5
WARNING
Air openings to combustion area must not be
obstructed. Provide adequate supply of combustion
air in accordance with Installation Code for Oil
Burning Appliances, CSA 139.
!
1.
Ventilation of boiler room must be adequate enough to
provide suf
fi
cient air to properly support combustion
and venting.
2.
When the boiler is located in an uncon
fi
ned space in a
building of conventional construction frame, masonry
or metal, in
fi
ltration normally is adequate to provide
air for combustion and ventilation. However, in any
building which has been altered to conserve energy
or to minimize in
fi
ltration, the boiler area should
be considered as a con
fi
ned space. If there is any
doubt, install air supply provisions for combustion
and ventilation in accordance with requirements of
authority having jurisdiction, or in the absence of such
requirements, CSA B139: Installation Code for Oil
Burning Equipment.
3.
When the boiler is installed in an uncon
fi
ned space,
in a building of unusually tight construction, air for
combustion and room 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 provided. Ducts may be used to
convey make-up air from the outdoors and shall have
the same cross-sectional area of the openings to which
they are connected.
Table 5 COMBUSTION AIR REQUIREMENTS
(Minimum Opening Requirement)
BTU/Hr
Input
(Mbh)
Uncon
fi
ned Area*
Con
fi
ned Area**
Outside
Inside
Outside Combustion Air
Combustion Air 1 Sq.
In./5000 BTU/Hr
(Step 4)
Combustion Air 1 Sq.
In./1000 BTU/Hr
(Min. 100 Sq. In.)
Vertical Ducts 1 Sq.
In./4000 BTU/Hr
(Figures 2 & 3)
Horizontal Ducts 1 Sq.
In./2000 BTU/Hr
(Figure 4)
133
27
133
33
67
140
28
140
35
70
161
32
161
40
81
* A space whose volume is not less than 50 cubic feet per 1000 BTU/Hour of all appliances installed in that space (cubic feet of space = height x
width x length)
** A space whose volume is less than 50 cubic feet per Mbh of all appliances installed in that space (cubic feet of space = height x width x
length)
VENTS
CHIMNEY
OR
L TYPE VENT PIPE
VENT PIPE
BASEBOARD
12"
12"
Figure 2 Combustion and Room Air From Inside
Buildings
VENTILATION AND COMBUSTION AIR
WARNING
Air openings to combustion area must not be
obstructed. By following the instructions below,
adequate combustion air can be maintained.
!
4.
When air for combustion and room ventilation is from
inside buildings, the con
fi
ned space shall be provided
with two permanent openings, one starting 12 inches
from the top and one 12 inches from the bottom of the
enclosed space. Each opening shall have a minimum
free area of 1 square inch per 1,000 BTU per hour of
the total input rating of all appliances in the enclosed
space, but must not be less than 100 square inches.
These openings must freely communicate with the
interior areas having adequate in
fi
ltration from the
outside. See
Figure 2 .
