Upc i 906 1 and 906 2.
B vent height above roof.
1 5 feet above the roof surface.
2 0 feet above the roof surface.
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.
This reduces the actual required height by 12 inches from our previous calculation of 64 inches.
Notice that metallic salts washing off of the metal bracing and other runout of the chimney flashing itself are preventing black algae from growing on some areas of this roof.
One of the fire safety features of double wall type b gas vent is that its outer wall insulated by the airspace beneath it requires only 1 clearance to combustible material in the structure.
Metal bracket on a b type vent metal chimney.
So 28 inches plus 24 inches is a chimney height of only 52 inches.
The 1992 vent sizing tables require that all type b gas vents terminate above the roof with a listed cap or listed roof assembly in accordance with the manufacturer s instructions.
Photo at above left.
However b vent chimney caps 12 and smaller may terminate a distance above the roof if 8 feet or more away from a vertical surface as given in this table.
Minimum height above the roof surface 1 flat to 7 12.
Type b vents must be equipped with their own special chimney caps.
If the cap is damaged or lost it should not be substituted with something not recommended by the manufacturer.
1 0 foot above the roof surface 1 7 12 to 8 12.
Table of rooftop chimney clearances for metal b vent chimneys flues.
2 5 feet above the roof surface.
Above the roof plumbing vent height.
Roof pitch rise run in inches.
Per the 10 and 2 rule once you are at the level of the peak you only need to be 2 feet above it.
In the case of type b or type l vents each length extending above the roof line must be certified for exterior use and so identified.
Please note that this rule doesn t generally apply to pellet and gas vent systems.
