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X
V V
V
V
V
X
V
= Vent terminal
= Air supply inlet
= Area terminal NOT permitted
= 9" U.S. (12" Canada)
C
A
L
B
C
B
B
C
C
B B
A
G
J
H
I
K
M
D E
V
V
X
V
F
Fixed Closed
Window
Operable
Window
D
36"
(91.4 cm)
7
MINIMUM CLEARANCES
Clearance Description US Installation Canadian Installation
A = Clearance above grade, veranda, porch,
deck, or balcony.
18 in (46 cm) 18 in (46 cm)
B = Clearance to window or door that may be
opened.
6 in (15.2 cm) for appliances < 10,000 BTU/hr (3kW);
9 in (23 cm) for appliances > 10,000 BTU/hr (3kW)
and < 50,000 BTU/hr (15kW);
12 in (30 cm) for appliances > 50,000 BTU/hr (15kW).
6 in (15.2 cm) for appliances < 10,000 BTU/hr (3kW);
12 in (30 cm) for appliances > 10,000 BTU/hr (3kW)
and < 100,000 BTU/hr (30kW);
36 in (91.4 cm) for appliances > 100,000 BTU/hr (30kW).
C = Clearance to permanently closed window. 9 in (229 mm) recommended to prevent window
condensation.
12 in (305 mm) recommended to prevent window
condensation.
D = Vertical clearance to ventilated soffit
located above the terminal within a
horizontal distance of 36 in (91.4 cm)
from center line of terminal.
24 in (61 cm) 24 in (61 cm)
E = Clearance to unventilated soffit. 24 in (61 cm) 24 in (61 cm)
F = Clearance to outside corner. 5 in (12.7 cm) 5 in (12.7 cm)
G = Clearance to inside corner. 24 in (61 cm) 36 in (91.4 cm)
H = Clearance to each inside of center line
extended above meter/regulator assembly.
3 ft (91.4 cm) within a height of 15 ft above the
meter/regulator assembly.
3 ft (91.4 cm) within a height of 15 ft above the
meter/regulator assembly.
I
= Clearance to service regulator vent outlet. 3 ft (91.4 cm) 3 ft (91.4 cm)
J = Clearance to non-mechanical air supply
inlet to building or combustion air inlet to
any other appliance.
6 in (15.2 cm) for appliances < 10,000 BTU/hr (3kW);
9 in (23 cm) for appliances > 10,000 BTU/hr (3kW)
and < 50,000 BTU/hr (15kW);
12 in (30 cm) for appliances > 50,000 BTU/hr (15kW).
6 in (15.2 cm) for appliances < 10,000 BTU/hr (3kW);
12 in (30 cm) for appliances > 10,000 BTU/hr (3kW)
and < 100,000 BTU/hr (30kW);
36 in (91.4 cm) for appliances > 100,000 BTU/hr (30kW).
K = Clearance to mechanical air supply inlet. 3 ft (91.4 cm) above, if within 10 ft (3 m) horizontally. 6 ft (1.83 m)
L = Clearance above paved sidewalk or paved
driveway located on public property.
7 ft (2.13 m) 7 ft (2.13 m)
M = Clearance under veranda, porch, deck, or
balcony.
18 in (46.0 cm) 18 in (46.0 cm)
In accordance with the current ANSI Z223.1 / NFPA 54 National Fuel Codes (latest editions).
In accordance with the current CAN/CSA-B149.1 Installation Code (latest editions).
A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single-family dwellings and serves both dwellings.
Only permitted if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the oor.
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Figure 5
NOTE:
•Local codes or regulations may require
different clearances.
•Location of vent termination must NOT
interfere with access to electrical service.
X
V V
V
V
V
X
V
= Vent terminal
= Air supply inlet
= Area terminal NOT permitted
= 9" U.S. (12" Canada)
C
A
L
B
C
B
B
C
C
B B
A
G
J
H
I
K
M
D E
V
V
X
V
F
Fixed Closed
Window
Operable
Window
D
36"
(91.4 cm)
X
V V
V
V
V
X
V
= Vent terminal
= Air supply inlet
= Area terminal NOT permitted
= 9" U.S. (12" Canada)
C
A
L
B
C
B
B
C
C
B B
A
G
J
H
I
K
M
D E
V
V
X
V
F
Fixed Closed
Window
Operable
Window
D
36"
(91.4 cm)
[DETAIL]
Inside Corner
EXTERIOR HORIZONTAL VENT TERMINATION CLEARANCE REQUIREMENTS
LENNOX HEARTH PRODUCTS • MONTEBELLO
®
SEE-THROUGH DIRECT-VENT GAS FIREPLACES (LSM40ST-N / LSM40ST-P) • INSTALLATION INSTRUCTIONS
Center Line of
Horizontal
Termination
Inside Corner
Ventilated
Soffit
Exterior Wall
[DETAIL]
See Item “D” in table below.