Alternate floor protection
All floor protection materials must be non-combustible ie.
Metal, brick, stone, mineral fiber boards). Any combustible
material may not be used.
The easiest means of determining if a proposed alternate floor
material meets requirements listed in this manual is to follow
R-value = thermal resistance
K-value = thermal conductivity
C-value = thermal conductance
1. Convert the specification to r-value;
If r-value is given, no conversion is needed.
If k-value is given with a required thickness (t) in
inches: R=1/k X T.
If c-value is given: R=1/C.
2. Determine the r-value of the proposed alternate floor
Use the formula in step 1 to convert values not
expressed as "R".
For multiple layers, add r-values of each layer to
determine overall r-value.
3. If the overall R-value of the sustem is greater than the
R-value of the specified floor protector, the alternate is
The specified floor protector should be 3/4" thick material with
a k-factor of 0.84. The proposed alternate is 4" brick with a c-
factor of 1.25 over 1/8" mineral board witha k-factor of 0.29.
Use formula above to convert specifications to
R-value. R=1/k x t= 1/.84 x .75 = .893
Calculate r of proposed system.
4" brick of c-1.25, therefore
R brick = 1/c = 1/1.25 = 0.80
1/8" mineral board of K = 0.29 therefore
R mineral board = 1/.29 x 0.125 = 0.431
Total R = R brick + R mineral board= 0.8 + 0.431=1.231
Compare proposed system R = 1.231 to specified R of
0.893. Since R is greater than required, the system
Thermal conductance =
Thermal conductivity =
Thermal resistance =
For the Jøtul F 3 requires floor protection with a minimum
insulating R-value of 1.1.
Alcove installation require a minimum R-value of 1.1. (If a UL/
ULC or whi listed hearth pad is not used.)