Convert Square millimetres per hour to Square feet per hour
Convert Square millimetres per hour (mm²/h) to Square feet per hour (ft²/h) instantly and accurately.
Conversion Formula
ft²/h = mm²/h × 1.076391042e-5
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.
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.
Quick Reference Table
| Square millimetres per hour (mm²/h) | Square feet per hour (ft²/h) |
|---|---|
| 1 mm²/h | 1.076 × 10-5 ft²/h |
| 2 mm²/h | 2.153 × 10-5 ft²/h |
| 5 mm²/h | 5.382 × 10-5 ft²/h |
| 10 mm²/h | 0.000107639 ft²/h |
| 25 mm²/h | 0.000269098 ft²/h |
| 50 mm²/h | 0.000538196 ft²/h |
| 100 mm²/h | 0.00107639 ft²/h |