Static load:-A piping system may respond far differently to a dynamic load than it would to a Static load of the same magnitude. Static loads are those which are applied slowly enough that the system has time to react and internally distribute the loads, thus remaining in equilibrium. In equilibrium, all forces and moments are resolved (i.e., the sum of the forces and moments are zero), and the pipe does not move.
Dynamic load:-With a dynamic load a load which changes quickly with time the piping
system may not have time to internally distribute the loads, so forces and
moments are not always resolved—resulting in unbalanced loads, and therefore
pipe movement. Since the sum of forces and moments are not necessarily equal to
zero, the internally induced loads can be different either higher or lower than
the applied loads.
Example
1. Random – Wind, Earthquake
2. Harmonic – Equipment Vibration, Pulsation, Acoustic Vibration
Impulse – Fluid Hammer, relief valve opening, slug flow