How to tell a False Hydro

[Nemrod]

Cracks in the necks of steel tanks ---never seen one. I would be very upset if somebody ruined one of my tanks for alleged cracks. I am Level II certified for NDI, what methods are you using to verify cracks in steel tanks? Just curious. N

 

[akdeepdiver]

The difference between a "crack" and a "fold" in any tank is important as one will disqualify the tank and the other is an entirely normal artifact of the manufacturing process. Not everyone knows the difference. In regard to a steel tank, a crack is exceptionally rare and a crack in a steel tank, especially an HP tank that is by definition very young in the time scale of steel tanks, would statistically raise suspicion.
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However if you find one that is suspicious just pick up the phone and call the facility. They are required by law to keep the test records and, especially if the test is recent, they should be able to access the records and verify the test was completed. If it has been a few years, the records may be filed away somewhere, but they should still be filed by month and year of the test and should not be that hard to locate. At worst someone has to spend a few minutes scanning the test sheets that month for the customer's name and then verify the serial number of the tank and the test results.

I run a hydro shop so hopefully I can clarify a couple points that DA Aquamaster pointed out. Neck folds are sometimes the result of manufacturing. They normally do not condemn a tank, but they can depending on how many threads they go through. If for example the fold only leaves three complete threads, that could compromise the integrity of the tank.

Additionally, yes shops are required to keep the records of the tanks they test. By law they need to keep the records for 5 years, or until the tank is retested and requalified again or taken out of service. Whichever comes first.