/welders. Obviously not all owners have the same operating procedures. This is not meant to be an eductional lecture for you specifically, I know you are very experienced in the world of transmission lines. But since you asked, there it is. And yes, many of these blow downs are hand cut branch connections designed to ASME B31.8. And no, EPA is not a big fan of this very common procedure.
jarsanb,
As you've already said, your example is far from a full size branch.
An open ended stack may see full OP, but it can never be asked to contain it ;)
Anyway, I've aired my take and will leave it at that other than to note that I specifically addressed my original comment to "transmission line construction", not operations.
J
By CWI7611 
Date 04-02-2015 22:50
Edited 04-02-2015 22:57
Haven't been on here for a while. Just got tired of discussions going off line. That's my problem not yours.
I think jarsanb is on the money but here is another view of the branch-on-run test. The nice thing about it, in the pipeline industry at least, you do the two test, 12" X 12" butt and 12" on 12" branch, you are qualified for everything with a few exceptions.
I don't know if any code or standard other than API 1104 requires the full size branch-on-run test. There is a reason why API requires this as I have been told (another time for this explanation). Anyway, templates for the full size branch are available but remember that every branch is not a full size branch and is usually only performed during the welder testing. I am not sure a full size branch is even allowed by codes or standards on gas (or oil) piping anymore regardless of the reinforcement type. Typically most branch connections are a reduced size branch for a lateral connection for a run from or to the mainline. So, having said that, it would be wise to know how to cut the branch pipe to fit the run pipe for a reduced size branch. These are usually made with the run pipe hot, or loaded, and done as a "hot tap" operation. So it is wise to have the knowledge to be able to cut the branch to fit as closely as possible to avoid a poor fit-up or an excessive amount of time grinding and fitting over and over again till the fit-up is satisfactory.
So I say yes it is good to learn how to "layout, cut, and fit" the branch. You can do that or spend time during fit-up or just hope the fit-up you get is "good enough".
On an operating pipeline the hole in the run pipe is cut after the branch is welded and the reinforcing is installed with a pressurized tapping machine. It is especially important to verify that all the welds be square with the branch and run pipe both. If these welds are not just near perfect you could end up cutting into your run pipe and removing some of the branch weld while performing the tap into the run pipe. It could end up being a bad day, really bad if you happen to be the one who made the weld out of square.
