It is also possible to consider arising hydraulic resistances at branches in the hydraulic calculation.

The determination of the additional coefficients of drag is based on calculation equations descriptive by B. Glück in the book "heating water systems for residential and industrial zones" and [1]. The procedure implemented in sisHYD is described in the following.

First 6 kinds of branches are differentiated:

1. Branch with an inlet and drainpipe:
   • If there is an angle between 45° and 125° or between 225° and 315° between the in and out pipe, then an additional coefficient of drag for both pipes of 1.2 results.
2. Branch with two inlets and one drainpipe (combination):
   • Case A (T-fitting in the passage):
     
3. Branch with one inlet and two drainpipes (separation):
   • Case A (T-fitting in the passage):
     
4. Branch with two inlet and two drainpipes (combination and separation):
   
5. Branch with one inlet and three drainpipes (separation):
   
6. Branch with three inlet and one drainpipe (combination):