There is no "wall thickness to withstand 100 psi" that is independent of the size of the tank. Stop thinking that that is a real thing. The thickness of the wall needed to withstand 100 psi increases as you make the tank bigger.

Here's a simple online calculator for wall thickness of pressure vessels. Change the radius of the vessel and watch the wall thickness go up in proportion.

https://www.engineersedge.com/calculators/shell_internal_pre...