Answer:
According to the help information, distributed loads in AutoPIPE are force-based inputs applied over a range of the model. These are used to represent loads such as contents in the pipe, weight of pipe insulation, wind load, snow, ice, or other uniform forces acting on the pipe, and are applied as static forces in a specified load case (e.g., Gravity).
A key point to remember, distributed loads are not considered as mass during dynamic analysis. They are only considered as static forces in the static analysis cases. The documentation for the DIST (Distributed Load) command explicitly states that distributed loads cannot be defined in dynamic load cases (such as R1, F1, H1, etc.), and are only valid for static load cases like GR, T1-T100, E1-E30, W1-W10, P1-P100, and U1-U140 [3].
In summary, distributed loads refer to any load that is distributed across a series of piping node points. It is important to capture all the loading acting on a system to recognizing possible problems and enhancing the design for safety and efficiency under various loading scenarios.