Page Coefficients of Thermal Conductivity Material Coefficient of Thermal Conductivity W/m °C Air Aluminum Brass Brick Concrete Copper Cork Felt Glass Glass fibre Iron cast Plastic cellular Steel Wood Wallboard paper .02 0 0 . .8 8 .04 .03 . .0 .0 .1 .07 Thermal Expansion of Solids Increase in length L α T � T where L original length α coefficient of linear expansion T � T rise in temperature Increase in volume V β T � T where V original volume β coefficient of volumetric expansion T � T rise in temperature coefficient of volumetric expansion x coefficient of linear expansion β α