Fireplace Installation
Continued
Note: For outdoor installations, fireplace enclosure must allow for adequate drainage and fresh air ventilation. It is recommended that a sealed, corrosion resistant catch pan with provision for drainage be installed under fireplace within fireplace enclosure.
Hearth Extension
A hearth extension projecting a minimum of 20" in front of and a minimum of 12" beyond each side of fireplace opening is required to protect combustible floor construction in front of fireplace. Fabricate a hearth extension using a material which meets the following specifications: a layer of noncombustible, inorganic material having a thermal conduc- tivity 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
Thermal conductivity "K" of materials can be obtained from manufacturer or supplier of noncombustible material. If hearth extension is to be covered, use noncombustible mate- rial such as tile, slate, brick, concrete, metal, glass, marble, stone, etc. Provide a means to prevent hearth extension from shifting and seal gap between fireplace frame and hearth extension with a noncombustible material (see Figure 6).
WARNING: Hearth extension
is to be installed only as shown
in Figure 6.
Seal Gap
Fireplace Front
Ember Protector
Fireplace Front |
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Raised Hearth |
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Ember Protector | Hearth |
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| Extension |
Fireplace Front | Seal Gap |
Elevated |
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Ember Protector |
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Mantels
A mantel may be installed if desired (see Figure 7). Woodwork such as wood trims, mantels or any other combustible material projecting from front face must not be placed within 12" (36" Models) or 18" (42/50" Models) of fireplace opening. Combustible materials above 12" (36" Models) or 18" (42/50" Models) and projecting more than 1 1/2" from fireplace must not be placed less than 15" (36" Models) or 21" (42/50" Models) from the top opening of the fireplace (NFPA STD 211, Sec.
Mantels or any other combustible material also may come up to side edge of black metal face of fireplace as long as projections from front face fall within limit shown in Figure 7.
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| 12 1/4" Ref. | Combustible | |
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| Material | ||
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| Safe | |
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| Zone for | |
6" |
| Projection of | ||
| Combustible | |||
Ref. | 33° | |||
Materials | ||||
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Min.15"(36" Models) |
| 3" Nom. |
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Min.21" (42/50" Models) Min.12" Models)(36" Min.18" (42/50" Models) |
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| 11/2" Max. |
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| Upper | |
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| Section of | |
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| Fireplace | |
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| Fireplace Opening |
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Top View of Fireplace
7.75" (36" Models) | FIREBOX |
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11.5" (42/50" Models) |
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| 3" Max. | |
SAFE ZONE | 4.5" | Combustible |
33° | Material | |
| Must Not | |
Min. to |
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| Overlap | |
Perpendicular |
| Front Face |
Side Wall |
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12" - 36" Models |
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18" - 42/50" Models |
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Figure 7 - Mantel Clearances to | ||
Combustible Material |
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