Furnace Vent Pipe Clearance

Below are the allowable clearances for a number of common situations.

Furnace vent pipe clearance.

Metal double wall b vent requires 1 inch minimum clearance. Transite a whitish looking cementious pipe containing asbestos material. See direct vents side wall vents for a complete table of recommended clearance distances from a direct vent gas appliance terminal to other building components or features. American gas association has certified the design of condensing furnaces for a minimum of 0 clearance from combustible materials with a single wall plastic vent pipe.

Metal single wall generally requires 6 inches of clearance. I m trying to confirm the necessary clearance for a direct vent concentric pipe on a 95 propane furnace. I know that the clearance from an operable window is 12 but what is the required distance from a side wall. In my situation there is a three foot space between the edge of a window and a wall.

Inadequate clearance from combustibles at the gas vent stack for the furnace at the drywall and wooden structural components. Colour illustration of direct vent sidewall terminal clearance distances adapted from american standard furnace installation instructions that in turn cites ansi z223 1 nfpa 54 national fuel gas code for us installations and cites csa b149 1 natural gas and propane installation code for canadian direct vent gas vent installations. I ve checked the vendor literature and don t see the specific senario that i m looking at. Early 1900 s to about 1975 it was used.

Clearance is the distance that is considered to be safe between a heat producing appliance chimney chimney liner vent pipe vent connector or other hot surfaces and combustible materials. The clearance between gas vents and combustible materials is listed by the manufacturer but is typically 1 inch for type b. Maximum horizontal section of the furnace water heater double wall vent pipe cannot be longer than 100 of the vertical vent pipe length. What are the allowable clearances.