Problem:

What is the hot load on a spring hanger in AutoPIPE?

Solution:

Please see the following AutoPIPE help section:

Help > Contents> Contents Tab> Reference Information> Hanger Selection Procedure> Hot Load Design Hanger Selection Procedure

This information will explain how AutoPIPE chooses a spring from the specified manufacture or why AutoPIPE changes the variable spring support to a Constant Spring or Rigid support.

As mentioned in the procedure the Hot Load in this case would be calculated by:

A rigid restraint (V-stop) replaces the hanger for the gravity (GR) load case. The calculated support reaction is the hot load to be carried by the hanger.

Then the maximum displacement is calculated from thermal movement. Knowing the displacement and Hot load  refer to the Spring hanger manufacture literature to interpolate the theoretical cold load on the spring. Enter the Cold load and spring rate into AutoPIPE's Undesigned spring hanger, and run analysis. 

Example:

GrT1P1 = analyzed Cold load on the spring hanger

GrT2P2 = analyzed Hot load on the spring hanger

Conclusion

From the spring hanger report we see the analyzed Hot Load and the interpolated Cold Load. The Spring Rate and interpolated Cold Load are using in AutoPIPE's analysis to calculate the actual analyzed cold operating condition (GrT1P1) and hot operating condition (GrT2P2). Notice that the hot load is lighter than the cold cold, this is because in this example, thermal case T2 caused the spring hanger location to rise up, putting less of a load on the spring hanger. 

See Also

Spring Hanger Selection

Bentley AutoPIPE