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D
V
V
E
FIXED
CLOSED
O
P
ERA
BL
E
O
PE
R
A
BL
E
FIXE
D
CLOSED
v
v
B
L
F
C
B
v
v
v
X
B
B
B
A
J
B
I
H
X
v
M
K
v
G
A
The following information should be used for determining the proper location of the vent
terminal for direct vent tankless water heaters.
V
VENT TERMINAL
X
AIR SUPPLY INLET
AREA WHERE TERMINAL IS NOT PERMITTED
Horizontal Vent Terminal Location
1 In accordance with current CSA-B149.1 Installation Codes.
2 In accordance with current ANSI Z223.1/ 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.
* For clearances not specified in ANSI 223.1/NFPA 54 or CSA-B149.12, one of the following shall be indicated:
a) A minmum clearance value determined by testing in accordance with section 2.20, or;
b) A reference to the following footnote: "Clearance in accordance with local installtion codes and the require-
ments of the gas supplier."
H = Clearance to each side of center line
extended meter/regulator assembly.
above
3 feet (91 cm) within a height 15 feet
(4.57 m) above the meter/regulator
assembly.
*
I = Clearance to service regulator
coaxial vent outlet.
3 feet (91 cm) *
J = Clearance to nonmechanical air
supply inlet to the combustion
air inlet to any building or other
appliance.
6 inches (15 cm) for appliances <
10,000 Btuh (3 kW), 12 inches (30 cm)
for appliances > 10,000 Btuh (3kW)
and < 100,000 Btuh (30kW), 36 inches
(91 cm) for appliances > 100,000 Btuh
(30kW).
6 inches (15 cm) for appliances < 10,000
Btuh (3 kW), 9 inches (23 cm) for
appliances > 10,000 Btuh (3kW) and <
50,000 Btuh (15kW), 12 inches (30 cm)
for appliances > 50,000 Btuh (15kW).
K = Clearance to 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)† *
M = Clearance under veranda, porch,
deck or balcony.
Not Allowed Not Allowed
Canadian Installations
1
US Installations
2
A= Clearance above grade, veranda,
porch, deck or balcony.
12 inches (30 cm) above anticipated
snow level.
12 inches (30 cm) above anticipated
snow level.
B= Clearance to window or door that
may be opened.
6 inches (15 cm) for appliances < 10,000
Btuh (3 kW), 12 inches (30 cm) for
appliances > 10,000 Btuh (3kW) and <
100,000 Btuh (30kW), 36 inches (91 cm)
for appliances > 100,000 Btuh (30kW).
6 inches (15 cm) for appliances <
10,000 Btuh (3 kW), 9 inches (23 cm)
for appliances > 10,000 Btuh (3kW)
and < 50,000 Btuh (15kW), 12 inches
(30 cm) for appliances > 50,000 Btuh
(15kW).
C= Clearance to permanently closed
window.
* *
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.
* *
E= Clearance to unventilated soffit.
* *
F= Clearance to outside corner.
* *
G= Clearance to corner.
* *
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