19
VENTING
The vent system must terminate so that proper clearances are maintained
as cited in local codes or the current edition of the National Fuel Gas
Code, ANSI Z223.1/NFPA 54, 7.3.4e and 7.8a,b, as follows:
1. The exit terminals of a mechanical vent system shall be not less
than 7 feet (2.13 m) above grade when located adjacent to public
walkways, see Figure 23.
2. A venting system shall terminate at least 3 feet (91 cm) above any
forced air inlet located within 10 feet (3.1 m), see Figure 23.
3. The venting system shall terminate at least 4 feet (1.2 m) below, 4 feet
(1.2 m) horizontally from or, 12 in. (30 cm) above any door, window
or gravity air inlet into any building.
The manufacturer also recommends that the vent termination should
not be installed closer than 3 feet (91 cm) from an inside corner of
an L shaped structure and not be less than 12 in. (30 cm) above
grade.
The vent shall terminate a minimum of 12’’ (30.5 cm) above expected
snowfall level to prevent blockage of vent termination, see Figure
23.
4. In cold climates, it is recommended that vent termination not be
mounted directly above or within 3 feet (91 cm) horizontally from an oil
tank vent or gas meter to avoid potential freeze-up from condensation,
see Figure 23.
Plan the vent system layout so that proper clearances are maintained
from plumbing and wiring.
Vent pipes serving power vented appliances are classifi ed by building
codes as “vent connectors”. Required clearances from combustible
materials must be provided in accordance with information in this
manual under FACTS TO CONSIDER ABOUT THE LOCATION and
VENT TERMINAL INSTALLATIONS, and with the National Fuel Gas
Code and local codes.
VENT TERMINAL INSTALLATION
1. After the point of termination has been determined, use the cover
plate as a template to mark the hole for the vent pipe to insert through
the wall. BEWARE OF CONCEALED WIRING AND PIPING INSIDE
OF WALL.
2. If the Vent Terminal is being installed on the outside of a fi nished wall,
it may be easier to mark both the inside and outside wall. Align the
holes by drilling a hole through the center of the template from the
inside through to the outside. The template can now be positioned
on the outside wall using the drilled hole as a centering point for the
template.
3. A) MASONRY SIDE WALLS
Chisel an opening approximately one half inch larger than the marked
circle.
B) WOODEN SIDE WALLS
Drill a pilot hole approximately one quarter inch outside of the marked
circle. This pilot hole is used as a starting point for a saws-all or sabre
saw blade. Cut around the marked circle staying approximately one
quarter inch outside of the line. (This will allow the vent pipe to easily
slide through the opening. The resulting gap will be covered up by
the vent terminal cover plates.) Repeat this step on inside wall if
necessary.
4. When the vent piping cannot pass through an outside wall at a
height greater than or equal to 12” above the ground (or above snow
accumulation level), then the installation can be modifi ed as shown
below.
FIGURE 22.
