the same kind of ceramic fiber products using under different conditions also have different long-term temperature. Such as industrial kiln operation system (continuous or intermittent kiln), fuel type, furnace atmosphere and other technological conditions are all the factors affecting the service life of ceramic fiber. There is no ideal method for determination of ceramic fiber heat resistance index. Usually these products will be heated to a certain temperature, and evaluate the difference between operating and the highest temperature according to the sample plus hotline shrinkage and crystallization degree
◆ Refractory insulation fiber classification temperature: it refers to the highest operating temperature. It is the test temperature when refractory fiber product is kept heating for 24h and gets 4% high temperature line shrinkage. This kind of product will have short service life under the temperature, so it is seldom applied.
◆ Operating temperature: it means safety using temperature for a long time. It is the test temperature when refractory fiber product is kept heating under fixed temperature for 24h and high temperature line shrinkage is less than 2.5%. Under the temperature, crystal fiber and non-crystal fiber transmission and grain growth speed is slow with stable property.