Fiberfrax® Durablanket® S

High-temperature RCF ceramic-fibre insulation blanket, classification 1250°C

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Fiberfrax® Durablanket® S is a needled ceramic-fibre blanket used where bio-soluble AES grades run out of thermal headroom. It is specified for the hot face of melting and annealing furnaces, fire-protective seals around high-temperature equipment, expansion joints in furnace linings, and thermal barriers in heavy process installations. The "S" variant is produced from spun aluminosilicate fibres, which yields longer fibre lengths and therefore higher tensile strength and better mat integrity during installation. Chemically the fibre is a mix of Al₂O₃ and SiO₂ with a melting point near 1760°C; classification temperature is 1250°C. Mean fibre diameter is approximately 3.25 μm. Note that RCF fibres fall under a different regulatory regime than AES (no Note Q exemption); standard occupational protective measures apply during cutting and installation.