Section 890.1450  Vent Grades and Connections

a)         Grade.  All vent and branch vent pipes shall be installed so as to drain back to the soil or waste pipe.  (See Appendix K.Illustration F.)

b)         Vertical Rise.  Where vent pipes connect to a horizontal soil or waste pipe, the vent shall be taken off above the center line of the soil or waste pipe, and the vent pipe shall rise vertically, or at an angle not more than 45 degrees from the vertical before offsetting horizontally or before connecting to the branch vent.  Exception: Wet vent and floor drain vents may connect horizontally.  (See Appendix K.Illustrations F, G and AA.)

c)         Height above Fixtures.  The connection between a vent pipe and a vent stack or stack vent shall be made at least 6 inches above the flood-level rim of the highest fixture served by the vent.  Horizontal vent pipes forming branch vents or relief vents shall be at least 6 inches above the flood-level rim of the highest fixture served. (See Appendix K.Illustration H.)

d)         Heel or Side-Inlet Bend.  A heel or side-inlet quarter bend or closet bend shall not be used as a dry vent when the inlet is placed in a horizontal position.  (See Appendix K.Illustration I.)  Heel or side inlet quarter or closet bends are permitted only in cases where the fixture connecting is vented.  (See Appendix K.Illustration I.)

e)         All main vents or vent stacks shall connect full size at their base to the building drain or to the main soil or waste pipe at or below the lowest fixture branch. (See Appendix K.Illustration EE).

(Source:  Amended at 38 Ill. Reg. 9940, effective April 24, 2014)