While poking around this morning, I came upon the website of one of the biggies in the high-temperature insulation world, Thermal Ceramics. Looking at the specs of their blanket materials, which is frequently used in stoves and to insulate liners, they have conductivity (K) vs temperature for various densities:
http://www.thermalceramics.com/upload/pdf/514-205.pdf
For the highest density material they post specs for (8 lbs/cu. ft), the R factor (1/K) at 500F degress is 2.27. (For context, that's about the same R-factor as a double-pane window.) It reduces quickly as temps rise, at 1000F it is 1.15 .
So when we see this material being used, it is not providing a huge insulating value, but more of a subtle tweak of temperatures.
This high-temp stuff is fascinating!
Oh, BTW, one can buy a 1/4" x 24" x 25' roll of this stuff for about $35 retail...
http://www.thermalceramics.com/upload/pdf/514-205.pdf
For the highest density material they post specs for (8 lbs/cu. ft), the R factor (1/K) at 500F degress is 2.27. (For context, that's about the same R-factor as a double-pane window.) It reduces quickly as temps rise, at 1000F it is 1.15 .
So when we see this material being used, it is not providing a huge insulating value, but more of a subtle tweak of temperatures.
This high-temp stuff is fascinating!
Oh, BTW, one can buy a 1/4" x 24" x 25' roll of this stuff for about $35 retail...