The Firesure® Fire Rated Letter Box Liner Kit is designed to upgrade existing fire-rated door sets where standard letter plates cannot be replaced. Manufactured from Firesure® intumescent material, this liner kit expands rapidly under heat to seal the letter plate aperture and maintain the fire integrity of the door.
Tested in accordance with BS 476: Part 22, the liner provides up to 40 minutes of fire resistance, making it suitable for FD30-rated doors and comparable 15 or 30-minute installations. It is ideal for listed buildings or special applications where the original letter plate must remain in place.
Key Features and Benefits
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Tested to BS 476: Part 22 – Provides up to 40 minutes fire protection
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Complies with BS 476 Class 0 to Building Regulations
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Manufactured from Firesure® intumescent material – Expands under heat to seal gaps
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Ideal for retrofitting – Designed to upgrade existing fire doors without replacing letter plates
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Self-adhesive backing – Simplifies installation and provides secure fit
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Supplied with fixing pins – Prevents liner displacement during use
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Moisture-resistant and non-toxic – Safe for long-term use in any environment
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Lightweight and easy to install – Single-person fitting possible
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Maintenance-free – Lifetime durability without loss of performance
Applications
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For upgrading existing fire-rated doors where letter plates cannot be removed
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Suitable for residential blocks, flats, offices, and listed buildings
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Designed for use with the Firesure® range of intumescent seals, hinges, and mastic
Product Codes and Sizes
| Code | Dimensions (mm) | Type | Notes |
|---|---|---|---|
| FSLBL/K1 | 700 x 40 x 4 | Self-adhesive liner kit | Includes fixing pins |
| FSLBL/K2 | 900 x 40 x 4 | Self-adhesive liner kit | Includes fixing pins |
| FSLBL/K3 | 700 x 60 x 4 | Self-adhesive liner kit | Includes fixing pins |
| FSLBL/K4 | 900 x 60 x 4 | Self-adhesive liner kit | Includes fixing pins |
| FSLBL/TR1 | 5m x 40 x 4 | Trade roll | Can be trimmed to size |
| FSLBL/TR2 | 5m x 60 x 4 | Trade roll | Can be trimmed to size |
Fire Rating: Up to 40 minutes (tested to BS 476: Part 22)
Material: Firesure® Intumescent Sheet
Finish: Brown self-adhesive liner
Installation: Self-adhesive backing and panel pins supplied
Installation Guidance
Ensure the liner is applied to a solid fire-rated door only. Surfaces must be clean and dry before application. For best results, seal edges and any residual gaps with Firesure® Intumescent Mastic to maintain certified fire performance.