1.1 Scope of EN 1999-1-5(1) EN 1999-1-5 applies to the structural design of aluminium structures, stiffened and unstiffened, that have the form of a shell of revolution or of a round panel in monocoque structures.(2) EN 1999-1-5 covers additional provisions to those given in the relevant parts of EN 1999 for design of aluminium structures.NOTE Supplementary information for certain types of shells is given in EN 1993-1-6 and the relevant application parts of EN 1993 which include:- Part 3-1 for towers and masts;- Part 3-2 for chimneys;- Part 4-1 for silos;- Part 4-2 for tanks;- Part 4-3 for pipelines.(4) The provisions in EN 1999-1-5 apply to axisymmetric shells (cylinders, cones, spheres) and associated circular or annular plates, beam section rings and stringer stiffeners, where they form part of the complete structure.(5) Single shell panels (cylindrical, conical or spherical) are not explicitly covered by EN 1999-1-5. However, the provisions can be appl