Sooner or later you have to do it. Better an easier in shop.

Note: You're referring to atmospheric hydrostatic testing?

Better for it to be late and right than for it to be on time and wrong.

API .... American Petroleum Institute ?

That's an economic decision, do you have experience that there's a high probability of success of the hydrostatic test (ie shop has a good workmanship track record) ?

If not, I would not recommend field testing. You lose less time if you test in the lab (induce the failure earlier) and have to repair or remake the tank if it fails.

Also the contractual requirements may prevent a field test or repairs, check with your contracts people before you decide.

Many tanks and vessels are tested at site after erection. But it is always advisable to do it at manufacturer's premises. After hydro test it may require clean-up and drying, it is much easier to carryout at shop, perticularly for the vertical vessels which is more difficult after erection.

• Yes. To ascetain leak tightness before transporting to site, you may carry out pneumatic test of weld joints by Vacum- Box Test Method. Hydro test at site will result satisfactory. Hoewever, this should be acceptable to client.
• It is perferred to hydrotest tanks at site, after erection, to have in-situ conditions of Tank Floor, Anchoring etc.

N N Shah, Baroda

Check API 650 and API 653. There's an exemption from hydrotesting that requires engineering analysis and extra NDE. There's certain criteria that you have to meet and I don't remember what that is (I could be getting it confused with repairs on tanks too).

OK, so it doesn't get Client-witness-tested and insurance-tested at the factory. Then it arrives at site, it is erected and the first time it gets tested it leaks or gets damaged. Who is liable? The tank supplier? The transport company? The erection company? Where is the factory test report? Oh, dear, there isn't one. Whose money and time is going to be used to put it right, then, in a location where access is difficult and the workshop is somewhere else?

It's a recipe for arguments, more delays and financial penalties. These things can damage companies' reputations at one end all the way through to putting companies out of business at the other. And the end Client won't be happy, promise.

GET IT TESTED AT THE WORKSHOP, AND GET THE TEST WITNESSED AND DOCUMENTED. IF IT'S LATE, IT'S LATE.

Thanks for your suggestions. We are going for test at site

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