Tech Bulletin

TB-108
10/2014
INSIDE
CORNER DETAIL
FIXED
CLOSED
OPERABLE
FIXED
CLOSED
OPERABLE
B
B
B
A
J
B
M
C
F
B
B
E
D
L
G
A
H
K
I
[1] A vent shall not terminate directly above a sidewalk or paved driveway that is
located between two single family dwellings and serves both dwellings.
[2] Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of
two sides beneath the floor.
 For clearances not specified in ANSI Z223.1/NFPA 54, clearances are in accordance
with local installation codes and the requirements of the gas supplier.
Clearance to opposite wall is 24 inches (60 cm).
X
V
AIR SUPPLY INLET
VENT TERMINAL
AREA WHERE TERMINAL
IS NOT PERMITTTED
SNOW
TERMINATION
Clearance in
Ref. A also
applies to
anticipated
snow line
Direct Vent (Indoor Units) Other Than Direct Vent (Outdoor units)
Ref
Description
Canadian
Installations (CSA
B149.1)
US Installations
(ANSI Z223.1 / NFPA 54)
Canadian Installations
(CSA B149.1)
US Installations
(ANSI Z223.1 / NFPA 54)
A
Clearance above grade, veranda, porch, deck, or
balcony
12 inches (30 cm) 12 inches (30 cm) 12 inches (30 cm) 12 inches (30 cm)
B
Clearance to window or door that may be opened
36 inches (91 cm) 12 inches (30 cm)
6 in (15 cm) for appliances ≤
10,000 Btuh (3 kW), 12 in (30
cm) for appliances > 10,000 Btuh
(3 kW) and ≤ 100,000 Btuh (30
kW), 36 in (91 cm) for appliances
>100,000 Btuh (30 kW)
4 ft (1.2 m) below or to side
of opening; 1 ft (300 mm)
above opening
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 feet (91 cm) within a
height 15 feet (4.5 m)
above the meter/
regulator assembly
*
3 feet (91 cm) within a height 15
feet (4.5 m) above the meter/
regulator assembly
*
I
Clearance to service regulator vent outlet
36 inches (91 cm) * 36 inches (91 cm) *
J
Clearance to nonmechanical air supply inlet to
building or the combustion air inlet to any other
appliance
36 inches (91 cm) 12 inches (30 cm)
6 in (15 cm) for appliances ≤
10,000 Btuh (3 kW), 12 in (30
cm) for appliances > 10,000 Btuh
(3 kW) and ≤ 100,000 Btuh (30
kW), 36 in (91 cm) for appliances
>100,000 Btuh (30 kW)
4 ft (1.2 m) below or to side
of opening; 1 ft (300 mm)
above opening
K
Clearance to a mechanical air supply inlet
6 feet (1.83 m)
3 feet (91 cm) above if
within 10 feet (3 m)
horizontally
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)  * 7 feet (2.13 m)  *
M
Clearance under veranda, porch, deck, or balcony
12 inches (30 cm)  * 12 inches (30 cm)  *
Technical Bulletin 108-Updated Terminal Clearances for Outdoor Water Heaters
The purpose of this technical bulletin is to communicate clearance updates (Shaded references B and J in the table below)
for outdoor tankless water heaters. As part of Rinnai's CSA certification updates, manuals for outdoor tankless water
heaters have been updated with the latest clearances as required by the latest editions of National Fuel Gas Code ANSI
Z223.1/NFPA 54 and ANSI Z21.10.3 standards.