The Junction Loss Models panel, shown in Figure 1, allows user to select one of three available loss models for use primarily in the Fittings & Losses tab of the Pipe Properties window:

• 1-K (Traditional) Only

• Include 3-K (Darby)

• Include Equivalent Lengths

Enabling 3-K or Equivalent Length losses will add additional options to the Bend Junction, Valve Junction, and the Fittings & Losses tab in the Pipe Properties windows.

The 3-K and equivalent length options can be useful to better represent losses when laminar flow occurs, or when it is required to generate an NFPA report for the model.