If it is not possible to obtain proper clearance to grade by a straight
out confi guration, the termination may be raised by the use of a pair
of 90° elbows. (
Figure 9
, Exhaust Detail Only)
NOTICE
NOTE: Length of pipe and elbows count toward maximum
allowable vent length as shown in Table 6.
Besides the initial increaser/reducer, the venting system must stay
consistent in regards to pipe diameter through out the entire vent
length. Th
e vent may also terminate in a vertical venting confi gura-
tion through the roof. No termination fi tting is required.
Th
e exhaust pipe extending through the roof must extend 18” above
the highest point where it extends through the roof, surface and
above any obstruction within an 18” horizontal distance. (
Figure
11
)
Exterior vent pipe greater than 24” should be insulated with ½”
insulation to prevent moisture from freezing within the pipe and
accumulating.
Size the exhaust pipe as specifi ed in
Table 6
- Direct and Non-Di-
rect Vent Lengths. Th
is table lists the maximum allowable length of
pipe with respect to the number of 90° elbows used. For the purpos-
es of this calculation, one 90° elbow is equivalent to two 45° elbows.
Avoid locating the terminal in locations where dripping condensate
may cause problems such as sidewalks, patios, above planters, near
windows where exhaust gases may cause fogging, etc. Avoid locat-
ing the termination too close to shrubs and other vegetation. Th
e
condensate may stunt or kill them.
!
CAUTION
Moisture in the fl ue gases condenses as it leaves the termi-
nal. Th
is moisture can freeze on exterior walls, on soffi
ts,
and other nearby objects. Some discoloration is to be
expected; however, improper location or installation can
cause structural or exterior fi nish damage to the building.
Caulk all cracks, seams or joints within a 6 foot radius of the termi-
nation.
Do not terminate under a deck unless there is adequate clearance to
prevent damage from the fl ue gases. A termination may be located
at the end of a patio deck. Piping running beneath the deck must be
suitably insulated and suspended in a manner to prevent condensate
from collecting and freezing.
Do not locate the terminal on the side of the building facing the
prevailing winter winds.
In Canada
In addition to the general guidelines, in Canada, the non-direct vent
exhaust shall not terminate:
• Directly above a paved sidewalk or paved driveway which
is located between two single-family dwellings and serves
both dwellings;
• Less than 7 feet above a paved sidewalk or paved driveway
located on public property;
• Within 6 feet of a mechanical air supply inlet to any build-
ing;
• Above a meter/regulator assembly within
3 feet horizontally of the centerline of the regulator;
• Within 6 feet of any service regulator vent outlet;
• Less than 12” above grade level or anticipated snow level;
• Within 12” of any door, window, or non-mechanical air
supply inlet to any building;
• Within 12” of the combustion air inlet of any other appli-
ance;
• Underneath a veranda, porch or deck, unless (a) the veran-
da, porch or deck is fully open on a minimum of two sides
beneath the fl oor, and (b) the distance between the top of
the vent termination and the underside of the veranda,
porch or deck is greater than 12”.
In The U.S.A.
In addition to the general guidelines, in the United States, the non-
direct vent exhaust shall be installed in accordance with the follow-
ing:
• Th
e clearance from the bottom of the terminal to grade
shall be 12”.
• Th
e vent shall not terminate over public walkways or over
an area where condensate or vapor could create a nuisance
or hazard.
• Th
e vent terminal shall be installed 4 feet below, 4 feet
horizontally from, or 1 foot above any door, window, soffi t,
under eave vent or gravity air inlet to the building.
• Th
e vent terminal shall have a minimum horizontal clear-
ance of 4 feet from electric meters, gas meters, regulators
and relief equipment.
• Locate the vent terminal 3 feet above any forced air inlet
located within 10 feet. Any fresh air or make-up air inlet,
such as for a dryer or furnace area is considered a forced air
inlet.
12 - VENTING GUIDELINES
20
