Hello I have a steam duct shell of

[selvakumardc]

Hello
I have a steam duct shell of 3.2 m diameter and I will have to weld a opening of 2 m diamter and this nozzle opening is directly fouling with my 3.2 dia shell Circumfrential weld joint. I am aware the ASME Sec Viii allows the nozzle in the joint but being this large opening I want to know the design and NDT requirements. I have limitations like cannot perform RT but UT is possible to all extent both inside and outside of shell. The shell is 16 mm thick and same is the opening. No RF pad used.design pressure and temperatures are 1.5 barg, 120 Deg C also full vacuum. Please advise am I allow to cut the CS joint of shell and open for 2m opening. 3.2 m shell has no RT or UT performed which is designed for Nil category.

 

[TGS4]

For starters, the answer depends on your Code of Construction.

On the off-chance that this is for ASME Section VIII, Division 1 construction, what value of weld joint efficiency are you using for this weld that you will now cut through? And how are you determining that no reinforcing pad (or other reinforcement) is required? (Note that I am specifically asking the paragraph and/or Appendix that you are performing these calculations)

Your R/t is 100 - that's pretty high for full vacuum.

What inspection are you going to propose for the nozzle-to-shell junction? What detail are you proposing to use?

 

[MJCronin]

What is your code of record ? Is this an original design or repair ?

Have you ever designed a joint in either a pressure vessel or a segment of piping ?

"No RF pad (to be) used" ..... Really ? with zero experience you make this restriction ?

Pad reinforcement may be your only alternative .... But we don't know that until you decide upon a code of record.

(Yes, we all know that pads are both expensive and difficult to fabricate)

Are you familiar with the "area replacement technique" calculation method as described in the ASME VIII code ?

What are your materials and welding techniques ? Are they all code approved ?.... As a material description, "CS" is not good enough

Do you actually have a drawing of what you propose to do or just some vague ideas, lack of punctuation, poor word usage and immediate demands...

Can anyone else out there have complete understanding what this person is demanding ?

MJCronin
Sr. Process Engineer

 

[MJCronin]

Does your 3.2 m diameter/16 mm wall "steam duct" have a full vacuum rating ?

Unless there are exterior stiffeners, I strongly doubt it ....

If not, please explain why your new 2m branch must have FV ?

No pictures available.. ???

Have you considered contracting with an experienced Consulting Engineer for assistance with this task ?

MJCronin
Sr. Process Engineer

 

[MJCronin]

https://www.eng-tips.com/viewthread.cfm?qid=72539

MJCronin
Sr. Process Engineer

 

[chicopee]

Since I don't know what a steam duct shell is as I have never heard of such item, pictures would be worth a thousand words.