Convert Square feet per hour to Square millimetres per hour
Convert Square feet per hour (ft²/h) to Square millimetres per hour (mm²/h) instantly and accurately.
Conversion Formula
mm²/h = ft²/h × 92903.04
About Square feet per hour
The square foot per hour (ft²/h) equals ≈2.581 × 10⁻⁵ m²/s and is the dominant unit in US engineering practice for thermal diffusivity of building materials and industrial insulation. ASHRAE handbooks, Perry's Chemical Engineers' Handbook, and NFPA fire-resistance tables all list diffusivity in ft²/h. Steel: ≈0.4-0.5 ft²/h; concrete: ≈0.023 ft²/h; mineral wool: ≈0.005 ft²/h. 1 ft²/h = 0.09290304/3600 m²/s.
About Square millimetres per hour
The square millimetre per hour (mm²/h) equals 1/3 600 000 000 m²/s, the smallest practical thermal diffusivity unit. It is used in very slow heat-transfer processes such as diffusion through frozen soils or phase-change materials studied over many hours. Heavy clay soils can show diffusivity values of 1-2 mm²/h. 1 mm²/h = 1e-6/3600 m²/s.
Quick Reference Table
| Square feet per hour (ft²/h) | Square millimetres per hour (mm²/h) |
|---|---|
| 1 ft²/h | 92903 mm²/h |
| 2 ft²/h | 185806 mm²/h |
| 5 ft²/h | 464515 mm²/h |
| 10 ft²/h | 929030 mm²/h |
| 25 ft²/h | 2322580 mm²/h |
| 50 ft²/h | 4645150 mm²/h |
| 100 ft²/h | 9290300 mm²/h |