Underground Storage Tank (Containing Gas)

[Ezequiel1982]

Hello To All,

Can anyone tell me if exits a code/standard to design and calculate an underground storage tank besides EPA´s rules?. For expample, to calculate the thichness..

As far as I know, UST is not covered by ASME and API.

Best regards!

 

[jdarco]

Look at UL, I know they have standards for underground gas tanks, both in metals and fiberglass. I just can't remember the numbers off the top of my head.

 

[MJCronin]

Standards UL58, 1746 and 1316 all address underground tanks.

http://www.petrolplaza.com/technology/articles/MiZlbiYxMDI0NSYmMSYxJjQ1Jg==

What do you mean by your word "calculate" ?????

 

[lganga]

Friend
It is calculated as a PV ASME-CODAP-MERKBLATTEN etc.
The problem here is to design the conditions to avoid any explosion
I suppose it is undergroudn because of risk of explosion
may be is anothe problem.
The other are the corrosion proteciotn
Luis

 

[Ezequiel1982]

Thanks a lot for the answers.
Luis, I´ve been cheking and reading the ASME & API code (ASME VIII, API650, etc) and I couldn´t find anything about the UST. There are for aboveground, but not for underground as far as I know. However, could you tell me which chapter/section of ASME/CODAP/MERKBLATTEN should I read?

I´m looking for a code like API653 (aboveground storage tank) but for undergound storage tank.

Regards,

Ezequiel

 

[chicopee]

By "gas" are you referring to gasoline?

 

[Ezequiel1982]

Hello,

No. It´s LPG (Liquefied petroleum gas ).

ASME VIII Div. 1 for external pressure is not correct (as far as I know) to design an underground storage tank.

Best regards,

Ezequiel P. Fresquet

 

[lganga]

EZEQUIEL 1982

Is the vessel going to be installed underground? but not on soil. It has to be inspected so the installation is underground and the vessel mounted over a concrete reinforced basin with a top cover and its inspection manhole.So it is a Pressure vessel that can be calculated by ASME orr others. Why do you need to calculate for external pressure?
Please visit the web and you will find cases of LPG PV used in underground service.
Attached here in an example. Maybe you also need a anodic protection.
Regards

 

[MJCronin]

Ezequiel....

In the USA, it is more common to store LPG in an aboveground horizontal pressure vessel. The vessel is most commonly designed to ASME VIII

Keeping a horizontal vessel aboveground ensures that periodic inspections can be done easily, and that pressure relief devices, excess flow check valves....etc are accessable.

I believe that placing the vessel underground for safety is not viewed as the best idea because of the difficulties in inspection.

The US LPG marketplace seems to have adjusted itself to only sell aboveground tanks and vessels.

http://www.storagetankspropane.com/

Good information in NFP-58......

Please respect us......complete this thread and let us know about your final plans...

 

[Ezequiel1982]

Hello,

Thanks a lot for your answers.

The tank is a pressure vessel (horizontal). What I want to calculate is the critical load caused by the soil above (generates a external pressure) the tank when it´s empty which is the worst condition. To calculate this, I´m using FEM theorys.

ASME VIII div1 and div2 gives a way to calculate the critical load under external pressure. The code use 1atm as the external pressure which is quite different from the effects of the soil above it.

When I compare the critical load using finit element theory and the critical load using ASME there is a significant diference.

Regards,

Ezequiel

PS: Luis, thanks for your example.

 

[chicopee]

A little late as I was out of town. I have designed many concrete pads of UST's storing propane. All installations that I have done, the tanks were at buried at most 2' below grade depending on the height of the domes. As long as the tanks are rated to be buried by their manufacturers, there is no need for you to perform further calculations. Of course, logic should prevail that is no traffic over the buried tanks, no earth spoils stored over the tanks,etc...

 

[MJCronin]

I am a little confused....

While I realize that things are commonly done "because that what the customer/regulator wanted" I truly do not understand what is gained by placing propane tanks beneath an earth cover.

Burial certainly must promote external corrosion and make the tank harder to inspect.

If there were a gas leak, burial would make the tank more difficult to cool and to fight the fire.

It would not significantly mitigate the effects of an explosion.

Aside from somehow making people feel better, why do you want to do this ?

 

[Ezequiel1982]

well, in this part of the world many Oil & Gas companies have decided bury the LPG(liquified petroleum gas) tanks (pressure vessel, just for know the internal pressure is 17.5 Km/cm^2)

My question was to know if ASME has a code or standard regarding the evualuation and acceptance criteria to verify the integrity (structural) of the tank when it is empty, considering the weight of the soil above it as external pressure.

I don´t think that using the ASME VIII Div 1 to calculate critical load or the buckling coeficient under external pressure is the best choice.

If you compare the results of the ASME VIII Div. 1 wit the results using the finit element theory, they are quite different.

So, If you have to design a tank (pressure vessel) under external pressure, How would you do it?. Which code would you use?

I´m sorry if my English is not so good.