| Reading | What it tells you |
|---|---|
| Static pressure | System pressure with zero demand — sets the top of your curve |
| Residual pressure | Pressure at the test hydrant while flowing — drop indicates supply stiffness |
| Pitot pressure | Velocity head at the outlet — convert to flow with Q = 29.84·c·d²·√P (gpm, psi, in) |
| Coefficient c | 0.90 (smooth outlet), 0.80 (square outlet), 0.70 (projecting outlet) |
| 20 psi residual | Standard reference point for available supply |
Hinweise
- Plot static/residual on N^1.85 graph paper; the projected line at 20 psi gives the available flow.
Quelle
NFPA 291 (2022) Chapter 4.
Cite this page
- APA
- FireTwin AI (2026). Hydrant flow test interpretation. FireTwin AI. https://firetwin.eu/de/data/hydrant-flow-test
- IEEE
- FireTwin AI, "Hydrant flow test interpretation," FireTwin AI, 2026. [Online]. Available: https://firetwin.eu/de/data/hydrant-flow-test