PV with SW Connections Hydrotest 4

[abuanaselmasry]

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

 

[GenB]

I know that in Sect. I ,half inch can be added I'm not sure in Sect Viii-1
A new vessel, Ask your inspector too allow adding the nozzles and re-hydro. Then Ammend the data sheet.

 

[SnTMan]

abuanaselmasry, it is common to weld pipe with excess length to the SW fitting and cap it. In the field, the owner cuts off the cap and attaches to the remaining pipe.

Regards,

Mike

 

[moltenmetal]

If you weld pipe into it and cap it, the client's tiepoint connection would no longer be a socket weld...the customer would have to cut off the pipe entirely and weld to the socket, which is part of the pressure boundary and hence would require a re-hydrotest, or they would have to add a socket weld coupling to the pipe - ugly, with two welds required instead of one etc. Better to use a flange or a threaded half coupling than socket weld attachments to a vessel.

 

[abuanaselmasry]

Dear Mr. Mike (SnTMan)
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

 

[SnTMan]

There are couplings available that have both NPT and SW provisions, with the threads kind of counterbored into the female socket. A threaded plug can be used to close it for test / ship. It can then be used as an SW connection (to attach a pipe?) or the threaded plug can be seal welded, if desired.

Regards,

Mike

 

[abuanaselmasry]

This last reply is a kind of out-of-box ideas. I will try with out procurement if they can easily source such crazy couplings

Regards,
M.Salaheldin
Static Equipment Mechanical Design Engineer

 

[SnTMan]

abuanaselmasry, not out-of-box around here

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

 

[jte]

abu-

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.

 

[abuanaselmasry]

Thanks Mr. Mike for the catalog.

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

 

[moltenmetal]

Temperature gauge/instrument nozzles are generally solved by adding the thermowell to the scope of the vessel, or making the nozzle flanged, assuming that a threaded connection is not acceptable. The latter is preferable if the thermowell is a damage or corrosion replacement item.

 

[SnTMan]

Well really, push comes to shove, you just cut one rather small fillet weld, remove the thing not wanted, replace with the thing wanted.

Regards,

Mike

 

[abuanaselmasry]

Mr. Mike, it looks that I didn't get what do you mean by the last post

Regards,
M.Salaheldin
Static Equipment Mechanical Design Engineer

 

[SnTMan]

abuanaselmasry, I was just referring to the fact that to change out a socket welded piece of pipe for a SW valve, for example, is not really too big a deal. Depending on material, of course

Regards,

Mike

 

[moltenmetal]

SnTMan, the issue is the need to re-hydrotest- not a small issue!

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!

 

[SnTMan]

Well, if the client specifies SW, the client gets SW. What the client does to put the vesseel in service is his business. He must have some kind of plan to deal with it.

Regards,

Mike

 

[moltenmetal]

Clients have dumb-@sses and newbies working for them, no different than vessel shops! I've learned an enormous amount from good designers and mechies at vessel shops about how to specify vessels to avoid problems like this. I would have learned little if a) I'd been afraid to ask or too arrogant to listen, or b) they'd been happy to just build whatever I put on paper and leave me with all the unanticipated problems to sort out myself. Coming here is a start, but I would hope that the vessel shop would call people and get design intent clarified on issues like this rather than just building what's on the spec sheet.

 

[SnTMan]

molenmetal, Job is sold, where do you stop? Temps, pressures, service, metallurgy, vessel configuration, orientation, paint & coatings, aux connections, ratings, facings, corrosion allowance, gaskets, what?

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

 

[moltenmetal]

I've made a good living not assuming that anything I'm given which fails my initial sniff-test is well-considered direction rather than a suggestion- until I've confirmed the design intent and pointed out the issues. I also try my best to communicate what I'm trying to accomplish rather than telling people exactly how I want it done. Worth the phone call or e-mail for the learning content if nothing else. No need to fight if it's what they want for what they consider to be good reasons, and no reason to rub their nose in it if you've caught a mistake- there's such a thing as handling this kind of thing the wrong way. But just 'cause it's sold doesn't mean it isn't dumb-@ss, and I've earned a lot of respect- and repeat business- because I don't stand on ceremony. Your own mileage may differ of course.

 

[SnTMan]

moltenmetal, not trying to start any arguments here. Most of what you talk about is more properly done at the proposal stage. Afterwards, if an honest-to-god mistake is found, it of course gets worked out. Othewise, as I said, if it ain't wrong, its right.

Butting out now

Regards,

Mike