08-30 Ancillary building sewage ejector

Question: 08-30Code Section: 7Date: 12 October 2008OBC 2006 Reference: BCA 1.(1), 3.7.4.1.(1) , 7.1.5.4., 7.4.9.4., 7.5.7.2(2), 7.5.8.4(5), 7.6.3.1.(4)

Question submitted: (A) new Home that was built this summer. There is a guest Bunkie out back with a 3 piece bathroom in it. I want to know if this separate building is required to have a three inch stack through the roof or if individual vents changing to 3 inch prior to roof penetration is acceptable. I guess I would call this a ancillary building. The drain from this Bunkie drains into the sewage ejector in the basement as gravity to the septic is not possible.

Interpretation: Since the current definition of 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”, thus, the existing building drain must extend into the ancillary building in question, or the guest Bunkie must be provided with a building drain on its own. However, the local authority having jurisdiction can exercise their power under Division A of the Code in accepting a site specific proposal based on meeting the Objectives and Functional Statements of the Code.

Under the Building Code Act, the local municipality is the authority having jurisdiction for enforcing the Act and its Regulations, and the permit applicants should contact the appropriate building/plumbing official with respect to any specific proposal.

By definition BCA 1.(1) this is a building and must meet all the requirements of a building.

7.1.5.4.(1) Piping in an building shall be connected to the public services separately from piping of any other building, except that an ancillary building on the same property may be served by the same service.

7.4.9.4. and 7.5.8.4(5) still applies and if the H.W.T. is in the building then 7.6.3.1.(4) as well.  “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. This building has a water closet , therefore 4″ building drain (7.4.9.4) and 3″ stack (7.5.7.2(2))

3.7.4.1.(1) Except as permitted in sentence (3), each building situated on a property in which a public or municipal water main is located shall be provided with or have accessible to its occupants a plumbing system including a potable water supply, a sanitary drainage system and plumbing fixtures.

Interpretation: Approved at AMES 2009