Enerzone Destination 1.5 Installation And Operation Manual page 33

If non-combustible material floor protection needs to be added in front of and level with the hearth
extension of the masonry fireplace, an R factor equal to or greater than 2 is required.
The use of an R value is convenient when more than one material is going to be used in the hearth
extension to cover the combustible surface. This is because R values are additive, whereas K
values are not.
There are two ways to calculate the R factor of the floor protection. First, by adding the R-values of
materials used, or by the conversion if the K factor and thickness of the floor protection are given.
To calculate the total R factor from R factors of the materials used, simply add the R-values of
materials. If the result is equal to or greater than the R-value requirements, the combination is
acceptable. To know the R-values of some selected materials, see table Thermal Characteristics
of Common Floor Protection Materials.
Example:
Required floor protection R of 1.00. Proposed materials: four inches of brick and one inch of
®
Durock board
Four inches of brick (R = 4 x 0,2 = 0,8) plus 1 inch of Durock
This R value is larger than the required 1.00 and is therefore acceptable
Destination 1.5 Insert Installation and Operation Manual
0.8 + 0.52 = 1.32.
®
(R = 1 x 0.52 = 0.52).
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