Piping systems experience different types of loadings, categorized into three basic loading types — sustained, thermal and occasional loads.
Unitel Technologies uses the CAESAR program to conduct pipe stress analysis.
Sustained load: these mainly consist of internal pressure and dead-weight. Dead-weight is from the weight of pipes, fittings, components such as valves, operating fluid or test fluid, insulation, cladding, lining, etc.
Thermal load: these refer to the “cyclic” thermal expansion or contraction of piping as it goes from one thermal state to another. When the pipe is “restrained” in the directions it wants to thermally deform (such as at equipment nozzles and pipe supports), the constraint on free thermal deformation generates cyclic thermal stresses and strains throughout the system. In order to avoid “fatigue” failure due to cyclic thermal loads, the piping system should be made flexible (and not stiff).
Occasional load: this third type of loads is imposed on piping systems by occasional events such as earthquake, wind or a fluid hammer.