Orton Pyrometric cones are used worldwide to monitor heatwork and temperature uniformity inside kilns. What is heatwork, you ask? It is defined as temperature and time at temperature. This video shows the Orton three-cone system in action. Each cone is designed to bend based on a different amount of heatwork. The guide cone is the first to deform; the firing cone is next and is the cone to watch during a firing. The guard cone is only needed when the kiln's heatwork exceeds the firing cone's range. If the guide cone and firing cone fully deform, then the guard cone is used to measure the firing temperature.