650 Tank 1

[JSPCGY]

Dear Friends,
Contractor has hydrotested a storage tank built to API 650.

It is noticed that some tank settlement has taken place at the edges and at different points in the bottom floor.

What are the acceptable limits for different types of tank settlements and please advise which code / standard provides these limits.

Please note that tank has not been put into service and contractor has not formally handed over the tank to owner.

Thanks in advance.

 

[IFRs]

650 is silent on the acceptable limits of settlement. It does say, however that if settlement measurements are specified by the Purchaser, any differential settlement greater than 13 mm per 10 m (1/2 in. per 32 ft) of circumference or a uniform settlement over 50 mm (2 in.) shall be reported to the Purchaser for evaluation. But this does not address your question. 653 covers tanks after they have been put in service. I'm interested in the responses of others here!

 

[bernoullies123]

650 is as noted by IFRs.

653-2005 Section 12.5 Measured Settlement during hydrostatic testing provides the requirements for the initial survey and the evaluation for acceptance per Appendix B.

If the settlement is beyond that specified then the contractor should provide you with a design analysis which indicates that it is safe to put the tank in operation.