To edit the pipe sizing table schedule project list, go to
Ribbon: DMP: Customization->Project Customization-> 
Pipe Sizing Table Schedule Label Group
Pulldown Menu: DM Plumbing->Customization->Schedule Labels->Project Lists->Edit Pipe Sizing Table Schedule Project List
To edit the pipe sizing table schedule standards list, go to
Ribbon: DMP: Customization->Standards Customization-> 
Pipe Sizing Table Schedule Label Group
Pulldown Menu: DM Plumbing->Customization->Schedule Labels->Standards Lists->Edit Pipe Sizing Table Schedule Standards List
Select Pipe Sizing Table Dialog Box
Select the pipe sizing table to edit and press the OK button. The Table Label Display and Order dialog box for the selected group will appear.
Table Label Display and Order Dialog Box
See the Common Schedule Dialog Box Information section for more information about using the Move Up and Move Down buttons and the Key, Label, Width, Display, and Schedule Title fields.
Pipe Size: The pipe size specified in the Pipe Sizing Tables dialog box.
Horizontal Flow: The horizontal flow specified in the Pipe Sizing Tables dialog box.
Vertical Flow: The vertical flow specified in the Pipe Sizing Tables dialog box.