Convert Inches of Water to Pounds per Square Foot
Convert Inches of Water (inH₂O) to Pounds per Square Foot (lbf/ft²) instantly and accurately.
Conversion Formula
lbf/ft² = inH₂O × 5.202330048
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 Pounds per Square Foot
One pound per square foot (psf) ≈ 47.88 Pa - the standard structural engineering load unit in US practice. Building codes specify design loads in psf: residential floors 40 psf; office buildings 50-80 psf; assembly areas 100+ psf; snow loads can exceed 100 psf. Wind pressure on building facades, soil bearing capacity for shallow foundations, and lateral earth pressure in retaining walls are all in psf. The related unit ksf (1,000 psf = 47.88 kPa) covers higher-capacity soils and deep foundations. 1 psf = 47.88 Pa.
Quick Reference Table
| Inches of Water (inH₂O) | Pounds per Square Foot (lbf/ft²) |
|---|---|
| 1 inH₂O | 5.20233 lbf/ft² |
| 2 inH₂O | 10.4047 lbf/ft² |
| 5 inH₂O | 26.0117 lbf/ft² |
| 10 inH₂O | 52.0233 lbf/ft² |
| 25 inH₂O | 130.058 lbf/ft² |
| 50 inH₂O | 260.117 lbf/ft² |
| 100 inH₂O | 520.233 lbf/ft² |