Structural flanges are flanges which are used to splice sections of stack together, rather than using a weld. They are bolted flange assemblies similar to those used in a pipe; however, these flanges are not designed to contain pressure (that is a much more complicated design as outlined by pressure vessel codes such as ASME Sec. VIII, Div. 1, Appendix 2), but these flanges are only intended to resist structural loadings. The design of these flanges is based upon the criteria found in "Mechanical Engineering Design" by Shigley.