Installation / Operation Instruction Manual
21
Figure 11b - Direct Vent and Powered Direct Vent Terminal Clearances
Canadian
Installations
1
US Installations
2
Canadian
Installations
1
US Installations
2
A=
Clearance above
grade, veranda,
porch, deck or
balcony
12 inches
(30 cm)
12 inches
(30 cm)
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
B=
Clearance to
window or door
that may be
opened
6 in (15cm) for
appliances ≤10,000
Btuh (3kW); 12 in
(30 cm) for
appliances >10,000
Btuh (3kW) and
≤100,000 Btuh
(30kW); 36 in (91
cm) for appliances
>100,000 Btuh (30
kW)
6 in (15 cm) for
appliances ≤10,000
Btuh (3 kW); 9 in (23
cm) for appliances
>10,000 Btuh (3 kW)
and ≤ 50,000 Btuh
(15 kW); 12 in (30
cm) for appliances
>50,000 Btuh (15
kW)
I=
Clearance to service
regulator vent outlet or oil
tank vent
36 inches
(91 cm)
*b
C=
Clearance to
permanently
closed window
*b
*b
J=
Clearance to non-
mechanical air supply inlet
to building or the
combustion air inlet to any
other appliance
6 in (15cm) for
appliances ≤10,000
Btuh (3kW); 12 in (30
cm) for appliances
>10,000 Btuh (3kW)
and ≤100,000 Btuh
(30kW); 36 in (91 cm)
for appliances
>100,000 Btuh (30 kW)
6 in (15 cm) for
appliances ≤10,000
Btuh (3 kW); 9 in (23
cm) for appliances
>10,000 Btuh (3 kW)
and ≤ 50,000 Btuh
(15 kW); 12 in (30
cm) for appliances
>50,000 Btuh (15
kW)
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
12 inches
(30 cm) *a
12 inches
(30 cm) *a
K=
Clearance to a mechanical
air supply inlet
6 feet
(1.83 m)
3 feet (.91 m) above
if within 10 feet (3.1
m) horizontally
E=
Clearance to
unventilated soffit
12 inches
(30 cm) *a
12 inches
(30 cm) *a
L=
Clearance above paved
sidewalk or paved driveway
located on public property
7 feet
(2.13 m) †
*b
F=
Clearance to
outside corner
*b
*b
M=
Clearance under a veranda,
porch, deck, or balcony
12 inches
(30 cm) ‡
12 inches
(30 cm) ‡
G=
Clearance to
inside corner
36 inches
(91 cm) *a
36 inches
(91 cm) *a
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”.










