What Fire Rating Does Calcium Silicate Insulation Have?
Calcium silicate insulation achieves the highest possible fire classification: A1 non-combustible under EN 13501-1 and Class A under GB 8624 (Chinese national standard). It is one of the few insulation materials suitable for both thermal insulation and passive fire protection applications.
Fire Classification Standards
| Standard | Classification Achieved | Meaning |
|---|---|---|
| EN 13501-1 | A1 | No contribution to fire at any stage, including fully developed fire |
| GB 8624 | Class A (A1) | Non-combustible material. No flame spread, negligible smoke production |
| EN 1634-1 (Door Assembly) | Up to 120 minutes | 40mm GF-1100 board as fire door core achieves 2-hour integrity rating |
How Calcium Silicate Provides Fire Protection
The fire protection mechanism is endothermic dehydration. Calcium silicate (xonotlite) contains approximately 2.1% chemically bound water in its crystal structure. When the fire-exposed face of the board heats up past approximately 750°C, this water is released as vapor. The dehydration reaction absorbs heat energy (approximately 600 kJ/kg of water), which cools the unexposed face of the board and delays the temperature rise on the protected side.
Additionally, the board's microporous structure provides insulation value that slows conductive heat transfer through the thickness. The combination of endothermic cooling and thermal resistance means that a 40mm board can maintain the unexposed face below 180°C (the typical failure temperature for steel structures) for up to 120 minutes in a standard fire test.
Fire Door Core Performance
Mingfa's GF-1100 fire door core board, at 40mm thickness, achieves a 120-minute integrity and insulation fire rating in steel door assemblies tested to EN 1634-1. This performance is achieved through a combination of the factors above, plus the board's excellent screw-holding strength (which keeps door hardware attached during fire exposure) and its dimensional stability (which prevents gaps opening at door edges as the fire progresses).
For detailed specifications of our fire-rated products, see our fire protection products page. For the comparison with other fire door core materials, see our calcium silicate vs vermiculite comparison.