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127055-01_H
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OPTIONAL OUTSIDE AIR KIT (MODEL AK4/AK4F)
The installation of an outside air kit should be performed during the rough
framing of the fireplace due to the nature of it's location. Outside combus-
tion air is accessed through a vented crawl space (AK4F) or through a
sidewall (AK4). See page 13 for instructions of operating air kit.
CAUTION: Combustion air inlet ducts shall not
terminate in attic space.
The maximum height for the air vent can not exceed
3 feet below the flue gas outlet of the termination.
HEARTH EXTENSION
A hearth extension projecting a minimum of 16" in front of and a
minimum of 8" beyond each side of the fireplace opening is required
to protect combustible floor construction in front of the fireplace.
Fabricate a hearth extension using a material which meets the fol-
lowing specifications: a layer of noncombustible, inorganic material
having a thermal conductivity of k=0.84 BTU IN/FT, HR. F (or less) at
1" thick. For example, if the material selected has a k factor of 0.25,
such as glass fiber, the following formula would apply:
0.25 x 1.0" = 0.30" thickness required
0.84
Thermal conductivity "k" of materials can be obtained from the manu-
facturer or supplier of the noncombustible material. If the hearth
extension is to be covered, use noncombustible material such as
tile, slate, brick, concrete, metal, glass, marble, stone, etc. Provide
a means to prevent the hearth extension from shifting and seal gap
between the fireplace frame and hearth extension with a noncom-
bustible material (see Figure 3).
WARNING: Hearth extension is to be installed only
as shown in Figure 3.
Figure 3 - Hearth Extension
Seal Gap
Fireplace Front
Ember Protector
Fireplace Front Raised
Hearth
Fireplace Front Elevated
Ember Protector
Ember Protector
Seal Gap
Hearth
Extension
MANTELS
A mantel may be installed if desired (see Figure 4). Woodwork such
as wood trims, mantels or any other combustible material project-
ing from the front face must not be placed within 12" of the fireplace
opening and within 9" of top louver opening. Combustible materials
above 12" and projecting more than 1
1
/
2
" from the fireplace must not
be placed less than 12" from the top opening of the fireplace (NFPA
211, Section - Clearance from Combustible Material).
Mantels or any other combustible material also may come up to the
side edge of the black metal face of the fireplace if projection from
front face falls within the limit shown in Figure 4.
Figure 4 - Mantel Clearances to Combustible Material
FIREBOX
SAFE ZONE
Top View of Fireplace
2" (51 mm) Max.
3.0"
(77 mm)
Min. to
Perpendicular
Side Wall
12" (305 mm)
8" (204 mm)
33°
Combustible
Material Must Not
Overlap Front Face
FIREPLACE INSTALLATION
Continued
12
1
/
4
"
(312 mm)
Ref.
15"
(381 mm)
Min.
12"
(305 mm)
Min.
6"
(153 mm)
Ref.
1
1
/
2
"
(38 mm)
Max.
3" (77 mm)
Nom.
33°
Combustible
Material
Safe Zone for
Projection of
Combustible
Materials
Fireplace Opening
Upper
Section of
Fireplace
