This chapter shows that the flange materials are homogeneous and explains stable mechanical properties in the elastic regime. One of the more challenging areas of design technology is the design of pipe flanges and stiffener configurations which are difficult, if at all possible, to describe by a single formula or theory. The chapter also shows that by accepting only a moderate error, the design formulas derived for the straight flanges can be applied to tapered hub configurations by assuming average thickness of the hub. The orientation of forces and moments appears to be such that the highest stresses are more likely to be in the pipe rather than the flanges in a compact configuration. Reinforcement of cylindrical vessels and large piping often calls for design of circumferential stiffeners fastened firmly to the shell. Design of cover plates with radial stiffeners represents a special case of joint technology, if the stiffeners are welded to the base plate.