Please advise me on which Code is applicable to the case where a client wants a 200 cubic meter above ground tank which has a "cone down" base. However, the base is suspended above the ground level. The skirt reaches down to the foundation and the cone would then be welded inside the tank so that it allows a space underneath where a sump is located. The sump has a drain take off but also (I guess) a pump or some other equipment located there. The client wants to transport the tank from one location to another in time so it should not be permanently fixed to the civils.
API-650 provides only for bottoms fully supported by the foundation. I though API-620 is the applicable code in this case but someone else told me it is also not applicable without giving a reason.

I am using Etank to design this tank so any pointers how to approach this problem in Etank2000 is appreciated.

Thanks
Michael