321 Studios Oil Furnace FLR110D48E User Manual
Page 24
Manual 2100-422
Page 22
APPLIANCES LOCATED IN CONFINED
SPACES
In unconfined spaces in buildings, infiltration may be
adequate to provide air for combustion, ventilation, and
dilution of flue gases. However, in buildings of
unusually tight construction, additional air shall be
provided using the method described under “All Air
From Outdoors” in Figure 13.
An unconfined space (such as an open basement) must
have a minimum volume of 50 cubic feet per 1,000
BTUH of total of all appliances in area. Adjoining
rooms may be counted as one area only if there are not
doors between the rooms.
Shown in Table 8 are the required minimum areas in
square feet to qualify as an unconfined space for
various total BTUH input ratings. The table is based on
a room(s) with 8 foot ceiling heights.
If the unconfined space is within a building having
insufficient air because of tight construction, the air for
combustion and ventilation shall be obtained from
outdoors or from spaces freely communicating with the
outdoors. Under these conditions a permanent opening
or openings have a total free area of not less than one
square inch per 5,000 BTU per hour (28 square inches
per hour ) of total input rating of all appliances shall be
provided. For combustion air options see Page 20,
“Combustion Air Requirements”.
MIS-1336
NOTE: Each opening shall have a free area of
not less than one square inch per 1,000
BTU per hour (140 square inches per
gallon per hour) of the total input
rating of all appliances in the
enclosure.
FIGURE 12
APPLIANCES LOCATED
IN CONFINED SPACES
ALL AIR FROM INSIDE THE BUILDING
ALL AIR FROM INSIDE BUILDING
The confined space shall be provided with two
permanent openings, one near the top of the enclosure
and one near the bottom. Each opening shall have a
free area of not less than one square inch per 1,000
BTU per hour (140 square inches per gallon per hour)
of the total input rating of all appliances in the
enclosure freely communicating with interior areas
having in turn adequate infiltration from the outside.
(See Figure 12.) Also see Table 9 on the following
page for specific ventilation opening requirements for
the furnace only.
The flow of combustion and ventilating air must not
be obstructed from reaching the furnace.
TABLE 8
SQUARE FEET REQUIRED TO
QUALIFY AS UNCONFINED SPACE
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7
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