Convert Inches of Water to Kilopounds per Square Inch
Convert Inches of Water (inH₂O) to Kilopounds per Square Inch (ksi) instantly and accurately.
Conversion Formula
ksi = inH₂O × 3.612729200e-5
About Inches of Water
One inch of water column (inH₂O or in WC) = pressure from 1 inch of fresh water at standard gravity ≈ 249.09 Pa. The standard unit for low-pressure measurement in US HVAC and plumbing: ductwork static pressure, fan performance, filter ratings, and gas appliance manifold pressures are all specified in inches WC. Household natural gas supply pressure is typically 7 in WC (0.25 psi). Blower door tests for building air-tightness use 50 Pa ≈ 0.2 in WC test pressure. 1 inH₂O = 249.089 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
| Inches of Water (inH₂O) | Kilopounds per Square Inch (ksi) |
|---|---|
| 1 inH₂O | 3.613 × 10-5 ksi |
| 2 inH₂O | 7.225 × 10-5 ksi |
| 5 inH₂O | 0.000180636 ksi |
| 10 inH₂O | 0.000361273 ksi |
| 25 inH₂O | 0.000903182 ksi |
| 50 inH₂O | 0.00180636 ksi |
| 100 inH₂O | 0.00361273 ksi |