SUPREME UL 127, Руководство пользователя

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VISION SUPREME FIREPLACES
12
4.2 The Hearth Extension U.S.A Only
The minimum dimensions of the hearth
extension are specified in figures 9. The hearth
extension is to be covered with non-combustible
materials only, such as steel, cement or mortar,
stone, brick, ceramic tiles. Unidentified
materials may be combustible: verify the
product specifications prior to installation.
The hearth extension must extend a minimum of
16 inches measured from the door of the
woodstove and extended all the way back to the
woodstove.
WARNING: The hearth extension is to be
installed only as illustrated in figure 9.1 or 9.2. The hearth extension
should extend a minimum of 16 inches from the door.
The non-combustible hearth extension must be
constructed of materials having a minimum R-
Value of 0.78.
The R-Value is a measurement of the insulating
properties of materials at a reference thickness.
When different materials are combined, the total
R-Value is the sum of the individual R-Values.
Example:
Durock ½” R-Value: 2 x .390 =.780
Ceramic ¼” R-Value: .020
Total R-Value: .780 + .020 = 0.800
The combination of 1” Durock with a ceramic
tile is acceptable as a hearth extension since the
total R-Value is higher than the required .78.
Alternatively, the insulating properties can be defined as:
K-Factor: Thermal conductivity.
C-Factor: Thermal conductance.
In this case convert to R-Value as following.
Convert specification to R-Value :
i. R-Value given - no conversion needed.
ii. K-Factor is given with a required thickness (T) in inches: R = 1/k T
iii. C-Factor is given: R = 1/C
R-Values of common hearth materials:
Material
Thickness R-Value
Brick
4”
.800
Brick 2-1/4” .450
Cement Board (Durock)
½”
.390
Limestone
1”
.153
Slate
1”
.100
Concrete
1’
.095
Marble
1”
.090
Granite
1”
.083
Ceramic Tile
¼”
.020
Figure 9.1 – Hearth Extension U.S.A
Figure 9.2 – Hearth Extension U.S.A