39
11
11
Finishing
A. Non-Combustible Materials
• Materials which will not ignite and burn, composed of
any combination of the following:
- Steel
-
Iron
- Brick
- Tile
- Concrete
- Slate
- Glass
- Plasters
• Materials reported as passing
ASTM E 136, Standard
Test Method for Behavior of Metals, in a Vertical Tube
Furnace at 750° C
B. Combustible Materials
• Materials made of or surfaced with any of the following
materials:
- Wood
- Compressed
paper
- Plant
fi
bers
- Plastic
• Any material that can ignite and burn;
fl
ame proofed or
not, plastered or un-plastered
74 in.
(1880 mm)
50 in.
(1270 mm)
12 in.
(305 mm)
12 in.
(305 mm)
Raised Hearth
20 in. (508 mm)
minimum
Flush Hearth
30 in. (762 mm)
minimum
Figure 11.1 Hearth Extension Dimensions
Table 11.2
C. Hearth Extension
WARNING! Risk of
fi
re!
High temperatures, sparks,
embers or other burning material falling from the
fi
replace
may ignite
fl
ooring or concealed combustible surfaces.
• Protective metal hearth strips MUST be installed.
• Hearth extensions MUST be installed exactly as
speci
fi
ed.
Table 11.1
Hearth Extension Insulation Alternatives-Total minimum R Value must equal 1.03
Material
k per inch
thick
r per inch
thick
Minimum
thickness
required
Hearth & Home HX3, HX4 (Micore 300™)
0.49
2.06
1/2 in.
USG Micore 160™
0.39
2.54
1/2 in.
USG Durock™ Cement Board
1.92
0.52
2 in.
Cement Mortor
5.0
0.20
5-1/8 in.
Common Brick
5.0
0.20
5-1/8 in.
Ceramic Tile
12.50
0.08
12-1/4 in.
Armstrong™ Privacy Guard Plus
0.46
2.18
1/2 in.
Marble
14.3-20.0
0.07-0.05
14-5/8 in. - 20-3/8 in.
R = 1/k x inches of thickness
• You MUST use a hearth extension with this
fi
replace.
• This
fi
replace 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 11.1
to convert a k value to an R value,
• Refer to Table 11.2 for hearth extension insulation
alternatives.
Heatilator • I100 • 35144 • Rev AA • 11/08
Î