Breckwell SWC31 Owner's Operation And Instruction Manual page 22

ALTERNATE FLOOR PROTECTOR CALCULATIONS
Alternate materials may be rated with C-factor (Thermal Conductance) or k-factor (Thermal Conductivity) ratings which must
be converted to R-value to determine if the alternate material meets the tested requirements. The following instructions provide the
proper information and formulas for conversion to R-value.
To determine if alternate materials are acceptable follow this sequence.
Convert material specifi cations to R-value:
a. R-value given — no conversion necessary
b. k-factor is given with a required thickness (T) in inches: R = 1/k x T
c. C-factor is given: R = 1/C
Determine the R-value of proposed alternate fl oor protector:
a. Use formulas in step 1 above to calculate R-value of proposed material(s).
b. For multiple layers, add R-values of each layer to determine overall R-value.
If the overall R-value of the fl oor protector system is equal to or greater than the fl oor protector specifi cations given, the alternate
is acceptable.
Defi nitions:
Thermal conductance (C) =
Thermal conductivity (k) =
Thermal resistance (R) =
Example:
The specs of fl oor protector material should be 3/4-inch thick material with a k-factor of 0.84. The proposed alternative material
is 4" brick with a C-factor of 1.25 over 1/8-inch mineral board with a k-factor of 0.29.
Step 1: Convert specs to R-value.
R = 1/k x T = 1/0.84 x 0.75 = 0.893 System must have a R-value of 0.893 = Rspecs
Step 2: Calculate R-value of individual components.
4" Brick with C-factor = 1.25. R = 1/C = 1/1.25 = 0.80 = Rbrick
1/8-inch (0.125") mineral board with k-factor = 0.29. R = 1/0.29 x 0.125 = 0.431 = Rmin.brd.
Step 3: Add R-values of components to get total R-value of system.
Rbrick + Rmin.brd = 0.80 + 0.431 = 1.231 = Rsystem
Step 4: Compare Rsystem to Rspecs.
Rsystem = 1.231 is larger than Rspecs of 0.893. System R-value exceeds the required specifi cations and therefore is an acceptable
alternative.
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