The top of the chimney should be at least 3 ft 0 92 m above the roof surface.
Boiler vent height over roof.
Gas vents 12 inches 305 mm in size or smaller with listed caps shall be permitted to be terminated in accordance with figure g2427 6 5 provided that such vents are at least 8 feet 2438 mm from a vertical wall or similar obstruction.
There are many variables dictating how well a vent system will operate.
1 0 foot above the roof surface 1 7 12 to 8 12.
Vent system capacity 5.
Vertical blue line along the left side of the chimney in our photo.
In all areas exhaust vents should be at least 1 foot above roof surface.
This specification makes sure steep roof slopes are cleared.
Minimum height above the roof surface 1 flat to 7 12.
Roof pitch rise run in inches.
Flue gas temperature flue gas temperature affects vent operation because the hotter the gases are the lighter they are.
Table of rooftop chimney clearances for metal b vent chimneys flues.
Exhaust vents must not be located where they might be obstructed by drifting snow consult local experience as to the height of snow drifts against buildings.
Shown below is the exterior wall of the same installation.
Above the roof surface with a listed cap or listed roof assembly.
The stained wall photo photo below shows what can happen at a direct vented high efficiency heating boiler if the vent is not properly sloped through the wall.
Our photo above shows an energy kinetics oil fired heating boiler vented using an oem direct vent system.
A category i vent system works by allowing heated flue products to rise vertically so the vent pipe must rise vertically from the boiler vent connection as soon as possible.
1 5 feet above the roof surface.
B vent height above roof that s why i made the b vent rule of 1 2 8 to remember it from the chimney rule of 3 2 10.
You should also limit the length of the horizontal flue pipe.
The at the 1 means 1 foot minimum for 6 12 and under and then goes up according to that chart.
Restrictions to flow and 6.
Exhaust vents must be protected against rain and equipped with back flow prevention features e g flap dampers.
Above the roof plumbing vent height.
2 5 feet above the roof surface.
Heat loss in the vent 3.
Vent pipes should extend to outdoors above the building roof and should terminate vertically not less than 6 above the roof surface nor more than 24 and must be at least 12 from any vertical surface such as a nearby sidewall.
All horizontal runs of vent pipe must rise 1 4 inch per foot of run to maintain proper draft in the vent.
