It is a fundamental principle that all piping systems require support and some degree of flexibility. Today’s pipe stress engineer must go beyond checking for just allowable pipe stresses but must also check for load limitations on the equipment and/or support structure. In this regard, it is helpful to look at several alternative solutions for the same application and compare the different end loading results. four alternative solutions can include rigid pipe loops, traditional unrestrained rubber expansion joints, as well as two other more advanced rubber expansion joint arrangements. An example application of a 36” diameter carbon steel pipe with a 100’ axial run under 90 psi with temperature fluctuation of 100°F will be used. Each solution will restrain the pressure thrust forces, absorb the axial thermal movement of 0.8” and keep the piping system within allowable stresses. However, each solution will have very different end loads.
18-07: Managing Pipe Stresses and End Loads Utilizing Rubber Expansion Joints
Lloyd B. Aanonsen, P.E., General Rubber Corp.