hole for nozzle is larger that the OD of the nozzle 1

[taba94]

hi
in one of our project when we wanted to insert and fit up and weld the nozzle to the shell we founded that the hole is larger than the OD of the nozzle. are we allowed to weld overlay to fit it and use the present wps or we should do s/th else?
is there any reference that prohibit or allow this or address this problem?
regards

 

[cbPVme]

Do you have a specific question?

 

[dik]

The hole for the nozzle in the tank is larger than the OD of the nozzle. He's wanting to know if he can weld a plate to the tank over the hole and cut a new hole the proper size. He's also wanting to know if there is any regulation that prescribes this solution or if the solution is not correct.

Dik

 

[mk3223]

May check the Code requirements for the tank design and/or repair for your case, such as API 650, 653, etc.

 

[ScottofArabia]

How much bigger is the nozzle o.d to the nozzle o.d? What's the root gap?

 

[taba94]

the distance between edges is about 30 mm and the root gap is should be 3mm

 

[DekDee]

You don't mention what code you are working to ?
I don't think it matters because "building up" 27 mm of parent metal to give yourself a 3 mm root gap is a big No/No.
Consult the designer and/or the client for a decision (and sack the person who cut the hole)

 

[SnTMan]

Hopefully, you still have the drop. Full penetration weld it back in place, full RT the weld, recut the hole the proper size. Not an uncommon occurance.

Regards,

Mike

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

 

[gtaw]

Patch the oversized hole (really, 2 1/2 inches larger than the nozzle?)using same material and using CJP butt joint, cut the correct diameter hole, and breath with slow and deep breaths.

Best regards - Al

 

[taba94]

thanks for your replies

 

[LittleInch]

taba,

it would help a lot if you could say,

What design code / shell?
Is this a pressure vessel or an atmospheric tank? what you can do with a tank you might not be able with a PV.
Could you insert a larger nozzle and then reduce down?
ask the vendor if he's happy with a bigger nozzle or perhaps a slightly longer nozzle stand off if you need to add a reducer
How thick is the shell
what size nozzle are we talking about?

But I agree - weld build up like this is not acceptable.

and then always remember "measure twice (or three or four), cut once"

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[DekDee]

LI has given IMHO the only professional way to resolve - add a larger nozzle and reduce.

No offence to SnTMan and gtaw but "patches" in tanks or vessels are not recommended due to the fact they are quite often undocumented - no NDT / No traceability due to the fact the person / persons who stuffed up want to try and keep it hidden.
Patch it, grind it, throw some paint on and nobody will know !!
Even if it is documented would you as a buyer want an unexplained and unnecessary circular weld in your tank / vessel ?

 

[SnTMan]

DekDee, on the contrary, to flush-patch and full RT the repair is fairly common in PV work, due to mislocated or incorrectly sized holes cut in a shell.

Clients typically prefer this to re-working their piping or delayed delivery. Nobody is hiding anything.

Regards,

Mike

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

 

[DekDee]

Mike,
I spent 4 years as a radiographer and I could fill a book with the amount of patched up holes in tanks and vessels I have witnessed with no traceability at all.
I am a Welding Inspector and ex-welder of 15 years so I can tell pretty easily when there is excessive grinding / sanding in a specific location that it is not due to the removal of a temporary attachment.
If I had a request to radiograph all the code mandated "critical" welds on a tank / vessel and I saw a clear indication of a "patched" hole it is my duty of care to inform someone.
As I stated previously - many of these patches are performed with no ones knowledge due to the fact the person who has done it is embarrassed and wants to hide the rework as quickly as possible.
Cheers,
Shane

 

[SnTMan]

DekDee, understood, and thanks. Again, it is all done in the open. I do not disagree with your position, just relating what I have seen.

Regards,

Mike

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