Monessen Hearth 424WBST manual Minimum Wall Clearances, Hearth Installation

424WBST Designer Woodburning Fireplaces

Minimum Wall Clearances

WITH	WITHOUT
Noncombustible	Noncombustible
Surround Facing	Surround Facing
4" BRICK	Shaded area starts
	1/2" away from
(Example material)	edge of unit
		4"

E	F**	Firebox	E	D
		Opening

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 = 1.09) 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"		56O" minimum

	A	B	C	D	E	F	G	H	J	K
424WBST	16"	12"	48°	41°	18"	14"	8"	16"	48"	24"
FP714	(406 mm) (305 mm)				(457 mm)	(356 mm)	(203 mm)	(406 mm)	(1219 mm)	(610 mm)

Fig. 24 Combustible side wall protection and hearth extension dimensions.

Hearth Installation

A hearth extension is required to protect a combustible floor in front of the fireplace. Refer to Figure 24 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 24 must be a durable noncombustible material with a minimum (total) 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 the insulation material must be covered with a noncombustible decorative covering or a piece of

.018” minimum sheet metal, to protect hearth extension material. (Fig. 24)

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. 24 and 26)

WARNING: HEARTH EXTENSION MUST BE IN- STALLED IN ACCORDANCE WITH FIGURES 24 AND 25.

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 resis- tance (Rt).

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