Finishing; Hearth Extension - Heat & Glo EXCLAIM-50 Owner's Manual

8 8

Finishing

A. Hearth Extension
A hearth extension must be installed with all fi replaces to
protect the combustible fl oor in front of the fi replace from
both radiant heat and sparks. See Figures 8.1 -8.4.
High temperature
(300°F min.) continuous,
non-combustible sealant
HX3 or HX4
Hearth Ext
Tile, stone or other
or equivilent
non-combustible material
insulation
(see Table below)
Floor constructed of wood or
other combustible material
Figure 8.1 Hearth Extension Construction
WARNING
Fire Risk
• Metal hearth strips MUST be installed.
Sparks or embers may ignite fl ooring.
This fi replace has been tested and approved for use with a
hearth extension insulated to a minimum R value of 1.03.
To substitute materials for the factory-available hearth ex-
tensions, see Figure 8.3 and calculate insulation alterna-
tives as per Table 8.1 and the following formulas:
• Thermal conductivity per inch thickness = k
• k = (BTU)(inch) / (foot
• Required thickness = Rk
• Thermal resistance per inch thickness = r
2
• r = (foot )(hour)(°F) / (BTU)(inch)
• Required thickness = R / rB.
Table 8.1
Hearth Extension Insulation Alternatives-Total minimum R Value must equal 1.03
Material
Hearth & Home HX3, HX4 (Micore 300™)
USG Micore 160™
USG Durock™ Cement Board
Cement Mortor
Common Brick
Ceramic Tile
Armstrong™ Privacy Guard Plus
Marble
30
Protective
Metal Hearth
Strip
2 in. (51 mm)
required
2
)(hour)(°F)
k per inch
thick
0.49
0.39
1.92
5.0
5.0
12.50
0.046
14.3-20.0
Heat & Glo • EXCLAIM-50 • 4013-041 Rev Q • 06/07
Metal strips are placed 2 in. (51 mm) under the front
of the fireplace and must extend beyond the front
and sides of fireplace opening by 2 in. (51 mm).
Figure 8.2 Positioning the Protective Metal Hearth Strips
Fire Risk
•
High temperatures or hot embers may ignite
concealed combustibles.
Minimum
r per inch thickness
thick required
2.06 1/2 in.
3.54 1/2 in.
0.52 2 in.
0.20 5-1/8 in.
0.20 5-1/8 in.
0.08 12-1/4 in.
2.18 1/2 in.
0.07-0.05 14-5/8 in. - 20-3/8 in.
1 in. (25 mm) overlap
WARNING
Hearth extensions must be installed
exactly as specifi ed.