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Up Topic Welding Industry / Technical Discussions / Standard for distance from weld to flange
- - By SEMark Date 01-29-2015 23:53
Hi everyone,
I am designing a pipe system and trying to determine how much access I should have between the weld prep on a pipe and the body of a flange nearby.  So far the only number I have come up with is a 30 degree approach angle, which means my pipe weld can be fairly close to the flange (just over 1" away on a 3" pipe).  This appears to be more of a rule of thumb than something specified in a standard.

Is there a standard that deals with minimum required access to a weld location on a pipe?

Thanks,
Mark
Parent - - By 803056 (*****) Date 01-30-2015 13:57
None that I am aware of. You have not defined the welding process, but keep in mind that you need to provide sufficient access for the welding apparatus as well as a direct line of sight and access for the welder's head, helmet, hands, filler metal, etc., around the entire circumference of the pipe joint. You can't weld it if you can't see it.

Limited access will make it that more difficult to weld. Not that there are no welders with the skills needed to weld where there is limited access, it just makes it that much more difficult to deposit a sound weld.

Al
Parent - - By kcd616 (***) Date 01-30-2015 16:59
Al
I disagree:eek::red:
as well as a direct line of sight and access for the welder's head, helmet
I have this magic mirror
if I can access the joint
I can weld it
BUT, for me to walk in with magic mirror  cost lots of $$$$$$$$$$$$$$$$
for me to strike an arc and use magic mirror just sign a blank check
I will fill in name and #############:twisted::evil::eek::smile:
sincerely,
Kent
Parent - - By 123weld (*) Date 01-31-2015 04:17
Kent, is there any specific type of mirror that you prefer.   I notice your magic mirror is singular.    I don't use a mirrors much, but when I do, they crack quite a bit.   I buy a bunch of them at the 99 cent store.    I wasn't sure if you found a shape or type that w/stood welding better
Parent - By 46.00 (****) Date 01-31-2015 06:55
You don't use glass mirrors, your best bet is too use highly polished stainless steel. Although I used to use glass mirrors for GTAW quite a lot!
Parent - By ssbn727 (*****) Date 01-31-2015 08:32
Rectangular or oval shaped but, you need to trim the rectangular mirror first and have an interchangeable knuckle for quick changing depending on the application scenario... I would also use either clear glass or clear plastic although I definitely prefer clear glass to protect the mirror face from spatter because the more mirrors you break, the worse and longer your bad luck will be which is why I have had such bad luck in my life. It's from breaking all of those mirrors when I was in training duh! Oh yeah moving by thinking backwards - What a concept!!!:lol::yell::yell::twisted::yell::lol::grin::smile::surprised::wink::roll::cool:

Respectfully,
Henry
Parent - By ssbn727 (*****) Date 02-03-2015 06:10
Yeppers!

Ullman's were the only one's EB used back in those days and the difference now is that they no longer off the oval shaped bodies and I understand why... Back then there wasn't too much interest in the oval shaped mirror bodies and you had to wait for quite some time for an order to come in... So, I don't remember who came up with the idea of having the Tin Knocker's to make them instead by supplying them a roughed up original and they went ahead and made 20 of them and it only took them a week! Needless to say that EB no longer ordered the oval mirror bodies again an could be the reason why they no longer offer them as an accessory... We also modified stingers with knuckles or elbows if you prefer fabricated in order to get into locations where the welder's arm wasn't long enough nor could bend in such a manner to repair and hanger weld or any other type of weld that needed just a tad more weld on it so it would be signed off as acceptable... Bottom line is that we came up with some really cool accessories for mirror welding inside the Submarines we built or were building at the  time.

Respectfully,
Henry
Parent - By welderbrent (*****) Date 01-30-2015 15:19
Mark,

WELCOME TO THE AWS WELDING FORUM!!

As I don't do a lot of pipe welding nor pipe inspections I purposely awaited another response before welcoming you and chiming in.

Now, as to only the question of access with no consideration of weld code, application, joint, process then AISC makes some comments in the same venue as Al expressed.  There is a definite need and, on the part of the engineer/detailer, a responsibility to provide adequate clearance for the work to be performed.  AISC deals with both welding and bolting in designing of joints that allow for the needed clearances.  If you can't get to it then it can't be done to a level that would instill confidence in the product and insure the public safety. 

So, while I tend to agree with Al that there is no specific applicable code or standard that would provide the answer and/or direction you request, there is the common sense factor, safety factor, quality factor, and direction by one standard that would verify the obligation to provide a reasonable amount of clearance.

He Is In Control, Have a Great Day,  Brent
Parent - - By pipewelder_1999 (****) Date 01-30-2015 22:15
If you gotta think about how close you CAN get it, you probably need to look at it in real life and see how its gonna be to weld.  Do all you can to make the joint weldable. If its as easy as you can get it, then it is what it is.

The standard is sometimes mentioned in the field its the DU 1.1 "Specification for those who didn't have a clue.". As with many welding terms, the slang version is "I'd like to meet the idiot that drew this"

Have a good one.

Gerald
Parent - By ssbn727 (*****) Date 01-31-2015 00:21
I couldn't have wrote that any better Gerald!
- - By SEMark Date 01-30-2015 18:07
Thanks for the responses and the welcome.

Application is B31.3 steam service.  Pipe is carbon steel, 3" sch 160. Access "should be" good... ie visibility of weld, other structures in the way, etc.  My concern is mostly for the proximity of the flange to the weld prep on the pipe.  I get to choose however far away that weld prep should be, but the longer I make it, the more it costs!  Ever a balance between pleasing the accountant and the guy in the field!

Is your electrode perpendicular to the pipe through all the passes?
Parent - - By 803056 (*****) Date 01-30-2015 18:34
I guess I don't understand something here. The flange is either a slip-on, socket, or weld neck, so how do you get to choose the distance between the flange and the joint? Are you welding a nipple / short length of pipe to the flange in the "shop" prior to installation?

Best regards - Al
Parent - - By SEMark Date 01-30-2015 20:09
Yes, you can think of it exactly that way.  To be honest, it's not really a flange, it is a body that has dimensions similar to a slip on flange.  Consider it like I am machining a slip on flange with a stub length of pipe sticking out.  I can choose the length of the piece sticking out.

Thanks, and sorry I can't be clearer without posting screenshots, etc.
Parent - By 803056 (*****) Date 01-31-2015 02:07
Make the stub end equal to 1/2 the outside diameter of the flange. The stub end can be beveled to 37 1/2 degrees, root face equal to 1/16 inch, counterbore the ID to ensure the ID and OD are concentric.

I am in the process of reformating my hard drive, so only the essential programs are currently loaded. If I had all my programs loaded I could send you a sketch. Sorry.

Best regards - Al
Parent - - By WeldinFool (**) Date 02-02-2015 19:15
I would suggest that you match the dimensions found on a 3" weld-neck flange.
Parent - By pipewelder_1999 (****) Date 02-03-2015 00:39
I like this one the best, or maybe just a touch longer .
Parent - By pipewelder_1999 (****) Date 01-30-2015 22:19
If its going to be welded AFTER its bolted up, then the bolts/studs can be an issue but t hat shouldn't be the way its done.

Very "Non-Textbook" electrode travel angles are used in real life. An example is water wall panels on a boiler. Extreme "push" or "pull" angles are used at at the membrane or tangent section. the same thing can be done on pipe. As with many things welding related, its not "by the book" but its been working for years.

Gerald
Up Topic Welding Industry / Technical Discussions / Standard for distance from weld to flange

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