Vacuum Issues
Vacuum Issues
(OP)
Anyone have experience with a vessel (ca 1980) that has a U-1 indicating full vacuum not even being close under the current code? Still has original thickness, looks good, and is sufficiently thick for the pressure rating. BUT, the vacuum is the issue. Evaluating to origianl code is not an option.
Any thoughts??
Any thoughts??





RE: Vacuum Issues
RE: Vacuum Issues
Most likely they do not ever run much vacuum.
Thanks for the input.
RE: Vacuum Issues
My guess is that your vessel was designed for half vacuum. Prior to 1998 (or perhaps the '96 or '97 Addenda) VIII-1 UG-28(f) stated that vessels ...shall be designed for a maximum allowable external working pressure of 15 psi or 25% more than the maximum possible external pressure, whichever is smaller. I designed many vessels to half vac using an external design pressure of 9.375 (that's 1.25*7.5). Somewhere along the way to the U1 form the "half vac" got changed to "full vac."
jt
RE: Vacuum Issues
Is there no current code condition for partial vacuum?
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RE: Vacuum Issues