Brute Mini JV
Page 9
Boiler Size
Outside Air Area
Inside Air Area
sq. in
sq. cm
sq. in.
sq. cm
50
15
97
100
645
75
20
129
100
645
100
25
161
100
645
125
32
206
125
807
160
40
258
160
1032
225
60
387
225
1452
*Area indicated is for one of two openings: one at floor level
and one at the ceiling, so the total net free area would be
double the figures shown. For special conditions, refer to
NFPA54 ANSI Z223.1. In Canada, refer to the National
Standard CAN1-B149.1 or .2, which differs from this table.
NOTE: Check with louver manufacturers for Net Free Area of
Louvers. Correct for screen resistance to the Net Free Area if a
screen is used.
Table 3. Minimum Recommended
Air Supply to Boiler Room
Exhaust Fans or Vents: Any equipment which
exhausts air from the boiler room can deplete the
combustion air supply or reverse the natural draft
action of venting system. This could cause flue
products to accumulate in the boiler room. Additional
air must be supplied to compensate for such exhaust.
The information in
Table 3
is not applicable in
installations where exhaust fans or blowers of any
type are used. Such installations must be designed by
qualified engineers.
If a blower or fan is used to supply air to the boiler
room, the installer should make sure it does not create
drafts which could cause nuisance shutdowns. If a
blower is necessary to provide adequate combustion
air to the boiler, a suitable switch or equivalent must
Figure 3. Chimney Venting.
Figure 4. Vertical Venting.
CHIMNEY
LINER
THIMBLE
VENT
SYSTEM
BOILER
CLEANOUT
CHIMNEY
LINER
VENT
SYSTEM
BOILER
CLEANOUT
THIMBLE
1/4"
PER FT.
(20mm PER M)
SLOPE
1/4"
PER FT.
(20mm PER M)
SLOPE
12" (305mm)
SECTION 3.
Air and Venting
3A. Combustion Air Supply
The boiler location must provide sufficient air
supply for proper combustion, and ventilation of
the surrounding area as outlined in the latest edition
of U.S. ANSI standard Z223.1 or in Canada, CAN/
CGA-B149.1 or .2, and any local codes that may be
applicable.
In general, these requirements specify that the
boiler rooms which represent confined spaces should
be provided with two permanent air supply openings;
one within 12 inches (305mm) of the ceiling, the other
within 12 inches (305mm) of the floor.
NOTE:
In Canada, follow Canadian Standard,
CAN/CGA-B149 or local codes.
Outside Air Supply:
When combustion air is
supplied directly through an outside wall, each
opening should have a minimum free area of one
square inch per 4,000 BTU/h (6 sq. cm per 1.2 kW)
input of the total input rating of all appliances in the
enclosed area.
Inside Air Supply:
When combustion is supplied
from inside the building, each opening should have
a minimum free area of one square inch per 1,000
BTU/h (6 sq. cm per 0.3 kW) input of the total input
rating of all appliances in the enclosed area. These
openings should never be less than 100 square inches
(645 sq. cm).
