Installation
900683-01F, 10/2018
Innovative Hearth Products
DRT3500 Series Direct-Vent Gas Fireplaces
13
VENT TERMINATION CLEARANCES
These instructions should be used as a guideline and do not supersede local codes in any way. Install venting with the
most restrictive requirements as outlined in these instructions, local codes, these instructions, the current National
Fuel Gas Code (ANSI Z223.1/NFPA 54) in the USA or the current standards of CAN/CGA-B149.1 in Canada.
Vertical Vent Termination Clearances
Terminate multiple vent terminations according to the installation codes listed above and Figure 3.
Figure 3 - Multiple Terminations
6”
(153 mm)
12”
(305 mm)
minimum
Terminate single vent caps relative to building components according to Table 6.
Table 6 - Termination Heights for Vents above Flat or Sloped Roofs (NFPA 54 / ANSI Z223.1)—Gas Vent Rule
Roof Pitch
Termination Height *
Flat to 6/12
1.0 ft (0.3 m)
6/12 to 7/12
1.25 ft (0.38 m)
7/12 to 8/12
1.5 ft (0.46 m)
8/12 to 9/12
2.0 ft (0.61 m)
9/12 to 10/12
2.5 ft (0.76 m)
10/12 to 11/12
3.25 ft (0.99 m)
11/12 to 12/12
4.0 ft (1.22 m)
12/12 to 14/12
5.0 ft (1.52 m)
14/12 to 16/12
6.0 ft (1.83 m)
16/12 to 18/12
7.0 ft (2.13 m)
18/12 to 20/12
7.5 ft (2.29 m)
20/12 to 21/12
8.0 ft (2.44 m)
12
X
Roof pitch is X/12
2 ft
minimum
2 ft minimum
Lowest
discharge
opening
H*
*H = minimum height from roof to
lowest discharge opening of vent
Horizontal overhang
Vertical
wall
Vent
termination
Storm collar
Concentric
vent pipe
Flashing
1” (26mm) minimum
clearance to combustibles
TERMINATION HEIGHTS FOR VENTS ABOVE
FLAT OR SLOPED ROOFS
Horizontal Vent Termination Clearances
The horizontal vent termination must have a minimum of 6” (152 mm) clearance to any overhead combustible
projection of 2-1/2” (64 mm) or less (Figure 4). For projections exceeding 2-1/2” (64 mm) (Figure 4). For additional
vent location restrictions refer to Table 7.
All horizontal terminations may be located as close as 6” (152mm) to any (non-combustible and combustible)
exterior sidewall. This distance may be decreased to 2” (51mm) for noncombustible exterior sidewalls with all
approved terminations (Table 7).
Figure 4 - Horizontal Vent Termination Clearances
Combustible projection
2-1/2” or less in length
Combustible projection
greater than 2-1/2” in length
Ventilated
soffit - 18”
(457 mm)
Unventilated
soffit - 12”
(305 mm)
6” (152mm)
Termination kit
Termination kit
6”
