IPC 708.3

IPC 704.1

For pipes 3 inches and larger, the minimum slope is 1/8 inch per foot. A slope of 1/4 inch per foot exceeds the minimum and is acceptable. While the minimum would suffice, a steeper slope within reason provides better flow velocity and self-scouring action.

IPC 705.5

ABS and PVC cannot be joined with solvent cement. These dissimilar plastics require a listed mechanical coupling (such as a banded no-hub coupling) or approved transition fitting.

IPC 706.3

Sanitary tees may only be used for vertical-to-horizontal transitions. For horizontal-to-horizontal connections, a wye with 45-degree bend or combination wye-bend must be used to maintain proper flow.

IPC 802.1

This installation is correct. Ice machines, food-handling equipment, and similar appliances must discharge through an indirect waste connection to prevent sewage backflow from contaminating food or ice. The 2-inch air gap exceeds the minimum requirement (1 inch or two times the pipe diameter, whichever is greater) and ensures a physical break between the fixture drain and the sanitary system. This is one of the first cross-connection control lessons taught at the UA hall — if it makes food or ice, it gets an air gap.

IPC 905.2

The vent connection must be above the trap weir (the overflow point of the trap). Connecting below the weir makes it a wet vent carrying waste, not a true vent, and will not properly protect the trap seal.

IPC 905.5

Vent pipes must rise vertically to a point at least 6 inches above the flood-level rim of the highest fixture served before turning horizontal. This prevents waste from backing up into the vent.