12 on 12 branch test

[NBS Welding]

Hey fellas, interesting topic. I myself have a few issues with this test myself. I am a long time pipeline welder,mostly mainline or big inch up here in Canada. I only became aware of this test a couple years ago when the company I work for sent our welders to a procedures course with some of our American company welders. They filled us in on this test procedure. My first thought is, where would you ever use this in the real world?? You never do a size on size without full encirclement as there is too much stress put on the carrier. Secondly we always use factory fittings now and never fabricate them. Thirdly you can not torch cut the hole if it is for a hot tap and if it is in service piping no cellulose is allowed as it introduces hydrogen to the weld and causes hydrogen induced cracking. Just seems odd to me why you would test people on something that is probally never going to be used??

I tested for Columbia Natural Gas sometime around 2003 and they required that I fabricated and welded a 6" tee upside down with old school 6010, yes sir, the old red rod that almost nobody uses anymore. I ask then why we would need to fabricate a tee since they are not used on pipelines and why would we weld with red rod since they don't use that anymore either. I was told that I had to fabricate the tee to prove I had the skill to do it and I had to weld it with red rod because that rod emits the worst weld splatter and I had to prove that I could handle that much fire falling on me without it affecting my ability to make the weld.
Well it was and still is the hardest test I have ever taken but I passed. I have not heard of any companies since then that had such a big test. I had to weld 6" .380 wall with the pipe vertical, then 6" .125 wall with the pipe horizontal, then two 1 1/4" with the pipe horizontal, the 16" with the pipe 45 degrees, and then the 6" upside tee .380 wall.
Columbia Natural Gas has been gone for years now since they got bought by Chesapeake. I don't hear of any companies anymore with that big of a test.

[Kyllemall]

One thing I might have missed throughout this thread is that all the welders in my shop say that it is .250 wall pipe and the book and template both say .375 which is standard wall. If I use the books lengths to mark the pipe on .250 the fit isn't worth a damn and the book only goes to thicker pipe. Anyone else have to test with .250 or am I missing something? Thanks.

[SmoothOperator]

Need to cut on outside of your layout lines.....that creates a smaller opening on your "fishmouth " & transfers to your hole cutout...

[ahanasky]

this is all good info. I have taken this test uphill several times but never downhill until next week. The part about spacing before marking the hole and cutting is a great tip. Thanks to all for the info . I always just marked it and cut and dealt with it. I am going to try it this way now before my test

[SmoothOperator]

Best info. I've ever seen is posted over on rigwelder.com that site has step by step guide and picture and tips on doing the 12 on 12 ..........Remember ...." Welding a 12" bellhole is to see if you can weld.....doing the 12"on 12" branch is an endurance test to see if you can weld pissed off"...

[pipewelder]

@kacotton --Question concerning branch test. Slowly trying to make my way to the field but I had a question concerning pipe size and branch testing. Have a small metal lathe that will turn a 9.5 inch swing over the ways but I can't turn anything bigger. I was looking at a Mathey Dearman 2SA pipe beveler and its a little steep for me right now, so my question is regarding a 8 inch branch. I would only assume that if i was able to weld a 8 inch branch that a 12 inch would not really be much different...is that a correct statement? Being that my lathe will only handle the 9.5 inch I was wanting to face some coupons and do some practicing. Would you think there would be a big difference in the technique of practicing on an 8 inch vs 12 inch? Hope that is not a ridiculous question.