Finishing; Non-Combustible Materials; Combustible Materials; Hearth Extension - Heat & Glo Heat&Glo RUTHERFORD-36 Owner's Manual

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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
C. Hearth Extension
WARNING! Risk of fi re! High temperatures, sparks, em-
bers or other burning material falling from the fi replace may
ignite fl ooring or concealed combustible surfaces.
• Metal hearth strips MUST be installed (Section 7.C.).
• Hearth extensions MUST be installed exactly as
specifi ed.
Table 12.1
R = 1/k x inches of thickness
Table 12.2
Hearth Extension Insulation Alternatives-Total minimum R Value must equal 2.32
Material
Hearth & Home HX3, HX4 (Micore 300™)
USG Micore 160™
USG Durock™ Cement Board
Cement Mortar
Common Brick
Ceramic Tile
Armstrong™ Privacy Guard Plus
Marble
k per inch
thick
0.49
0.39
1.92
5.0
5.0
12.50
0.46
14.3 to 20.0
Heat & Glo • RUTHERFORD-36 • 4059-341 Rev D • 03/09
• 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
2.32.
• 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 12.1 to convert a k
value to an R value,
• Refer to Table 12.2 for hearth extension insulation
alternatives.
12 in.
(305 mm)
36 in.
(914 mm)
60 in.
(1524 mm)
(R value of hearth must be
equal to or greater than 2.32)
Figure 12.1 Hearth Extension Dimensions
R per inch
thick Minimum thickness required
2.06 1 in. (25.4 mm)
2.54 1 in.(25.4 mm)
0.52 4 in. (101.6 mm)
0.20 10 in. (254 mm)
0.20 10 in. (254 mm)
0.08 25-3/4 in. (654 mm)
2.18 1 in. (25.4 mm)
0.07 to 0.05 29-1/2 to 41 in. (749.3 to 1041.4 mm)
12 in.
(305 mm)
Raised Platform
20 in. (508 mm) Minimum
Flush Hearth
30 in. (762 mm) Minimum
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