Section 890.1590  Combination Waste and Vent (Floor and Hub Drains Only)

Combination Waste and Vent.  A combination waste and vent is permitted only where structural conditions preclude conventional plumbing. Appurtenances delivering large quantities or surges of water shall not be discharged to a combination waste and vent.

a)         The waste piping and trap in a combination waste and an end vented (both ends) system shall be a minimum of 4 inch diameter and in accordance with Appendix A, Tables G and H.  The waste piping and trap shall be at least 2 pipe increments larger than the pipe size required by Appendix A, Tables G and H, and at least 2 pipe increments larger than any fixture/appurtenance discharge tail piece.  Only one floor drain shall be connected to each branch of a combination waste and vent.

b)         A branch more than 15 feet in length shall be separately end vented. The minimum area of any vent installed in a combination waste and vent system shall be ½ the area of the drain pipe served.

c)         Sinks, lavatories and other fixtures that are roughed-in above the floor shall not be permitted on a combination waste and vent system.

d)         Long mains shall be provided with additional relief vents located at intervals of every one hundred feet.  (See Appendix K: Illustration FF.)

(Source:  Amended at 28 Ill. Reg. 4215, effective February 18, 2004)