9
Venting continued-
Canadian
Installations1US Installations2
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) 4 feet (1.2 m) below or
to the side of opening;
12 inches (30 cm) above
opening
C= Clearance to permanently closed
window *b *b
D= Vertical clearance to ventilated soffit
located above the terminal within a
horizontal distance of 2 feet (61 cm)
from the center line of the terminal
*b *b
E= Clearance to unventilated soffit *b *b
F= Clearance to outside corner *b *b
G= Clearance to inside corner *b *b
H= Clearance to each side of center line
extended above meter/regulator
assembly
3 feet (91 cm)
within a height
15 feet (4.6 m)
above the
meter/regulator
assembly
*b
I= Clearance to service regulator vent
outlet or oil tank vent 36 inches
(91 cm) *b
J= Clearance to non-mechanical air
supply inlet to building or the
combustion air inlet to any other
appliance
12 inches (30
cm) 4 feet (1.2m) below or to
side of opening; 12
inches (30 cm) above
opening.
K= Clearance to a mechanical air supply
inlet 6 feet
(1.83 m) 3 feet (91 cm) above if
within 10 feet
horizontally
L= Clearance above paved sidewalk or
paved driveway located on public
property
7 feet
(2.13 m)† 7 feet
(2.13 m)†
M= Clearance under a veranda, porch,
deck, or balcony 12 inches (30
cm) ‡ *b
1 In accordance with the current CAN/CGA-B149 Installation Codes.
2 In accordance with the current ANSI Z223.1-(Latest edition)/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 a veranda, porch, deck or balcony is fully open on a minimum of two sides beneath the
floor.
*a) A minimum clearance value determined by testing in accordance with section 2.20.
*b) “Clearance in accordance with local installation codes and the requirements of the gas supplier”.
The vent system must terminate so that proper clearances are maintained as cited
in local codes or the latest edition of the National Fuel Gas Code, ANSI
Z223.1.73.4e and 7.8a, b as follows:
1. Do not terminate near soffit vents or crawl space or other area where condensate or
vapor could create a nuisance or hazard or cause property damage.
2. Do not terminate 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.
3. Do not terminate the exhaust vent terminal over public area or walkways where
condensate or vapor can cause nuisance or hazard.
4. The vent shall terminate a minimum of 12” (25.4 cm) above expected snowfall level
to prevent blockage of vent termination.
