How to check the failure vacuum pressure of api tank

[jimhou]

would you please tell me how to calculate the failure vacuum pressure of api tank?

 

[tonycola]

The allowable vacuum pressure for an API 650 tank is 1 inch water, and it is 1 oz per square inch for API 620 tanks. If additional vacuum rating is desired, then calculation should be performed to verify that the structural integrity of the tank is sufficient for the desired vacuum.
Generally accepted good engineering practice should be used to perform this analysis.

 

[SSC2002]

tonycola

Where do you get the allowable vacuum pressure values for API 620 from? Is it by calculation or in a clause?

 

[tonycola]

See API-620, 10th ed. paragraph 5.10.5.2

 

[lmg]

Since you can use employ the Good Engineering Practices, one option would be to work under ASME VIII / Div 1, UG-28.

 

[JoeTank]

The storage tank industry (at least the field erected tank side of the industry) has not generally embraced ASME VIII as the factor of safety is a bit high for their liking. When using ASME VIII some tank designers have used the ASME UG28 procedure, but have lowered the factor of safety. In addition to the ASME VIII approach, I suggest you consider the Steel Plate Fabricators Handbook. Also, you may be interested to know that API's Subcommittee on Pressure Vessels and Tanks is developing an appendix for vacuum design of ASTs.

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com