Specifications
Installation: Piping
20 GAND-SVX01B-EN
as depicted in Figure 11 , p . 21.
6. The equivalent lengt
h of the vent system must not be
less than five feet (1.5 m) and must not exceed 50 feet
(1
5.2 m). Equivalent length equals the total length of
straight pipe plus 10 feet (3.1 m) for each 90-degree
elbow and fi
ve feet (1.5 m) for each 45-degree elbow.
7. Each slip joint must be secured with at least three
cor
rosion resistant screws. Two full turns of 3M™ #425
Aluminum Foil tape or its equivalent must be used to
seal each joint. General Electric RTV-108, Dow
Corning
®
RTV-732, or an equivalent may be used
instead of the tape.
8. For horizontal vent systems
longer than five feet
(1.5 m), the system must be supported from overhead
building structures at three-foot (1-m) intervals.
9. The exhaust vent system m
ust remain at a minimum
distance of six inches (152 mm) from all combustible
m
aterials. Any part of the vent system that passes
through a combustible material must be properly
insulated.
For a VERTICAL vent pipe section that passes through
a fl
oor or roof, an opening four inches (102 mm)
greater in diameter is required. The opening must be
insulated and flashed in accordance with applicable
installation codes.
A HORIZONTAL section of an exhaust vent system that
passes through a combustible wall must be
constructed and insulated as shown in Figure 14, p. 21.
10. The top of a VERTICALLY VENTED exhaust system
must
extend at least three feet (1 m) above the roof
surface that it passes through. The point of termination
for a HORIZONTALLY VENTED exhaust system must be
at least 12 inches (305 mm) from the exterior of the
w
all that it passes through. In addition, the termination
point must be at least three feet (1 m) above grade or
a
bove the snow line, more than six feet (2 m) from the
combustion air inlet of another appliance, more than
three feet (1 m) from any building opening, and more
than
three feet (1 m) from, and not directly above, any
gas meter or service regulator (refer to Figure 13, p. 21
and Figure 14, p. 21).