Vermont Castings EWF30
Side Wall Protection
Adjacent combustible side walls that are within mini- mum dimensions shown in Figure 25 of the fireplace opening must be protected with CFM Corporation Wall Shield Model SP40 or a specifically built wall shield described in Figure 20.
The special wall shield design described in Figure 20 is an alternate method of adding protection to side walls and can be used in place of the SP40 with the same wall clearances specified for the SP40. Rt must =1.85 minimum.
Examples of wall shield insulation:
1. Manville - CERAFORM 126, K=.27, 1/2 inches thick
2. EH2416, K = .458,
1 inch thick required.
Hearth Installation
A hearth extension is required to protect a combustible floor in front of the fireplace. Refer to Figure 26 for mini- mum dimensions and mounting detail.
NOTE: Hearth Extension must not cover the air inlet opening of a fireplace.
The hearth extension described in Figure 26 must be a durable noncombustible material with a minimum (total) Rt value of 1.09; see Figure 24 for examples. The over- all height (above a combustible floor), depth and width must be as indicated, with the extension centered to the fireplace opening.
The top of insulation must be covered with a
Secure the hearth extension to the floor to prevent shifting, using trim molding or other similar means at three (3) outer edges. Seal crack between the fireplace hearth and hearth extension with a noncombustible material. (Figs. 25 and 26)
WARNING: Hearth extension must be installed in accordance with Figure 25. Top of hearth extension must be level with bottom of fireplace.
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 (K), may be obtained from manufacturer of the material. Factors are related by the formula K = 1/R. (Fig. 24)
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 Equiva- lents
To determine the thickness required for any new mate- rial:
NEW | K of new material (per inch) | thickness | |
required = |
| 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).
COMMON MATERIALS AND FACTORS
MATERIAL | K* | R | MINIMUM |
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THICKNESS | ||||
EH2416 |
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(CFM Corporation) 0.916 2.18 | 1.0 in.** |
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Common Brick 5.0 | 0.10 | 5.46 in.** |
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R Value is for 1/2 inch. |
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* Units of K = BTU/SQ FT/HR/˚F/IN | ||||
** Thickness of Listed Material | FP533ADD | |||
Fig. 24 Hearth extension material factors. |
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| 2 x 4 Header - Do not | |
Wall Covering |
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| notch at standoffs | |
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| Noncombustible | ||
Noncombustible |
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Decorative |
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Facing |
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Seal all cracks |
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| NOTE: No |
between fireplace sur- |
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round (steel) and wall |
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| may cover |
materials with noncom- |
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| black cast |
bustible material. |
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| face. |
Cast Front |
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Noncombustible |
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Decorative |
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Covering |
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FP1202a |
| Safety Strips - Must be | ||
| overlapped 1/2” minimum | |||
Fig. 25 Sealing gaps.
16 | 20008662 |
