But then I already knew that. 1 This applies to both combustible and non-combustiblewalls 3. The system must be supported along its horizontal length at all elbow locations and joints (every forty-eight inches or less) using straps around pipes maintaining clearance to combustibles as per table on page 3. Reduced clearance based on required clearance to combustibles (inches)** 36: 18: 9: 6: 1/8-inch unpainted aluminum plate spaced 1 inch off the wall: 3: 3: 3: 3: 1/8-inch painted aluminum plate spaced 1 inch off the wall: 28: 9: 3: 3: Unpainted galvanized sheet metal Manufacturer's Standard The fiberglass won't burn, but I wonder if that area of the pipe could get too hot. “B” and “L” vents may be in accordance with the appliance and vent listing. This gas vent connector is tested and listed by UL for one-inch (1") clearance to combustibles and to insulation in an unenclosed installation. Double walled stovepipe requires a 6 inch clearance to combustibles and cannot be concealed within a wall or ceiling. The fix for this condition is often to cut back any wood that is too close to the vent pipe so that there is proper clearances. When installing a factory built chimney and you need interior Double wall, uninsulated, or “B” vent - Clearance to combustibles is typically 6 inches. The sticker on the pipe, still just ledgable, says 2" clearance to combustables, and doesn't mention non combustables at all. AmeriVent is a complete gas venting system, from 3” to 30” pipe diameters in 7 different pipe lengths, to single- to multi-appliance hook-ups. You must convert to the appropriate Class A chimney system before passing through a combustible wall or ceiling. PolyPro® Double Wall (PDF, 798KB ) PolyPro® with B Vent (PDF, 426KB ) Spec Sheets: PolyPro® Single Wall Specifications (PDF, 98KB)(Docx,36.0KB) Submittals: PolyPro® Submittal (PDF, 3.1MB) Bulletins: PolyPro® Wall Strap (PDF, 136KB ) DuraVent Approval for HTP (PDF, 136KB ) DuraVent Approval for Westinghouse (PDF, 158KB ) DVL's double-wall, air-insulated design reduces clearances to combustibles from 18 in. Does Type B Gas Vent have a fire rating? 4. I think you are a bit confused and need clarifications first of all single wall pipe clearance to combustiables is 18" and that is in all directions We are talking about the pipe th extends fron the flue collar into a chimney Meaning Class A chimney in your case Double wall connector pipe distance to combustiables is set by the manufacturer usually 6" My insulation touches the Metal Vent insulated double wall pipe. to 6 in., the closest clearance to a wall of any connector pipe. 8. Should the vent be a single wall vent, then either cutting back the wood or switching the single wall to a double wall may make this task easier. DVL's double-wall, air-insulated design reduces clearances to combustible materials from 18" to 6", the closest clearance to a wall of any connector pipe. DVL is a double-wall stove pipe that completes the venting system by connecting the wood stove to the chimney. DVL double-wall stovepipe completes the venting system when used with one of DuraVent's chimney products, such as DuraTech, DuraPlus, or DuraPlus HTC. Double wall, insulated - Clearance to combustibles should be 1 or 2 inches, or as the appliance or vent … system cannot be moved in or out of wall. Vent pipe hangers made from plumber's strap and a wall bracket (VPH) should be used at each end of a flexible length that is not attached to a fixed point; i.e., an appliance outlet. This one-inch is a typical clearance for all brands of Type B Vent, but each section of vent pipe is marked with the clearance required by Underwriter Laboratories, so it should be checked. 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. I would be more conceraned about insulating right up to a single wall pipe. Type B Gas Vent requires a minimum of one-inch clearance to combustibles.