replacing the 12" RFSO flange 1

[Syahar1975]

Dear experts,

We have a 12" shell nozzle made from 12" RFSO 15# flange.

After installation to the tank by mistake the surface of this nozzle is damage and client instructed us to replace.

DO you have the procedure for this purpose ?

I would use arc gouge to gouge the fillet weld. Due some grinding on the neck then install the new flange and due PT.

There is also suggestion to cut the neck and make a new spool (flange with neck). If we are using this method, is there any clause in API 650 about how far minimum the but weld joint on the neck of the nozzle to the shell or to fillet weld ?

The projection from the shell to this nozzle is 250 mm.

Any comments would be appreciated.

 

[IFRs]

I think I would cut off the flange and replace it with a weld neck flange

 

[Syahar1975]

Good morning IFRS,

Yeah this is also good alternative.

We measure the length of the WNRF nozzle from the flange surface to the end of the neck. Then we cut the existing shell nozzle based on that length.

So we will have but weld joint from WNRF to existing nozzle neck.

PT for this butt weld I believe is sufficient.

Regards,

Syah

 

[Duwe6]

PT, or MT if it is magnetic, are good choices. With PT you can ensure that there are no pinhole leaks.

 

[Syahar1975]

Ok Duwe6,

Thanks for your advice.

 

[11echo]

Do it like IFRs suggests! You'll save your self a lot of heart acne and money if you do!

 

[Syahar1975]

Yes 11echo,

That is the best and economist way.

Thanks

Syah

 

[Soln]

Weld neck is a tricky weld to make in the field, and requires x-ray. I would gouge the damaged flange off, and replace with RFSO. Is there concern with heat affected zone HAZ? Remove 1/2" past weld from the neck- there will likely still be plenty of projection.

Does the job- economical-

 

[11echo]

I have to respectfully disagree with roughandtumble, I work out in the oil fields and we add weld neck flanges to existing piping all the time, same thing with X-raying the weld ...IF needed. PLUS using a weld neck flange you can now match the existing nozzle projection off the tank and have the capability to bolt up to any existing piping WITHOUT any modification.

 

[valleytank]

The only time a weld neck would get tricky is if it were low to the ground. Have done many of these modifications with x-ray no problems and like 11echo stated you should be able to meet your desired projection still.