Pennsylvania Statutes Title 53 P.S. Municipal and Quasi-Municipal Corporations § 4636. Horizontal vent pipes

Where rows of fixtures are placed in a line, ninety (90) degree fittings will be allowed.  Trapped vent pipes are strictly prohibited.  No vent pipe from house side of any trap shall connect with ventilation pipe, or with sewer, soil, or waste-pipe.  Vent pipes from several traps may be connected together, or may be carried into main vent line above the highest fixture.  Where one vertical vent line connects with another, an inverted “Y” fitting must be used.  Branch vent pipes must be connected as near to crown of trap as possible.

Where future connections are left in the roughing of soil and waste lines, vent connections must also be provided.