#ABY R.2 October 2020
Hussong Mfg. Co., Inc. • Kozy Heat Fireplaces
INSTALLATION PLANNING
17
3.9 Alternate Floor Protection Material
How to determine if alternate floor protection materials are acceptable:
•
All floor protection materials must be non-combustible (i.e., metals, brick, stone, mineral fiber boards, etc.).
•
Any organic materials (i.e., plastics, wood, paper products, etc.) are combustible and must not be used.
•
The floor protection specified may include some form of thermal designation, such as R-value (thermal resistance), K-factor (thermal
conductivity), or C-factor (thermal conductance).
Procedure:
A. Convert specification to R-value:
I. R-value given:
no conversion needed
II. k-factor is given with a required
thickness (T)
in inches:
R=1/k x T
III. C-factor is given:
R=1/C
B. Determine the R-value of proposed alternate floor protector:
I. Use formula in step (a) to convert values not expressed as ‘R’. For multiple layers, add R-values of each layer to determine overall R-value.
C. If overall R-value of the system is greater than the R-value of specified floor protector, the alternate is acceptable.
EXAMPLE:
The specified floor protector should be 3/4 inch 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 with a k-factor of .29.
Step (a): Use formula above to convert specification to R-value.
R = 1/k x T = 1/.84 x .75 = 0.893.
Step (b): Calculate R of proposed system.
To determine the R value of 4” brick with C =1.25;
R
brick
= 1/C = 1/1.25 = 0.80
To determine the R value of the 1/8” mineral board with k = 0.29;
R
mineral board
= 1/k x T (thickness of board) = 1/.29 x .125 = .431
To determine the Combined R value of brick and mineral board =
R
brick
+ R
mineral board
= .8 + .431 = 1.231
Step (c): Compare proposed system of R of 1.231 to specified R of .893. Since proposed system R of 1.231 is greater than required (specified R of
8.93), the system is acceptable.
Definitions:
Thermal conductance
Thermal conductivity
Thermal resistance
C=
k=
R=
Btu
(hr)(ft
2
)(ºF)
W
(m
2
)(ºK)
(Btu)(in)
(hr)(ft
2
)(ºF)
W
(m)(ºK)
Btu
(hr)(ft)(ºF)
(ft
2
)(hr)(ºF)
Btu
(m
2
)(ºK)
W
=
=
=
=
IMPERIAL
UNITS
METRIC
UNITS
