Re-pad for self integrally nozzle

[alieng1982]

Hi,
Can I use reinforcement pad for self integrally nozzle? The area available is less than the area required, so I want to use Re-pad to increase area available.

Thanks for your quick response

 

[TGS4]

I think that you need to explain your situation first. Things such as:
1) Code of Construction
2) Materials, temperatures, pressures
3) A better explanation of what you mean by "self integrally nozzle".

 

[alieng1982]

I use ASME Sec. VIII, nozzle material is SA-350 LF2 C1, Design T:100F, Design P:1440 PSIG, nozzle size is 28" (special forging with different hub and neck thickness),
Can I use Re-pad to increase area available?

Thanks,

 

[SnTMan]

alieng1982, well, chances are you can do it but it's kind of a nasty detail. Can you not just increase the forging thickness? If a pad is added it is no longer an integrally reinforced detail, if one is required.

Regards,

Mike



The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[jte]

alieng-

Ok, to follow on with TGS4's thread... You are an engineer. Be specific. Fine, you have an ASME Section VIII vessel. Shall we ask three more questions in this game of 20 Questions? Is your enquiry related to:
ASME VIII Division 1?
ASME VIII Division 2?
ASME VIII Division 3?

Are there service considerations such as cyclic service or thermal shock which might impact the decision making if an experienced engineer were involved?

But to jump to some opinions here based on a statistically likely response that the vessel involved is a Div. 1 vessel with no service considerations:
Can you use a repad to increase the area available for a typical integrally reinforced nozzle configuration? Yes, the code does not prohibit this.

But... Consider the impact to your reputation prior to going down this road. If I have to venture a guess, you are working for a fabricator who (ahem) "poorly machined" a forging and is now trying to find a way to make it work despite good engineering judgment. I really hope you are not involved in the design of any vessels which my company will wind up owning.

There are high quality consultants in your province. I suggest you consult with one.

 

[alieng1982]

Dear Mike, The nozzle is already ordered and installed on the shell (expensive special forging) but the area available is less than required! I wanna use Re-pad to have some area.

Is it possible?

Thanks,

 

[SnTMan]

alieng1982, practically speaking, yes it is possible. Assuming (among other things) that an integral detail is not required by the contract or other rules, standards, etc.

I'll also say that, as your customer, if I were asked to approve this detail, I'd not likely do so. If "surprised" with it, I'd likely not accept the vessel.

You need to do your homework before proceeding.

Regards,

Mike



The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[marty007]

We have many customers that state in their specs that all connections be integrally reinforced with no repads. Is this the case with your customer?

 

[alieng1982]

No, there is no limitation to use Re-pad.

 

[SnTMan]

alieng1982, if you are building for a client, you should be having the discussion with them, not here. If not, then it likely makes little difference.

Might run it by your AI as well, make sure you can get it stamped, if required.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

EDIT: Can you get there by making the fillet weld bigger?

 

[jtseng123]

alieng1982, go for the re-pad to obtain more area if there is no prohibition of using re-pad. Our practice of re-pad thickness is not to exceed 1.25 of shell thickness. Prohibition of using re-pad is such as cyclic service, hydrogen service, etc.

 

[TGS4]

By what calculations have you determined that you don't have sufficient reinforcement?

 

[MrPDes]

If your nozzle is in a cylinder, you can use Appendix 1-10 in place of UG-37. This often reduces the area needing replacement considerably. Unless these methods are prohibited in customer specs, there is no need to inform the customer.

Alternatively, use Code Case 2695 for a nozzle in a head. Code Case 2695 will need to be mentioned in the Manufacturing Data report. It is not compulsory, however informing the customer may be a good idea.

 

[r6155]

Which is the amount of area to be added ?

Regards
r6155

 

[TGS4]

MrPDes - I was certainly leading the OP towards CC2695. I would not recommend Appendix 1-10, as the rules in there are obsolete compared to the rules in Part 4 of Division 2 (as described in CC2695).

 

[patidar123]

Hi alieng1982,

One more solution, increase the local shell thickness with inserting the insert plate, will help you to increase the available area of reinforcement.

Try this one.

Thanks

SBP