TITLE 77: PUBLIC HEALTHHome
PART 890 ILLINOIS PLUMBING CODE
CHAPTER I: DEPARTMENT OF PUBLIC HEALTH
SECTION 890.1490 INSTALLATION OF VENTS FOR FIXTURE TRAPS
Section 890.1490 Installation of Vents for Fixture Traps
a) Hydraulic Gradient. Fixture drains shall be vented within the hydraulic gradient between the trap outlet and the junction with another drain. The hydraulic gradient as applied to a gravity drain and its vent connection is interpreted as the grade line. (See Appendix A: Table I, and Appendix K: Illustration R.)
b) Different Level. If any stack has fixtures entering at different levels, the fixtures other than the fixtures entering at the highest level shall be vented, except as otherwise provided. (See Section 890.1510.)
c) Horizontal Branch Drains. Where a water closet discharges into a branch drain, each fixture discharging into that branch drain shall be individually vented; however, this does not include battery or circuit venting.