09-08 Circuit venting vertical leg

Question: 09-08Code Section: 7Date: 10 July 2009OBC 2006 Reference: 7.5.3., 7.5.6.3.(3)

Question: When circuit venting a group of water closets, is it permitted to install a Y and 45 on its back and have the water closets discharge vertically into the circuit vented branch? Some municipalities feel that the Y’s must be installed horizontally when circuit venting all fixtures. (water closets included)

OBC 2006: 7.5.3., 7.5.6.3.(3) Question Submitted: July 10, 2009 

Interpretation: The vertical “Y” and a 45 has always been somewhat of a controversial installation and the members of the CTC do not see any code contravention with this installation whether it’s used with circuit venting or wet venting.

References include 7.5.6.3.(3) indicating a maximum vertical plane of 1000mm, 7.5.6.3.(5) indicates the vent may be on the vertical leg and 7.5.6.2.(2) indicates that any wet vent may be flat.

Interpretation: Approved at AMES 2009