Firebox Installation
Continued
1/2" (1.27 cm) |
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Minimum to |
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Combustibles |
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Nailing |
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Flanges |
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Prepared | Nails or |
Framing | |
| Screws |
Figure 9 - Nailing Flanges
Hearth Extension
A hearth extension projecting a minimum of 16" in front of and a minimum of 8" beyond each side of the firebox opening is required to protect combustible floor construction in front of firebox (see Figure 10). Fabricate a hearth extension using a material which meets the following specifications: a layer of noncom- bustible, 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:
0.25x 1.0" = 0.30" thickness required
8" | MIN. |
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52 | / (92. MIN. |
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| 7cm) |
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Thermal conductivity "K" of materials can be obtained from manufacturer or supplier of noncombustible material.
If hearth extension is to be raised, a “Z” type ember protector must be used (see Figure 7, page 5, and Figure 11)
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| Noncombustible |
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| Hearth |
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| Extension |
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| 8" Max. |
1 | 1/2" Typ. | “Z” Type Ember |
Protector | ||
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| Noncombustible |
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| Hearth Extension |
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| “K” Factor |
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| .84 |
1 1/2" Typ. |
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| Ember Protector |
Figure 11 - Raised Hearth Extension
Venting Installation
Optional Outside air Kit
The installation of an outside air kit should be performed during the rough framing of the firebox due to the nature of it’s location. Outside combustion air is accessed through and exterior wall or a vented crawl space (see Figure 12, page 7).
CAUTION: Air inlet ducts must 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.
Avoid installing outside air eyebrow in areas where inlet opening may be blocked by snow, bushes or other obstacles. It should also be located beyond the reach of small children.
NONCOMBUSTIBLE
HEARTH EXTENSION
Figure 10 - Hearth Extension
For further details on installation of outside air kit, please refer to instructions included with air kit. For operating instructions, please refer to your owner's manual.
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