Table of Insulation Material R-Values & Other Properties
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Insulation materials R-values, rates of heat loss or gain, flame spread, toxicity, durability
What insulation "R" values should be used in a building insulation?
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Closed cell, HCFC or CFC gases;
0-12% shrinkage, Fire safety: may not be left exposed in living area; thermal drift with aging; foil faced improves performance to R7-8.; very good air bypass leak sealing properties
Also see INSULATION CHOICES
Closed cell;
0-12% shrinkage, Fire safety: may not be left exposed in living area. Initial R of 7.14 declines to 6.8 after several months of curing; very good air bypass leak sealing properties
Polyurethane spray insulation - open cell insulation
The R-value of wood varies by wood density, species, moisture content.
Notes to the Table of Building Insulation Properties
R-Value is expressed as rate of heat loss per hour per square foot per inch of thickness of material per deg. F - see "R" value definition at Definitions of R K U values
Insulation density is expressed in pounds per cubic foot of material
Permeability is expressed as the water vapor permeability of the material per inch of thickness. These numbers are most useful to compare one insulating material to another.
Absorption is the tendency of the insulation to absorb water in percent by weight. This is important for assessing the risk of mold in some materials
Flame Spread is a measure of fire resistance of the material. Use these numbers to compare one insulating material to another.
Smoke is a measure of fire safety - that is, the relative amount of smoke produced if the insulation is exposed to flame or combustion
Toxicity is a measure of fire safety - that is, toxins given off if the insulation is exposed to flame or combustion.
Polystyrene may be in molded or extruded forms and like some other plastic or foam insulations may be in open or closed cell form. (Closed cell foams are more moisture resistant). Polystyrene also is referred to as molded expanded polystyrene (MEPS), expanded polystyrene (EPS), and extruded polystyrene (XPS) - the most common foam board insulation product. MEPS & XPS are used in insulated structural panels and in insulating concrete forms (ICFs).
Links to details: Insulation product names in the first table column include links to articles that help identify and provide the properties of each insulating material listed.
Open vs. closed cell: Foam insulation densities vary among closed-cell vs open cell forms. Open cell foams are typically about 1/2 lb/cubic foot; Closed cell foams are more dense and rigid, typically about 2 lb/cu. ft.
C or Thermal conductance of these materials is the reciprocal of the R-value. C is known only when the k, the thermal conductivity of a material is known. k is the heat transmitted through a 1-inch thickness of homogenous material per square foot per hour when there is 1 degree of temperature change. k= (BTU * inch) / sq.ft. * hour * degF.
Air film: This table of R-values does not consider the insulating characteristic of the air film on each side of a surface nor the effects of wind on the air film or on the material itself. Some of these materials are more resistant to wind-caused heat transmission than others.
Moisture: Closed cell foams resist moisture uptake (good) but if construction is improper they can trap moisture (bad) leading to rot or mold problems in other building materials.
Insects: Exterior foam board on foundations can ease attack by wood destroying insects.
Fire & smoke: Foam insulation products present fire-smoke hazards and usually they must be protected with a fire barrier (usually 1/2" drywall).
R-Values for wooden log walls given by the U.S. DOE are in error except for square log walls. D-logs and round logs that are given a nominal log thickness, say 6" logs are calculated by DOE as having an R-value of just over 8. This is incorrect for non-square logs because the cross section of the log is 6" only at the log's widest point. A correct assessment of the R-value of a wooden log wall needs to be calculated based on the average wall thickness, considering the variation in thicknesses over the curvature of the logs. Therefore the DOE's value is on the "high" end of the R-value of a log wall.
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Thanks to Andrew Cole, FOAM FACTOR, a Canadian based installer of 2lb. Closed Cell foam. Mr. Cole informs us that they only work with this material. "We feel that the superior performance characteristics make it a far superior choice in building envelopes of all types. Our material of choice now is POLARFOAM 7300-0 SOYA which is manufactured by DEMILEC here in Canada." Mr. Cole can be contacted at 905-271-6644 or at acole@bestsprayfoam.com - 04/30/2009.
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