The installation of non-metallic piping systems to handle process fluids, utilities and waste streams is an every day occurrence in the chemical processing industry. Many of these installations replace existing metallic piping systems that have failed due to internal or external corrosion. The design of these non-metallic systems generally parallels the process used in metallic pipe design but with an increased factor of ignorance (safety factor). And, unfortunately, most of the design criteria specified for such systems is based on a “metal mind set”, especially on retrofit or replacement type piping systems. There are various software packages that address stress analysis of piping systems based on physical properties and geometry input by the user. These packages do not calculate the local stresses at supports other than the general affects of longitudinal beam bending. This paper will review “effective length” design methods for the determination of local pipe stresses caused by
externally applied support loads. Results will be compared with those predicted by one of the available finite element software packages.