U-1 from 1954
U-1 from 1954
(OP)
I have a U-1 form from a vessel constructed in 1954 from A212-B. The form is generally consistent with current U-1 forms, but there is section 17 parts f and g of the form which list hydrostatic stress in longitudinal joints and an "Allowable operating stress" based on this hydrostatic stress (2/3 of hydrostatic stress in longitudinal joints). Here is an image:

This "Allowable operating stress" is less than the allowable stress listed in 1952/54a for A212-B. 17,500 in the code vs. 13,760 on the U-1.
My questions:
What is the basis of the 13,760 psi listed and how is this used for design of the vessel at time of construction? For my rerate am I permitted to use 17,500 and ignore the 13,760 listed?

This "Allowable operating stress" is less than the allowable stress listed in 1952/54a for A212-B. 17,500 in the code vs. 13,760 on the U-1.
My questions:
What is the basis of the 13,760 psi listed and how is this used for design of the vessel at time of construction? For my rerate am I permitted to use 17,500 and ignore the 13,760 listed?





RE: U-1 from 1954
And I-213 states:
It appears to be a requirement that the vessel is subject to a hydrostatic test that will stress the limiting component to at least 1.5 times the allowable stress. I imagine that as long as you perform calculations and ensure that the test pressure is at least equal to 1.5 times the limiting component's MAWP, it would be acceptable for the rerate. This would all need to be confirmed with the jurisdiction and/or the AI however.
RE: U-1 from 1954
pdiculous963,
Thank you for the quick reply and code sections. I tracked down API-ASME 1951 today to educate myself. You are correct and this does explain. I appreciate your time and suggestion.