Tank thickness guidelines?

[ProjectEng]

I have a 30' diameter carbon steel tank, approx 37' high. Acidic water has been stored in this tank in the past so there is substantial pitting. The tank has a fixed roof and is always at atmospheric pressure. I have UT'd the tank in several spots.

I would like to know how much water I can safely hold in this tank if the wall thickness has decreased to 1/8". If you can point me to some websites that discuss this, that would be appreciated as well. I would prefer to see a quantitative method of determining how much water this tank can hold safely.

Thanks,

ProjectEng

 

[bimr]

You need to get a copy of the API Standard 650 Welded Steel Tanks for Oil Storage. The calculation for tank wall thickness is in that standard. There is also a AWWA D1000 that has similiar info.

This lecture discusses the aspects:

http://www.kuleuven.ac.be/bwk/materials/Education/master/wg15c/l0100.htm

There is a thread that is discussing steel tanks:

http://www.eng-tips.com/viewthread.cfm?spid=135&newpid=135&sqid=10762&tmac=logc

If you are not familiar with this, you might want to call someone like Fisher Tank. They build and repair steel tanks and can probably provide you with this information for free. They will be able to provide you knowledgeable and experiened advice.

Most of the tanks that I have seen of this size have had 1/4" thick lower rings and 3/16" rings toward the top.

A while ago, I had to repair a tank like this. The contractor came in and welded support brackets to the tank walls. Then, the contractor cut off the bottom ring and replaced it.

If you can't find this info, let me know and I can get it for you.