What is the function of an expansion joint in a piping system?

An expansion joint in a piping system primarily serves the function of accommodating thermal changes within the system. As fluids are heated or cooled, the materials in the piping expand or contract. Without a mechanism to allow for these movements, stress could build up in the pipes, potentially leading to mechanical failures such as cracks or ruptures. The expansion joint is designed to flex and absorb these changes in length or shape that occur due to temperature fluctuations, thus maintaining the integrity and reliability of the piping system.

While other options highlight important aspects of piping systems—such as connecting different materials, reducing vibrations, and providing support—none directly focus on the critical role of managing thermal expansion. Therefore, the primary and most relevant function of an expansion joint is to accommodate these thermal changes effectively.