Method Statement for New Underground Steel Storage Tank Fabrication & Erection

Put a big concrete slab under it, and strap the tank down. This will keep it from "floating" to the surface in the event of seismic soil fluidization. Other folks will no doubt provide further suggestions.

whether the tank is mounted /buried.?

Whats the design pressure.?

what is the shape of tank?

what is the medium carried by tank.?

If its atmospheric pressure , medium is flammable liquid and combustible liquids and cylinderical shell

then follow UL-58 rules

it gives rules for construction of shell,head,piping,connections,manways,bracing,marking

this code do not cover corrosion protection which may be required by Local,state authorities.

Corrosion protection systems are covered by UL-1746.

If the welded steel tanks are for oil storage then

follow API 650.

Both answers above are excellent, but as someone who's dealt with environmental remediation I say the best answer (if it will contain anything that could possibly become a pollutant) is:

1. Build it aboveground.
2. Leave it aboveground!

Due to some factor and criterias, when it has been decided that its underground, it means it is.

next is how to design it then how to fabricate and then installation comes.