PV with SW Connections Hydrotest
PV with SW Connections Hydrotest
(OP)
Our client insists to have a socket weld coupling as a temperature gauge nozzle in NPS 1 or less Size. My question is; Does any one have a past experience with this nozzle end configuration? How was the hydrotest conducted? Is there any code reference to allow opening and welding these connections after hydrotest with some further NDT?
There is one trick which I don't like to use it. The vessel can completely fabricated according to ASME VIII Div. 1 with ignoring all SW nozzles, and then welding of all SW connection as a repair work according to NB in which the hydrotest of such small connection attachments weld. But, it is not intention of NB code to applied for new vessels, and doesn't look good to supply a new vessel with both ASME-U and NB stamps.
Could you please advise.
Regards,
M.Salaheldin
Static Equipment Mechanical Design Engineer
There is one trick which I don't like to use it. The vessel can completely fabricated according to ASME VIII Div. 1 with ignoring all SW nozzles, and then welding of all SW connection as a repair work according to NB in which the hydrotest of such small connection attachments weld. But, it is not intention of NB code to applied for new vessels, and doesn't look good to supply a new vessel with both ASME-U and NB stamps.
Could you please advise.
Regards,
M.Salaheldin
Static Equipment Mechanical Design Engineer





RE: PV with SW Connections Hydrotest
A new vessel, Ask your inspector too allow adding the nozzles and re-hydro. Then Ammend the data sheet.
RE: PV with SW Connections Hydrotest
Regards,
Mike
RE: PV with SW Connections Hydrotest
RE: PV with SW Connections Hydrotest
Your reply was one of my ideas. But, later on I said if so, then what is the value of the socket weld. Why don't we weld a pipe direct to shell without the socket coupling?! Specially that most of the other nozzles are not flanged (most of the nozzles are BW ends).
My current idea is to weld a cap with bore diameter larger than the coupling OD as lap joint to the outer body of the coupling. After successful hydrotest "hope so :)" it is easier to remove this weld and grind the outer surface of the coupling without touching the Socket End. Still I'm not sure if this will work or no.
Regards,
M.Salaheldin
Static Equipment Mechanical Design Engineer
RE: PV with SW Connections Hydrotest
Regards,
Mike
RE: PV with SW Connections Hydrotest
Regards,
M.Salaheldin
Static Equipment Mechanical Design Engineer
RE: PV with SW Connections Hydrotest
See the attachment, pg 12 "B-1 Bosset" for example. Note I have no connection with this vendor, other that having a catalog.
Regards,
Mike
RE: PV with SW Connections Hydrotest
Provided that you are looking strictly at compliance with VIII-1, I don’t think you have much of a problem. It’s not clear to me from the thread whether you have a situation (1) with a SW coupling (more likely half-coupling) welded directly to the shell or (2) a pipe neck welded to the shell which then has a SW coupling welded to it.
If (1), then the fillet weld connecting the piping or instrument is NOT a Section VIII weld – it is clearly a piping weld. Build the vessel, add a SW plug, hydrotest the vessel, grind off the weld to remove the plug, done.
If (2), then the SW coupling itself is outside the scope of VIII; the scope ends at the cut end of the pipe. The fillet weld which attaches the coupling is B31. With this configuration you have two options: (a) Weld the pipe neck to the shell, add a bit of B31 material in the form of the coupling and its fillet weld to the pipe, then add a plug and hydrotest. Remove the plug.
I’m writing this up referring to a couple of Interpretations:
Interpretation: VIII-1-89-27R
Question (1): In UG-99(a), does the term completed vessels mean vessels on which no further welding will be done after the final hydrostatic test?
Reply (1): Yes.
Question (2): May operations such as weld end preparation, which could not be performed prior to the final hydrostatic test, be performed after the test but prior to the signing of the Manufacturer’s Data Report?
Reply (2): Yes
Interpretation: VIII-1-89-115
Subject: Section VIII, Division 1 (1986 Edition, 1988 Addenda), U-1(e)
Question: Two vessels were fabricated by a Manufacturer in accordance with the requirements
of Section VIII, Division 1 and were stamped accordingly. Nozzles with weld end connections were provided on the vessels. Are the field welds for the connections to these nozzles considered within the Scope of Section VIII, Division 1?
Reply: No, see U-1(e)(1)(a).
Now, since these Interpretations were issued, UW-21 addressing SW flanges was added which allows for a single weld to be used and remain code compliant. But this simply allows for the SW connection to be incorporated into the code if desired – it does not change the base scope limit from being the first circumferential weld off the shell.
RE: PV with SW Connections Hydrotest
Thanks Mr. jte for your brief explanation. My case is no. (1). My worry is only; if we weld a plug to the socket weld and try to remove it, this maybe damage the socket end of the coupling. My intention is to avoid welding to the socket end itself.
Regards,
M.Salaheldin
Static Equipment Mechanical Design Engineer
RE: PV with SW Connections Hydrotest
RE: PV with SW Connections Hydrotest
Regards,
Mike
RE: PV with SW Connections Hydrotest
Regards,
M.Salaheldin
Static Equipment Mechanical Design Engineer
RE: PV with SW Connections Hydrotest
Regards,
Mike
RE: PV with SW Connections Hydrotest
Install a SW half coupling on the shell, weld a piece of pipe into it, then cap the pipe, then hydrotest, then ship: the client then has to either a) cut the pipe and install a SW coupling on the PIPE (1 weld) and then weld their thermowell to it (another weld), or the client needs to cut the pipe out of the socket, install the thermowell, weld it in (1 weld to the vessel's pressure boundary), and then re-hydrotest the whole vessel, plus some R-stamp paperwork and an AI visit.
Same goes for a thread that has to be seal-welded: the seal weld requires a weld to the pressure boundary requiring a re-hydrotest.
...or add the thermowell to the pressure boundary, weld it in at the code vessel shop and include it in the hydrotest- client doesn't have to do anything- unless the thermowell is corroded or otherwise damaged in service, in which case it's an R-stamp issue again.
Assuming the client can't or doesn't want to supply the thermowell to you, wouldn't a flanged nozzle just be easier, again assuming threading isn't an option? Seems to me well worth the cost of a small flange!
RE: PV with SW Connections Hydrotest
Regards,
Mike
RE: PV with SW Connections Hydrotest
RE: PV with SW Connections Hydrotest
And yeah "Clients have dumb-@sses and newbies working for them" and so do they have experienced old hands, also just like the fabricators.
Job is sold, if it ain't WRONG, its RIGHT :)
Regards,
Mike
RE: PV with SW Connections Hydrotest
RE: PV with SW Connections Hydrotest
Butting out now :)
Regards,
Mike
RE: PV with SW Connections Hydrotest
moltenmetal-
I don't understand your basis for stating that the vessel in either case above must be hydrotested. In your first example, cutting the pipe out of the socket and welding a thermowell in does not require a Section VIII hydrotest. Simply put, the weld is a piping weld, and can be dealt with using additional NDE in lieu of a hydrotest.
Seal welding a threaded connection is also not a Code weld and thus does not require a hydrotest.
Can you clarify why you feel that these are Code welds?
RE: PV with SW Connections Hydrotest
RE: PV with SW Connections Hydrotest
Duwe6 and jte: your interpretation of what "first joint out" means differs from the way our vessel guys interpret ASME VIII-1. The way they interpret it, any weld to the pressure boundary requires a re-hydrotest. Doesn't matter if it's a support clip welded to the shell or head, a spot weld of an insulation support post, or a seal or socket weld to a half coupling- it's a weld to the pressure boundary.
Can you substitute special NDE for the re-hydro? I take jte's word on that, as I haven't looked into the repair section of the code too much. We try to avoid "repairs" like this by design, to the extent we can. That would include moving thermowells to a flanged nozzle or including them in the vessel scope.
The way we are currently taught to interpret the last joint out would include the weld to any socket weld coupling in the pressure boundary. Welds to the pipe itself are in pipe scope. But any weld in piping you can't hydro needs to be subjected to special NDE and a sensitive leak test, again unless I've misremembered the codes. Same problem- same solution in my opinion.
RE: PV with SW Connections Hydrotest
'Therein lies the rub.'
ASME VIII is only for construction of the vessel. Thus the rehydro [in the shop] makes some sense. Installing and repairing the vessel comes under National Board - NBIC - and/or API 510. That is delineated in the front of all three Codes. And once the U-1 is signed, the first connection out is indeed a 'pipe-code' connection. That part is in NBIC [don't think it's in 510].
Don't take my word for it, just call your state Boiler & PV board [I did - Indiana]
http://www.nationalboard.org/ViewMembers2.aspx
RE: PV with SW Connections Hydrotest
I don't see a need for nor any advantage in discussing whether a ladder clip field weld to a 1" CS shell would require a rehydrotest of the vessel. This thread is about making a connection to a nozzle which by its design is meant to have a welded connection.
In this case, I'm not interpreting the code. I'm leaving that to the Code Committee, and copied their thoughts as published in Interpretation VIII-1-89-115 in my post of 17 June above.
Your folks can choose to apply requriements more stingent than the intent of the Code Committee. Certainly I require much more than simple code compliance for vessels which we purchase. But I will choose to not be more stringent when it comes to welding B31 piping to a nozzle which is meant to be welded to. For what its worth, my company vessel spec's would not allow a SW connection to a vessel; all nozzles are to be flanged. Thus, I would hope to not deal with the topic of this thread with a newly purchased vessel. But we have vessels in service which are much older than I am, and not all new vessels are purchased strictly in accordance with company spec's.
To each their own... All I ask is that we be clear about "I choose to" as opposed to "the Code requires" statements.