Masonry Magazine October 1982 Page. 19
TABLE 1
Single-Face Fireplace Dimensions, Inches*.
Finished Fireplace Opening
Rough Brick Work
Flue Size
Steel Angle
A
B
C
D
E
F
G
H
J
K
L
M
N
24
24
16
11
14
18
8%
32
21
19
10
8 x 12
A-36
26
24
16
13
14
18
84
34
21
21
11
8
x 12
A-36
28
24
16
15
14
18
84
36
21
21
12
8 x 12
A-36
30
29
16
17
14
23
84
38
21
24
13
12 x 12
A-36
32
29
16
19
14
23
8%
40 21
24
14
12 x 12
A-42
36
29
16
23
14
23
84
44
21
27
16
12 x 12
A-42
40
29
16
27
14
23
84
48
21
29
16
12 x 16
A-48
42
32
16
29
14
26
84
50
21
32
17
16 x 16
B-48
48
32
18
33
14
26
8%
56
23
37
20
16 x 16
B-54
54
37
20
37
16
29
13
68
25
45
26
16 x 16
B-60
60
37
22
42
16
29
13
72
27
45 26
16 x 20
B-66
60
40
22
42
16
31 13
72
27
45
26
16 x 20
B-66
72
40
22
54
16
31
13
84
27
56
32
20 x 20
C-84
40
24
64
20
28 13
96
29
61 36
20 x 24
C-96
96
40
24
76
20
28 13
108
29
75
42
20 x 24
C-108
Adopted from The Donley Brothers Company, Book of Successful Fireplaces-How to Build Them, 18th Edition, 1965.
Flue sizes conform to modular dimensional system.
Angle sizes: A-3x3xis in., B-3½ x 3 x 14 in., C-5 x 32 x in.
SI conversion: mm in. x 25.4
`
CLEANOUT DOOR
-HEARTH SUPPORT
-STILLING CHAMBER
-AIR PASSAGEWAY
-ASHPIT
Typical Base Assembly
FIG. 2
AIR INTAKE
LOUVER
FOUNDATION
WALL
FOOTING
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Footings-Footings should be of concrete and at least 12 in. (300 mm) thick, and extend at least 6 in. (150 mm) beyond the fireplace walls on all sides. The footings should penetrate below the frost line unless they are located within a space maintained above freezing. Footings should be placed on undisturbed or properly prepared soil. Oversized chimneys may require special foundations.
`
Foundation Walls Foundation walls should be constructed of masonry or concrete. Most building codes require a minimum thickness of 8 in. (200 mm) for the foundation wall. If the foundation walls are of brick, it is recommended that the voids be filled solid with brick bedded in mortar except for the ashpit and external combustion air ducts, as shown in Figs. 1 and 2.
`
Structural Slab-The structural slab must be properly designed to support the weight of the fireplace. When the fireplace is constructed on a slab-on-grade, it is usually necessary to thicken the slab under the fireplace to support the loads from the fireplace and chimney.
`
Hearth Support. Support for the hearth can be provided in a number of ways. These include the use of corbeled brickwork, a structural slab, or cantilevered reinforced brick masonry. The general requirements for corbeling usually limit the maximum projection of each unit not to exceed one-half the height of the unit, or one-third its thickness. Unless reinforced, when corbeling from walls, the overall horizontal projection should be limited to one-half the wall thickness. The maximum horizontal overall and individual projections may also be limited depending on local code requirements and the design of the foundation. A hearth support featuring corbeling and a structural slab are shown in Figs. 1 and 2.
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