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Product Specification Manual - Destination 1.9
ENGLISH
If the value
(D)
is negative or zero, additional floor protection in front of the unit is not needed
because the masonry fireplace hearth extension is long enough. If the value
(D)
is positive, an
additional floor protection in front of the hearth extension at least equivalent to the result
(D)
must be added.
2.3 R Value
There are two ways to calculate the R-value 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 value from R values 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. R-values of some selected materials are shown below.
Table 3 : Thermal Characteristics of Common Floor Protection Materials
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MATERIAL
CONDUCTIVITY (K)
PER INCH
RESISTANCE (R)
PER INCH THICKNESS
Micore® 160
0.39
2.54
Micore® 300
0.49
2.06
Durock®
1.92
0.52
Hardibacker®
1.95
0.51
Hardibacker® 500
2.3
0.44
Wonderboard®
3.23
0.31
Cement mortar
5.00
0.2
Common brick
5.00
0.2
Face brick
9.00
0.11
Marble
14.3 – 20.00
0.07 – 0.05
Ceramic tile
12.5
0.008
Concrete
1.050
0.950
Mineral wool insulation
0.320
3.120
Limestone
6.5
0.153
Ceramic board (Fibremax)
0.450
2.2
Horizontal still air (1/8" thick)
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0.135
0,920**
Exemple:
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® (R = 1 x 0.52 = 0.52).
0.8 + 0.52 = 1.32.
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Information as reported by manufacturers and other resources.
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Horizontal still air can’t be «stack» to accumulate R-values; each layer must be separated with another non-combustible material.
