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Appendix A: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
this procedure.
R-value = thermal resistance
K-value = thermal conductivity
C-value = thermal conductance
1. Convert the specification to r-value;
a. If r-value is given, no conversion is needed.
b. If k-value is given with a required thickness (t) in
inches: R=1/k X T.
c. If c-value is given: R=1/C.
2. Determine the r-value of the proposed alternate floor
protector.
a. Use the formula in step 1 to convert values not
expressed as “R”.
b. 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
acceptable.
Example:
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.
Step A. Use formula above to convert specifications to
R-value. R=1/k x t= 1/.84 x .75 = .893
Step B. 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
Step C. Compare proposed system R = 1.231 to specified R of
0.893. Since R is greater than required, the system
is acceptable.
Definitions:
Thermal conductance =
C = btu = W
(Hr)(ft2)(f) (m2)(k)
Thermal conductivity =
K = btu = W = (btu)
(Hr)(ft2)(f) (m2)(k) (hr)(ft)(f)
Thermal resistance =
R = btu = (m2)(k) = (btu)(inch)
(Hr)(ft2)(f) W (hr)(ft2)(f)
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.)
USA/Canada