Header attachments, weldolets etc.

[SteveS58]

Headers and weldolet attachments

Is it allowed, by code, to attach a weldolet to a header, under the following conditions.

Please note: the position of the weldolet is as follows:-

The header is made up of two pieces of 10" pipe, joined together with a 10" tee-piece. Weldolets are fitted on the centreline / weld of the tee-piece to pipe welds.

Any advice is greatly appreciated.

If required I will try to get pictures to better show the issue.

 

[XL83NL]

Are you adding the weldolet onto the tee? Then no, not allowed, unless you re-qualify the thee per 304.7.2, as it is no longer a standard B16.9 tee.
Or; are you adding the weldolet over a circ seam? Why? Why not just next to the circ seam?

A sketch would certainly help. Please also include relevant design data (such pressure, temperature), material, design code, etc.

 

[LittleInch]

Codes are not normally in the business of allowing or not allowing things like this and there are many many similar threads about proximity of welds.

A picture would be great, but if I understand you correctly you're planning on inserting a ?" weldolet right on top of a 10" header circumferential pipe weld. No idea what welding procedure or testing you can use for that.

On the face of it sounds like a terrible move and all sorts of issues of welding in HAZ and mixing of weld metals, but probably not specifically permitted or not permitted.

If it's that close to a tee though you may be compromising the design of the fitting and creating a stress concentration on the tee for which it wasn't designed.

If it doesn't look right it isn't right.



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[SteveS58]

Many thanks, I will try and get a picture and send it on my next post.
Your assumptions are correction, ref' on the circumferential weld. I obviously agree with you, which is why I was asking for advice on my concerns. It would be nice if there was something in the ASME codes. I seem to remember reading something about not welding within 4 x the pipe wall thickness to an existing welded joint. Unfortunately I don't have access to any of the ASME doc's, as I am new to this position and just setting up on a site still under construction.

 

[XL83NL]

It would be nice if there was something in the ASME codes.

ASME Codes are not a cookbook type set of rules that covers everything. Read the foreword of the appliacble ASME standard.
Think of it as follows; if you buy a new shower for your bathroom, which comes with a manual on how-to to install it, and you install the shower acc. the manual, that doesnt mean you have become a professional plumber. It takes years of experience and mentorship to understand what it and is not in the codes, and how to address those things not in the codes.

I seem to remember reading something about not welding within 4 x the pipe wall thickness to an existing welded joint.

This is not part of the ASME codes. Some rules of good engineering practice (Recommended Practices), or client specs, may spell out such requirements, which typically pertain to hardenable materials. Austenitic materials are less prone to such issues.

Unfortunately I don't have access to any of the ASME doc's

If you dont have access to the applicable Codes, make sure to get a copy of the applicable codes by buying them.

I am new to this position and just setting up on a site still under construction.

In that case you better leave these questions to someone experienced in this field of work, like a pipe stress or mechanical engineer, and let him do the work. You obviously are not the right one answer this question.

 

[DekDee]

Agree 100% with XL83NL.

 

[LittleInch]

Also agree - for things stating construction issues you need to scour the company or design specification issued to the contractor for any minimum distances.

Or just reject the design / workmanship and hold your ground.

Things like 4t and 0.5D minimum distances are construction issues not normally covered by the design code.

Search minimum distance welds on this site and you'll see many opinions, but very few, if any "code" requirements or limitations.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[SteveS58]

Thanks Gents.