12
53D9025
FLOOR PROTECTION
The ability of insulating material to retard the transfer of heat may be expressed as either Thermal Con-
ductance (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 1/2 (.50)
C = .86)
K = C multiplies by the material thickness
(Example K = .86 multiplied by 1/2 (.50)
K = .43)
R= The material thickness divided by K
(Example R = 1/2 (.50) divided by .43
R = 1.16)
26
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”
53
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”
27”
52
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”
20”
68”
FP1886
hearth protction
8/08
Figure 11
Metal Safety Strip
Combustible
Floor
Hearth Protector
WARNING: The hearth extension and
the metal safety strip should be in-
stalled only in a horizontal relationship
to the fireplace, as illustrated.
12”
Min.
12”
Min.
20” Min.
FP1887
hearth extension
8/08
Figure 12
Top of Raised
Hearth
Floor Line with
Raised Hearth
Hearth Extension
Metal Safety Strip
With either type hearth extension minor shifting of the supporting floor or expansion and contraction 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 be-
neath the fireplace and extended under the hearth extension or into a mortar joint of the hearth extension
as shown by Figures 9 and 11. 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.
