Lennox Hearth II-T C INS operation manual Floor Protection Advantage II-T C FS, Listed Material

6”

153 mm

(153mm)

min.

6”

Top View

6”

153 mm

(153mm)

min.

6”

PLANNING YOUR INSTALLATION

FLOOR PROTECTION – Advantage II-T C FS

(For USA and Can- ada) This appliance requires 3/8" (10 mm) minimum non- combustible floor protection designed for solid fuel burning appliances having a thermal conductivity of k = .84 BTU in/ft or equivalent. If the floor protection is to be stone, tile, brick, etc., it must be mor- tared or grouted to form a continuous non-combustible sur-

face (See Using Alternate Material As Floor Protector below). If a chimney connector extends horizontally over the floor, protection must cover the floor under the connector and at least 2" (51 mm) to either side. The floor protector must fully cover the area beneath the appliance and extend 6” to the front, 6” to the sides, and up to 6” from the back (see illustra- tion above and following note).

*Note: When installed at clearances less than 6”, the floor protection is only required to extend to the wall.

FLOOR PROTECTION / HEARTH EXTENSION USING AL- TERNATE MATERIAL AS FLOOR PROTECTOR (also see Floor Protection above for freestanding models and Hearth Requirements, page 8 for the insert model)

The hearth pad or alternate material used as a floor/hearth protector must be constructed of a durable noncombustible material having an equal or better thermal conductivity value (lower k value) of k = .84 BTU / IN FT2 HR °F or a thermal resistance that equals or exceeds r = 1.19 HR °F FT2 IN/BTU with a minimum thickness of 3/8”. With these values, determine the minimum thickness of the alternate material required using the formula(s) and the table shown here (see chart - Approved Alternate Materials for Floor/Hearth Protection).

Note: Any noncombustible material having a minimum thickness of 3/8” (10 mm) whose k value is less than .84 or whose r value is more than 1.19 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 material may be used.

Methods of determining floor protection equivalents:

To determine the thickness required for the alternate material when either the k value or r value is known, use either the k formula or r formula:

Example: Durock Cement is to be used for the floor protec- tion. How thick must this material be? The following formulas give the means of determining minimum thickness required.

TM = minimum thickness required for alternate material kM = k value per inch of alternate material

TL = minimum thickness of listed material rM = r value per inch of alternate material

Using the k formula:

Minimum		k-value (per Inch)		Specified min.
thickness of	=	of alternate material	x	thickness
alternate		k-value (per inch)		of listed
material		of listed material		material

TM (inches) = kM x TL

.84

TM (inches) = 1.92 x .375 (3/8”)

.84

Answer using k: 2.29 x 0.375” = 0.858 = ~7/8”

7/8” thickness (minimum) Durock Cement will be required. Using the r formula:

TM (inches) = 1.19 x TL rM

TM (inches) = 1.19 x 375 (3/8”)

.52

Answer using r: 2.29 x 0. 375” = 0.858 = ~7/8”

7/8” thickness (minimum) Durock Cement 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 combinations of materials because “R val- ues” are additive where r and k values are not.

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

Example: Given that the required “R value” for a suitable floor pro- tector used must be equal to or greater than “R” = r x TL = 1.19 x

.375” = .45.

Listed Material

	Thermal Values		Specified
			Minimum
			Thickness
	k (per inch)	r (per inch)	TL
Listed Material →	.84	1.19	3/8” (.375)

Approved Alternate Materials for

Floor/Hearth Protection (**)

Alternative	Thermal Values		* Minimum
Materials ↓			Thickness
	k (per inch)	r (per inch)		TM
Kaowool M Board	.47	2.13	* 3/8”
Micore 160	.35	2.86	* 3/8”
Micore 300	.46	2.18	* 3/8”
Durock Cement	1.92	.52	7/8”
Hardibacker	1.95	.51	7/8”
Hardibacker 500	2.30	.44	1	1/8”
Cultered Stone	2.82	.35	1	5/8”
Hearthstone
Wonderboard	3.23	0.31	1	1/2”
Face brick	9.00	0.11	4	1/8”
Common brick	5.00	0.20	2	1/4”
Cement mortar	5.00	0.20	2	1/4”
Ceramic tile	12.5	.08	5 5/8”
Marble	~20.0	~.05		9”

Note: To convert inches to millimeters divide by .03937.

*After minimum thickness is calculated, the thickness can be no less than 3/8” (.375” / 10mm).

(**)If the floor protector to be used is a noncombustible material and is NOT listed on the chart above, the manufacturer of the material must provide either the listed k-value per inch or r-value per inch and the minimum acceptable thickness will need to be calculated per instruc- tions on this page.

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