SB44SS Outdoor Woodburning Fireplace
87D0059
13
FLOOr prOTeCTION
The ability of insulating material to retard the transfer of heat may be expressed as either Thermal
Conductance (C), Thermal Conductivity (K), or Thermal Resistance (R). The mathematical re-
lationship 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 noncombustible 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 12 through 16
. 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.
Figure 16
26
6
”
20”
68”
FP2239
floor protection
Figure 15
FP39
Metal Safety
Strip
Combustible
Floor
FP2240
floor protection 2
12”
Min.
12”
Min.
20” Min.
Top of Raised
Hearth
Floor Line with Raised
Hearth
Hearth Extension
Metal Safety
Strip
FP40
WarNINg:
The hearth extension and the
metal safety strip should be installed only
in a horizontal relationship to the fireplace.