53 Pa. Stat. § 14820
Safe waste-pipes must not connect directly with any part of the plumbing-system. Safe waste-pipes must discharge over an open, water supplied, publicly placed, ordinarily used sink, placed not more than three and one-half feet above the cellar floor. The safe waste from a refrigerator must be trapped at the bottom of the line only, and must not discharge upon the ground floor, but over an ordinary portable pan, or some properly trapped, water supplied sink, as above. In no case shall the refrigerator waste-pipe discharge over a sink located in a room used for living purposes.
The branches on vertical lines must be made by "Y" fittings, and be carried to the safe with as much pitch as possible. Where there is an offset on a refrigerator waste-pipe in cellar, there must be clean-outs to control the horizontal part of the pipe.
In tenement- and lodging-houses the refrigerator waste-pipes must extend above the roof, and not be larger than one and one-half inches, nor the branches less than one and one-quarter inches. Refrigerator waste-pipes, except in tenement-houses, and all safe waste-pipes, must have brass flap-valves at their lower ends. Lead safes must be graded, and neatly turned over beveled strips at their edges.
53 P.S. § 14820