RoofingMaterials.online features Lexcor’s Flash-Tite B-Vents Flashings. Flash-Tite B-Vent Flashings are pre-formed metal flashings for sealing chimneys or hot pipes to low slope roofing systems. Available for hot pipe diameters ranging from 5 to 12 inches, B-Vent Flashings feature a base fabricated from a single piece of spun metal that is free of joints or welds that may leak. The cone shaped design keeps combustible roof deck materials at a safe distance from the chimney while permitting heated air to vent out the top. An adjustable rain collar (sold separately) ensures an effective weatherproof seal, even during differential movement between the roof deck and the pipe.