Understanding API ICP653 Reading 7-Worksheet-04 Part1

4.4.7 Minimum "t" for Tank Bottom Plate
Two (2) Methods:
a. Deterministic (See 4.4.7.1) - A long, drawn out formula/data process. Not
normally used.
b. Probabilistic (See 4.4.7.2) - Normal process. Statistical analysis based on
thickness data resulting from visual, mechanical or UT survey.
4.4.7.3 If the minimum bottom "t", at the end of the in-service period of
operation, are calculated to be less than the bottom renewal thickness
given in Table 6-1 (page 6-3), the bottom shall be repaired as follows:
Lined, repaired, replaced or the interval to the next internal inspection
shortened. Unless an RBI program is in place.
Note:
Unlike “Shell” there is an additional “Lined”
Charlie Chong/ Fion Zhang