R-value


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R-value

[′är ‚val·yü]
(engineering)
An index of the ability of a substance or material to retard the flow of heat; higher numerical values correspond to higher insulating ability.

R-value

A unit of thermal resistance. A material’s R-value is a measure of the effectiveness of the material in stopping the flow of heat through it. The higher a material’s Rvalue, the greater its insulating properties and the slower the heat flow through it. Examples of higher R-values for residential buildings: R-50 ceilings, R-21 walls, and R-30 floors.

R-value

A measure of the thermal resistance of a material or component.
References in periodicals archive ?
Expanded polystyrene (EPS) foam billets alone have R-values of 4 to 7 per inch.
Those panels with low R-value can produce condensation or frost buildup on the door due to a lower surface temperature on the warm side.
The insulation adds to the R-value of the roof and provides a solid substrate for the single-ply system.
This case, consisting of one web and two CLBs, produced an R-value of particular interest.
The thousands of linear feet of pipe at the Woodinville and Portsmouth breweries are insulated with Styrofoam brand insulation, an extruded polystyrene insulation that has a rigid, closed-cell structure that resists water and moisture vapor and maintains R-value within the service temperature range of -297 to +160 degrees Fahrenheit.
Most of the changes to R-value requirements occurred in Zone-2, which encompasses most of Northern Ontario.
The Evaluation Report confirms a tested R-value of 6.
This next-generation product builds upon the Neopor brand, and delivers the highest true R-value performance of R-5 per inch.
Uses approximately 30 percent less material than other rigid foam insulation to achieve the same R-value, 1 percent maximum water absorption by volume, Incorporates a new polymeric flame retardant (PolyFR), Earned GREENBGUARD Gold Certification, Contributes points towards builder s LEEDA certification.
Griffiths and Zuluaga (2004) used a two-dimensional, steady-state FEM to calculate the effective R-value of ducts buried under three levels of loose-fill insulation, as shown in Figure 1.
roof now has an R-value of 38, making it extremely energy efficient.
4" thick, moisture-resistant, closed-cell foam core panel with damage resistant polymer interior facing providing high R-value and consistent temperature control.