Vermont Casting Encore NC 1450 Floor Protection for Fireplace Installations, of at least

Encore 1450 Non-Catalytic Woodburning Stove

D

B

E E

F

A

C

E E

F

A

EXAMPLE: The specified floor protector should be 1/2- inch thick material with k-factor of 0.84. The proposed alternate is 4” brick with an r-factor of 0.2 over 1/8” mineral board with a k-factor of 0.29

Step a: Use formula above to convert specification to R-value: R = 1k x T =0.841 x 0.5 = 0.59

Step b: Calculate R of proposed system. 4” brick of r = 0.2, therefore:

Rbrick = 0.2 x 4 = 0.8

1/8” mineral board of k = 0.29, therefore

U.S. Canada

A.39” 43” (1092 mm)

B.45” 49” (1245 mm)

C.12” 12” (305 mm) 8” Connector

10” 10” (255 mm) 6” Connector

D.6” 8” (200 mm)

E.6” 8” (200 mm)

F.16” 18” (450 mm)

Required thermal protection: 1/2” (13 mm) mini- mum noncombustible material with an R-value

of at least 0.59. ST500

Fig. 12 Required floor protector dimensions for both top-and rear-exiting stove.

How to Determine if Alternate Floor Protection Materials are Acceptable

All floor protection must be noncombustible (i.e. met- als, brick, stone, mineral fiber boards, etc.). Any organic materials (i.e. plastics, wood paper products, etc.) are combustible and must not be used. The floor protection specified includes some form of thermal designation such as R-value (thermal resistance) or k-factor (ther- mal conductivity).

Procedure:

1.Convert specifications to R-value:

i.R-value given - no conversion needed.

ii.k-factor is given with a required thickness (T) in inches: R = 1k x T

iii.K-factor is given with a required thickness (T) in R = 1 x Tinches:

K x 12

iv. r-factor is given with a required thickness (T) in inches: R = r x T

2. Determine the R-value of the proposed alternate floor protector:

i. Use the formula in Step 1 to convert values not expressed as R.

ii. For multiple layers, add R-values of each layer to determine overall R-value.

3. If the overall R-value of the system is greater than the R-value of the specified floor protector, the alter- nate is acceptable.

Rmineralboard = 0.291 x 0.125 = 0.431

Rtotal = Rbrick + Rmineralboard = 0.8 + 0.431 = 1.231

Step c: Compare proposed system Rtotal of 1.231 to specified R of 0.59. Since proposed system Rtotal is greater than required, the system is acceptable.

Definitions
R =	(ft2)(hr)(°F)		k =	(Btu)(in)		= K x 12
		Btu		(ft2)(hr)(°F)
K =		(Btu)(ft)	r =	(ft2)(hr)(°F)	=		1
	(ft2)(hr)(°F)			(Btu)(in)			k

Floor Protection for Fireplace Installations

Do not assume that your fireplace hearth is completely noncombustible.

Many fireplace hearths do not meet the “completely noncombustible” requirement because the brick or concrete in front of the fireplace opening is supported by heavy wood framing. (Fig. 13) Because heat passes through brick or concrete readily, it can easily pass through to the wood. As a result, such fireplace hearths can be a fire hazard and are considered a combustible floor.

Keep in mind, also, that many raised hearths will extend less than the required clearance from the front of the heater when it is installed. In such cases, sufficient floor protection as described above must be added in front of the hearth to satisfy the minimum floor protector requirement from the front of the stove: 16” (406 mm) from the front in the United States and 18” (450 mm) from the front in Canada.

Hearth rugs do not satisfy the requirements for floor protection.

Fireplace installations also have special clearance requirements to the side walls, side decorative trim, and fireplace mantel. This information follows in the section

on Fireplace and Mantel Trim Shields.

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