Design and Analysis of Expansion Joint Liners

Abstract

The expansion joints (EJ) are included in the piping systems to provide flexibility to accommodate displacements due to thermal expansion and other causes. Some EJs have internal liner to streamline flows and to also protect the EJ bellows convolutions from degradation. The EJ liners are not a pressure boundary components and therefore not subject to strict code requirements and analyses but are designed using the guidelines in the Expansion Joint Manufacturers Association (EJMA) standard. In some cases if the EJ liners are not properly sized and may be subject to reverse flow condition, the consequences can be very significant in terms of unexpected flow blockage due to failure of EJ liner in a piping system. This paper describes the guidelines for designing the EJ liners, their failure modes and the analysis methodologies used to assess acceptability of the EJ liner designs.