IPC 608.15.4.2

IPC 607.3.2

When a backflow preventer or check valve is installed on the water service (creating a closed system), a thermal expansion tank is required. Without it, heated water expanding has nowhere to go and can cause dangerous pressure buildup.

IPC 608.1

A garden hose submerged in a pool creates a direct cross-connection. If a back-siphonage event occurs, contaminated pool water can be drawn into the potable supply. Hose bibbs must have vacuum breakers and hoses must never be submerged.

IPC 608.15.1

Faucets and fill valves must maintain an air gap of at least 1 inch or two pipe diameters (whichever is greater) above the flood-level rim of the fixture. A spout that can be submerged creates a backflow risk.

IPC 608.16.4 / ASSE 5013

The relief port discharge must terminate with an air gap above any drain receptor. Without an air gap, a cross-connection is created at the very device meant to prevent cross-connections. The discharge must also be visible to indicate when the relief valve is operating.

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.