|Question: 08-22||Code Section: 7||Date: 7 May 2008||OBC 2006 Reference: 188.8.131.52.; 184.108.40.206|
Question: (There is) a concern over what is a building drain and how should it be installed.
Interpretation: A sanitary building drain means a building drain that conducts sewage to a building sewer from the most upstream soil or waste stack, branch or fixture drain serving a water closet. The building drain is the lowest horizontal piping, including any vertical offset, that conducts sewage, clear water waste or storm water by gravity to a building sewer. 220.127.116.11(2) and (3) states that a sanitary building drain (minimum of 4 inch) is terminated at a 3 inch soil stack or a 3 inch waste stack or a 3 inch vent stack. 18.104.22.168 states that where a building drain enters the building above floor level, the building drain may be deemed to terminate at the first horizontal to vertical change of direction. A building drain must terminate at its most upstream end to the farthest SOIL STACK serving a water closet. This soil stack must extend a minimum of 3" to open air. If the stack is at the front of the building and a kitchen sink is at the back of the building then the building drain ends at the soil stack at the front of the building.
Approved at AMES 2008