IPC 608.16.4 / ASSE 5013

🔧 Plumbing

What it means on the job

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.

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Related IPC sections

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 608.15.4.2

This is a cross-connection violation. A hose connection that can be submerged below the flood-level rim creates a backflow hazard. The dirty mop water in the sink could be siphoned back into the potable water supply during a back-siphonage event. A listed atmospheric vacuum breaker (ASSE 1001) or hose connection vacuum breaker (ASSE 1011) must be installed on the hose bibb.

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.

CraftIQ explanations are original educational commentary written in trade language and verified against the cited standards. Always confirm requirements against the code edition adopted by your jurisdiction — this is training material, not a substitute for the code book or your AHJ.