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7
Clearance Requirements from Vent Terminations to Building Openings
US Installations¹
Canadian Installations²
A =
Clearance above grade, veranda, porch, deck or
balcony
12 in (30 cm)
12 in (30 cm)
B =
Clearance to window or door that may be opened
4 feet (1.2 m) below or to side of opening;
1 ft (30cm) above opening
6 in (15 cm) for appliances ≤ 10,000
Btuh (3 kw), 12 in (30 cm) for
appliances > 10,000 Btuh (3 kw) and
≤ 100,000 Btuh (30 kw), 36 in (91 cm)
for appliances > 100,000 Btuh (30 kw)
C =
Clearance to permanently closed window
*
*
D =
Vertical clearance to ventilated soffit located above
the terminal within a horizontal distance of
2 ft (610 cm) from the center line of the terminal
*
*
E =
Clearance to unventilated soffit
*
*
F =
Clearance to outside corner
*
*
G =
Clearance to inside corner
*
*
H =
Clearance to each side of center line extended above
meter / regulator assembly
*
*
I =
Clearance to service regulator vent outlet
*
Above a regulator within 3 ft (91 cm)
horizontally of the vertical center line of
the regulator vent outlet to a maximum
vertical distance of 15 ft (4.5 m)
J =
Clearance to nonmechanical air supply inlet to
building or the combustion air inlet to any other
appliance
4 ft (1.2 m) below or to side of opening;
1 ft (30 cm) above opening
6 in (15 cm) for appliances ≤ 10,000 Btuh
(3 kw), 12 in (30 cm) for appliances
> 10,000 Btuh (3 kw) and ≤ 100,000 Btuh
(30 kw), 36 in (91 cm) for appliances
> 100,000 Btuh (30 kw)
K =
Clearance to a mechanical air supply inlet
3 ft (91 cm) above if within 10 ft (3 m)
horizontally
6 ft (1.83 m)
L =
Clearance above paved sidewalk or paved driveway
located on public property
7ft (2.13 m)
7 ft (2.13 m) †
M =
Clearance under veranda, porch, deck or balcony
*
12 in (30 cm) ‡
¹
In accordance with the current ANSI Z223.1/NFPA 54 Natural Fuel Gas Code
²
In accordance with the current CSA B149.1, Natural Gas and Propane Installation 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. Lennox recommends avoiding this
location if possible.
＊
Clearance in accordance with local installation codes and the requirements of the gas supplier. Clearance to opposite wall is 24 in (60 cm).
