8
IM-BW4-5-02
[240013014 Rev. B [12/15/2020]
Comply with NPFA-31
Standard for the Installation of
Oil Burning Equipment
(latest edition), and applicable
provisons of local building codes to provide combustion and
ventilation air.
Provide enough fresh air to assure proper combustion.
Fire in the boiler uses oxygen. It must have continuous
supply. Air in the house contains only enough oxygen to
supply burner for short time. Outside air must enter the
house to replace air used by the burner. Study the following
examples 1 and 2 to determine your fresh air requirements.
EXAMPLE 1: Boiler Located in Unconfined Space
If your boiler is in an open area (un-partitioned basement)
in conventional house, air that leaks through cracks around
doors and windows will usually be adequate to provide air
for combustion. Doors should not fit tightly. Do not caulk
cracks around windows.
An unconfined space is defined as space whose volume is
not less than 50 cubic feet per 1,000 Btu per hour of total
input rating of all appliances installed in that space.
EXAMPLE 2: Boiler Located in Confined Space
A.
All Air from Inside the Building:
Confined
space shall be provided with two permanent openings
communicating directly with additional room(s) of sufficient
volume so the combined volume of all spaces meets the
criteria for unconfined space. Total input of all combustion
equipment installed in combined space shall be considered
in making this determination. Each opening shall have
minimum free area of one square inch per 1,000 Btu per
hour of total input rating of all combustion equipment in the
confined space, but not less than 100 square inches. One
opening shall be within 12 inches of top and one within 12
inches of bottom of the enclosure.
Example: Your boiler is rated at 100,000 Btu per hour.
Water heater is rated at 30,000 Btu per hour. Total is
130,000 Btu per hour. You need two grilles, each with 130
square inches of FREE opening. Metal grilles have about
60% FREE opening. To find louvered area needed, multiply
free opening required by 1.7 (130 x 1.7 = 221.0 sq. in.
louvered area). In this example, two grilles each having 8”
x 30” (240 sq. in.) louvered area would be used.
FRESH AIR FOR COMBUSTION
WARNING
Asphyxiation, fire hazard. Do not obstruct air
openings to combustion area. Follow instructions
below, to maintain adequate combustion air.
!
NOTICE
Install outside air intake if you use fireplace or
kitchen or bathroom exhaust fan. These devices rob
boiler and water heater of combustion air.
Figure 4 - Air Openings For Boiler Located In
Confined Space (Utility Room
)
