Convert Millimeters of Water to Micropascals
Convert Millimeters of Water (mmH₂O) to Micropascals (µPa) instantly and accurately.
Conversion Formula
µPa = mmH₂O × 9806650
About Millimeters of Water
One millimetre of water column (mmH₂O) = pressure from 1 mm of fresh water at standard gravity = exactly 9.80665 Pa. Preferred for very low differential pressures in HVAC: ductwork static pressures, fan curves, filter resistance, and building pressurisation are in mm WC. Gas valve operating pressures are typically 0.5-3 mm WC; clean-room cascade differentials 12-25 mm WC. A domestic gas hob manifold operates at ~20 mm WC on natural gas. Also used in spirometer calibration and hospital oxygen delivery systems. 1 mmH₂O = 9.80665 Pa.
About Micropascals
A micropascal (µPa) is 10⁻⁶ Pa - the standard reference unit for sound pressure levels in acoustics. The threshold of human hearing in air is 20 µPa, which defines 0 dB SPL; underwater acoustics uses 1 µPa as its reference (0 dB re 1 µPa). Blue whale calls reach ~189 dB re 1 µPa at source. Industrial noise regulations, architectural acoustics, and loudspeaker sensitivity specifications all trace back to µPa reference levels. Solar wind pressure near Earth averages ~1-6 nPa, rising to hundreds of µPa during major solar storms. 1 µPa = 10⁻⁶ Pa.
Quick Reference Table
| Millimeters of Water (mmH₂O) | Micropascals (µPa) |
|---|---|
| 1 mmH₂O | 9806650 µPa |
| 2 mmH₂O | 19613300 µPa |
| 5 mmH₂O | 49033300 µPa |
| 10 mmH₂O | 98066500 µPa |
| 25 mmH₂O | 245166000 µPa |
| 50 mmH₂O | 490333000 µPa |
| 100 mmH₂O | 980665000 µPa |