DuraVent 8DVL-48 8" Inner Diameter - DVL Stove Pipe - Double Wall - 48" Pipe Len, Black The DVL Double-Wall Black Pipe is designed for installation with minimum clearances to combustibles. Clearances: 6" clearance to wall, 8" clearance to ceilings, including cathedral ceilings. Construction Material: .016" stainless steel inner with .018" galvanized outer, painted black. Diameter: 8".