Related Resources: heat transfer

Insulation Material Thermal Conductivity Chart

Heat Transfer Engineering

Various Insulation Material Thermal Conductivity Chart

R-values per inch given in SI and Imperial units (Typical values are approximations, based on the average of available results. Ranges are marked with "–".

Material m2·K/(W·in) ft2·°F·h/(BTU·in) m·K/W
Vacuum insulated panel 5.28–8.8 R-30–R-50
Silica aerogel 1.76 R-10
Polyurethane rigid panel (CFC/HCFC expanded) initial 1.23–1.41 R-7–R-8
Polyurethane rigid panel (CFC/HCFC expanded) aged 5–10 years 1.10 R-6.25
Polyurethane rigid panel (pentane expanded) initial 1.20 R-6.8
Polyurethane rigid panel (pentane expanded) aged 5–10 years 0.97 R-5.5
Foil faced Polyurethane rigid panel (pentane expanded)     45-48
Foil-faced polyisocyanurate rigid panel (pentane expanded ) initial 1.20 R-6.8 55
Foil-faced polyisocyanurate rigid panel (pentane expanded) aged 5–10 years 0.97 R-5.5
Polyisocyanurate spray foam 0.76–1.46 R-4.3–R-8.3
Closed-cell polyurethane spray foam 0.97–1.14 R-5.5–R-6.5
Phenolic spray foam 0.85–1.23 R-4.8–R-7
Thinsulate clothing insulation 1.01 R-5.75
Urea-formaldehyde panels 0.88–1.06 R-5–R-6
Urea foam 0.92 R-5.25
Extruded expanded polystyrene (XPS) high-density 0.88–0.95 R-5–R-5.4 26-40
Polystyrene board 0.88 R-5.00
Phenolic rigid panel 0.70–0.88 R-4–R-5
Urea-formaldehyde foam 0.70–0.81 R-4–R-4.6
High-density fiberglass batts 0.63–0.88 R-3.6–R-5
Extruded expanded polystyrene (XPS) low-density 0.63–0.82 R-3.6–R-4.7
Icynene loose-fill (pour fill) 0.70 R-4
Molded expanded polystyrene (EPS) high-density 0.70 R-4.2 22-32
Home Foam 0.69 R-3.9
Rice hulls 0.50 R-3.0 24
Fiberglass batts 0.55–0.76 R-3.1–R-4.3
Cotton batts (Blue Jean insulation) 0.65 R-3.7
Molded expanded polystyrene (EPS) low-density 0.65 R-3.85
Icynene spray 0.63 R-3.6
Open-cell polyurethane spray foam 0.63 R-3.6
Cardboard 0.52–0.7 R-3–R-4
Rock and slag wool batts 0.52–0.68 R-3–R-3.85
Cellulose loose-fill 0.52–0.67 R-3–R-3.8
Cellulose wet-spray 0.52–0.67 R-3–R-3.8
Rock and slag wool loose-fill 0.44–0.65 R-2.5–R-3.7
Fiberglass loose-fill 0.44–0.65 R-2.5–R-3.7
Polyethylene foam 0.52 R-3
Cementitious foam 0.35–0.69 R-2–R-3.9
Perlite loose-fill 0.48 R-2.7
Wood panels, such as sheathing 0.44 R-2.5 9
Fiberglass rigid panel 0.44 R-2.5
Vermiculite loose-fill 0.38–0.42 R-2.13–R-2.4
Vermiculite 0.38 R-2.13 16-17
Straw bale 0.26 R-1.45 16-22
Papercrete   R-2.6-R-3.2  
Softwood (most) 0.25 R-1.41 7.7
Wood chips and other loose-fill wood products 0.18 R-1
Snow 0.18 R-1
Hardwood (most) 0.12 R-0.71 5.5
Brick 0.030 R-0.2 1.3-1.8
Glass 0.025 R-0.14
Poured concrete 0.014 R-0.08 0.43-0.87

Cork

Cork is probably one of the oldest insulation materials used commercially, and in the past it was the most widely used insulation material in the refrigeration industry. At present, due to the scarcity of cork-producing trees, its price is relatively high in comparison with other insulating materials. Therefore, its use is very limited, with the exception of some machine foundations to reduce the transmission of vibrations. It is available as expanded slabs or boards as well as in granular form, its density varies from 110 to 130 kg/m 3 and it has an average mechanical resistance of 2.2 kg/m 2 . It can only be used up to temperatures of 65 °C. It has good thermal insulating effectiveness, is fairly resistant to compression and is difficult to burn. Its main technical limitation is the tendency to absorb moisture with an average permeance to water vapor of 12.5 g cm m -2 day -1 mmHg -1 . Table A & B gives some typical characteristics of cork.

TABLE A
Thermal conductivity and density values at 0 °C of fiberglass insulation

Type

Density

Thermal conductivity

(kg/m 3 )

(W m -1 °C -1 ) / (kcal h -1 m -1 °C -1 )

Type I

10-18

0.044/0.038

Type II

19-30

0.037/0.032

Type III

31-45

0.034/0.029

Type IV

46-65

0.033/0.028

Type V

66-90

0.033/0.028

Type VI

91

0.036/0.031

Glass fibre, resin bonded

64-144

0.036/0.031

Source : Prepared by authors based on data from Melgarejo, 1995.

TABLE B
Thermal conductivity and density values at 20-25 °C of cork insulation

Type

Density

Thermal conductivity

(kg/m 3 )

(W m -1 °C -1 ) / (kcal h -1 m -1 °C -1 )

Granulated loose, dry

115

0.052/0.0447

Granulated

86

0.048/0.041

Expanded cork slab

130

0.04/0.344

Expanded cork board

150

0.043/0.037

Expanded bonded with resins/bitumen

100-150

0.043/0.037

Expanded bonded with resins/bitumen

150-250

0.048/0.041

Source : Prepared by authors based on data from Melgarejo, 1995.

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