16
Figure 13. Vent Termination Clearances for Direct Vent Furnaces
VENT TERMINAL
AIR SUPPLY INLET
AREA WHERE TERMINAL IS NOT PERMITTED
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 fl oor.
* For clearances not specifi ed in ANSI Z223.1 / NFPA 54 or CSA B149.1, the following statement shall be included:
“Clearance in accordance with local installation codes, and the requirements of the gas supplier
and the manufacturer’s installation instructions.”
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
6 inches (15 cm) for appliances
10,000 Btuh (3 kW), 12 inches (30
cm) for appliances > 10,000 Btuh
(3 kW) and 100,00 Btuh (30 kW),
6 inches (15 cm) for appliances
10,000 Btuh (3 kW), 9 inches (23
cm) for appliances > 10,000 Btuh
(3 kW) and 50,000 Btuh (15 kW),
C =
Clearance to permanently closed window
*
*
D =
Vertical clearance to ventilated soffi t located
above the terminal within a horizontal
distance of 2 feet (61 cm) from the center
line of the terminal
*
*
E =
Clearance to unventilated soffi t
*
*
F =
Clearance to outside corner
*
*
G =
Clearance to inside corner
*
*
H =
Clearance to each side of center line
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 (1.83 m)
*
J =
Clearance to nonmechanical air supply inlet
to building or the combustion air inlet to any
other appliance
6 inches (15 cm) for appliances
10,000 Btuh (3 kW), 12 inches (30
cm) for appliances > 10,000 Btuh
(3 kW) and 100,00 Btuh (30 kW),
6 inches (15 cm) for appliances
10,000 Btuh (3 kW), 9 inches (23
cm) for appliances > 10,000 Btuh
(3 kW) and 50,000 Btuh (15 kW),
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) ‡
*
