| Pipe material | C value (NFPA 13) | Notes |
|---|---|---|
| Unlined cast iron | 100 | Legacy systems only |
| Black steel (dry / pre-action) | 100 | Higher loss from internal corrosion |
| Black steel (wet) | 120 | Default for new wet systems |
| Galvanized steel | 120 | Same as black wet |
| Cement-lined cast or ductile iron | 140 | Underground mains |
| Copper | 150 | Limited use, residential |
| CPVC | 150 | Listed light-hazard only |
| Stainless steel | 150 | High-end and food-grade |
Quelle
NFPA 13 (2022) Table 28.2.4.6.1.
Cite this page
- APA
- FireTwin AI (2026). Hazen-Williams C-factors for fire protection piping. FireTwin AI. https://firetwin.eu/de/data/hazen-williams-c-factors
- IEEE
- FireTwin AI, "Hazen-Williams C-factors for fire protection piping," FireTwin AI, 2026. [Online]. Available: https://firetwin.eu/de/data/hazen-williams-c-factors