1
In accordance with the current CSA B149.1
Natural Gas and Propane Installation Code.
2
In accordance with the current ANSI Z223.1 / NFPA 54
National Fuel Gas Code.
† A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family
dwellings and serves both dwellings.
Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.
* Clearance in accordance with local installation codes and the requirements of the gas supplier.
In addition to the clearances specified, the following items shall be accounted for during
installation:
• Do not terminate near soffit vents or crawl space or other area where condensate or
vapor could create a nuisance hazard or cause property damage.
• Do not locate the exhaust vent terminal where condensate or vapor could cause damage
or could be detrimental to the operation of regulators, relief valves, or other equipment.
• Do not locate the exhaust vent terminal over public area or walkways where condensate
or vapor can cause nuisance or hazard.
• Do not locate the vent terminal in proximity to plants/shrubs.
• The vent and air intake shall terminate a minimum of 12" (25.4 cm) above expected
snowfall level to prevent blockage.
CAUTION
Never install air intake terminal above vent (exhaust) terminal.
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SECTION IV: INSTALLATION (cont.)
VENT & COMBUSTION AIR INTAKE (cont.)
Table 8:
Direct Vent Terminal Clearances
Canadian Installations
1
US Installations
2
A = Clearance above grade, veranda,
porch, deck, or balcony
12 inches (30 cm)
12 inches (30 cm)
B = Clearance to window or door that
may be opened
12 inches (30 cm)
12 inches (30 cm)
C = Clearance to permanently closed
window
*
*
D = Vertical clearance to ventilated
soffit located above the terminal within
a horizontal distance of 2 feet (61 cm)
from the centerline of the terminal
*
*
E = Clearance to unventilated soffit
*
*
F = Clearance to outside corner
*
*
G = Clearance to inside corner
*
*
H = Clearance to each side of centerline
extended above meter/regulator
assembly
3 feet (91 cm) within a height 15 feet
above the meter/regulator assembly
*
I = Clearance to service regulator vent
outlet
3 feet (91 cm)
*
J = Clearance to non-mechanical air
supply inlet to building or the
combustion air inlet to any other
appliance
12 inches (30 cm)
12 inches (30 cm)
K = Clearance to a mechanical air
supply inlet
6 feet (1.83 m)
3 feet (91 cm) above if within
10 feet (3 m) horizontally
L = Clearance above paved sidewalk or
paved driveway located on public
property
7 feet (2.13 m)†
*
M = Clearance under veranda, porch,
deck, or balcony
12 inches (30 cm)
*
††
††
