Convert Millimeters of Water to Nanopascals
Convert Millimeters of Water (mmH₂O) to Nanopascals (nPa) instantly and accurately.
Conversion Formula
nPa = mmH₂O × 9806650000
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 Nanopascals
A nanopascal (nPa) is 10⁻⁹ Pa - the pressure scale of deep interplanetary space. LIGO and Virgo gravitational wave detectors must isolate mirror displacement signals against noise floors in the nanopascal regime. Low Earth orbit residual atmosphere is ~100 µPa; deep interplanetary space is ~1-10 nPa depending on solar wind activity. Thermospheric gas layers above 200 km altitude fall into the nPa-µPa range. Casimir force calculations and quantum vacuum fluctuation modelling also operate at nanopascal scales. 1 nPa = 10⁻⁹ Pa.
Quick Reference Table
| Millimeters of Water (mmH₂O) | Nanopascals (nPa) |
|---|---|
| 1 mmH₂O | 9.807 × 109 nPa |
| 2 mmH₂O | 1.961 × 1010 nPa |
| 5 mmH₂O | 4.903 × 1010 nPa |
| 10 mmH₂O | 9.807 × 1010 nPa |
| 25 mmH₂O | 2.452 × 1011 nPa |
| 50 mmH₂O | 4.903 × 1011 nPa |
| 100 mmH₂O | 9.807 × 1011 nPa |