Fireproof sealing of cable trays

Fireproof sealing of cable trays requires using certified materials with specified thicknesses and installation methods to achieve the desired fire-resistance rating.Fireproof Materials and Ratings

Cable tray penetrations must be sealed with fire-rated materials such as intumescent pillows, firestop packs, mineral wool, or intumescent coatings. For example, AF BAGS are intumescent and ablative pillows certified under EN 1366-3 for up to EI 240 fire resistance. They can seal cables up to 21 mm in diameter with a sealing depth of 120 mm and are suitable for walls, floors, and sandwich panels . Similarly, SpecSeal Cable Spray is an intumescent coating applied to grouped cables, requiring a minimum 1/8-inch wet film thickness to provide effective fire protection .

Installation Guidelines

1. Measure the cable tray dimensions to determine the number and size of fireproof pillows or coating coverage needed .
2. Seal all gaps tightly: For large openings, a fire-resistant backing plate may be required before applying firestop materials .
3. Maintain proper packing thickness: Gaps between firestop packs and cables should not exceed 1 cm², with a minimum packing thickness of 24 cm for slab penetrations .
4. Use appropriate materials: Firestop packs, firestop mastic, or mineral wool can be used depending on the penetration type and fire rating required .
5. Ensure accessibility and maintenance: Fireproof pillows can be repositioned for system maintenance, while coatings and wraps should be inspected periodically for integrity .

Fireproofing Methods

• Fire Wrap Systems: Passive multilayer barriers installed around trays, suitable for retrofit projects and irregular routing .
• Intumescent Coatings: Reactive paints that expand under heat to form an insulating char, ideal for new builds and hygiene-sensitive environments .
• Firestop Packs and Mineral Wool: Used for wall and slab penetrations, ensuring tight sealing and compliance with fire-resistance ratings .

Compliance and Inspection

• Fireproof sealing must comply with EN 1366-3 or equivalent local standards.
• Regular inspection is required to check for corrosion, damage, or compromised sealing, especially in outdoor or high-humidity environments .
• Ensure that sealing does not interfere with cable tray functionality or airflow, which is critical for heat dissipation . By following these guidelines, cable tray penetrations can achieve the required fire-resistance rating, maintain safety, and allow for maintenance without compromising the fireproof seal.