How far must a pipe sleeve be built into a masonry wall for pipes passing through?

A pipe sleeve is used to protect pipes that pass through masonry walls by providing a smooth surface and preventing damage to the pipes and the wall itself. When it comes to the dimensions of the sleeve, the International Residential Code (IRC) specifies that a sleeve must be built into the masonry wall with a diameter of at least two pipe sizes greater than the outside diameter of the pipe being used. This ensures adequate space for thermal expansion and contraction, as well as for any potential movement of the pipe, thereby maintaining the integrity of both the pipe and the wall.

In practice, if a pipe has a certain diameter, using a sleeve that is two sizes larger allows for proper ventilation and prevents any interference that could lead to structural issues or pipe damage over time. This consideration is particularly important for pipes that may carry fluids subject to temperature variations or contain materials that might cause the pipe to expand or contract.

While other options suggest varying degrees of sleeve size, the requirement for a two-size larger sleeve is grounded in the need for functional stability and protection. Not requiring a sleeve presents risk as it does not provide adequate coverage or support for the pipe and any potential environmental impacts from moisture or physical stress.