Reference Materials

Double-wye fittings videos

  1. Video 1 - At first glance, this video appears to show back-graded pipe. However, as seen, the water does eventually clear indicating that it is sloped correctly and that the backflow/pooling appears to be a result of the geometry of the double-wye

  2. Video 2 - Note that in this video, as the flow goes through the double-wye that some water goes into the branch lines and the hydraulic depth is reduced. We believe that the impact of this is more significant when the hydraulic depth is deeper such as flow behind a solid.

  3. Video 3 - You can see some toilet paper come down a branch line hit the edge on the opposing side of the pipe creating a blockage.