Ashley AC2000 - Alternate Floor Protector Calculations

-21-
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 speci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 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 oor protector system is equal to or greater than the oor protector specications
given, the alternate is acceptable.
Denitions:
Thermal conductance (C) = =
Thermal conductivity (k) = = =
Thermal resistance (R) = =
Example:
The specs of 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 specications and therefore
is an acceptable alternative.
BTU
(hr)(ft²)(°F)
W
(m²)(°K)
(Btu)(inch)
(hr)(ft²)(°F)
W
(m²)(°K)
BTU
(hr)(ft²)(°F)
(hr)(ft²)(°F)
BTU
(m²)(°K)
W