What is the minimum size of a pipe sleeve required for a building drain passing through a foundation wall?

• A. One pipe size
• B. Two pipe sizes
• C. Three pipe sizes
• D. Four pipe sizes

Answer: (B)

The minimum size of a pipe sleeve required for a building drain passing through a foundation wall is two pipe sizes larger than the outside diameter of the pipe that is being sleeve. This requirement ensures that there is sufficient space around the pipe to accommodate any movement, thermal expansion, and insulation, as well as to allow for proper drainage and maintenance access.

Using a sleeve that is two pipe sizes larger helps prevent any potential blockages or compression on the pipe, which could occur if the sleeve were too tight or restricted. Additionally, having extra space allows for proper sealing around the pipe to prevent moisture or pests from entering the building through the foundation wall. This practice also aligns with plumbing codes, which prioritize the longevity and functionality of plumbing systems within structures.