Fireproof sealing of vertical cable tray openings

Vertical cable trays can be effectively fireproofed using fire-rated trays, intumescent pillows, firestop packs, or specialized coatings to maintain electrical continuity and prevent flame spread.

Key Fireproofing Methods

1. Fire-Rated Cable Trays and Coatings Vertical cable trays can be constructed from galvanized steel, stainless steel, or flame-retardant composites. Surfaces are often coated with fire-retardant paint to slow flame propagation and increase heat resistance. Fireproof coatings should remain intact, and any damage or corrosion must be addressed immediately to maintain effectiveness . 2. Firestop Pillows and Packs For vertical penetrations through walls or floors, intumescent fireproof pillows (e.g., AF BAGS) are widely used. These are certified under EN 1366-3 for up to EI 240 fire resistance. They consist of a non-combustible fiberglass casing filled with intumescent compounds and thermal insulators, allowing easy insertion even in thin structures. They can be repositioned for maintenance and are suitable for cables up to 21 mm in diameter . 3. Firestop Boards, Mineral Wool, and Sealants Fire-rated boards, mineral wool, and firestop mastic can be used to seal gaps around vertical cable trays. For large openings, a fire-resistant backing plate is recommended. Gaps between firestop materials and cables should not exceed 1 cm², and packing thickness should be at least 24 cm to ensure a reliable seal . 4. Specialized Fireproof Systems In critical facilities like hospitals, airports, or petrochemical plants, full-tray protection systems are used. Examples include:

• Tecbor® B panels: 40 mm panels covering the tray, tested under UNE ENV 1363-1 and UL 1709, providing up to 2 hours of electrical maintenance.
• Tecbor Preparada® Joint Paste: Applied directly to cables and trays with a thickness of 3.6 mm, also achieving 2 hours of electrical continuity and fire protection .

Installation Considerations

• Maintain adequate clearance between cables for heat dissipation.
• Use perforated or wire mesh trays to improve airflow.
• Ensure mechanical stability with proper supports, clips, or ties.
• Inspect fireproof coatings, pillows, and sealants periodically for corrosion, damage, or degradation .
• Follow manufacturer guidelines for sealing depth, cable diameter, and fire-resistance rating.

Summary

For vertical cable trays, fireproofing involves a combination of fire-rated trays, intumescent pillows, firestop packs, and specialized coatings or panels. Selection depends on the fire-resistance requirement, cable type, and structural constraints. Proper installation and regular inspection are essential to ensure long-term fire safety, electrical continuity, and compliance with standards .