Vacuum Rating of Atmospheric Storage Tanks
Vacuum Rating of Atmospheric Storage Tanks
(OP)
I have an atmospheric storage (actually 20 in w.c.) tank with a flat bottom, 2:12 cone roof. It's not built to API 650 but looks a lot like one. I was wondering how high of vacuum rating it could take.
API 650 specifically says limit the tank to 1-inch w.c. external pressure.
FM Loss Prevention Bulletin No. 13.23 says 1 3/4-inch w.c. vacuum for roofs having at least 3/16-inch roofs.
Are there any other industry guidelines w/o perform a rigorous calculation???
API 650 specifically says limit the tank to 1-inch w.c. external pressure.
FM Loss Prevention Bulletin No. 13.23 says 1 3/4-inch w.c. vacuum for roofs having at least 3/16-inch roofs.
Are there any other industry guidelines w/o perform a rigorous calculation???





RE: Vacuum Rating of Atmospheric Storage Tanks
RE: Vacuum Rating of Atmospheric Storage Tanks
RE: Vacuum Rating of Atmospheric Storage Tanks
Code Case 2286-1 (ASME VIII Div 1 and Div 2) or
Code Case N-284-1 (ASME III Div 1)
Both of these limit the D/t ratio to 2000:1 with the nuclear case also limiting the minimum thickness to 1/4".
Caution should still be applied, especially when dealing with existing tanks since deviations from true circular form are generally the cause of vacuum type failures.