Abstract: This invention corresponds to a freestanding tank assembly with structural framing (1) that contains: One self-supporting cylindrical tank (2) of vertical storage of fluids, whose relation face Height/Diameter (H/D) is between 2.5 and 3.5, and has a volumetric capacity between 68.14 m3 (18000 liquid gals) and 75.71 m3 (20000 liquid gals). One structural framing (3) formed by a longitudinal portion (3a) and one base portion (3b), assembled together forming “L”, being such longitudinal portion (3a) joined to self-supporting cylindrical tank (2) through solid mounts (3c), being such base portion (3b) joined to flat base (2c) of self-supporting cylindrical tank (2) in such way that such base portion (3b) of quadrilateral main surface surrounding the flat base (2c) circular of self-supporting cylindrical tank (2).