Hearth Extension, Building And Finishing - Heatilator MEL36 Installation Manual

B. Hearth Extension, Building and Fin-
ishing
WARNING! Risk of Fire! High temperatures, sparks,
embers or other burning material falling from the fire-
place may ignite flooring or concealed combustible
surfaces.
• Protective metal hearth strips MUST be installed.
• Hearth extensions MUST be installed exactly as
specified.
A hearth extension must be installed with all fire-
places to protect the combustible floor in front of the
fireplace from both radiant heat and sparks.
• You MUST use a hearth extension with this
fireplace.
• Refer to Figure 6.3 for minimum dimensions of
combustible material.
• This fireplace has been tested and approved for use
with a hearth extension insulated to a minimum R
value of 1.03.
• The hearth extension material MUST be covered
with tile, stone or other non-combustible material.
• Manufactured hearth materials will usually have a
published R value (resistance to heat) or k value
(conductivity of heat). Refer to the formula in Table
6.1 to convert a k value to an R value,
• Refer to Table 6.2 for hearth extension insulation
alternatives.
Figure 6.3 Minimum Non-Combustible Hearth Extension Dimensions
20 Heatilator • MEL36, MEL42 Installation Manual • 4044-212 • Rev D • 01/06/15
C
A
B
C
D
WARNING! Risk of Fire!
• Maintain clearances.
• Framing or finishing material used on the front of the fireplace
closer than the minimums listed, must be constructed entirely
of non-combustible materials (i.e., steel studs, concrete board,
etc.).
Table 6.1
R = 1/k x inches of thickness
Table 6.2
Hearth Extension Insulation Alternatives, R Value = 1.03
Material
Hearth & Home HX3, HX4
USG Micore 300™
USG Durock™ Cement Board
Cement Mortar
Common Brick
Ceramic Tile
Armstrong™ Privacy Guard Plus
Marble
Model #
MEL36
MEL42
k per inch r per inch
thick thick
0.49 2.06
0.49 2.06
1.92 0.52
5.0 0.20
5.0 0.20
12.50 0.08
0.46 2.18
14.3-20.0 0.07-0.05 14 5/8 in. - 20 3/8 in.
A B C
in. 36 52 8
mm 914 1321 203
in. 42 66 12
mm 1067 1676 305
Minimum
thickness
required
1/2 in.
1/2 in.
2 in.
5 1/8 in.
5 1/8 in.
12 1/4 in.
1/2 in.
D
16
406
20
508