Convert Feet of Water to Kilopounds per Square Inch
Convert Feet of Water (ftH₂O) to Kilopounds per Square Inch (ksi) instantly and accurately.
Conversion Formula
ksi = ftH₂O × 0.000433527504
About Feet of Water
One foot of water column (ftH₂O) ≈ 2,989 Pa - the US customary equivalent of cmH₂O used in civil and hydraulic engineering. Municipal water supply systems are designed for 40-80 psi head ≈ 92-184 ft; fire suppression sprinkler systems require minimum 7 psi ≈ 16 ft. Well pump specifications, sump pump head ratings, irrigation mainline pressure, and drainage calculations all use feet of head. 1 ft of water = 12 in WC = 0.4335 psi ≈ 2,989 Pa.
About Kilopounds per Square Inch
One ksi (kilopound per square inch) = 1,000 psi ≈ 6.895 MPa - the standard engineering stress unit in the US. ASTM A36 structural steel: 36 ksi yield, 58-80 ksi tensile. ASTM A325 high-strength bolts: 92 ksi proof load. AISC steel construction tables, FAA/MIL-SPEC aerospace allowables, and ASME Section VIII pressure vessel design all use ksi. Fracture toughness (K_IC) for steels: 50-200 ksi·√in. Convenient because it keeps large structural stresses as manageable 3-digit numbers. 1 ksi = 6.895 MPa.
Quick Reference Table
| Feet of Water (ftH₂O) | Kilopounds per Square Inch (ksi) |
|---|---|
| 1 ftH₂O | 0.000433528 ksi |
| 2 ftH₂O | 0.000867055 ksi |
| 5 ftH₂O | 0.00216764 ksi |
| 10 ftH₂O | 0.00433528 ksi |
| 25 ftH₂O | 0.0108382 ksi |
| 50 ftH₂O | 0.0216764 ksi |
| 100 ftH₂O | 0.0433528 ksi |