Vogelzang International PB65XL - Manual (Page 15)

VGZ-003 / 20120327.0 www.vogelzang.com PB65XL / Page 15
FLOOR PROTECTOR MATERIAL CALCULATIONS
This stove has been tested for and must be installed on a floor protector with the proper Thermal Resistance or R-value
as stated in step 1 of the installation instructions under “Locating Stove” section of this manual. If the floor protector ma-
terials listed in the instructions are not available, materials with an equivalent R-value may be substituted.
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.
1. Convert material specifications 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
2. Determine the R-value of proposed alternate floor 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.
3. If the overall R-value of the floor protector system is equal to or greater than the floor protector specifications given,
the alternate is acceptable.
Definitions:
Thermal conductance(C) =
BTU
=
W
(hr)(ft 2 )(°F) (m 2 )(°K)
Thermal conductivity (k) =
(Btu)(inch)
=
W
=
Btu
(hr)(ft 2 )(°F) (m)(°K) (hr)(ft)(°F)
Thermal resistance (R) =
(ft 2 )(hr)(°F)
=
(m 2 )(°K)
Btu W
Example:
The specs of floor 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
specifications and therefore is an acceptable alternative.