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FIG. 5 – EXTERIOR EXHAUST TERMINAL LOCATIONS
NOTES: Location of the termination of the vent pipe shall
be in accordance with the National Fuel Gas Code; A.N.S.I.,
Z223.1 (see requirements below) and any local codes which
are applicable. Only one boiler may be exhausted through each
vent hood.
a. The exit terminals of mechanical draft systems shall not
be less than 7 feet above grade when located adjacent to
public walkways.
b. A venting system shall terminate at least 3 feet above any
forced air inlet located within 10 feet.
c. The venting system shall terminate at least 4 feet below,
4 feet horizontally from or 1 foot above any door, window or
gravity air inlet into any building.
LOCATION
The exhaust terminal must be positioned:
•
so that spent gases will freely disperse without
re-entering the building.
•
to permit smoke pipe from the boiler to slope
upward not less than ¼" per foot with no more
than a 6' horizontal run.
•
in correct relationship to the combustion air inlet.
See paragraph 3 in the section titled "Intake Air"
for more information.
The exhaust terminal must not be located beneath a
porch or crawl space.
d. An appliance with an input of over 50,000 BTU per hour
shall require a 12 inch vent termination clearance from any
opening. The bottom of the vent terminal and any air intake
shall be located at least 12 inches above grade level.
e. Forced draft systems shall be designed and installed so
as to prevent leakage of vent gasses into building.
f. The vent termination point shall not be installed closer
than 3 feet from an inside corner of an L-shaped structure.
g. Terminate the vent above normal snow line. Avoid
locations where snow may drift and block the vent. Ice or
snow may cause the boiler to shut down if the vent becomes
obstructed.
!
The importance of the exhaust terminal location
cannot be overemphasized. The exhaust terminal
must be located so that prevailing winds cause
exhausted flue products to disperse away from the
building. A stagnant area where exhaust products
can gather or a wind blowing exhaust products back
towards the building may cause undesirable odors
to enter the building through any available seams
or openings, including the vent itself. Exhaust
products blown back towards the building may
also cause discoloration of building materials. In
certain conditions, flue gas will condense and form
moisture. When this occurs, steps should be taken
to prevent building materials at the exhaust terminal
from being damaged by exhausted flue gas.
9
!
CAUTION
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