18-29-912.3 Size.

   The minimum size of a combination drain and vent pipe shall be in accordance with Table 18-29-912.3.

Table 18-29-912.3
Size of Combination Drain and Vent Pipe
(for Floor Drains Only)

Diameter Pipe (inches)	Maximum Number of Drainage Fixture Units
	Connecting to a horizontal branch or stack	Connecting to a building drain or building subdrain
2	3	4
2 1/2	6	26
3	12	31
4	20	50
5	160	250
6	360	575

 

For SI: 1 inch = 25.4 mm.