We are talking about an atmospheric tank which cannot be tested with water as it is already in service. The proposal is an hydrostatic test using Bunker fuel to be able to verify that there are no leaks and obtain the operating permit. 3 years ago the bottom and the first course were replaced. On that occasion we , X-rayed and vacuum tested the bottom. In visual inspection the tank does not have leaks, does the standard allow not to do more tightness tests, how do you proceed? Can you conduct a tightness test with the product?

ANSWER

An Hydrostatic test with the product is tempting, but it is a very naive mistake.

I recommend doing the test with water for reasons that you may already know.

1. Water weighs more

2. If there is a leak, you won´t fall into an expensive repair procedure.

3. You don´t test a tank completely with your product. You risk problems when selling the tank or changing service.

Those are three reasons out of many why testing with water is best. The hydrostatic test is the main test of a tank, any tank. Needless to say, you should never do a tank test using gas or air, it is dangerous.

I understand you are going to do a change of service. I understand that they did not hydrostatic test 3 years ago, and they put it into service and now they want to increase the severity of the service to fill the tank with bunker.

You can use it for bunker, but …… UP TO WHAT LEVEL ??

If you conduct a proper test, the change of service can be done without hesitation.

As for the standard, it is mandatory to do the hydrostatic test. 3 years ago the test should have been done. The standard requires it for major repairs.

It is required more so now that there is a change of service towards one of greater severity and that the equipment is in a condition of uncertainty compared to 3 years ago. This also eliminates the risk that insurers will not pay you in case of spills.

CAN IT BE DONE?

An experienced inspector who knows the history of the equipment can take the risk of making the change of service to a low, maximum level, but the standard is very clear in the obligatory nature of the test .

Even if the person is an ace, even then you have to review the legal requirements so that in case of failure you don´t to pay with everything you have.

What if you had to sell the asset? The buyer could not receive it.

I recommend you do the hydrostatic test of the tank with water.

ABOUT “THIGHTNESS TEST”

Saying “tightness test” is an understatement. It does not express what the test does. The test checks …

1) leaks

2) overall strength

3) settlement

4) brittle fracture testing

more or less in that order of importance. So if you don’t do the test now, you wouldn’t be securing point number 2.