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In the United States and Canada, the R-value that describes the performance of thermal insulation is typically quoted in square foot degree Fahrenheit hours per British thermal unit (ft 2 ⋅°F⋅h/Btu). For one square foot of the insulation, one Btu per hour of heat flows across the insulator for each degree of temperature difference across ...
atmosphere-cubic foot per second: atm cfs [citation needed] ≡ 1 atm × 1 cu ft/s = 2.869 204 480 9344 × 10 3 W: BTU (International Table) per hour: BTU IT /h ≡ 1 BTU IT /h ≈ 0.293 071 W: BTU (International Table) per minute: BTU IT /min ≡ 1 BTU IT /min ≈ 17.584 264 W: BTU (International Table) per second: BTU IT /s ≡ 1 BTU IT /s ...
This is convenient because one pound mass exerts one pound force due to gravity. Note, however, unlike the other systems the force unit is not equal to the mass unit multiplied by the acceleration unit [11] —the use of Newton's second law, F = m ⋅ a, requires another factor, g c, usually taken to be 32.174049 (lb⋅ft)/(lbf⋅s 2).
lbm/cu in: 45359237/1638.7064 ... btu =BTU Calorie =Cal ft.lbf =ftlbf ft·lbf =ftlbf g-cal-15 =cal-15 ... foot per second: feet per second: m/s: Feet per second ...
As such, these are ready extensions of any system of containing length, mass, time. Stephen Dresner [7] gives the derived electrostatic and electromagnetic units in both the foot–pound–second and foot–slug–second systems. In practice, these are most associated with the centimetre–gram–second system.
Units for other physical quantities are derived from this set as needed. In English Engineering Units, the pound-mass and the pound-force are distinct base units, and Newton's Second Law of Motion takes the form = where is the acceleration in ft/s 2 and g c = 32.174 lb·ft/(lbf·s 2).
BTU mean: quadrillion British thermal units: quad quad assumes the 59 °F Btu and the "long scale" quadrillion (10 15) 1.0 ...
In the United States, U-value is expressed as British thermal units (Btu) per hour-square feet-degrees Fahrenheit: Btu/(h⋅ft 2 ⋅°F) Within this article, U-values are expressed in SI unless otherwise noted. To convert from SI to US customary values, divide by 5.678. [1]