Two standard area change loss geometries are available: the conical transition and the abrupt transition.

The conical expansion correlation (Crane, 1988Crane Co., Flow of Fluids Through Valves, Fittings, and Pipe, Technical Paper No. 410, Crane Co., Joliet, IL, 1988., A26) is

The conical contraction correlation (Crane, 1988Crane Co., Flow of Fluids Through Valves, Fittings, and Pipe, Technical Paper No. 410, Crane Co., Joliet, IL, 1988., A26) is

The abrupt expansion correlation (Idelchik, 2007 Idelchik, I. E., Handbook of Hydraulic Resistance, 4th edition, CRC Press, Boca Raton, FL, 2007. , 246) is

The abrupt contraction correlation (Idelchik, 2007 Idelchik, I. E., Handbook of Hydraulic Resistance, 4th edition, CRC Press, Boca Raton, FL, 2007. , 254) is

Note: While a 180 degree conical transition is the same as an abrupt transition, Crane's conical contraction equation gives a different result at 180 degrees compared to Idelchik's abrupt contraction equation. Therefore, it is up to the user to determine which one to use.

All K factor equations are provided here in terms of the upstream pipe. The K factor in terms of the downstream pipe can be found as follows: