Jumat, 10 Januari 2014
Minggu, 26 Mei 2013
PERBANDINGAN R-VALUE BAHAN INSULASI SECARA UMUM
Thermal Conductivity is the measure of the amount heat that will be transmitted through a one inch (1") thick piece of homogenous material, one square foot (1 ft.2) in size, in one (1) hour, when there is a one degree Fahrenheit (1° F) temperature change. The equation for "k" is:
Polyurethane is a highly efficient insulator. For every two inches of polyurethane foam, this much of another insulating material would be needed for equivalent insulatin performance: "U-value" (or U-factor) measures heat transfer through insulation or a building component over time, under standardized conditions. Since it's an inverse measurement to R-value (R = 1/U), a low U-value number indicates a superior insulator.
|Insulation Material||R-value Range||Thickness to match 2"|
|Polyurethane Foam||R 5.6 - 8.0 /inch||2 inches|
|Polystyrene||R 3.8 - 5.0 / inch||3.1 inches|
|Cellulose||R 3.6 - 3.8 / inch||3.7 inches|
|Rock & Glass wool||R 2.9 - 3.8 / inch||4.0 inches|
|OSB Sheathing||R 1.25 / inch||10.9 inches|
|Plywood||R 1.25 / inch||10.9 inches|
|Concrete Block||R 0.25 / inch||54 inches|
|Brick||R 0.2 / inch||68 inches|
Sprayed Polyurethane Foam (SPF) will have an R-Value of 7.14 when it is newly installed. After it ages a few months, the R-Value will reduce to somewhere around 6.88. The C-value (C) is a measure of the Thermal Conductance of the material and is the reciprocal of R, or
C is determined only when the Thermal Conductivity (k) of a material is known.