Double Bottom for Existing Tanks

Question

Double Bottom for Existing Tanks

Inchtain (Petroleum)

(OP)

22 Apr 21 10:57

Assalam Alykom,

Is there a certain requirement in API where it specifies the use of double steel bottoms for the existing Above Ground Crude Storage Tanks?

Maybe, because it is easier, in terms of construction, for Tanks in existence to adopt this option.

Is there a support for my assumption?

Thanks

LittleInch (Petroleum) · Answer 1 · 2021-04-22 11:55:43

API doesn't make requirements like that.

If you're repairing an existing tank, you need to make your own decisions and justify them. You can't lean on API to do that for you I'm afraid.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

HTURKAK (Structural) · Answer 2 · 2021-04-23 06:55:51

Quote (Inchtain
Is there a certain requirement in API where it specifies the use of double steel bottoms for the existing Above Ground Crude Storage Tanks?...)

Not sure that the thread is for replacement of bottom or leak detection system..

If it is for repair/replacement , refer to API 653 9.10 repair of bottom and 9.10.2 Replacement of Entire Tank Bottom.

If it is for leak detection,pls. look API 650 appendix I (UNDERTANK LEAK DETECTION AND SUBGRADE PROTECTION ) for applicable options.

One of them , ( excerp from the same ),

Inchtain (Petroleum) · Answer 3 · 2021-04-23 08:25:59

Hello,

Thanks for the feedback.

The thread is about providing a leak detection system for an existing tank that has a fit-for-purpose single bottom.

In this case, tank owners shall go for the double bottom (Envelope) technique, or have another alternatives?

I noticed that API 650 Appendix I mentioned new tanks under I 1.1 NOTE.

Kindest regards,

HTURKAK (Structural) · Answer 4 · 2021-04-24 07:36:21

Quote (Inchtain

...In this case, tank owners shall go for the double bottom (Envelope) technique, or have another alternatives?

I noticed that API 650 Appendix I mentioned new tanks under I 1.1 NOTE.

Kindest regards,)

I am not sure i understand your post.. If you decide to replace the Entire Tank Bottom , you may use a similar detail ( API 650 Fig. I -4) , with concrete spacer and grooves on top side.

As far as i understand, you have concerns and not clear about what to do..

If this is the case, I will strongly advise you to get services of an engineering group having experience on tank maintenance, repair ,...They may conduct some inspections and tests and prepare a final report showing the viable repair options..

P.S. I know corrosivity of sand at your region.. You may ask to the old engineers ( collapse of PCCP pipes with dia. 4.0 m at great man made river project without C.P.)..

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