Large storage tanks - leak testing of tank bottoms
Large storage tanks - leak testing of tank bottoms
(OP)
Not sure if i'm in the right forum here (it's not a pressure vessel type question) but i'll ask the question anyway. We have a number of large atmospheric storage tanks (50-80m dia) that we inspect on a 15 -20yr basis. After repairing the tank bottoms all welds are vacuum tested before coating to ensure they are free from cracks. Normally once the tank bottom has been vacuum tested, driving of vehicles/lifts is forbidden as they can cause cracking of welds as the tank plates flex. Our current contractor wants us to paint the tank bottom after vaccum testing and then afterwards drive a 2000kg lift around the tank bottom as we set the tank roof up. We are worried that this lift can now cause cracking of the welds under the coating that cannot be detected with a vacuum test. Any thoughts/ideas would be welcome.





RE: Large storage tanks - leak testing of tank bottoms
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RE: Large storage tanks - leak testing of tank bottoms
RE: Large storage tanks - leak testing of tank bottoms
Regardless of how you protect the tank bottom, I would lengthen the time of the vacuum test probably by a factor of two to allow time for the paint coating to fail over a crack.
David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
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RE: Large storage tanks - leak testing of tank bottoms