MPC’s collapsible tank is unique because it features a patented design, optimized by finite element analysis, that includes rounded corners to redistribute shell stress uniformly throughout the tank. In other collapsible tanks, sharp corners create perpendicular stress in seams on the side walls and at the ends and corners of the tanks. The greater curvature of the MPC flexible tank corners, on the other hand, tend to create tangential stress which the corners withstand consistently. This greatly reduces the possibility of maintenance leaks and is far superior to competitive pillow tanks.