The DuraPlus system from is designed to stay cool on the outside, provide a draft on the inside and boost stove efficiency, offering a fire-safe design that protects both the chimney and building. This Triple-Wall Chimney Stove Pipe features two insulating layers consisting of a ceramic blanket plus air space. The ceramic blanket insulation is held securely in position, eliminating spots common with loose-fill type insulations. In the event of a creosote fire, the compressible blanket insulation permits the chimney liner to expand outwardly in a radial direction. Designed for normal, continuous operation at 1000F flue gas temperatures, DuraPlus is subjected to rigorous and stringent HT requirements of the UL standard, including one hour at 1400F, plus three 10-minute chimney fire tests at 2100F.