Atmospheric tank design code

[FFEA]

Is it possible to design a leg-supported atmospheric storage tank as per ASME VIII Div. 1? I was thinking in API 650 but it states "This Standard applies only to tanks whose entire bottom is uniformly supported..." which is not my case. Which other International Standard could I use?

Thanks!

 

[JStephen]

It depends on the circumstances.
Quite often, small leg-supported tanks or silos just aren't built to any standard. Or they may be built to API-650 or other standards "to the extent applicable".
An atmospheric tank is exempt from ASME Section VIII, but could be built to the code if desired. If the fabricator routinely builds pressure vessels, and if the tank is vessel-shaped (IE, F&D heads), this would probably be pretty reasonable.
I believe UL-142 and possibly API-620 allow tanks to be leg-supported, but don't give any guidance on the design, and include additional testing, etc., that may not be desired.
There is an AWWA D100 standard for water tanks that includes leg-supported tanks. Typically used for large municipal water towers. It gives some requirements for the design, but doesn't include a cookbook-type design, either.

 

[gr2vessels]

API 620 is a design code for legs supported atmospheric tanks. So is the ASME VIII-1 for pressure vessels supported on legs. Obviously, the pressure vessel design will end far more expensive than an API 620 tank.
Cheers,
gr2vessels

 

[MJCronin]

What is the diameter, shell height, and maximum operating pressure ?

MJCronin
Sr. Process Engineer

 

[Swlamech]

I've seen multiple cone bottomed leg supported tanks design and built using API-650 for the liquid level/Wall thickness of the cylindrical portion, API-620 for the cone bottom (if less apex angle greater than 60º), and ASME/COMPRESS for the leg calculations.

COMPRESS will allow the input of such a vessel/tank and do the leg calculations for it then the rest is piece-mealed using portions of the codes that provide guidance.

Often I will complete an FEA to verify the design.

 

[robyengIT]

AWWA D100 should be read in connection with AWWA Manual M42