Exhaust Vent Terminal; Air For Combustion And Ventilation; A.4.A Combustion Air From Room; A.4.B Ducted Combustion Air - Bradford White OmniTech BONH1250 Installation And Operation Instructions Manual

Material
ABS
PVC, sch. 40
CPVC, sch. 40
Single wall galv. Steel
Polypropylene
Table 5. Required Combustion Air Pipe Material
2.A.3

Exhaust Vent Terminal

An exhaust vent terminal must be installed. If an exhaust vent terminal is not available with the certified vent system, the
manufacturer suggests the use of a coupler fitting from the certified vent system into which the vent terminal screen can be
installed. Laars offers vent terminals, shown in Table 6. Be sure to locate both vent and combustion air terminals per the
instructions in section 2.C Locating Vent & Combustion Air Terminals.
Size
1250
1500
1750
2000
2500
3000
Table 6. Horizontal Vent and Air Terminations
2.A.4

Air for Combustion and Ventilation

Boilers and water heaters must have provisions for
combustion and ventilation air in accordance with Section
9.3, Air for Combustion and Ventilation, of the National Fuel
Gas code, ANSI Z223.1, or Sections 7.2, 7.3, or 7.4 of CSA
B149.1, Installation Codes, or applicable provisions of the
local building codes.
The unit may receive combustion air from the space in
which it is installed, or it can be ducted directly to the unit
from the outside. Ventilation air must be provided in either
case.
2.A.4.a Combustion Air From Room
In the United States, the most common requirements
specify that the space shall communicate with the outdoors
in accordance with method 1 or 2, which follow. Where
ducts are used, they shall be of the same cross-sectional
area as the free area of the openings to which they
connect.
Method 1:
Two permanent openings, one commencing
within 12 inches (30 cm) of the top and one commencing
within 12 inches (30 cm) of the bottom, of the enclosure
United States
ANSI / ASTM D1527
ANSI / ASTM D1785 or D2665
ANSI / ASTM F441
26 gauge
ULC S636 Class 2C
Exhaust Vent
D2012004
D2012001
D2012002
shall be provided. The openings shall communicate
directly, or by ducts, with the outdoors or spaces
that freely communicate with the outdoors. When
directly communicating with the outdoors, or when
communicating to the outdoors through vertical ducts,
each opening shall have a minimum free area of 1
square inch per 4000 Btu/hr (5.5 square cm/kW) of total
input rating of all equipment in the enclosure. When
communicating with the outdoors through horizontal
ducts, each opening shall have a minimum free area of
not less than 1 square inch per 2000 Btu/hr (11 square
cm/kW) of total input rating of all equipment in the
enclosure.
Method 2:
within 12 inches (30 cm) of the top of the enclosure, shall
be permitted. The opening shall directly communicate
with the outdoors or shall communicate through a
vertical or horizontal duct to the outdoors or spaces that
directly communicate with the outdoors and shall have a
minimum free area of 1 square inch per 3000 Btu/hr (7
square cm/kW) of the total input rating of all equipment
The air pipe material must be chosen
based upon the intended application
of the boiler or water heater and must
be installed according to the vent
manufacturer's installation instructions.
Laars Part Number
CA011904
CA011901
CA011902
One permanent opening, commencing
Page 17
Canada
Inlet Air