Section 3 — Stack and Intake Vent Sizing and Installation
3-4 Part No. 750-363
terminations are suited to moving flue gases and water vapor away
from building exterior surfaces and air intakes.
1. Combustion gases can form a white vapor plume in the winter.
The plume could obstruct a window view if the termination is
installed in close proximity to windows.
2. Prevailing winds could cause freezing of condensate and water/
ice buildup on building, plants or roof.
3. The bottom of the vent terminal, as well as the air intake, shall
be located at least 24 inches above grade, including normal
snow line.
4. Un-insulated single-wall metal vent pipe shall not be used
outside in cold climates for venting combustion gas.
5. Through-the-wall vents for Category II and IV appliances and
non-categorized condensing appliances shall not terminate over
public walkways or over an area where condensate or vapor
could create a nuisance or hazard or could be detrimental to the
operation of other equipment. Where local experience indicates
that condensate is a problem with Category III appliances, this
provision shall also apply.
6. Locate and guard vent termination to prevent accidental contact
by people and pets.
7. DO NOT terminate vent in window well, alcove, stairwell or other
recessed area, unless previously approved by local authority.
8. DO NOT terminate above any door, window, or gravity air intake.
Condensate can freeze causing ice formations.
9. Locate or guard vent to prevent condensate from damaging
exterior finishes. Use a 2' x 2' rust resistant sheet metal backing
plate against brick or masonry surfaces. Extend the termination
at least 2” from exterior surface.
10. DO NOT extend exposed stack pipe outside of building. In
winter conditions condensate could freeze and block stack
pipe.
Note:
During winter months check the vent cap and make sure no
blockage occurs from build up of snow. Condensate can
freeze on the vent cap. Frozen condensate on the vent cap
can result in a blocked flue condition.
U.S. Installations- Refer to latest edition of the National Fuel Gas
Code.
Vent termination requirements are as follows:
1. Flue vent must terminate at least eight (8) feet above or eight (8)
feet horizontal from any HVAC air inlet to the building, including
combustion air intakes. Vent must terminate at least three (3)
feet above any door or window.
2. The vent must not be less than seven (7) feet above grade when
located adjacent to public walkways.
3. Terminate vent at least three (3) feet above any forced air inlet
located within ten (10) feet.
To Next Page
Loading...
