10
Floor Protection
All woodstoves require floor protection when installed on a
com bustible surface. You m ust place use protector
equivalent to 3/8' asbestos m illboard covered with 24
gauge m etal. The floor protector m ust extend 16" in front of
the door side, 8" on each side and 8" in the rear of the unit
and under the chim ney connection and 2" beyond each
side. See Figure 4.
The k, C or R factor that correlates with the floor protector
m aterial used during the test if the room heater is not
provided with a floor protector. The units of m easure for k,
C and R factors shall use the sam e applicable units.
Directions and exam ples on how to use alternate m aterials
and how to calculate equivalent thickness shall be shown.
An easy m eans of determ ining if a proposed alternate floor
protector m eets requirem ents listed in the appliance
m anual is to follow this procedure:
1. Convent specifications to R-value
a. R-value is given - no conversion is needed.
b. K-factor is given with a required thickness (T) in
inches: R=1/k+T
c. C-factor is given: R=1/C
2. Determ ine the R-value of the proposed alternate floor
protector.
a. Use the form ula in step 1 to convert values not
expressed as “R”.
b. For m ultiple layers, add R-values of each layer to
determ ine the overall R-value.
3. If the overall R-value of the system is greater than the R-
value of the specified floor protector, the alternate is
acceptable.
EXAM PLE:
The specified floor protector should be 3/4 inch thick
m aterial with a k-factor of .84.
The proposed alternate is 4" brick with a C-factor of 1.25
over 1/8" m ineral board with a k-factor of .29.
Step 1: Use form ula above to convert specification to
R-value. R=1/kT = 1/0.84 x .75 = .893
Step 2: Calculate R of proposed system .
4" brick of C - 1.25, therefore
R brick = 1/C = 1/1.25 = 0.80
1/8" m ineral board of k+ 0.29, therefore
R m in.bd. = 1/0.29 x 0.125 = 0.431
Total R = R brick + R brick + R m ineral Board
= 0.8 + 0.431 = 1.231
Step 3: Com pare the proposed system R of 1.231 to
specified R of 0.893. Since proposed system
R is greater than required, this is acceptable.
Definitions:
Note: Asbestos cannot be used. Asbestos is used as a
standard only. 3/8 inch asbestos m illboard has a “K” factor
of 0.84. The newer substitute CERAFORM board has a “K”
factor of 0.21. Your floor protector m ust have an equivalent
or better “K” factor than the above recom m endations.
