6
1.
Ventilation of boiler room must be adequate enough to
provide sufficient air to properly support combustion.
2.
When boiler is located in an unconfined space in a
building of conventional construction frame, masonry
or metal, infiltration normally is adequate to provide
air for combustion and ventilation. However, in any
building which has been altered to conserve energy
or to minimize infiltration, the boiler area should be
considered as a CONFINED SPACE. Provide combustion
air and ventilation air in accordance with the section
“Air for Combustion and Ventilation,” of NFPA 31:
Standard for the Installation of Oil-Burning Equipment.
COMBUSTION AIR REQUIREMENTS
(MINIMUM OPENING IN SQUARE INCHES)
INPUT
(Mbh)
*UNCONFINED AREA
**CONFINED AREA
OUTSIDE
COMBUSTION AIR
INSIDE
COMBUSTION AIR
OUTSIDE
COMBUSTION AIR
1 IN
2
/5000Btu/HR
(PARAGRAPH 4)
1 IN
2
/1000 Btu/HR
(MIN 100IN
2
) (Figure
1)
1 IN
2
/4000 Btu/HR
(Figures 2&3)
1 IN
2
/2000 Btu/HR
(Figure 4)
119
24
119
30
60
140
28
140
35
70
175
35
175
44
88
203
41
203
51
102
224
45
224
56
112
245
49
245
62
123
259
52
259
65
130
294
59
297
74
147
* 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).
3.
When a boiler is installed in an unconfined 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.
VENTILATION & COMBUSTION AIR
WARNING
Asphyxiation, fire hazard. Do not obstruct air
openings to combustion area. Follow instructions
below, to maintain adequate combustion air.
!
