Thermal Conductivities, k, of Common Materials 
.           Btu-ft          . 
ft^2 - hr - degree F 

                                                                        Temperature degrees F 
Materials                                                70            200            400            800            1200            1600            2000 
Air                                                            0.015        0.018         0.023 

Construction materials 
    brick, red                                             c 0.4 
    Concrete, cinder                                    0.2 
                    1:4 dry                                    0.44 
                    stone                                      0.54 
    Pyrex glass                                          c 0.6 
    Rubber                                                  c 0.1 
    Sand, dry                                              c 0.2 
    Sandstone                                            c 1.0 
    Wood                                                    c 0.1 

Graphite 
    longditudinal                                        95 
    -100 mesh powder                                0.1 

Materials                                                70            200            400            800            1200            1600            2000 

Insulating materials 
    Asbestoes fiber. 36 lb/ft^3               0.09          0.11            0.12           0.13 
    Diatomaceous earth powder             0.039        0.042          0.048        0.061 
                            18 lb/ft^3 
     Lampblack                                         0.04 
     85% magnesia 13lb/ft^3                    0.034        0.036         0.040 
    Mineral wool, fiberous                       0.023 

Metals, solid 
    Aluminium                                            120 
    Brass                                                    60 
    Cast iron                                               30 
    Copper                                                 220 
    Gold                                                     170 
    Lead                                                       20 
    Magnesium                                            90 
    Mercury(liquid)                                       7 
    Nickel                                                    35 
    Platinium                                               40 
    Silver                                                    240 
    Steel, low carbon                                  25 
    Steel, stainless                                       9 
    Zinc                                                        65 

Materials                                                70            200            400            800            1200            1600            2000 

Oils, miscellaneous hydrocarbons      c 0.08 

Refractory materials (see note below) 
    90% alumina brick                                            1.70            1.56           1.34           1.19             1.13              1.10 
    Chrome brick                                                                        0.84           0.90           0.94             0.97              0.99 
    Fireclay brick                                                    0.57             0.60           0.67           0.74             0.80              0.87 
    Graphite                                                                                61              42              33                26                 18 
    Magnesite brick                                                                     3.0             2.8             2.4               2.0                1.7 
    Silica brick                                                        0.57             0.63            0.75           0.88             1.00             1.13 
    Silicon carbide brick                                                             17.5           14.6            12.5            9.6                7.9 

Water                                                     0.35        0.39 

Note:  Thermal conductivities of refractories may differ considerablly from these representative values due 
to differences in structure and porosity and changes occurring during service