COMMON MATERIALS AND FACTORS
WR / WC Series Woodburning Fireplace
Side View
MATERIAL | K* | R | MINIMUM | |
THICKNESS | ||||
EH2416 | 0.458 | 1.09 | 0.50 in.** | |
(MHSC) | ||||
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Common Brick | 5.0 | 0.10 | 5.46 in.** | |
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R Value is for 1/2 inch.
*Units of K = BTU/SQ FT/HR/˚F/IN ** Thickness of Listed Material
FP533ADD
Fig. 24 Hearth extension material factors.
WARNING: HEARTH EXTENSION MUST BE IN- STALLED IN ACCORDANCE WITH FIGURE 23 AND MUST NOT COVER THE BOTTOM FRONT OPENING OF THE CIRCULATING MODEL.
Alternate noncombustible materials may be used providing the (total) thermal resistance (Rt value) of the alternate material employed is greater than or equal to R = 1.09. Thermal resistance (R) or thermal conductivity
Wall Covering
Noncombus- tible Decorative Facing
Seal all cracks between fireplace surround and wall materials with noncom- bustible material
Noncombustible Decorative Cover- ing
Hearth Extension
Insulation
FP550
2 x 4 Header (Do not notch at standoffs)
Seal crack between fireplace and hearth extension with noncom- bustible material
Safety Strips
Must be overlapped 1/2" minimum
(K), may be obtained from manufacturer of the material. Factors are related by the formula K = 1/R.
T = given thickness
R = thermal resistance for a given thickness (T) K = thermal conductivity
Noncombustible material with a lower R value may be used, provided thickness of material is sufficiently greater to maintain an equivalent (total) thermal resis- tance (Rt).
Example of Determining Hearth Extension Equivalents
To determine the thickness required for any new mate- rial:
NEW |
| K of new material (per inch) | thickness | |
required | = |
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| X of listed |
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thickness |
| K of listed material (per inch) | material | |
Example for Common Brick
T (new) = 5.0/0.458 x 0.50 in. = 5.46 in. (new required thickness).
Fig. 25 Sealing gaps.
20014528 | 17 |