A hinged expansion joint is a metallic assembly, that can rotate in a single plane, used to absorb changes resulting from piping thermal expansion or contraction.^[1]

They include hinges, attached to the expansion joint ends with a pair of pins, which allow angular movement in a single plane, restrain the pressure thrust, and prevent the expansion joint from deflecting axially, either in extension or compression.^[2] It is recommended that the hinges should be used in sets of two or three.^[3] The expansion joint hinges provide for angular movement and will resist pressure thrust forces.^[4]

Individual hinged expansion joints used in piping systems are restricted to pure angular rotation by its hinges. As a pair, hinged expansion joints will function together to absorb lateral deflection. Advantages of hinged expansion joints are that they are typically compact in size and structurally rigid.^[5]