Nozzle Wall Thinning Evaluation

[jrley]

Are there any thoughts about using ASME UG-45 (along with UG-27, -28, -37, -40) in the evaluation of a tmin for nozzle neck thickness? Or should UG-45 be left for the design and fabrication of a new vessel?

Thanks
jrley

 

[prex]

Can't see any difference between new and existing (?): can you be more specific on your concerns?

prex

http://www.xcalcs.com

Online tools for structural design

 

[jrley]

Dealing with wall thinning due to FAC (flow accelerated corrosion)on FW Heaters. Do not have Tmeasured yet. As it now stands,the nozzle neck will have to at least be .875*Tnom which will definitely keep the neck stronger than the connecting pipe. Seems to conservatve. Curious if other places have been using UG-45 in their methodology for nozzle qualification due to FAC.

 

[jte]

jrley-

Sounds like you have a vessel with standard wall nozzles and no corrosion allowance: "...the nozzle neck will have to at least be .875*Tnom." That would be unusual and not a happy place to be. From a fitness for service perspective, the nozzle can be thinner, but you need to be sure to evaluate all loads, including piping loads combined with internal pressure to ensure that the nozzle will be safe for continued service.

You might find API-579 Section 5 to be useful.

jt

 

[deanc]

Not for pipe-but. ASME SecVIII Appendix 32

Check this site and the links---NACE

http://www.fitness4service.com