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.
Furnace vent high above roof.
What is vented is a residual corrosive condensate of water and carbon dioxide.
Vent caps 12 and smaller may terminate a distance above the roof if 8 feet or more away from a vertical surface as follows.
This structure generally uses the furnace vent pipe through roofbecause the b venting pipe is designed in vertical manner.
Table of type b vent rooftop clearance requirements.
Also known as the type b this vent is operating on the natural air convection.
Vents must be tall enough so burned gases exit above a roof line and.
When the vent is withdrawing air from the house it expels the gas outside through the vent.
Goose neck vent the master flow 4 in.
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.
How to vent a furnace in a roof.
If your furnace has an afue rating of 90 percent or above it will have a flue pipe that goes out of the side of your house.
While one foot above the roof surface may meet the recommendations for fire clearances in one storey buildings or in buildings with heating equipment on the uppermost floor the total chimney height may be inadquate to establish sufficient and safe draft unless you extend the chimney.
It s made of zinc coated galvanized steel for durability and reliability.
Above the roof surface with a listed cap or listed roof assembly.
Roof pitch is easily calculated and if you don t know how read my article understanding and calculating roof pitch.
Vents can also be terminated above the roof.
Goose neck vent in black can be used to cover exhaust pipes extending through your roof or for attic ventilation.
Notes to the table above 1 measure on the up roof or shorter height side of the chimney 2 watch out.
A high efficiency condensing furnace can achieve efficiency ratings of 90 or above.
First you ll need to know the pitch of your roof.
High efficiency furnaces produce different combustion gases than standard efficiency furnaces.
The single pipe non direct vent system is used where there is no real need for a separate combustion air intake vent.
The master flow 4 in.
So the gases can float up through the flue pipe and out of your roof.
All gas furnaces must be vented to allow exhaust gases from the combustion process to escape.
It uses a venting system to extract that heat before venting.
