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Insulation Data

Page history last edited by jim mason 7 years, 6 months ago

return to Practical Engineering

 

We've split our info on insulation into two separate pages: Insulation Data and Insulation Products.  You are currently on the Insulation Data page.  Here you will find charts on R values and temp tolerance for common insulative materials.  The Insulation Products page is our running reference and commentary on where, what and why of various products we have tried and might have something to say about them.

 

Insulation for gasifiers needs to be concerned with both insulative performance and tolerance to high temperature.  In general, as high temperature tolerance increases, insulative performance decreases.  Most of the refractory ceramics that are survive high temps very well, also tend to be relatively poor insulators.  Of course money and esoteric materials can find exceptions to this trend, but such is the starting point from which to get oriented.  One can also consider layering insulation materials, so that temp resistance is favored against the heat source, and insulative performance is favored for surrounding layers.

 

Here now is a helpful summary chart from wikipedia for understanding relative insulation performance.  Note that some relatively common materials and inexpensive materials are good insulators.  Exotic high cost insulators are not necessarily an improvement.   The chart shows numerically why we have found Perlite to be a great insulative value.

 

This chart rates insulators with their R value.   A higher R value is better insulation.  Formally, R value = material thickness / thermal conductivity.   Thus R value is the inverse of thermal conductivity.   There is a very complete thermal conductivity chart on the bottom of this page.

 

 

 

Material  ↓ Value per inch (Min)  ↓ Value per inch (Max)  ↓ Reference  ↓
Still Air   R-5 (0.88)  
Still Air with convective currents R-1 (0.18) (or less) R-5 (0.88) (Still)  
Wood chips and other loose-fill wood products R-1 (0.18)    
Snow R-1 (0.18)    
Straw bale R-1.45 (0.26)   [3]
Wood panels, such as sheathing R-2.5 (0.44)    
Vermiculite loose-fill R-2.13 (0.38) R-2.4 (0.42)  
Perlite loose-fill R-2.7 (0.48)    
Rock and slag wool loose-fill R-2.5 (0.44) R-3.7 (0.65) [8]
Rock and slag wool batts R-3 (0.52) R-3.85 (0.68)  
Fiberglass loose-fill R-2.5 (0.44) R-3.7 (0.65) [8]
Fiberglass rigid panel R-2.5 (0.44)    
Fiberglass batts R-3.1 (0.55) R-4.3 (0.76)  
High-density fiberglass batts R-3.6 (0.63) R-5 (0.88)  
Cementitious foam R-2 (0.35) R-3.9 (0.69)  
Cellulose loose-fill R-3 (0.52) R-3.8 (0.67) [9]
Cellulose wet-spray R-3 (0.52) R-3.8 (0.67) [9]
Cotton batts (Blue Jean Insulation) R-3.7 (0.65)   [10]
Icynene spray R-3.6 (0.63)   [11]
Icynene loose-fill (pour fill) R-4 (0.70)   [11]
Urea-formaldehyde foam R-4 (0.70) R-4.6 (0.81)  
Urea-formaldehyde panels R-5 (0.88) R-6 (1.06)  
Polyethylene foam R-3 (0.52)    
Phenolic spray foam R-4.8 (0.85) R-7 (1.23)  
Phenolic rigid panel R-4 (0.70) R-5 (0.88)  
Molded expanded polystyrene (EPS) low-density R-3.7 (0.65)    
Molded expanded polystyrene (EPS) high-density R-4 (0.70)    
Extruded expanded polystyrene (XPS) low-density R-3.6 (0.63) R-4.7 (0.82)  
Extruded expanded polystyrene (XPS) high-density R-5 (0.88) R-5.4 (0.95)  
Open-cell polyurethane spray foam R-3.6 (0.63)    
Closed-cell polyurethane spray foam R-5.5 (0.97) R-6.5 (1.14)  
Polyurethane rigid panel (Pentane expanded) initial R-6.8 (1.20)    
Polyurethane rigid panel (Pentane expanded) aged 5-10 years R-5.5 (0.97)    
Polyurethane rigid panel (CFC/HCFC expanded) initial R-7 (1.23) R-8 (1.41)  
Polyurethane rigid panel (CFC/HCFC expanded) aged 5-10 years R-6.25 (1.10)    
Polyisocyanurate spray foam R-4.3 (0.76) R-8.3 (1.46)  
Foil-faced polyisocyanurate rigid panel (Pentane expanded ) initial R-6.8 (1.20)    
Foil-faced polyisocyanurate rigid panel (Pentane expanded) aged 5-10 years R-5.5 (0.97)    
Silica aerogel R-10 (1.76)    
Vacuum insulated panel R-30 (5.28) R-50 (8.80)  
Cardboard R-3 (0.52) R-4 (0.70)  
Thinsulate clothing insulation R-5.75 (1.01)    

chart from Wikipedia: http://en.wikipedia.org/wiki/R-value_(insulation)

 

 

Detailed info on Perlite insulation over temp range

http://www.engineeringtoolbox.com/perlite-insulation-k-values-d_1173.html

 

Detailed info on Mineral Wool insulation over temp range

http://www.engineeringtoolbox.com/mineral-wool-insulation-k-values-d_815.html

 

Detailed Info on Fiberglass insulation over temp range

http://www.engineeringtoolbox.com/fiberglas-insulation-k-values-d_1172.html


Detailed Info on Polyurethane insulation over temp range

http://www.engineeringtoolbox.com/polyurethane-insulation-k-values-d_1174.html

 

Other R value charts

http://www.coloradoenergy.org/procorner/stuff/r-values.htm

http://www.progress-energy.com/custservice/flares/billtoolkit/rvalues.asp

 

 

 

Temperature limits of some common insulation materials are indicated in the table below:

Insulation Material Low Temperature Range High Temperature Range
(oC) (oF) (oC) (oF)
Calcium Silicate -18 0 650 1200
Cellular Glass -260 -450 480 900
Elastomeric foam -55 -70 120 250
Fiberglass -30 -20 540 1000
Mineral Wool 0 32 1000 1800
Phenolic foam     150 300
Polyisocyanurate or polyiso -180 -290 150 300
Polystyrene -50 -60 75 165
Polyurethane -210 -350 120 250

from Engineering Toolbox: http://www.engineeringtoolbox.com/insulation-temperatures-d_922.html

 

 

 

Charts of Thermal Conductivity

 

Thermal conductivity, or heat transfer coefficients, of some common materials and products are indicated in the table below.

  • 1 W/(mK) = 1 W/(moC) = 0.85984 kcal/(hr moC) = 0.5779 Btu/(ft hr oF)

 

Thermal Conductivity - k - (W/mK)

Material/Substance

Temperature (oC)

25

125

225

Acetone

0.16

 

 

Acrylic

0.2

 

 

Air

0.024

 

 

Alcohol

0.17

 

 

Aluminum

250

255

250

Aluminum Oxide

30

 

 

Ammonia

0.022

 

 

Antimony

18.5

 

 

Argon

0.016

 

 

Asbestos-cement board

0.744

 

 

Asbestos-cement sheets

0.166

 

 

Asbestos-cement

2.07

 

 

Asbestos, loosely packed

0.15

 

 

Asbestos mill board

0.14

 

 

Asphalt

0.75

 

 

Balsa

0.048

 

 

Bitumen

0.17

 

 

Benzene

0.16

 

 

Beryllium

218

 

 

Brass

109

 

 

Brick dense

1.31

 

 

Brick work

0.69

 

 

Cadmium

92

 

 

Carbon

1.7

 

 

Carbon dioxide

0.0146

 

 

Cement, portland

0.29

 

 

Cement, mortar

1.73

 

 

Chalk

0.09

 

 

Chrome Nickel Steel (18% Cr, 8 % Ni)

16.3

 

 

Clay, dry to moist

0.15 - 1.8

 

 

Clay, saturated

0.6 - 2.5

 

 

Cobalt

69

 

 

Concrete, light

0.42

 

 

Concrete, stone

1.7

 

 

Constantan

22

 

 

Copper

401

400

398

Corian (ceramic filled)

1.06

 

 

Corkboard

0.043

 

 

Cork, regranulated

0.044

 

 

Cork

0.07

 

 

Cotton

0.03

 

 

Carbon Steel

54

51

47

Cotton Wool insulation

0.029

 

 

Diatomaceous earth (Sil-o-cel)

0.06

 

 

Earth, dry

1.5

 

 

Ether

0.14

 

 

Epoxy

0.35

 

 

Felt insulation

0.04

 

 

Fiberglass

0.04

 

 

Fiber insulating board

0.048

 

 

Fiber hardboard

0.2

 

 

Fireclay brick 500oC

1.4

 

 

Foam glass

0.045

 

 

Freon 12

0.073

 

 

Gasoline

0.15

 

 

Glass

1.05

 

 

Glass, Pearls, dry

0.18

 

 

Glass, Pearls, saturated

0.76

 

 

Glass, window

0.96

 

 

Glass, wool Insulation

0.04

 

 

Glycerol

0.28

 

 

Gold

310

312

310

Granite

1.7 - 4.0

 

 

Gypsum or plaster board

0.17

 

 

Hairfelt

0.05

 

 

Hardboard high density

0.15

 

 

Hardwoods (oak, maple..)

0.16

 

 

Helium

0.142

 

 

Hydrogen

0.168

 

 

Ice (0oC, 32oF)

2.18

 

 

Insulation materials

0.035 - 0.16

 

 

Iridium

147

 

 

Iron

80

68

60

Iron, wrought

59

 

 

Iron, cast

55

 

 

Kapok insulation

0.034

 

 

Kerosene

0.15

 

 

Lead Pb

35

 

 

Leather, dry

0.14

 

 

Limestone

1.26 - 1.33

 

 

Magnesia insulation (85%)

0.07

 

 

Magnesite

4.15

 

 

Magnesium

156

 

 

Marble

2.08 - 2.94

 

 

Mercury

8

 

 

Methane

0.030

 

 

Methanol

0.21

 

 

Mica

0.71

 

 

Mineral insulation materials, wool blankets ..

0.04

 

 

Molybdenum

138

 

 

Monel

26

 

 

Nickel

91

 

 

Nitrogen

0.024

 

 

Nylon 6

0.25

 

 

Oil, machine lubricating SAE 50

0.15

 

 

Olive oil

0.17

 

 

Oxygen

0.024

 

 

Paper

0.05

 

 

Paraffin Wax

0.25

 

 

Perlite, atmospheric pressure

0.031

 

 

Perlite, vacuum

0.00137

 

 

Plaster, gypsum

0.48

 

 

Plaster, metal lath

0.47

 

 

Plaster, wood lath

0.28

 

 

Plastics, foamed (insulation materials)

0.03

 

 

Plastics, solid

 

 

 

Platinum

70

71

72

Plywood

0.13

 

 

Polyethylene HD

0.42 - 0.51

 

 

Polypropylene

0.1 - 0.22

 

 

Polystyrene expanded

0.03

 

 

Porcelain

1.5

 

 

PTFE

0.25

 

 

PVC

0.19

 

 

Pyrex glass

1.005

 

 

Quartz mineral

3

 

 

Rock, solid

2 - 7

 

 

Rock, porous volcanic (Tuff)

0.5 - 2.5

 

 

Rock Wool insulation

0.045

 

 

Sand, dry

0.15 - 0.25

 

 

Sand, moist

0.25 - 2

 

 

Sand, saturated

2 - 4

 

 

Sandstone

1.7

 

 

Sawdust

0.08

 

 

Silica aerogel

0.02

 

 

Silicone oil

0.1

 

 

Silver

429

 

 

Snow (temp < 0oC)

0.05 - 0.25

 

 

Sodium

84

 

 

Softwoods (fir, pine ..)

0.12

 

 

Soil, with organic matter

0.15 - 2

 

 

Soil, saturated

0.6 - 4

 

 

Steel, Carbon 1%

43

 

 

Stainless Steel

16

17

19

Straw insulation

0.09

 

 

Styrofoam

0.033

 

 

Tin Sn

67

 

 

Zinc Zn

116

 

 

Urethane foam

0.021

 

 

Vermiculite

0.058

 

 

Vinyl ester

0.25

 

 

Water

0.58

 

 

Water, vapor (steam)

 

0.016

 

Wood across the grain, white pine

0.12

 

 

Wood across the grain, balsa

0.055

 

 

Wood across the grain, yellow pine

0.147

 

 

Wood, oak

0.17

 

 

Wool, felt

0.07

 

 

 

from Engineering Toolbox: http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html

Properties of some common ceramics are indicated in the table below:

 

Material Specific Gravity Coefficient of Linear Expansion
(106ppm/oC)
Maximum Safe Operating Temperature
(oC)
Thermal Conductivity
(10-3cal/cm2/ cm/sec/oC)
Tensile Strength
(psi)
Compressive Strength
(psi)
Flexural Strength
(psi)
Modulus of Elasticity
(106 psi)
Porcelain 2.2-2.4 5.0-6.5 400 4-5 1500-2500 25000-50000 3500-6000 7-10
Alumina Porcelain 3.1-3.9 5.5-8.1 1350-1500 7-50 8000-30000 8000-25000 20000-45000 15-52
High-Voltage Porcelain 2.3-25.5 5.0-6.8 1000 2-5 3000-8000 25000-50000 9000-15000 7-14
Zirconia Porcelain 3.5-3.8 3.5-5.5 1000-1200 10-15 10000-15000 80000-150000 20000-35000 20-30
Lithia Porcelain 2.3-4 1 1000     60000 8000  
Cordierite Refractory 1.6-2.1 2.5-3.0 1250 3-4 1000-3500 20000-45000 1500-7000 2-5
Alumina Silicate Refractory 2.2-2.4 5.0-7.0 1300-1700 4-5 700-3000 13000-60000 1500-6000 2-5
Magnesium Silicate 2.3-2.8 11.5 1200 3-5 2500 20000-30000 7000-9000 4-5
Steatite 2.5-2.7 8.6-10.5 1000-1100 5-6 8000-10000 65000-130000 16000-24000 13-15
Forsterite 2.7-2.9 11 1000-1100 5-10 8000-10000 60000-100000 18000-20000 13-15
Titania/Titanate Ceramics 3.5-5.5 7-10   8-10 4000-10000 40000-120000 10000-22000 0.3-0.5
  • 1 psi (lb/in2) = 6,894.8 Pa (N/m2)

 

  • Porcelain is a ceramic material made by heating selected and refined materials often including clay in the form of kaolinite to high temperatures.
  • Cordierite is a crystalline magnesium aluminosilicate
  • Steatite, also known as soapstone or soaprock, is a metamorphic rock, a talc-schist. It is largely composed of the mineral talc and is rich in magnesium.
  • Forsterite (Mg2SiO4) is the magnesium rich end-member of the olivine solid-solution series.

copied from  http://www.engineeringtoolbox.com/ceramics-properties-d_1227.html

 



Thermal Conductivity at Room Temperature
Image : Thermal Conductivity at Room Temperature  Fine Ceramics / Aluminum Nitride150W/m·K, Silicon Carbide60W/m·K, Alumina32W/m·K, Silicon Nitride20W/m·K, Zirconia3W/m·K  Metals / Cemented Carbide85W/m·K, Carbon Steel41W/m·K  Materials with low thermal conductivity should be selected for thermal insulation, and those with high thermal conductivity should be selected for heat dissipation and uniformity. (Measuring method / JIS R 1611-1997 / ISO 18755: 2005)

copied from http://global.kyocera.com/fcworld/charact/heat/thermalcond.html

 

-----------------------------------------------------------------------------------------

 

Chart of thermal conductivity changes over temp for common ceramics

ThermalConducityCeramicsOverTemp.pdf

from http://www.engin.brown.edu/organizations/EWB/GISP/Callster%20-%20chapter_17.pdf

 

----------------------------------------------------------

 

Microtherm vs Aerogel vs other common ceramic insulators over temp range

 

--------------------------------------------------------------------------------

 

Rath ceramic fiber papers http://www.rath-usa.com/pds-ceramic-fiber-paper.html 

 

 

 

Convert between different units of Thermal Conductivity (k)

1 W/(mK) = 1 W/(moC) = 0.85984 kcal/(hr moC) = 0.5779 Btu/(ft hr oF)

 

or use the converter here: http://www.engineeringtoolbox.com/thermal-conductivity-calculator-d_857.html

Multiply with
Convert from Convert to
Btu ft / (h ft2 oF) Btu in / (h ft2 oF) Btu in / sec ft2 oF) Cal / (cm s oC) Kcal / (cm s oC)
Btu ft / (h ft2 oF) 1 12 0.0033 0.0041 4.134 10-6
Btu in / (h ft2 oF) 0.0833 1 0.000278 0.00035 3.45 10-7
Btu in / (sec ft2 oF) 300 3600 1 1.24 0.0012
Cal / (cm s oC) 241.9 2903 0.806 1 0.001
Kcal / (cm s oC) 2.42 105 2.9 106 806.3 1000 1
Kcal / (m h oC) 0.672 8.06 0.0022 0.00278 2.778 10-6
Erg / (cm s oC) 5.78 106 6.93 10-5 1.92 10-8 2.39 10-8 2.389 10-11
Joules / (m h oC) 1.61 10-4 0.00193 5.35 10-7 6.64 10-7 6.635 10-10
Watt / (ft oC) 1.89 22.8 0.0078 0.0078 7.84 10-6
Watt / (m oK) 0.58 6.94 0.0024 0.0024 2.39 10-6
Multiply with
Convert from Convert to
Kcal / (m h oC) Erg / (cm s oC) Joules / (m h oC) Watt / (ft oC) Watt / (m oK)
Btu ft / (h ft2 oF) 1.49 173076 6230 0.527 1.73
Btu in / (h ft2 oF) 0.124 14423 519 0.044 0.14
Btu in / (sec ft2 oF) 446.5 5.19 107 1.87 106 158.2 519
Cal / (cm s oC) 360 4.19 107 1.51 106 127.6 418
Kcal / (cm s oC) 360000 4.19 1010 1.51 109 1.276 105 4.18 105
Kcal / (m h oC) 1 116300 4187 0.354 1.16
Erg / (cm s oC) 8.6 10-6 1 0.036 3.05 10-6 1 10-5
Joules / (m h oC) 0.00024 27.78 1 8.47 10-5 2.78 10-4
Watt / (ft oC) 2.82 328123 11811 1 3.28
Watt / (m oK) 0.86 1 105 3600 0.305 1

 

 

Here are some more charts of Thermal Conductivity

http://en.wikipedia.org/wiki/Thermal_conductivity

http://en.wikipedia.org/wiki/List_of_thermal_conductivities

 

JPG - 161.6 kb

 

 

 

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