Considerations for selecting and using rubber expansion joints

Because process designers, installers and end-users all have differing perspectives with regard to a process, each group has different concerns when it comes to selecting expansion joints. Learning about the different concerns can position all stakeholders for better decisions and better outcomes.

Expansion joints in chemical process plants are critical components and are used with process equipment for providing stress relief due to pipe growth. For lower temperature systems, these expansion joints are categorized into three groups based on materials of construction - synthetic elastomer, polytetrafluoroethylene (PTFE)-lined rubber or convoluted PTFE expansion joints — these expansion joints are used to dissipate movement between equipment and piping segments, as well preventing leaks from areas where pipes and equipment are connected (Figure 1). Often, rubber or PTFE-lined rubber expansion joints are found off the suction and discharge ends of pumps where temperature dictates. Rubber expansion joints are also used on heat exchangers, tanks and cooling towers. Convoluted PTFE expansion joints can be found off tanks and low-pressure pumping systems.