You will find brief explanations on important technical terms from the area of high-temperature technology in our glossary.
The classification temperature is defined as the temperature where a product has a certain linear shrinkage after 24 hours of heat application in the electrically heated laboratory furnace and an oxidising atmosphere. Depending on the type of product, the values vary from 2% in insulation boards and shapes to 4% in needled blankets.
The classification temperature is indicated in steps of 50°C. In contrast to insulation products of amorphous fibres (ASW/RCF), products of polycrystalline mullite/alumina wool (PCW) can be used permanently up to the indicated classification temperature. For ASW/RCF, the permanent application is by about 100°C to 150°C below the indicated classification temperature.
Heating elements can be operated in different maximum application temperatures depending on their quality. A corrosion in the cone and/or in the heating zone (Le) happen, when the maximum application temperature prescribed for the heating element is regularly exceeded and thus it is operated at excessively elevated temperatures.