To determine the need to add floor protection (D) beyond the hearth extension (A), the following
calculation must be done using the data in
this section: D = B - G.
E
A
B
D
G
FLOOR PROTECTOR:
NON-COMBUSTIBLE MATERIAL
Figure 23: Additional Floor Protection - Raised Installation
Dimension
Maximum
of the hearth
Extended
Dimension
Minimum
of the hearth
Extended
If the value (D) is negative or zero, additional floor protection in front of the unit is not needed
because the masonry fireplace hearth extension is long enough. If the value (D) is positive, an
additional floor protection in front of the hearth extension at least equivalent to the result (D)
must be added.
9.2.1
Installation Raised of 4" (102 mm) and Less
If non-combustible material floor protection needs to be added in front of and level with the
hearth extension of the masonry fireplace (F = 4" [102 mm) or less), an R-value equal to or
greater than 1.00 is required and should extend at least 22" (559 mm) in front of the unit (B).
Refer to
«Figure 24: Additional Floor Protection - Not Raised Installation»
9.2.2
Installation Raised of More Than 4" (102 mm)
If the extension of the masonry hearth is raised at least 4" (102 mm) from the floor protection, a non-
combustible material, without an R-value, must extend at least 16" (406 mm in USA) or 18" (457 mm
in Canada) in front of the unit (B). Refer to
F
C
HEARTH SLAB:
NON-COMBUSTIBLE MATERIAL
Table 4 : Data for Floor Protection Calculation
A
B
See section
9.2.1 and
extension
9.2.2
See section
9.2.1 and
extension
9.2.2
«Figure 23: Additional Floor Protection - Raised
«Table 4 : Data for Floor Protection Calculation»
A
B
D
G
FLOOR PROTECTOR:
NON-COMBUSTIBLE MATERIAL
Figure 24: Additional Floor Protection - Not Raised Installation
C
D
4"
G = (A-C)
(102 mm)
D=B- G
2 ¾"
G = (A-C)
(70 mm)
D=B- G
E
F
C
HEARTH SLAB:
NON-COMBUSTIBLE MATERIAL
E
Air Jacket
Flush with
7 ⅛"
fireplace
(181 mm)
facing
Back from
8 ½"
fireplace
(216 mm)
facing 1 ⅜"
Installation».
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