| Size (in) | DCVA loss (psi) | DCVA loss (bar) | RPZ loss (psi) | RPZ loss (bar) |
|---|---|---|---|---|
| 2 | 6 | 0.41 | 12 | 0.83 |
| 3 | 5 | 0.34 | 11 | 0.76 |
| 4 | 4.5 | 0.31 | 10 | 0.69 |
| 6 | 4 | 0.28 | 9 | 0.62 |
| 8 | 3.5 | 0.24 | 8 | 0.55 |
| 10 | 3 | 0.21 | 7.5 | 0.52 |
Notes
- Values are typical mid-range; use manufacturer curves for final calc.
Source
Manufacturer published curves (Watts, Wilkins, Ames); USC FCCCHR.
Cite this page
- APA
- FireTwin AI (2026). Backflow preventer pressure losses. FireTwin AI. https://firetwin.eu/data/backflow-preventer-loss
- IEEE
- FireTwin AI, "Backflow preventer pressure losses," FireTwin AI, 2026. [Online]. Available: https://firetwin.eu/data/backflow-preventer-loss