22
53D9041
B36LA & B36RA Woodburning Fireplaces
OUTSIDE COMBUSTION AIR PRECAUTIONS & RECOMMENDATIONS
NOTE:
The use of outside air for combustion is optional unless required by building codes. It is
only necessary to supply outside combustion air to one side of the fireplace. Use the Model OAC4
combustion air kit.
Outside Combustion Air Recommendations
1. Extremely long runs and numerous turns in the duct leading from the fireplace to the combustion
air assembly should be avoided. These conditions will increase the resistance to the free flow
of air through the duct. Refer to
Figure 24
for methods of installing the outside air for combus-
tion assemblies.
2. The combustion air assembly should be located at an exterior location, which is not likely to be
accidentally blocked in any manner. The assembly should be located above the snow line to
prevent blockage by snow accumulation.
3. The combustion air inlet assembly should never be mounted in a garage or storage area where
combustible fumes such as gasoline might be drawn into the fireplace.
4. Combustion air can be drawn form the crawl space under a house when an adequate supply of
air is provided by open ventilation.
5. Do not take combustion air from attic space or garage space.
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Second Floor
Firestop
Spacer
Duct Ext-
edned to
Miss Joist
To Out-
side Wall
Installation Above Base-
ment or Crawl Space
Plate
Basement Wall
Above
snow
Level
Basement Installation
Termination Cap
Figure 24
Firestop
Spacer
Inlet Grille in
Soffit (Over-
hang)
8’ Max.
CAUTION:
Do not
take combustion air
from attic space or
garage
Concrete Slab Installation
FP2172
