tank bottom thickness statistical method

[darthsoilsguy2]

hello,
API 653 mentions testing a tank bottom by collecting a bunch of individual thickness tests as opposed to the floor scanner... yet it doesn't go into much detail. it's on the test a bit too but i was unable to find it.. am i missing something? maybe it use to exist but was removed by committee?

 

[JN316]

An example of this will be a proprietary program called extreme value analysis wherein set of UT's are plugged into the program. The program then analyzes the set of data and spits out probability(ies) of having very thin to hole-through floor plates.

Since cost of scanning is nowadays insignificant, you will be better off with scanning with UT verification on suspected spots.