85Installing a Common Vent System
9.8 Exhaust Vent Termination Clearances (For Direct Vent)
Ref Description Canadian Direct Vent Installations U.S. Direct Vent Installations
A
Clearance above grade, veranda, porch, deck, or
balcony
12 in (30 cm) 12 in (30 cm)
B Clearance to window or door that may be opened 36 in (91 cm) 12 in (30 cm)
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 inside corner * *
H
Clearance to each side of center line extended
above meter/regulator assembly
3 ft (91 cm) within a height
15 ft above the meter/regulator
assembly
*
I Clearance to service regulator vent outlet 3 ft (91 cm) *
J
Clearance to nonmechanical air supply inlet to
building or the combustion air inlet to any other
appliance
36 in (91 cm) 12 in (30 cm)
K Clearance to a mechanical air supply inlet 6 ft (1.83 m)
3 ft (91 cm) above if within10
ft (3 m) horizontally
L
Clearance above paved sidewalk or paved
driveway located on public property
7 ft (2.13 m)† *
M Clearance under veranda, porch deck, or balcony 12 in (30 cm)‡ *
1 In accordance with the current CSA B149.1 Natural Gas and Propane Installation Code
2 In accordance with the current ANSI Z223.1 / NFPA 54 National Fuel Gas Code
† A vent shall not terminate directly above a sidewalk or a paved driveway that is located between two single family dwellings, that serves both dwellings.
‡ Permitted only if the veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.
* Clearance in accordance with local installation codes and the requirements of the gas supplier.