TITLE 77: PUBLIC HEALTHHome
PART 890 ILLINOIS PLUMBING CODE
CHAPTER I: DEPARTMENT OF PUBLIC HEALTH
SECTION 890.1440 VENT TERMINAL SIZE
Section 890.1440 Vent Terminal Size
a) Vent Terminal Size. Each vent extension through the roof shall be a minimum of three (3) inches in diameter and no smaller than the vent which it terminates. Vent terminals shall not be screened.
b) Increasers. Changes in size or diameter of vent terminals shall be made by the installation of a long increaser commencing at least one (1) foot below the roof.