The DuraPlus system from DuraVent is designed to stay cool on the outside, provide a hot 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 hot 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 1000-degree F flue gas temperatures, DuraPlus is subjected to rigorous and stringent HT requirements of the UL standard, including one hour at 1400 degrees Fahrenheit, plus three 10-minute chimney fire tests at 2100 degrees Fahrenheit.