C. Sidewalls/Surrounds
•Locate adjacent combustible sidewalls a minimum of 24 in. (610 mm) from fireplace opening.
•Mantle leg, surround, stub wall, whether combustible or noncombustible, may be constructed as shown in Figure 6.3.
Note: Grid depicts 1 inch squares.
22 3/8 in.
[568 mm]
FLUSH
FRONT
50° | angle |
|
18 1/2 in.
[470 mm]
24 in. 
[610 mm]
| BRICK | 4 in. | |
| [102 mm] | ||
| FRONT | ||
|
| ||
42 in. |
|
|
|
[1067 mm] |
|
| 19 3/4 in. |
39° |
| ||
angle | [500 mm] | ||
(1343 mm) |
|
| |
|
|
| |
| 24 in. |
| |
| [610 mm] |
| |
Figure 6.3 Mantel Leg, Surround or Wall Projection (acceptable on both sides of opening)
D. Frame the Fireplace
Figure 6.4 shows typical framing using combustible materials (2x4 lumber shown).
•Observe all required air space clearances to combustible materials as shown in Figure 6.2.
2 in. (51 mm) min. air space clearance from chimney.
Note: Framing must be extended straight up, all the way to the ceiling.
Header MUST NOT be notched!
C
D
A
BD
D = extra space needed for outside air connection.
If outside air duct has no bend, this dimension may be reduced as long as minimum clearances are met.
Model # |
| A | B * | C ** | D |
BIR42 | in. | 53 7/8 | 28 3/8 | 74 1/2 | 12 |
|
|
|
|
|
|
| mm | 1368 | 721 | 1892 | 305 |
|
|
|
|
|
|
*If interior of chase will be drywalled, add the thickness to this meaurement.
**Adjust header height for raised floor under fireplace.
Figure 6.4 Framing the Fireplace
20 | Heatilator • Birmingham BIR42 • |