Specifies the node number for the equipment where the restraint is freed. You can also specify the corresponding free code to tell CAESAR II which of the restraint or anchor directions to free. For nozzles that are further removed from the hanger usually only the Y direction should be freed. Anchors or restraints simulating equipment connections that are in the immediate vicinity of the hanger are usually freed during the hanger design restrained weight run so that loads normally going to the equipment nozzle are carried by the hanger.
Hangers are commonly used around equipment nozzles to support the weight of the pipe as it thermally expands away from the nozzle. The hanger can usually be designed to take almost the full weight of the pipe between the anchor and the hanger if the anchor is freed when making the restrained weight calculation. The pipe going to the anchor is treated just like a free end, but only for the hanger weight calculation only.
The Free Restraint at Node box works in conjunction with the Free Code box. If the Free Code is not specified for an anchor, then the software assumes that the anchor is completely free for the restrained weight run.
The restrained Weight hanger design pass is the first analysis step in the hanger design. It is run automatically by CAESAR II. The following steps comprise the restrained weight run:
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Putting rigid Y restraints at each hanger location.
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Removing anchors and restraints that are to be freed.
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Running the weight analysis to find the hot hanger loads.
Nonlinear restraints are not freed during hanger design.