4342
Ref. Clearance Description US Install Canada InstalI
A Above grade, veranda, porch, deck, or
balcony.
12 inches
(300 mm)
12 inches
(300 mm)
B To window or door that may be opened. 12 inches (300
mm)
36 (910 mm)
C Permanently closed window. * *
D Vertical to ventilated soffit, located
above the terminal within a horizontal
distance of 2 feet (61 cm) from the
center line of the terminal.
* *
E
To unventilated soffit. *
*
F To outside corner. * *
G To inside corner. * *
H
To each side of center line extended
above meter regulator assembly.
*
3 feet (910
mm) within a
height 15 feet
(4.5 m) above
the meter/
regulator
assembly
I To service regulator vent outlet. * 36 inches
(910 mm)
J
To non-mechanical air supply inlet to
building or the combustion air inlet to
any other appliance.
12 inches
(300 mm)
36 inches
(910 mm)
K To a mechanical air supply inlet. 3 feet (91cm)
above if within
10 feet (3000
mm)
horizontally
6 feet (1.83 m)
L Above paved sidewalk or paved
driveway located on public property.
* 7 feet (2.13 m)
**
M Under veranda, porch, deck, or
balcony.
* 12 inches
(300 mm)
Number of 900 elbows
0 1 2 3 4 5 6
41 feet
(12.5m)
35 feet
(10.7m)
29 feet
(8.8m)
23 feet
(7.0m)
17 feet
(5.2m)
11 feet
(3.4m)
5 feet
(1.5m)
THIS TABLE IS PROVIDED FOR REFERENCE ONLY.
Please consult latest version of these standards to ensure installation is in
compliance with current guidelines.
* For clearances not specified in ANS Z223.1/NFPA 54 or CSA B149.1, clearances
are in accordance with local installation codes and the requirements of the gas
supplier.
** 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.
Maximum Vent Length
1. Determine the number of 90 degree elbows in the vent system (Two 45 degree
elbows count as one 90 degree elbow).
2. Refer to below table to find the maximum vent length based on the number of
elbows
Example: If you have one elbow, then your maximum vent length is 35ft (10.7m)
]
Vertical Terminations
The air intake requires a return bend or tow 90º elbows to prevent entry of rain.
The vent termination and air intake must be in the same pressure zone.
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