Weldolet vs Custom Pipe Modification 2

[Fooooks]

Hi Eng-Tips,

I was not sure what to call the second fitting I am talking about. My welders at the company are questioning their foreman on the weldolets he is ordering for a project. They are asking why they cannot just modify a piece of pipe with the saddle cut out and weld it onto a pipe to eventually hot tap. Is there a reason to put their minds at ease to use a weldolet as opposed to them creating their own version of a weldolet without the thicker base?


Thank you,

 

[pennpiper]

Fooooks,
You should ask the Foreman and the welders if they are qualified to do the calculations necessary to insure the "Jury-Rig" branch fitting will meet Code?


Sometimes its possible to do all the right things and still get bad results

 

[Fooooks]

Pennpiper,
I was looking at other posts on the forum to see which code to follow. What code or standard should I be referencing or pointing them towards? ASME B16.9 ?

 

[pennpiper]

Yes!

Sometimes its possible to do all the right things and still get bad results

 

[LittleInch]

The design code generally won't allow it.

The design code is really ASME B 31.3 or .4/8 16.9 doesn't specify integrally re-inforced branch fittings. See figure 328.5.4. of ASME B 31.3

The basic premise of a tee connection is that the volume of metal removed in the hole in the header pipe is replaced within a short distance around the hole by an equal volume of metal. This has been shown by long service and design calculations to provide sufficient re-inforcement to stop the branch pipe form being ripped off or failing due to internal pressure.

Rather than having to do this calculation every time for each combination of header size, branch size, wall thickness, material strength etc etc, Bonney Forge did it all for everyone decades ago and created the "weldolet".

Now anyone can make one, but call it an "integrally reinforced branch fitting".

The attached might help you. Especially the first few pages

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

 

[Fooooks]

Thank you for the literature and the response. I have looked up 328.5.4 and my mind is at ease. I imagine they are trying to cut corners where possible to avoid extra welds.

 

[DSB123]

I feel a potential failure in the offing unless the branch is properly designed and manufactured. "Don't let the Cowboys prevail"

 

[Fooooks]

MJCronin,
The foreman is on vacation for two weeks, and so I believe they are trying to squeeze by where they can. I do not know if they have done such things in the past, and I am still learning. This is the reason for my asking, and they have been informed already and will not be doing this again. It will be relayed to the foreman when he returns that his workers were trying to cut corners and wait for materials to arrive on site.

Thank you all for the posts.

 

[gtaw]

What is interesting and scary is how many times one sees the integrally reinforced fitting installed incorrectly. "But it's just low pressure!"

Best regards - Al

 

[XL83NL]

Through the years Ive gathered documentation on the weld design for olets; we often see the manufacturers take a short cut and not complete all passes. I keep thiese documents ready just in case this happens (sgain) ...

http://files.engineering.com/getfile.aspx?folder=b0d34abc-a2a2-4dcf-8b1f-67e1acde2a42&file=olets.rar

 

[DSB123]

XL83NL,
Yes I have heard the argument that the amount of weld only needs to be the same thickness as the branch pipe!!!! Where do thes enumpties come from - definitely not from this planet!!!

 

[Fooooks]

XL83NL,
Wow thank you for the documents, very helpful. I have printed these out to give to the foreman to ensure it is posted in the shop for easy access in case anyone has any questions.