Specifications
1
87D0058
SB50HB Series Woodburning Fireplace
The ability of insulating material to retard the transfer of heat may be expressed as either Ther-
mal Conductance (C), Thermal Conductivity (K), or Thermal Resistance (R). The mathematical
relationship of these values and the formulas for converting one value to another is as follows:
C=K divided by the material thickness
(Example C = .43 divided by 1/ (.50)
C = .86)
K = C multiplies by the material thickness
(Example K = .86 multiplied by 1/ (.50)
K = .43)
R= The material thickness divided by K
(Example R = 1/ (.50) divided by .43
R = 1.16)
With either type hearth extension minor shifting of the supporting floor or expansion and contrac-
tion may eventually cause a crack to develop between the hearth extension and the face of the
fireplace. To help prevent the crack from developing, the hearth extension materials must be
firmly fastened in place. Wall ties should be screwed to the face of the fireplace and imbedded
in the mortar joints of brick, stone, or other non-combustible materials. The metal safety strip
packed with the fireplace must be placed beneath the fireplace and extended under the hearth
extension or into a mortar joint of the hearth extension as shown by Figures 10, 13, and 14. In
the event a crack does eventually develop, the metal safety strip will serve as a barrier to prevent
sparks or embers from falling from the fireplace onto combustible flooring materials.
59”
30”
58”
2856O”
20”
74”
FP2223
hearth protection
Figure 13
Metal Safety Strip
Combustible
Floor
FP3
Hearth
Protection
The hearth extension and the
metal safety strip should be installed only
in a horizontal relationship to the fireplace.
12”
Min.
12”
Min.
20” Min.
FP2224
hearth ext front
Top of Raised Hearth
Floor Line with
Raised Hearth
Hearth
Extensions
Metal Safety
Strip
Figure 14
FP4