Instructions / Assembly

®
System1738 Installation Methods 7
Pitched Roof Terminations
Snorkel and concentric termination:
(a) In accordance with the requirements of the 2018
edition of the NFPA 54/ANSI Z223.1 National Fuel
Gas Code, gas vents that are 12 inches or less in
size and located not less than 8 ft from a vertical
wall or similar obstruction shall terminate above the
roof in accordance with Figure 9 and Table 1.
(b) Snorkel and Concentric Vent Roof termination
clearances shall be installed in accordance with the
requirements in Figures 8 & 9.
(c) To avoid recirculation of exhaust gas on roof
snorkel terminations, the end of the vent pipe
must be higher than the intake pipe. The minimum
vertical separation between the end of the vent
pipe and the end of the intake pipe is 8 inches (see
Figure 8).
Figure 9:
Typical Pitched Roof Concentric Vent Termination
Roof pitch is x/12
H (minimum) -
Minimum height from roof
to lowest discharge opening
Listed
cap
Lowest discharge opening
Listed
gas vent
System1738 Roof flashing
x
12
(d) The run of intake and vent pipes for a snorkel
termination in general should be installed as close
together as possible. Roof penetration shall maintain
a 3" maximum separation (see Figure 8)
(e) Terminate the vent piping of a snorkel termination
straight up when through a chimney or fortified
penetrations (see Figure 8).
(f) Intake piping of a snorkel termination through the
roof must be directed straight down through the
use of two 90° elbows (see Figure 8).
(g) Reference the Concentric Vent Termination Kit
section of this guide for full installation instructions of
this termination option.
8" MIN.
Separation
Typical Roof Termination
3" MAX separation
Insulation in
unconditioned
space
Reducer Coupling
Approved Penetration
and Flashing as per
Building Code
Unconditioned
Attic Space
12" Above avg.
snow accumulation
Provide support for
intake and vent lines
Install condensate drain
as per appliance
manufacturer’s
recommendations
Vent Intake
Figure 8:
Typical Pitched Roof Snorkel Termination
Roof Slope
H (minimum)
ft
Flat to 6/12 1.0
Over 6/12 to 7/12 1.25
Over 7/12 to 8/12 1.5
Over 8/12 to 9/12 2.0
Roof Slope
H (minimum)
ft
Over 9/12 to 10/12 2.5
Over 10/12 to 11/12 3.25
Over 11/12 to 12/12 4.0
Over 12/12 to 14/12 5.0
Roof Slope
H (minimum)
ft
Over 14/12 to 16/12 6.0
Over 16/12 to 18/12 7.0
Over 18/12 to 20/12 7.5
Over 20/12 to 21/12 8.0
TABLE 1