Heat & Glo LifeStyle EXCLAIM-36T-C, EXCLAIM-36H-C owner manual Finishing, Hearth Extension

8 Finishing

A. Hearth Extension

A hearth extension must be installed with all fireplaces to protect the combustible floor in front of the fireplace from both radiant heat and sparks. See Figures 8.1-8.5.

	High temperature
	(300°F min.) continuous,
HX3 or HX4	non-combustible sealant		Fireplace
	non-combustible material			Protective
insulation
Hearth Ext	Tile, stone or other
or equivilent
(see Table below)				Metal Hearth
				Strip
		2 in. (51 mm)
Floor constructed of wood or		required
other combustible material

Figure 8.1 Hearth Extension Construction

WARNING

Fire Risk

•Metal hearth strips MUST be installed. Sparks or embers may ignite flooring.

This fireplace has been tested and approved for use with a hearth extension insulated to a minimum R value of 1.16.

To substitute materials for the factory-available hearth ex- tensions, see Figure 8.3 and calculate insulation alterna- tives as per Table 8.1 and the following formulas:

•Thermal conductivity per inch thickness = k

•k = (BTU)(inch) / (foot2)(hour)(°F)

•Required thickness = Rk

•Thermal resistance per inch thickness = r

•r = (foot2)(hour)(°F) / (BTU)(inch)

•Required thickness = R / rB.

Table 8.1

Hearth Extension Insulation Alternatives, R Value = 1.16

	k per	r per	Minimum thickness
			required
	inch	inch
Material	thick	thick	in.	mm
Hearth & Home HX3, HX4	0.43	2.33	1/2	13
USG Micore 300™	0.46	2.18	1/2	13
USG Durock™ Cement Board	1.92	0.52	2-1/4	57
Cement Mortar	5.0	0.20	5-7/8	149
Common Brick	5.0	0.20	5-7/8	149
Ceramic Tile	12.50	0.08	14-5/8	371
Armstrong™ Privacy Guard Plus	.046	2.18	1/2	13
	14.3 to	0.07 to	16-5/8 to	422 to
Marble	20.0	0.05	23-3/8	594

1 in. (25 mm) overlap

Metal strips are placed 2 in. (51 mm) under the front of the fireplace and must extend beyond the front and sides of fireplace opening by 2 in. (51 mm).

Figure 8.2 Positioning the Protective Metal Hearth Strips

WARNING

Fire Risk

•Hearth extensions must be installed exactly as specified.

High temperatures or hot embers may ignite concealed combustibles.

66 in.	20 in.
(1676 mm)
	(508 mm)

12 in.

(305 mm)

Figure 8.3 Hearth Extension Dimensions

Heat & Glo • EXCLAIM-36C Woodburning Fireplace • 4013-093 Rev G • 08/06 25