R-stamp 1

[jtseng123]

I know this has been discussed for many times whether R-stamp is requred or not. It seems the opinion is very divided.
Now I just got a phone call from south America, a new vessel arrived but missing a platform support clip. Jobsite will weld the clip, and asking me R-stamp is required or not. Any expert please advise. Is there any code case to waive the R-stamp just for welding a clip ?

 

[gr2vessels]

Far from being an expert, I am merely stating my opinion and experience.
After hydrotest, one should not weld a missing lug, a missing skirt, a missing nozzle or anything the manufacturer considers a valuable attachment post completion of manufacture.
I can see incomplete vessel delivered 'in time', without all the welded attachments, to be added on site. Who can stop this, if it is not illegal to add welded attachments? How about adding a couple of new lifting lugs, because the existing ones by design error are interferring with a nozzle??
Any welded attachment must be rigurously designed, fabricated and installed in accordance with the code and the regulating authority.
I would not allow welding the clip without R-stamp.
Cheers,
gr2vessels

 

[metengr]

I would require an organization that has a valid R-Certificate. Why take chances? If the Jurisdiction does not require anything, I would still mandate an R-Stamp if I were the owner, period, end of conversation.

 

[jamesl]

I have not checked latest NBIC. R-stamp can be waived only if you can justify the welding work as "routine repair". If a clip is non load bearing part and there is no PWHT, then welding the clip is a routine repair. For example, welding insulation pins or studs to pressure parts is routine repair, and does not require R-stamp.

Platform clips carry significant load. Welding such clips to vessel is a repair, not routine repair, and requires R-stamp.

 

[jtseng123]

Ditto all of you. Very good points. I already told them R-stamp is required. The weld will be MT root and final passes and hardness test.
Now come to serious part: this vessel was PWHT'd due to wet sour service, 5/8" thick carbon steel. The fillet weld for clip is only 1/4". Since the clip is not facing the content, can I just preheat to 200F without doing local PWHT ? My thinking is, due to the small fillet weld, the hardness of the base metal on inside shall not have any impact ?

 

[metengr]

In reference to the above R-Stamp in this context above means a repair organization that holds a valid R-Certificate from the National Board. R-Stamp as to stamp an item means nothing without the organization that is capable of having the Certificate. People keep bringing this issue up regarding routine repairs and repairs. This is not what is intended by the phrase an R-Stamp is required.

 

[jamesl]

Are we talking about a R-stamp holder doing the work or stamping the repair? I thought we were talking about stamping. R-stamp holder is not a big deal in the US. It is the part about inspector involvement during repair, stamping and nameplate that people try to avoid.

 

[metengr]

It is about the holder of an R-Stamp doing welding work, not about routine repairs, or repairs or alterations.

 

[jtseng123]

We always hire R-stamp holder to do the work, regardless where it is. And I do not think any end user will allow any non-R stamp holder to mess around their own vessels. So, this is not an issue.

 

[metengr]

And I do not think any end user will allow any non-R stamp holder to mess around their own vessels. So, this is not an issue.

Not true. I can't tell you how many times end users have questioned why a contractor needs an R-Certificate for repair work on this web site because either they do not want to spend the dollars and have a qualified repair organization or the end user simply does not know. This is typically the main problem, not about specific stamping because the NBIC is very clear about what is stamped.