TITLE 77: PUBLIC HEALTHHome
PART 890 ILLINOIS PLUMBING CODE
CHAPTER I: DEPARTMENT OF PUBLIC HEALTH
SECTION 890.1550 OFFSETS AT AN ANGLE LESS THAN 45 DEGREES FROM THE HORIZONTAL IN BUILDINGS OF FIVE OR MORE STORIES
Section 890.1550 Offsets at an Angle Less Than 45 Degrees from the Horizontal in Buildings of Five or More Stories
a) Offset Vents. Offsets less than 45 degrees from the horizontal in a soil or waste stack, except as provided in Section 890.1350, shall comply with subsections (b) and (c) of this Section. (See Appendix K: Illustration CC.)
b) Separate Venting. The stack section below the offset and the stack section above the offset shall be vented as separate soil or waste stacks.
c) Offset Reliefs. Offsets shall be vented by installing a relief vent as a vertical continuation of the lower section of the stack or as a side vent connected to the lower section between the offset and the next lower fixture or horizontal branch. The upper section of the offset shall be provided with a yoke vent. The diameter of the vents shall not be less than the diameter of the main vent, or of the soil or waste stack, whichever is smaller.