Parabolas can be the only conic sections that are considered functions because they pass the vertical line test. We have worked with parabolas before in quadratic equations, but parabolas formed by conic sections are a little different.
Toilet drainage rough-in steps. 1  Cut a hole in the subfloor just large enough for the bottom part of the toilet flange to sit. 2  If your installing the drainage underground, excavate the trench and have a supply of clean backfill ready (sand or gravel) to grade and cover the pipe.
The purpose of vents is to allow air to enter the plumbing drainage waste and vent system and equalize pressure when water drains out of the system maintaining the integrity of the water trap that prevents sewer gases from entering the building through fixture drains.