Page 17
SECTION IV: INSTALLATION (cont .)
VENT & COMBUSTION AIR INTAKE (cont.)
Table 9: Power Vent Terminal Clearances
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.
3) If locally adopted installation codes specify clearances different than those illustrated, then the most stringent clearance shall prevail.
† 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.
* Manufacturer’s recommendation. Must be in accordance with local installation codes and requirements of the gas supplier.
In addition to the clearances specified, the following items shall be accounted for during installation:
• Do not terminate near soffit vents or crawl space or other area where condensate or vapor could create a
nuisance hazard or cause property damage.
• Do not locate 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.
• Do not locate the exhaust vent terminal over public area or walkways where condensate or vapor can cause
nuisance or hazard.
• Do not locate the vent terminal in proximity to plants/shrubs.
• The vent and air intake shall terminate a minimum of 12” (25.4 cm) above expected snowfall level to prevent
blockage.
CAUTION
Never install air intake terminal above vent (exhaust) terminal.
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 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)
4 feet (1.2 m) below or to side
of opening; 1 foot (300 mm)
above opening
C = Clearance to permanently closed
window
12 inches (30 cm)
*
12 inches (30 cm)
*
D = Vertical clearance to ventilated
soffit located above the terminal within
a horizontal distance of 2 feet (61 cm)
from the centerline of the terminal
12 inches (30 cm)
*
12 inches (30 cm)
*
E = Clearance to unventilated soffit
12 inches (30 cm)
*
12 inches (30 cm)
*
F = Clearance to outside corner
2 ft (60 cm)
*
2 ft (60 cm)
*
G = Clearance to inside corner
18 in (45 cm)
*
18 in (45 cm)
*
H = Clearance to each side of centerline
extended above meter/regulator
assembly
3 ft (91 cm) within a height
of 15 ft (4.6 m)
*
Clearance in accordance with local
installation codes and the require-
ments of the gas supplier.
I = Clearance to service regulator vent
outlet
3 ft (91 cm)
Clearance in accordance with local
installation codes and the require-
ments of the gas supplier.
J = Clearance to non-mechanical
air supply inlet to building or the
combustion air inlet to any other
appliance
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)
4 feet (1.2 m) below or to side
of opening; 1 foot (300 mm)
above opening
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)†
Cannot be located above public
walkways or other areas where
condensate or vapor can cause
nuisance or hazard.
M = Clearance under veranda, porch,
deck, or balcony
12 inches (30 cm) ‡
12 inches (30 cm) ‡
