46
Table 17. Vent Termination Clearances
VENT TERMINAL
AIR SUPPLY INLET
AREA WHERE TERMINAL IS NOT PERMITTED
VENTING INFORMATION
Clearance Location
CANADIAN INSTALLATIONS
a
US INSTALLATIONS
b
Direct Vent (2-pipe) &
Conventional Vent (1-pipe)
Furnaces
Direct Vent
(2-pipe) Furnaces
Conventional Vent
(1-pipe) Furnaces
A =
Clearance above grade, veranda, porch, deck, balcony, or
maximum expected snow level.
12 inches (30cm)
12 inches (30cm)
12 inches (30cm)
B = Clearance to window or door that may be opened.
6 inches (15cm) for
appliances < 10,000 Btuh (3kW)
6 inches (15cm) for
appliances < 10,000 Btuh (3kW)
4 ft. (1.2m) below or to side of opening;
1 ft. (300mm) above opening
12 inches (30cm) for appliances
10,000 Btuh - 100,000 Btuh (30kW)
9 inches (23cm) for appliances
10,000 Btuh - 50,000 Btuh (30kW)
36 inches (91cm) for
appliances > 100,000 Btuh (30Kw)
12 inches (30cm) for
appliances > 50,000 Btuh (30Kw)
C = Clearance to permanently closed window
*
*
*
D =
Vertical clearance to ventilated soffi t located above the
terminal within a horizontal distance of 2 feet (61cm) 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 (91cm) within a height 15 feet
above the meter/regulator assembly
*
*
I = Clearance to service regulator vent outlet.
3 feet (1.83m)
*
*
J =
Clearance to non-mechanical air supply inlet to building
or the combustion air inlet to any other appliance.
6 inches (15cm) for
appliances < 10,000 Btuh (3kW)
6 inches (15cm) for
appliances < 10,000 Btuh (3kW)
4 ft. (1.2m) below or to side of opening;
1 ft. (300mm) above opening
12 inches (30cm) for appliances
10,000 Btuh - 100,000 Btuh (30kW)
9 inches (23cm) for appliances
10,000 Btuh - 50,000 Btuh (30kW)
36 inches (91cm) for
appliances > 100,000 Btuh (30Kw)
12 inches (30cm) for
appliances > 50,000 Btuh (30Kw)
K = Clearance to mechanical air supply inlet.
6 feet (1.83m)
3 feet (91cm) above if within
10 feet (3m) horizontally
3 ft. (91cm) above if within
10 feet (3m) horizontally
L =
Clearance above paved sidewalk or driveway located on
public property.
7 feet (2.13m)
c
*
7 ft. (2.13m)
M = Clearance under veranda, porch, deck, or balcony.
12 inches (30cm)
d
*
*
NOTES:
a
In accordance with the current CSA B149.1 Natural Gas and Propane Installation Guide Code
b
In accordance with the current ANSI Z223.1 / NFPA 54 Natural Fuel Gas Code
c
A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.
d
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 manufacturers installation instructions”
