Convert Inches of Water to Millipascals
Convert Inches of Water (inH₂O) to Millipascals (mPa) instantly and accurately.
Conversion Formula
mPa = inH₂O × 249088.91
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 Millipascals
A millipascal (mPa) is 10⁻³ Pa. It appears primarily in rheology as the millipascal-second (mPa·s = centipoise) for dynamic viscosity: water at 20°C is 1.002 mPa·s; olive oil ~80 mPa·s; honey 2,000-10,000 mPa·s. Food technology, polymer processing, pharmaceutical formulation, and inkjet printing all specify flow behaviour in mPa·s. Partial pressures of trace atmospheric gases and ultra-high-vacuum leak rates measured by residual gas analysers are also expressed in millipascals. 1 mPa = 10⁻³ Pa.
Quick Reference Table
| Inches of Water (inH₂O) | Millipascals (mPa) |
|---|---|
| 1 inH₂O | 249089 mPa |
| 2 inH₂O | 498178 mPa |
| 5 inH₂O | 1245440 mPa |
| 10 inH₂O | 2490890 mPa |
| 25 inH₂O | 6227220 mPa |
| 50 inH₂O | 12454400 mPa |
| 100 inH₂O | 24908900 mPa |