Abstract: A freight container for transporting a pressurized fluid at a design pressure P, including a tank and mounted within an ISO frame. The tank includes a vessel formed of a material having an ultimate tensile strength S.sub.U. The vessel has a cylindrical shell having an inside radius R.sub.I and a thickness T.sub.s which is less than that of prior art freight containers and substantially equal to: (P*R.sub.I)/(1/3S.sub.u -0.5 P). Such a vessel conforms to ASME Boiler and Pressure Vessel Code, Section VIII, Division 2. The freight container may be mounted on a transport vehicle, before or after being filled with the pressurized fluid, and transported to a remote location.