1 In accordance with the current CSA B149, Natural Gas and Propane Installation Code.
2 In accordance with the current ANSI Z223.1 NFPA 54, National Fuel Gas Code.
* These numbers are only estimates. Clearance in accordance with installation codes and the requirements of the gas supplier.
t A vent shall not terminate directly above a side walk or paved driveway that is located between two single family dwellings and it serves both dwellings.
+ Permitted only if verandah, porch, deck, or balcony is fully open on a minimum of two sides beneath the floo
r.
NOTE: Venting terminals shall not be recessed into walls or siding.
Figure 18. Vent Termination Restrictions, refer to Table 2.
Initial Installation
QUALIFIED INSTALLERS ONLY
V
ent
t
eRmination
R
estRictions
:
A
A
D E
L
B
C
F
B
B
B
J
M
K
G
H
I
Openable
Fixed
Closed
Openable
Fixed
Closed
Termination Cap
Air Supply Inlet
Gas Meter
G
G
Restriction Zone
(Termination not allowed)
N
O
Letter
Canadian Installation
1
US Installation
2
Description
A
12 in (30 cm)
Clearance above grade, verandah, porch, deck, or balcony.
B
12 in (30 cm)
9 in (23 cm)
Clearance from window or door that may be opened.
C
12 in (30 cm)*
Clearance from permanently closed window (to prevent
condensation).
D
24 in (60 cm)*
Vertical clearance to ventilated soffit located above the
terminal, within a horizontal distance of 2 ft (60 cm) from
center line of terminal.
E
18 in (45 cm)*
Clearance to unventilated soffit.
F
12 in (30 cm)*
Clearance to outside corner.
G
12 in (30 cm)*
Clearance to inside corner.
H
3 ft (91 cm) within a height of
15 ft (4.5 m) above the meter/
regulator assembly
3 ft (91 cm) within a height of
15 ft (4.5 m) above the meter/
regulator assembly*
Clearance to each side of center line extended above
meter/regulator assembly.
I
3 ft (91 cm)
3 ft (91 cm)*
Radial clearance around service regulator vent outlet.
J
12 in (30 cm)
9 in (23 cm)
Clearance to non-mechanical air supply inlet to building, or
the combustion air inlet to any other appliance.
K
6 ft (1.83 m)
3 ft (91 cm) above if within 10
ft (3 m) horizontally
Clearance to mechanical air supply inlet.
L
7 ft (2.13 m)t
7 ft (2.13 m)*t
Clearance above paved sidewalk or paved driveway located
on public property.
M
12 in / 30 cm+
12 in / 30 cm*+
Clearance under verandah, porch, deck, or balcony.
N
12 in (30 cm)*
Clearance horizontally to any surface (such as an exterior
wall) for vertical terminations.
O
12 in (30 cm)
Clearance above roof line for vertical terminations.
Table 2: Vent termination clearances, refer to Figure 18.
15
