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Venting Information
Table 14. Vent Termination Clearances
CLEARANCE LOCATION
US Installations
a
Direct Vent
(2-pipe) Furnaces
Conventional Vent
(1-pipe) Furnaces
A =
Clearance above grade, veranda, porch, deck,
balcony, or maximum expected snow level.
12 inches (30cm)
12 inches (30cm)
B =
Clearance to window or door
that may be opened.
6 inches (15cm) for
appliances < 10,000 Btuh (3kW)
4 ft. (1.2m) below or to side
of opening; 1 ft. (300mm)
above opening
9 inches (23cm) for appliances
10,000 Btuh - 50,000 Btuh (30kW)
12 inches (30cm) for
appliances > 50,000 Btuh (30Kw)
C =
Clearance to permanently closed window
*
*
D =
Vertical clearance to ventilated soffit located above the terminal within
a horizontal distance of 2 feet (61cm) from the center line of the
terminal.
*
*
E =
Clearance to unventilated soffit.
*
*
F =
Clearance to outside corner.
*
*
G =
Clearance to inside corner.
*
*
H =
Clearance to each side of center line extended above meter/regulator
assembly.
*
*
I =
Clearance to service regulator vent outlet.
*
*
J =
Clearance to non-mechanical air supply inlet to
building or the combustion air inlet to any other
appliance.
6 inches (15cm) for
appliances < 10,000 Btuh (3kW)
4 ft. (1.2m) below or to side
of opening; 1 ft. (300mm)
above opening
9 inches (23cm) for appliances
10,000 Btuh - 50,000 Btuh (30kW)
12 inches (30cm) for
appliances > 50,000 Btuh (30Kw)
K =
Clearance to mechanical air supply inlet.
3 feet (91cm) above if within
10 feet (3m) horizontally
3 ft. (91cm) above if within
10 feet (3m) horizontally
L =
Clearance above paved sidewalk or driveway
located on public property.
*
7 ft. (2.13m)
M =
Clearance under veranda, porch, deck, or
balcony.
*
*
a: In accordance with the current ANSI Z223.1 / NFPA 54 Natural Fuel Gas Code
* For clearances not specified in ANSI Z223.1 / NFPA 54, the following statement shall be included: “Clearance in accordance with local installation codes, and the
requirements of the gas supplier and the manufacturers installation instructions”
VENT TERMINAL
AIR SUPPLY INLET
AREA WHERE TERMINAL IS NOT PERMITTED
