Vermont Casting SR42, SR36, SC42, SC36 manual Hearth Installation, Minimum Wall Clearances

Majestic Fireplaces® SR/SC Series

■9. Hearth Installation

A hearth extension is required to protect a combustible floor in front of the fireplace. Refer to Figure 23 for minimum dimensions and mounting detail.

Note: Hearth Extension must not cover the air inlet opening of a fireplace.

The hearth extension described in Figure 23 must be a durable non-combustible material with a minimum (total) Rt value of 1.09; see Figure 24 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 non- combustible decorative covering or a piece of .018” minimum sheet metal, to protect hearth extension material. (Fig. 23)

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 fire- place hearth and hearth extension with a non-combus- tible material. (Figs. 23 and 25)

WARNING: HEARTH EXTENSION MUST BE INSTALLED 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 (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 resistance (Rt).

Minimum Wall Clearances

WITH	WITHOUT
Noncombustible	Noncombustible
Surround Facing	Surround Facing

Shaded area starts

1/2" away from

4" BRICKedge of unit. (Example material)

			4"
E	F**	FIREBOX	E	D
		OPENING
C**		A - Min. clearance
		to combustible
		perpendicular wall
SIDE		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" Majestic 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 On-Site Construction)

	G	G
	H
		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"	¹⁄₂" minimum

	A	B	C	D	E	F	G	H	J
SR/SC36	16"	12"	48°	41°	18"	14"	7³⁄₄"	16"	48"
	406mm	305mm			457mm	356mm	197mm	406mm	1219mm
SR/SC42	20"	12"	42°	35°	18"	14"	11¹⁄₂"	20"	61¹⁄₂"
	508mm	305mm			457mm	356mm	292mm	508mm	1562mm	FP594

Fig. 23 Combustible side wall protection and hearth extension dimensions.

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