Fireproof describes the property of a ceramic material to withstand high temperatures without softening. Under German standard DIN 51060, the term is defined via the Seger cone fall point: the softening point of a standardised test piece (Seger cone) under defined heating conditions.
Classification under DIN 51060
DIN 51060 classifies refractory ceramic raw materials and products into three levels by their measured Seger cone fall point:
| Level | Seger cone fall point |
|---|---|
| Heat-resistant | up to 1,500 °C[2] |
| Fireproof | 1,500 °C to 1,800 °C[2][3] |
| Highly fireproof | above 1,800 °C[2][3] |
A material is therefore considered fireproof once its Seger cone fall point reaches at least 1,500 °C.[3]
Distinction from lining
Fireproof is a material property, not a component name. Lining is the physical refractory brickwork of a melting or holding furnace, while furnace lining is the general term for a furnace’s refractory lining as a whole. A material can be fireproof without being installed as a lining at all, for example as a brick or raw mix in storage.
References
- DIN 51060:2000-06, Feuerfeste keramische Rohstoffe und feuerfeste Erzeugnisse – Definition der Begriffe feuerfest, hochfeuerfest (refractory ceramic raw materials and refractories – definitions of the terms refractory, high refractory). Language-independent standard, cited by number.
- H+M Refractories GmbH: Feuerfeste Werkstoffe nach DIN 51060 (refractory materials under DIN 51060, German only, no English edition available). Product page, accessed 27 August 2026.
- Gießerei-Lexikon: Feuerfeste Erzeugnisse (refractory products, German only, no English edition available). Accessed 27 August 2026.