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Table L: Category I Vertical Venting
1
Vent lengths are based on a lateral length of 2 ft. Refer to the latest edition of the NFGC for further
details. When vertical height exceeds 25 ft, consult factory prior to installation.
* Subtract 10 ft per elbow. Max. 4 elbows.
Termination
The vent terminal should be vertical and should termi-
nate outside the building at least 2 ft above the highest
point of the roof that is within 10 ft. The vent cap
should have a minimum clearance of 4 ft horizontally
from and in no case above or below (unless a 4 ft hori-
zontal distance is maintained) electric meters, gas
meters, regulators and relief equipment. The distance
of the vent terminal from adjacent public walkways,
adjacent buildings, open windows and building open-
ings must be consistent with the NFGC (U.S.) or B149
(Canada). Gas vents supported only by flashing and
extended above the roof more than 5 ft should be se-
curely guyed or braced to withstand snow and wind
loads.