Heat & Glo LifeStyle BAY-40 owner manual Finishing, Hearth Extension, ¨ Table

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 8.1-8.3.

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 1.03.

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.

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

Figure 8.1 Hearth Extension Construction

Protective

Metal Hearth

Strip

¨Table 8.1

Hearth Extension Insulation Alternatives-Total minimum R Value must equal 1.03

			Minimum
	k per inch	r per inch	thickness
Material	thick	thick	required
Hearth & Home HX3, HX4 (Micore 300™)	0.49	2.06	1/2 in.
USG Micore 160™	0.39	2.54	1/2 in.
USG Durock™ Cement Board	1.92	0.52	2 in.
Cement Mortor	5.0	0.20	5-1/8 in.
Common Brick	5.0	0.20	5-1/8 in.
Ceramic Tile	12.50	0.08	12-1/4 in.
Armstrong™ Privacy Guard Plus	0.46	2.18	1/2 in.
Marble	14.3-20.0	0.07-0.05	14-5/8 in. - 20-3/8 in.

Heat & Glo • Multi-Sided Woodburning Fireplace • 34977 Rev T • 11/07 27