Lennox International Inc BV4000C operation manual Alternative Floor Protection Materials

PLANNING YOUR INSTALLATION

FLOOR PROTECTION

This appliance requires a heat resistant non- combustible approved fireplace hearth or hearth exten- sion. If a hearth extension is used it must be a 3/8" (minimum) UL approved hearth pad or equivalent. If the floor protection is to be stone, tile, brick, etc., it must be mortared or grouted to form a continuous non- combustible surface (See Using Alternate Material As Floor Protector on this page).

This protected area must extend a minimum of 16" to the front of the fuel door opening and 8" beyond both sides of the fuel door opening

HEARTH PROTECTION

USING ALTERNATE MATERIAL AS A FLOOR PROTEC- TOR/HEARTH EXTENSION

The alternate material used as a hearth extension must be constructed of a durable noncombustible material having an equal or better insulating value (lower k value) of k = 1.28 BTU/IN FT2 HR ° F or a thermal resistance that equals or exceeds r = 78 HR ° F FT2 IN/BTU. With these values, determine the minimum thick- ness/material required using the formula and the table shown here (see chart - Alternative Floor Protection Materials).

Note: Any noncombustible material having a thickness of 1” whose k value is less than 1.28 or whose r value is more than .78 is acceptable. If the alternate material used has a higher k value or lower r value will require a greater thickness of the material used. In some cases, if the k value is less or the r value higher, a thinner mate- rial may be used.

Methods of determining floor protection equivalents

To determine the thickness required for any material when either the k or r values are known:

TM = Thickness of material in inches KM = K value of desired material TL = Minimum listed thickness

Example: Micore CV230 is to be used for the floor pro- tection. How thick must this material be?

The following formulas give the means of determining minimum thickness required of alternate materials.

Using the k formula:

Desired Thickness		k value of desire		Minimum thickness
of the alternate	=	material (per inch) x		of Listed
material		k value of listed		Material
		material (per inch)
TM (inches) =	KM	x TL
	1.28
TM (inches) =	0.43*		x 1”
	1.28

Answer using k = 0.34 x 1” = 0.34 = 3/8” 3/8” thickness Micore will be required.

Using the r formula:

TM (inches) = 0.78 x TL rM

TM (inches) = 0.78 x 1” 2.33*

Answer using r = 0.34 x 1” = .034 = 3/8” 3/8” thickness Micore will be required.

At times it is important to know what combination of materials are acceptable for use as floor protection. The “R values” are used to determine acceptable combina- tions of materials because “R values” are additive where r and k values are not.

“R value” = 1 = r x thickness of material used k

ALTERNATIVE FLOOR PROTECTION MATERIALS

Listed	Values		Min. Thick
Material	k (per inch)	r (per inch)		TL
Millboard	1.28	0.78		1”
Alternative	Values		Min. Thick
Materials	k (per inch)	r (per inch)		TL
Wonderboard	1.92	0.56	1	1/2”
Common brick	5.00	0.20	3	7/8”
Cement mortar	5.00	0.20	3	7/8”
Ceramic tile	12.5	0.08	9	3/4”
Marble	11.0	0.09	8	5/8”
Micore CV230	0.43	2.33	3/8”
(U.S. Gypsum)
Ceraform 126	0.27	3.70	1/4”
(Johns-Manville)

Example: Given that the required “R value” for a suitable floor protector used must be equal to or greater than: “R” = r x TL = 0.78 x 1” = 0.78.

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