Nozzle Flange Replacement
Nozzle Flange Replacement
(OP)
Hello,
I had a simple question about the replacement of a nozzle flange face on a vertical storage tank that falls under API 650/653. According to 650, the nozzle assembly has to be thermally stress relieved because of its material grade, shell thickness, NPS...
My question: Is it allowable to just replace flange face only with a new weld neck flange without any thermal stress relief (i.e. not having to shop fab and insert the entire assembly)? I could not find anything in the code that governs this but I was wondering if anyone out there had any experience.
Thanks
D
I had a simple question about the replacement of a nozzle flange face on a vertical storage tank that falls under API 650/653. According to 650, the nozzle assembly has to be thermally stress relieved because of its material grade, shell thickness, NPS...
My question: Is it allowable to just replace flange face only with a new weld neck flange without any thermal stress relief (i.e. not having to shop fab and insert the entire assembly)? I could not find anything in the code that governs this but I was wondering if anyone out there had any experience.
Thanks
D





RE: Nozzle Flange Replacement
Joe Tank
RE: Nozzle Flange Replacement
"The stress-relieving requirements need not include the flange-to-neck welds or other nozzle-neck and manhole-neck attachments, provided the following conditions are fulfilled:
a. The welds are outside the reinforcement (see 5.7.2.4).
b. The throat dimension of a fillet weld in a slip-on flange does not exceed 16 mm (5/8 in.), or the butt joint of a welding neck flange does not exceed 19 mm (3/4 in.)."
However, there are also other considerations. This is just a partial quote. Please review the entire section to be sure you qualify.