1.1 Scope of EN 1993-4-2(1) EN 1993-4-2 provides rules for structural design of vertical cylindrical, conical and pedestal above-ground steel tanks for the storage of liquid and liquified gas products.(2) EN 1993-4-2 is applicable to the design for resistance of cylindrical walls and flat bottoms constructed using unstiffened plates. The design of conical and dome roofs as shell structures (unsupported) or as supported on a structural framework (supported) are also covered.(3) EN 1993-4-2 is only applicable to the requirements for resistance and structural stability of steel tanks.(4) EN 1993-4-2 only covers steel tank structures in Tank Groups 1, 2 and 3, as defined in this document.NOTE Tank Group 4 is not defined in this standard (see 3.1.41).(5) This document is applicable to tanks within the following dimensional limits (see EN 1991-4):Tank aspect ratio hS/d