0 votes

API 653 stress value for tank minimum thickness

asked May 8, 2016 in Calculation by michelnr (590 points)
In accordance with API-653, Section, the stress value to be used to calculate the tank minimum thickness is given as 21,000 psi.

The question is should we change the stress value if material type and grade are known?

3 Answers

+1 vote
answered May 9, 2016 by Tadd Pham (5,620 points)
I believe you did not provide a complete question, but I will comment based on your current question the way you posed.

First of all, if you are given or required to used a stress value of 21,000 psi, you can tabulate based on P&T to arrive at the material you need.

However, when you are given the material type and grade by project's requirements and based on the design P&T, you should have the required stress value if tabulated correctly.

So the answer is yes, the stress value should change accordingly!
+1 vote
answered May 10, 2016 by Normandy (21,040 points)
API-653 is is the standard for Oil & Water Storage field erected tank built to API-650, typical storage tank.

Tanks of this standard is typically designed and used low grade Carbon Steel, low tensile strength such as SA-515. Yield Strength is between 30-38 ksi depending on grade.

If you provide more information like the material type and grade, that can help to answer your question a bit further.
0 votes
answered May 11, 2016 by sabdullayev (5,290 points)
I agree with the posts above that more information is needed. It seems that you are dealing with a repaired tank so I guess that is why you mentioned API-653.