PAGE 3
FIGURE 1
ENTILATION & COMBUSTION AIR
WARNING: AIR OPENINGS TO COMBUSTION AREA MUST NOT BE
OBSTRUCTED. BY FOLLOWING THE INSTRUCTIONS BELOW, ADEQUATE
COMBUSTION AIR CAN BE MAINTAINED
* Unconfined area: A space whose volu e 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 volu e 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).
1. Ventilation of the boiler roo ust be adequate to provide sufficient air to properly
support co bustion per the latest revision of the National Fuel Gas Code, ANSI Z223.1
section 5.3.
2. When a boiler is located in an unconfined space in a building or conventional construction
fra e, asonry or etal building, infiltration nor ally is adequate to provide air for
co bustion and ventilation. However, if the equip ent is located in a building of unusually tight
construction (See the national Fuel Gas Code, Ansi Z223.1 section 1.7), the boiler area
should be considered as a confined space. In this case air for co bustion and ventilation shall
be provided according to part 5 on page 4. If there is any doubt, install air supply provisions
in accordance with the latest revision of the National Fuel Gas Code.
3. When a boiler is installed in an unconfined
space, in a building of unusually tight
construction, air for co bustion and ventilation
ust be obtained fro outdoors or fro
spaces freely co unicating with the
outdoors. A per anent 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 ay be used to convey akeup air
fro the outdoors and shall have the sa e
cross-sectional area of the openings to which
they are connected.
4. When air for co bustion and ventilation
is fro inside buildings, the confined space
shall be provided with two per anent
openings, one starting 12 inches fro the top
and one 12 inches fro the botto of the
enclosed space. Each opening shall have a
ini u free area of 1 square inch per one thousand (1000) BTU per hour of the total input
rating of all appliances in the enclosed space, but ust not be less than one hundred (100)
square inches. These openings ust freely co unicate directly with other spaces of
sufficient volu e so that the co bined volu e of all spaces eets the criteria for an
unconfined space.
