1. Manville - CERAFORM 126, K=.27, 1/2 inches thick
2. MHSC - 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 24 for minimum dimensions and mounting detail.
NOTE: Hearth Extension must not cover the air inlet/outlet opening of a fireplace.
The hearth extension described in Figure 24 must be a durable noncombustible material with a minimum (to- tal) Rt value of 1.09; refer to Figure 25 for examples. The overall 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 noncom- bustible decorative covering or a piece of .018” mini- mum sheet metal, to protect hearth extension material. (Fig. 24)
CWC Series Woodburning Fireplace
Secure the hearth extension to the floor to prevent shift- ing, 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. 22 and 26)
WARNING: HEARTH EXTENSION MUST BE IN- STALLED IN ACCORDANCE WITH FIGURE 24 AND MUST NOT COVER THE BOTTOM FRONT OPENING OF THE CIRCULATING MODEL.
Alternate noncombustible materials may be used provid- ing the (total) thermal resistance (Rt value) of the alter- nate 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. Fac- tors 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).
Minimum Wall Clearances
WITH |
| WITHOUT | |
Noncombustible |
| Noncombustible | |
Surround Facing |
| Surround Facing | |
|
| Shaded area starts | |
4" BRICK |
| 1/2" away from | |
(Example material) |
| edge of unit | |
|
| 4" | |
E F** | FIREBOX | E | |
| OPENING | D | |
C** | A - Min. clearance | ||
| |||
| to combustible |
| |
SIDE | perpendicular wall |
| |
B - Min. clearance | SIDE | ||
WALL | to combustible | WALL | |
| perpendicular wall when | ||
| using noncombustible wall shield* | ||
Combustible material permitted within shaded area.
*Noncombustible wall shield requires 1" MHSC EH2416 insulation (minimum R Value = 1.85) between decorative noncombustible rigid covering and combustible wall.
Minimum height and width is 40" x 40".
**Dimension/degree of angle will vary depending on thickness of noncombustible surround facing.
Minimum Hearth Extension Dimensions
(for
| H | G | G |
|
|
| |
|
|
| J |
| Seal cracks |
|
|
May install | between the |
| |
noncombustible | fireplace |
|
|
decorative | and hearth |
|
|
covering | extension with |
| |
OR .018" min. | noncombustible |
| |
sheet metal | material |
| FIREPLACE |
|
|
| HEARTH |
4" MIN. |
|
|
|
COMBUSTIBLE | MINIMUM | Safety strips | |
FLOOR | INSULATION | must overlap | |
| VALUE "R" | 56O" minimum | |
|
| A | B | C | D | E | F | G | H | J |
|
| CWC400 | 16" | 12" | 48° | 41° | 18" | 14" | 7³⁄₄" | 16" | 48" |
|
|
| 406 mm | 305 mm |
|
| 457 mm | 356 mm | 197 mm | 406 mm | 1219 mm |
|
| CWC500 | 20" | 12" | 42° | 35° | 18" | 14" | 11¹⁄₂" | 20" | 61¹⁄₂" |
|
|
| 508 mm | 305 mm |
|
| 457 mm | 356 mm | 292 mm | 508 mm | 1562 mm | FP594A |
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Fig. 24 Combustible side wall protection and hearth extension dimensions.
87D1504 | 15 |