Section 890.1540  Relief Vents

Stacks with More Than Ten (10) Branch Intervals.  Soil and waste stacks in buildings having more than ten (10) branch intervals shall be provided with a relief vent at each tenth interval, beginning with the top floor, or may be installed mid-way between the first and twentieth interval.  The size of the relief vent shall be equal to the size of the vent stack to which it connects. The lower end of each relief vent shall connect to the soil or waste stack through a wye below the horizontal branch serving the floor, and the upper end shall connect to the vent stack through a wye at least 42 inches above the floor level.