1- Vent systems are installed to eliminate trap siphonage, reduce back pressure and vacuum surges, promote rapid and silent flow of wastes, and ventilate the sewer.
2- Sizing the system: The sizing of vent system piping is based on fixture unit values and length of the piping, then refer to pipe sizing table in Uniform Plumbing Code (UPC) or State Plumbing Code book. See below:
3- Vent system types:
3- Vent stacks: