Help please, I need to build a pressure vessel for air over water / solvent. I need to be able to pressure up to 200 PSI. I would like to build this vessel with aluminum plate but do not know the ratings of the steel plate and aluminum plate. This vessel is 24 high" x 48" wide x 120" long. In other words, long and flat.

I know that air compresser tanks, round, are capable of 200 PSI using a 3 / 16" thick wall steel metal. When the structure is changed from round to square it obviously affects the need for a thicker metal. So, if steel, what thickness ? If Aluminum, what thickness ? Is there a caluclation method of steel vs aluminum that I can use. Or a rule of thumb. Or can someone just give me some anecdotal information on what would be the size of the plate needed to construct this unit.

Dave Glassel