The PipeNominalDiameters sheet in the Piping Specification.xls workbook defines what nominal pipe diameters (NPD) are valid for the different piping materials classes. These NPDs appear on the New Pipe Run dialog box in the Nominal Diameter box.
It is your responsibility to make certain that each piping commodity within the piping materials class, each size combination in the Branch Intersection rule, and each tap size in the Permissible Taps rule is consistent with the list of permissible nominal piping diameters defined here. The specific permissible values represented by a size range for a specific piping commodity will be limited to the values specified by the rule that fall within that range.
Spec Name (Required)
Type the name of the piping materials class for which you are defining valid nominal pipe diameters. The piping materials class that you enter must be defined on the Piping Materials Classes.
Type the nominal pipe diameter that you want available for the piping materials class.
NPD Unit Type (Required)
Specify the units for the nominal pipe diameter value that you entered in the NPD column. For example, type mm or in.