IBC Technologies Inc.
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VFC 15-150 and VFC 45-225
1.4.2 “Category IV” Venting
A “Category IV” venting system, as
described herein, is one in which air for
combustion is taken from the ambient air
around the boiler. Vent piping is run
horizontally or vertically to the outdoors.
Follow the same vent material and travel
instructions as per the previous
provisions of Section 1.4.
Note:- the maximum equivalent length
must not exceed the stated distance per
Table 3. It is not permitted to add to the
exhaust length by transfer of unused
intake allowance.
1.4.2.1
Ventilation and Air Supply
To support combustion, an ample air
supply is required. This may require
direct openings in the boiler room to the
outside. If the boiler is not in a room
adjacent to an outside wall, air may be
ducted from outside wall openings.
Provisions for combustion and ventilation
air must be made as follows: in the USA,
in accordance with Section 5.3
Air for
Combustion and Ventilation of the
National Fuel Gas Code
, ANSI Z223.1
(latest edition), or applicable provisions
of the local building codes; in Canada, in
compliance with B149.
The following lists are recommendations
for buildings of energy-saving
construction, fully caulked and weather-
stripped:
•
An opening to the outside, within 18”
of the floor, but no less than 6” off the
floor, should be provided in the room.
Each opening should be covered in a
grill, and have an area of 1 sq. in. per
1,000 BTUh for ALL APPLIANCES
in the area.
•
Openings must not be closed or
reduced. Doors and windows used
for air supply must be locked open.
•
Mechanical draft exhaust or supply
fans are not to be used in or near the
boiler area
•
Boiler combustion and ventilation
airflow must not be obstructed
Combustion air must not expose the
boiler to contamination - see
Section 1.3
- Location
, above. In other respects,
Category IV venting is installed in the
same manner as for the exhaust side of
Direct Vent installations.
1.4.3 Closet Installations
For installations in a confined space (such
as a closet), ventilation openings may be
needed through a door or wall to prevent
excessive heat from building up inside
the space.
The boiler shall not be exposed to
ambient conditions above 122°F (50°C)
or below 32°F (0°C).