For 18 feet of run you would have a rise of 72 inches.
Furnace vent pipe height above roof.
2 0 feet above the roof surface.
These galvanized steel vents were all installed at the same time but only the combustion vent is staining the roof.
Vent caps 12 and smaller may terminate a distance above the roof if 8 feet or more away from a vertical surface as follows.
I know about the 2 feet taller than the roof when a vertical wall is within 8 feet as in illustrated in my code check books.
Chimney chimney flue must terminate min.
Put the roof opening directly above the exhaust opening on the furnace.
The top of a chimney pipe must extend at least 2 feet above the peak of the roof if the pipe is within 10 feet of the peak.
Roof pitch rise run in inchesminimum height flat to 7 12 1 0 foot above the roof surface 7 12 to 8 12 1 5 feet above the roof surface 8 12 to 9 12 2 0 feet above the roof surface.
For the next example you have a shorter chimney height.
However i have searched archives on this and another site and have come across various interpretations of the height requirement.
If the previous calculation results in the required height of 64 inches we can see that the top of the pipe will not rise above the roof peak but would still meet the requirements of the rule.
If the pipe is farther than 10 feet from the roof.
Number 7 is the furnace exhaust.
2 5 feet above the roof surface.
Table of rooftop chimney clearances for metal b vent chimneys flues.
General rule the chimney should not be outside a window or other house opening.
Single wall metal pipe shall extend at least 2 feet 610 mm above the highest point where it passes through a roof of a building and at least 2 feet 610 mm higher than any portion of a.
1 0 foot above the roof surface 1 7 12 to 8 12.
The photo shows a b vent from a fan assisted furnace flue on a steep sloped hip roof.
Water heater installed close to the roof framing would need at least 5 long vertical vent pipe single wall vent pipe requires minimum 6 of clearance to combustible materials.
5 above the flue collar e g.
Minimum height above the roof surface 1 flat to 7 12.
1 5 feet above the roof surface.
Any moisture entering this pipe will be drained off before it reaches the furnace by components designed to divert condensation so it doesn t need to be protected.
