The Branch junction allows up to twenty-five connecting pipes. The Branch junction is the most flexible junction type for building network models that have flow splits. Other significant features are the ability to impose a flow source or sink at the junction and the ability to specify separate loss factors for each connecting pipe. The Branch junction must have at least two connecting pipes.

The Branch Properties Window follows the second of the two basic Properties window formats.

A table on the Loss Coefficients folder tab displays the connecting pipe information. This table grows in size to accommodate up to twenty-five connecting pipes. For each connecting pipe, the pipe table lists the reference flow direction and up to two loss factors. The first loss factor is for physical flow out of the branch and into the pipe. The second is for physical flow into the branch and out of the pipe. The loss factors can be specified independently or left as zero.

The Branch junction also offers you the option of specifying a flow source or sink at the junction in the Optional tab. According to AFT Arrow's convention, a source of flow into the system is defined as positive, while a consumption of flow with flow out of the system (a sink) is defined as negative. Along with the flow rate you must specify the fluid and temperature or enthalpy. A branch junction can be used to model a desuperheater using the enthalpy input.