ASME Pressure Vessel Dimensional Tolerances

[inspect58]

Does ASME Sect. VIII Div. I reference allowable tolerances for dimensions on a Pressure Vessel?
i.e. Nozzle projection, Nozzle orientation, elevation, etc?

 

[JoeTank]

ASME VII does not specify tolerance for the items you mention.

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com

 

[metengr]

No, these are considered manufacturing details that would be part of the engineering specification for fabrication of the vessel.

 

[inspect58]

While performing a dimensional inspection of a pressure vessel, the outside diamenter of a nozzle repad was found to be 1" less that the ASME code calcs. required. Would this dimension be considered as a tolerance issue, or should this be addressed as a defective material issue?

 

[unclesyd]

How was the thickness of the pad?

 

[metengr]

This is not a material defect issue, this is a nonconformance issue between what was found during shop fabrication and comparing to your original engineering calculations. The nonconformance should be dispositioned (for example by engineering) by whatever method your QC Manual describes.

Go back to ASME Section VIII, Div 1 and re-check the A(5) repad calc, and compare with your total area of reinforcement requirements.

 

[deanc]

metengr is correct in a way to deal with this.

Keep in mind-tolerance or not-if the item has anything that is below the minimum required diminsions by the Code calcs. it is unacceptable.

See UG-16,UG-96,Appendix 3. You may be able to do a "work around" under a NCR or may require additional material to be added.

 

[inspect58]

Thanks guys, I appreciate the info.