Part Number 550-141-186/0100
5
• Installation • Start-Up • Maintenance • Parts
Figure 2
Boiler room
partially or
completely
above grade
Combustion air
and ventilation
openings
(continued)
Air from inside building (boiler in interior room):
•
Tightly constructed buildings must be provided with openings to outside for combustion
and ventilation air. These openings must be sized to handle all fuel-burning appliances,
exhaust and ventilation fans and fireplaces.
•
When openings to boiler room are taken to interior spaces, provide two permanent
openings: a combustion air opening within 12 inches of floor and a ventilation opening
within 12 inches of ceiling. Each opening must provide a minimum free area of one
square inch per 1,000 Btuh input of all appliances in room plus requirements for any
exhaust fans in room. The interior space supplying combustion and ventilation air must
have adequate infiltration from outside.
Air directly from outside to boiler room:
•
Tightly constructed buildings must be provided with combustion air and ventilation
openings to boiler room which are adequate to handle the boiler needs plus the needs of
all other fuel-burning appliances, fireplaces and exhaust or ventilation fans.
•
Combustion and ventilation openings connecting directly or by ducting to outside, or to
attic or crawl spaces that freely connect with outside, must be sized as follows:
1. Outside wall or vertical ducting — one square inch per 4.000 Btuh input of all
appliances in room plus requirements for any exhaust fans or other appliances in
room.
2. Horizontal ducting — one square inch per 2,000 Btuh of all appliances in room plus
requirements for any exhaust fans or other appliances in room.
3. All ducting must be same size as permanent openings. Minimum area dimensions of
ducting must be no less than 9 square inches.
4. Other size ducting must comply with local codes.
Compensate for louver blockage when calculating combustion air and ventilation openings.
See
Figures 1 and 2
. Refer to manufacturer's instructions for sizing.
Adjustable louvers must be locked open and combustion air damper must interlock with
boiler controls to open automatically before boiler operation.
Grade
Louver
Duct size equal to
total louver area
Boiler room floor
186-02
