Backflow Reference
Common backflow scenarios and preventer types.
Reference
Reference
- Hose bibb to grade or yard Atmospheric vacuum breaker (AVB) or hose-bibb vacuum breaker.
- Lawn irrigation, no chemicals Pressure vacuum breaker (PVB).
- Lawn irrigation with chemicals or boilers Reduced-pressure principle assembly (RPZ).
- Fire sprinkler systems Double-check valve assembly (DCVA) or RPZ depending on hazard.
- Commercial dishwasher Air gap or RPZ depending on chemical use.
- Boiler with chemical treatment RPZ.
Checked against published worked examples from: IPC 2024 + project bundled backflow-prevention scenarios.
Details, formula, and sources
Formula or table(reference page; no compute) Common backflow hazards mapped to typical preventer types (RP, DCV, PVB, AVB, AG) per the cross-connection categories described in IPC 2027 Section 608 / AWWA M14.
Source and editionIPC 2027 (International Plumbing Code). Section 608. AWWA M14 by name.
Free accessFree read-only access at codes.iccsafe.org. AWWA M14 licensed; cross-connection program guides free at most state primacy agency sites.
What governsEstimate. AHJ and licensed plumber / gas fitter govern. Verify against the IPC / IFGC edition adopted in your jurisdiction.