6
!
!
VENTILATION & COMBUSTION AIR
COMBUSTION AIR REQUIREMENTS
(Minimum square inch openings)
MODEL #
*UNCONFINED AREA
**CONFINED AREA
OUTSIDE
COMBUSTION AIR
1 SQ. IN/5000 BTU/
HR (SEE
Figure #2
)
INSIDE
COMBUSTION AIR
1 SQ. IN. /1000
BTU/HR
(SEE
Figure #1
)
OUTSIDE COMBUSTION AIR
VERTICAL
DUCTS 1 SQ. IN.
/4000 BTU/HR
(SEE
Figures #2
& 3
)
HORIZONTAL
DUCTS 1 SQ. IN.
/2000 BTU/HR
(SEE
Figure #4
)
-50
10
100
13
25
-100
20
100
25
50
-125
25
125
32
63
-150
30
150
38
75
-200
40
200
50
100
*
Unconfined
area:
A space whose
volume is not less than 50 cubic feet
per 1000 BTU per hour of all appliances
installed in that space (cubic feet of space
= height x width x length).
**
Confined
area:
A space whose volume
is less than 50 cubic feet per 1000 BTU
per hour of all appliances installed in that
space
(cubic feet of space = height x width
x length).
Ventilation of the boiler room must be adequate to
1.
provide sufficient air to properly support combustion
per the latest revision of the National Fuel Gas Code,
ANSI Z223.1.
When a boiler is located in an unconfined space in a
2.
building or conventional construction frame, masonry
or metal building, infiltration normally is adequate to
provide air for combustion and ventilation. However, if
the equipment is located in a building of tight construction
(See the National Fuel Gas Code, ANSI Z223.1 latest
revision)
, the boiler area should be considered as a con-
fined space. In this case air for combustion and ventilation
shall be provided according to paragraph #5. If there is
any doubt, install air supply provisions in accordance with
the latest revision of the National Fuel Gas Code.
When a boiler is installed in an unconfined space, in a
3.
building of unusually tight construction, air for combus
-
tion and ventilation must be obtained from outdoors or
from spaces freely communicating with the outdoors.
A permanent opening or openings having a total free
area of not less than 1 square inch per 5,000 BTU per
hour of total input rating of all appliances shall be pro-
vided. Ducts may be used to convey makeup air from
the outdoors and shall have the same cross-sectional
area of the openings to which they are connected.
When air for combustion and ventilation is from inside
4.
WARNING
AIR OPENINGS TO COMBUSTION AREA MUST NOT BE OBSTRUCTED.
BY FOLLOWING THE INSTRUCTIONS BELOW, ADEQUATE
COMBUSTION AIR CAN BE MAINTAINED.