Convert Square inches per hour to Square millimetres per hour
Convert Square inches per hour (in²/h) to Square millimetres per hour (mm²/h) instantly and accurately.
Conversion Formula
mm²/h = in²/h × 645.16
About Square inches per hour
The square inch per hour (in²/h) equals ≈1.792 × 10⁻⁷ m²/s, used in US heat-transfer handbooks and HVAC insulation specifications. Pre-SI tables for building insulation board and refractory brick often list thermal diffusivity in in²/h. Firebrick: ≈3.5 in²/h; rigid foam: ≈0.8-1.2 in²/h. 1 in²/h = 0.00064516/3600 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 inches per hour (in²/h) | Square millimetres per hour (mm²/h) |
|---|---|
| 1 in²/h | 645.16 mm²/h |
| 2 in²/h | 1290.32 mm²/h |
| 5 in²/h | 3225.8 mm²/h |
| 10 in²/h | 6451.6 mm²/h |
| 25 in²/h | 16129 mm²/h |
| 50 in²/h | 32258 mm²/h |
| 100 in²/h | 64516 mm²/h |