P-K SONIC
TM
Gas Fired Boiler
T
T
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Technical Service 1.877.728.5351
echnical Service 1.877.728.5351
echnical Service 1.877.728.5351
echnical Service 1.877.728.5351
3.3.1 Air Inlet Requirements
3.3.1.1 United States Considerations
When air is supplied from inside the building, the total required volume shall be the sum of the required volume
for all the appliances located in the mechanical room. Adjacent rooms furnished with fixed openings
communicating directly with the mechanical room are considered part of the required volume. The minimum
volume is 50 ft
3
per 1000 Btu/hr (4.8 m
3
/kW) of installed appliance input capacity.
Openings used to connect indoor spaces to obtain the required minimum volume shall be sized as follows
:
•
When rooms are on the same floor, each opening shall have an area equal to 1 square inch for each 1000
Btu/hr (2200 mm
2
/kW) of installed appliance input capacity, but not less than 100 square inches. One
opening should commence less than 12 inches above the floor and the other less than 12 inches below
the ceiling. The minimum dimension of air openings shall be 3 inches
.
•
When rooms are on different floors, each opening shall have an area equal to 2 square inches for each
1000 Btu/hr (4400 mm
2
/kW) of installed appliance input capacity
.
When combustion air is supplied from outside the building, the boiler room shall be provided with one or two
openings to ensure adequate combustion air and proper ventilation
.
When using one permanent opening, the opening shall commence within 12 inches of the ceiling and shall
communicate directly with the outdoors or through a vertical or horizontal duct that communicates to the outdoors
.
Minimum free area of the opening is 1 square inch for each 3000 Btu/hr (700 mm
2
/kW) of installed appliance input
capacity, and not less than the sum of the areas of all vent connectors in the room.
Under no circumstances
shall the boiler room ever
be under a negative
pressure.
Particular care should be
taken when exhaust fans,
compressors, air-handling
units or other equipment
may rob air from the boiler.
Note that this equipment
might be in rooms other
than the boiler room. This
applies to both sealed
combustion and
atmospheric room
combustion air applications.
3.3.1.2 US Requirements
Air inlet requirements for the United States are established by NFPA
54/ANSI Z223.1 & NFPA/ANSI 211.
When using two permanent
openings, one opening shall commence within 12 inches above the floor
and the other within 12 inches below the ceiling, preferably on opposite
walls. The openings shall communicate directly, or by way of ducts, with
free outdoor air. The minimum net free area of the openings shall be
calculated in accordance with the following
:
•
When air is taken directly from outside the building, each
opening (minimum of two, as outlined above), 1 square inch for
each 4,000 Btu per hour (550 mm
2
/kW) of total boiler input is
required
.
•
When air is taken from the outdoors through a vertical duct into
the mechanical room, 1 square inch per 4,000 Btu per hour
(550
mm
2
/kW) of total boiler input is required.
•
When air is taken from the outdoors through a horizontal duct
into the mechanical room, 1 square inch per 2,000 Btu per hour
(1100 mm
2
/kW) of total boiler input is required.
