Complaint
The main steel body of S&F Double-wall tank (with the full name of "steel and FRP double-wall tank") is called "inner shell", and the FRP protecting layer is"outer shell".
When S&F Double-wall tank is buried underground, inner shell mainly endures the pressure from earth and stone. Although outer pressure acts on outer shell directly, it transfers to the inner shell at the same time. Therefore,the outer shell isn't the main part to keep the structure strength.
