Fire-Liners: Ceramic Wool vs. Drywall

[MVW]

There is much discussion on bulletin boards about the best materials to use in fire-lined gun safes (RSC).

http://www.6mmbr.com/gunsafes.html#fireproof

http://www.thehighroad.org/archive/index.php/t-284466

http://en.wikipedia.org/wiki/R-value_(insulation). This is a measure of the thermal resistance and has units of meters squared degrees Kelvin per Watt (Most data are provided in metric SI units. I will convert to English units, ft squared degrees F hour per Btu, at the end). R-value is defined as the thickness of the material divided by the thermal conductivity, which is discussed in http://en.wikipedia.org/wiki/Thermal_conductivity. Thermal conductivity has units of W/m K. Libraries are full of engineering data on construction materials, but some data are easily accessible on the web. http://www.engineeringtoolbox.com/th...ity-d_429.html

http://www.unifrax.com/web/UnifraxWebEU.nsf/By+Trade+Name/71DE767DCE5F584E80256FEF003B0DEA/$File/Fiberfrax%20Durablanket%20WR%20-%20E0204.pdf

Data on rock wool, another common insulating material, can be found at http://www.wilhams.com.my/images/pro_7_4.pdf

                 Thermal          R-Value (1”)   R-Value (1”)
               Conductivity      0.025 m thick   1/12ft thick
Material        (W/m K)            (m^2 K/W)     (ft^2 F/Btu) 
------------------------------------------------------------------------
Dry Air             0.025             1.00           5.8
Rock wool           0.033             0.76           4.4
Styrofoam           0.035             0.71           4.1
Ceramic wool        0.035             0.71           4.1
Fiberglass          0.042             0.60           3.4*
Gypsum              0.170             0.15           0.8
Type C drywall      0.258             0.10           0.6
Type X drywall      0.276             0.09           0.5
Portland Cement     0.290             0.09           0.5
Steel              50.2               0.0005         0.003

[MVW]

Material            Diffusivity           Conductivity      Capacity   Density
-------------------------------------------------------------------------------
Ceramic Wool        3.2x10exp(-7)           0.035              1140         96
Type-C Drywall      3.6x10exp(-7)           0.276              1017        752

[Librarian]

MVW, Chainsaw - thank you for a really interesting thread!

BTW, it took me forever to find out that if you wrap your tabular data in a code block - the # button in advanced editing - the software won't strip your spaces down to single, so you don't need the "." or "," fill characters.

[MVW]

Thanks for the tip Librarian. Much better formatting!